Copper dithiocarbamate complexes and copper sulfide nanoparticles : Synthesis, characterization and antifungal studies
- Authors: Botha, Nandipha Loveness https://orcid.org/0000-0001-8353-3512
- Date: 2015-01
- Subjects: Copper sulfide , Complex compounds , Nanoparticles
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24283 , vital:62598
- Description: Six dithiocarbamate ligands were synthesized from anisidine, aniline, ethyl aniline, butyl amine, morpholine and piperidine and used to synthesize homoleptic copper(II) dithiocarbamate complexes. The ligands and their corresponding complexes were characterized by conductivity measurement, FTIR and UV-Vis spectroscopy. The ligands were further characterized using NMR spectroscopy. The electronic spectra of the complexes showed that the coordination geometries around the Cu2+ ion is four coordinate square planar. FTIR spectroscopic studies indicated that the dithiocarbamate ligands are bidentately coordinated to the copper ion through the sulfur atoms with the C-S stretching frequencies changing from two peaks in the ligands to single sharp peaks in the corresponding metal complexes. The complexes were used as single source precursors to synthesize copper sulfide nanoparticles. All the six complexes were thermolysed at 180 oC to prepare copper sulfide nanoparticles and three of them were further thermolysed at 120 oC to study the effects of temperature on size and shape of the nanoparticles. All the nanoparticles were characterized with UV-Vis, PL, XRD, TEM, SEM and EDX. The optical properties of the as-prepared CuS nanoparticles showed that they are quantum confined with absorption band edges that are blue shifted compared to bulk CuS and all the as-prepared CuS nanoparticles showed narrow emission curves. The XRD diffraction patterns were indexed to the hexagonal covellite CuS crystalline phase with estimated particle sizes of 15.8-23.24 nm. These sizes are significantly different from the values, 3.02-98.94 nm obtained from TEM studies. The TEM images also showed nanoparticles with varied shapes with some agglomerations. SEM micrographs showed that the morphologies of the nanoparticles are mostly smooth surfaces and EDX spectra analyses confirmed the formation of the nanoparticles. Thermolysis of three of the complexes at 120 oC confirmed that temperature do affect the optical and structural properties of the CuS nanoparticles. Only three complexes soluble in DMSO were screened for their antimicrobial activity. Three complexes C1, C4 and C5 were screened against four fungi organisms, namely: Candida rugosa, Candida neoformans, Candida albicans and Trychophyton mucoides. All the compounds were promising as shown by the minimum inhibitory concentrations determined. C5 was the most active compound against all the organisms. They were also screened against four bacteria organisms and they were all active but not as they were against fungi organisms. , Thesis (MSc) -- Faculty of Science and Agriculture, 2015
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- Date Issued: 2015-01
Correlations between the occurence of virulent helicobacter pylori strains and chronic disease conditions in dyspeptic patients hospitalized in Chris Hani Baragwanath Hospital, Gauteng Province, South Africa
- Authors: Mzukwa, Asisipho
- Date: 2018
- Subjects: Helicobacter pylori infections Helicobacter pylori Bacterial diseases
- Language: English
- Type: Thesis , Masters , Microbiology
- Identifier: http://hdl.handle.net/10353/10885 , vital:35905
- Description: Introduction: Individuals predisposed to different chronic disease conditions such as type 2 diabetes mellitus (T2DM), hypertension (HPT) and human immunodeficiency virus (HIV) might be susceptible to persistent H. pylori colonization, which overtime encourages infection with virulent strains. The presence of different types of H. pylori virulence factors especially cagA, dupA and various combinations of vacA subtypes (s1/m1, s2/m1 and s2m2) confer a higher risk of gastric disease development. Aim: This study seeks to recover H. pylori from gastric biopsy specimen from patients with different chronic disease conditions referred to the GIT unit at Chris Hani Baragwanath Academic Hospital, Soweto, and confirm them and further determine the presence of virulent H. pylori strains in patients with T2DM, HPT and HIV. Methods: Gastric biopsies were obtained from 101 patients with different chronic disease conditions after obtaining consent between August 2017 and February 2018. H. pylori was isolated on selective Colombia blood agar. Presumptive isolates were identified following standard microbiology and biochemical technique. These isolates were confirmed by polymerase chain reaction (PCR) targeting the glmM gene. The H. pylori positive samples were further screened for cagA, dupA and vacA genotypes. Results: H. pylori was recovered from 26 patients, of which 8 were patients with T2DM, 10 with HPT and 8 with HIV. There was no correlation between H. pylori infection and the chronic conditions, but the majority of H. pylori positive participant carried virulent H. pylori strains. The cagA and the dupA genes were more prevalent in T2DM and HPT patients, however the association between these genes and the 2 chronic conditions was not significant. The vacA subtypes common in hypertensive patients compared to the other conditions were the s1m1, s1m2, and s2m2 and the association between these vacA forms and hypertension was significant. Majority of HIV infected patients were found to carry non-virulent H. pylori strains. Conclusion: The prevalence of H. pylori among the general population of patients with T2DM, HPT and HIV was low. Although infected patients are found to be carrying virulent strains of H. pylori, there is no significant association established between the virulent strains and the chronic conditions. Furthermore, HIV-infected patients were found to be carrying non-virulent strains of H. pylori.
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- Date Issued: 2018
Cost and return analysis of smallholder organic crop farms in the Eastern Cape province of South Africa
- Authors: Akharume, Celestine Ohi
- Date: 2017
- Subjects: Farms, Small -- South Africa -- Eastern Cape Profit -- South Africa -- Eastern Cape Organic farming -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MAgric
- Identifier: http://hdl.handle.net/10353/13730 , vital:39703
- Description: Agriculture remains an influential sector in South Africa in terms of its contributions to economic development and poverty reduction, notably in the rural areas. These include providing sufficient and affordable food for the constantly increasing population, providing cheap food for the developing industrial labor force, providing employment and livelihoods and supplying raw materials to the country’s rising domestic industrial sector. Despite phenomenal progress in integrating smallholder farmers into the mainstream economy since democratic reforms in the country, deteriorating soil quality through poor agricultural practices, land erosion, acidification and concerns about production and productivity and compliance with food safety standards are beginning to loom high. Hence, organic farming is identified as one of the sustainable approaches to farming. It is also believed to guarantee substantial net gains and to promote sustainable natural resource management with the possibility of enhancing overall agricultural productivity. Notwithstanding, organic farming is still being perceived negatively in South Africa and there is shortage of empirical studies which focus on cost and return of smallholder organic crop farms. It is in this regard that the study therefore seeks to analyze cost and return of smallholder organic crop farms in the Eastern Cape Province to contribute to knowledge on the relative economic advantages of organic agriculture at the smallholder sector. Specifically, the study profiled the socioeconomic characteristics of smallholder organic crop farmers, determined costs and returns, and estimated profitability and factors that constrain profitability of the smallholder organic crop farms. The research design used in this study was cross-sectional where data were collected at a single point in time. A multi- stage random sampling technique was used to obtain primary data from one hundred and sixty smallholder organic crop farmers (160) with the aid of structured questionnaires. Primary data were collected on demographic and socioeconomic characteristics, variable costs and fixed costs, and returns from the organic crop farms. Data collected were analyzed by Statistical Package for Social Sciences (SPSS) and the descriptive and inferential statistics involved were mean, frequency proportion, gross margin and net income analysis as well as OLS regression analysis. The results of the descriptive analysis showed that the proportions of women involved in organic crop farming were higher than that of men and many of the farmers cultivated on less than 1.0ha. The analysis of the data also showed that smallholder organic crop farms are undoubtedly profitable farm business, with attractive net farm income and lower production costs. The findings further affirmed that factors such as household size, gender, farming experience, number of years in school, farm size, source of labor and access to credit affect profitability and net farm income. Therefore, government is advised to encourage the practice of organic farming by giving short-term loans to smallholder farmers, to enable them invest more in their organic crop farms. There is also need for government to organize workshops and lectures, educating and enlightening individual smallholder organic crop farmers on modern organic farming techniques to enhance profitability of smallholder organic crop farms.
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- Date Issued: 2017
Cultivation, nutritional and pharmacological evaluation of Celosia argentea (L) Kuntze: an endangered wild vegetable in the Eastern Cape Province of South Africa
- Authors: Adegbaju, Oluwafunmilayo Dorcas
- Date: 2019-09
- Subjects: Celosia , Edible greens
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/19806 , vital:43250
- Description: Green leafy vegetables are important in human nutrition, but their cultivation is limited to a few staple ones. These vegetables possess high nutritious and therapeutic properties that could help in achieving nutritional security and alleviating the burden of some diseases. A typical example is Celosia argentea, which in South Africa, is little known and grossly under-utilized despite its numerous nutritional and pharmacological values. The present study investigated the cultivation, nutritional and pharmacological potentials of C. argentea at three stages of maturity of two trials. Evaluation of cultivation in the greenhouse towards possible domestication of C. argentea included seed viability test, seed germination under varying temperatures (5, 10, 15, 20 25 30, 35, 40°C), light conditions (continuous light, continuous darkness, alternating light and dark (12h light/12 dark photoperiod) and sowing depths (0, 1, 2, 3, 4 and 5cm). The nutritional evaluation assessed the proximal, mineral, vitamins and antinutrient content of the plant; while pharmacological potentials of C. argentea were evaluated by investigating the ultramorphology, phytochemical content, anti-oxidant, antimicrobial, toxicity and cell-based anti-inflammatory properties of the plant at different stages of growth. Germination experiment revealed that optimum seed germination requirements for C. argentea were 25°C, alternating light and dark regime and a sowing depth of 1cm. Microrphological assessment of C. argentea revealed that the leaves were amphistomatic; with the abaxial surface having higher stomata density. Characteristic, distinguishing protuberances were observed at the polar ends of the stomata on the adaxial surface of the plant epidermis, and the major elements on the foliar epidermis were beryllium, carbon, oxygen and potassium; while pigmentation and colouration, showing localization of bioactive compounds were mostly at the site where trichomes were abundant. Growth parameters and yield potential (plant height, stem girth, leaf area, number of leaves, number of branches, number of days to flowering, number of flowers as well as dry and fresh weight) of C. argentea showed that for agricultural practices on the field, increase in growth parameters should be expected around 4-5 weeks after transplanting while higher yield should be expected around 7-9 weeks after transplanting. The results encouraged cultivation during summer or late spring for best farm management. Proximal, mineral, vitamins and anti-nutrients content of C. argentea at three different maturity stages of two trials were performed using AOAC, ALASA and inductively coupled plasma-optical emission spectrometer techniques. Results revealed that the pre-flowering stage of growth had the highest ash (28.15± 0.10 percent) and crude protein (25.80 ± 0.20 percent) contents. While post-flowering stage had the highest carbohydrate (28.51± 0.20 percent and 36.16± 0.22 percent), crude fibre (33.41± 0.87 percent) and energy (435.28± 27.6 percent) with low fat and moisture (8.43± 0.15 percent and 6.35±0.09 percent) contents respectively; while no marked demarcation in most mineral contents in all the growth stages was observed. Zinc was highest at the flowering stage of growth, while vitamin contents decreased as the plant approached maturation. Antinutrients content of the plant was not dependent on growth stage. Total phenols, flavonoids and proanthocyanidin content of C. argentea were evaluated colourimetrically, while the antioxidant potency of the aqueous, acetone and methanolic extracts was measured using 2,2 diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), Ferric reducing antioxidant power (FRAP) and total antioxidant capacity (TAC) models. All the solvent extracts of the flowering stage had the highest total phenolic (80.75±4.21GAE/g), flavonoids (946.19±7.87QE/mg) and proanthocyanidin contents (100.90±1.29 CE/g); with the acetone extracts showing significantly higher phytochemical content. The flowering stage exhibited the best radical inhibitory activity, with the methanol extract having the highest scavenging power for ABTS and DPPH radicals, while acetone extract showed the highest inhibition against FRAP and highest total antioxidant capacity. The antimicrobial potential of the aqueous acetone and methanolic extracts of C. argentea evaluated using agar dilution method against six bacteria (Klebsiella pneumonia, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Bacillus cereus) and four fungal strains (Candida glabarata, Candida albicans and Penicillium aurantiogriseum and Penicillium chrysogenum) showed that Streptococcus pyrogenes and P. aeruginosa were susceptible to the methanol extracts of all the growing phases of both trials at 10 mg/mL; while Klebsiella pneumoniae was susceptible at 10 mg/mL to only the methanol post-flowering extracts of both trials. C. albicans and P. aurantiogriseum were highly susceptible to all the extracts. Possible toxicity evaluated using brine shrimp lethality assay and calculation of LC50 against brine shrimp nauplii revealed that C. argentea was not toxic at any stage of maturity at all concentrations evaluated. Anti-inflammatory activities and cytotoxicity of C. argentea extracts evaluated using RAW 264.7 macrophages and 3T3-L1 cell lines revealed that the acetone extract of the flowering stage had moderate anti-inflammatory activity with no significant toxicity against activated macrophages. Findings from this study indicate that C. argentea is a safe functional leafy vegetable of high nutritional and pharmacological importance which can easily be cultivated and domesticated in South Africa. This could significantly alleviate the burden of micronutrient deficiencies among pre-school children in rural communities. , Thesis (PhD) (Botany) -- University of Fort Hare, 2019
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- Date Issued: 2019-09
Cultural and heritage tourism trends in the Amathole District Municipality of the Eastern Cape Province, South Africa, 2004-2014
- Authors: Mboniswa, Mncedi Justice
- Date: 2017
- Subjects: Heritage tourism -- South Africa -- Eastern Cape Cultural property -- Repatriation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/7897 , vital:30798
- Description: The promotion of tourism in a country, especially those with high levels of poverty is one of the strategies that can potentially improve socio-economic conditions of citizens. In South Africa, cultural and heritage tourism is seen as one of the ways in which cultural resources can be utilised to benefit marginalised communities and individuals. Such resources can also serve as source of income since both domestic and international tourists can activate industry as they are interested in learning more about other cultures and heritage. There are on-going debates, however on what constitutes cultural and heritage tourism, who it benefits and how this enterprise is located within various communities of South Africa. This research therefore aims to fill this gap through investigating cultural and heritage tourism development trends within the Amathole District Municipality (ADM) and how this development trend impacts on employment creation and improving the socio-economic conditions of citizens within this area of ADM. To realise this aim, the study looks at the availability of cultural and heritage tourism structures within the ADM and the database records on these structures. This study adopts the community benefit tourism initiatives approach to tourism development in the Amathole District Municipality of the Eastern Cape Province. This qualitative study reveals how the community benefit tourism approach encompasses rewards to local communities, in as much as it enhances sustainability of tourism initiatives. In bringing out these aspects, the study also examines efforts of the government and private sector in the up-keeping of tourism initiatives, especially for marginalised communities of South Africa.
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- Date Issued: 2017
Design and Characterization of a 5 kw Xe-Lamp Solar Simulator
- Authors: Nwodo, Julian Chizoba
- Date: 2019
- Subjects: Solar energy
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/14671 , vital:40042
- Description: The design and characterisation of a 5kW Xenon lamp solar simulator is presented. This was accomplished through considering the design features of an ellipsoidal reflector, Xe lamp characteristics and casing, and power supply; assembly of an ellipsoidal, Xe-lamp simulator; design and building of an automated control system capable of remotely controlling the operating mode of the simulator; establishing the 3 scenarios that must be met to conform to a AAA class simulator; characterization of the simulator in terms of temporal stability, irradiance uniformity and spectral match; and application of the simulator and comparing it with STC rated values. The considerations for the type of material used for housing the components of the solar simulator were made. A 5kW DC power supply and igniter for the Xe-lamp was carefully selected since they provide necessary power for running the simulator. The simulator has the ability to be used in either horizontal or vertical position by adjusting the reflector. An automated control system capable of remotely controlling the operating mode of the simulator was built for this study, this system enables the simulator to be operated in either auto or manual modes. It also incorporates an irradiance, temperature, current and voltage feedback. The characterisation of the solar simulator was over a 2.1 m X 1.6 m test plane. The area under which the characterisation was carried out within the test plane is 110 cm x 129.5 cm. At the end of the steady state large area solar simulator characterisation, a class A spectral match, class A spatial uniformity, and a class B temporal instability was obtained
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- Date Issued: 2019
Design and development of a context sensitive rural development software application for eService provisioning
- Authors: Masikisiki, Lizo
- Date: 2018
- Subjects: Rural development Electronic commerce Computer networks
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/15332 , vital:40366
- Description: After more than a decade since South Africa realized the importance of Information and Communication Technology (ICT) and the role it can play to deliver services, the country is still confronted by a number of challenges challenges that hinder the implementation of a fully-fledged ICT-based system in a form of electronic government to better deliver services and information. While rural development remains as one of the country’s greatest concerns, ICT is among approaches and perspectives that are recognized for not only accelerating rural development but also for providing the country’s economic growth. This research was set to investigate approaches to implement ICT solutions for rural development and service provisioning in the context of electronic government. The research focused more on the technical skills to implement such ICT systems for the benefit of rural development and e-government stakeholders that have an interest in design and development of an integrated and interoperable solution to accelerate service delivery, especially in rural communities. A mixed methods approach was used throughout the research accompanied by an evolutionary prototyping to development the desired prototype. A study was then conducted to gain an understanding of the state and the needs of rural communities to date. The results of the study yielded a number of urbanized service providers that rural dwellers need to timeously visit to consume services. Scenarios to design and develop the intended prototypes were then drawn from these results. The overall implementation of the prototypes produced an integrated platform that allows multiple disparate systems to communicate, share and use information. The qualities of the prototype are what this research recommends to relevant to stakeholders in order to implement an integrated and interoperable e-government system that elevates rural development programs and service delivery.
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- Date Issued: 2018
Design and development of mobile-based e-Marketing application for communal farmers in Eastern Cape. South Africa.
- Authors: Fatumo, Dare Ebenezer
- Date: 2023-02
- Subjects: Food security , Agriculture , Agriculture -- Technology transfer
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27511 , vital:67421
- Description: The application of Information and Communication Technologies (ICT) in agriculture can augment farmers' production capabilities, this is a perception for all farmers worldwide, but there are some in communal areas who may not be as exposed to ICT tools as their commercial counterparts in urban areas, especially in developed communities. Food security in any society is a vital measure that should always be treated with high priority since humankind's existence is based on food availability. One major challenge with farmers in communal areas has been the marketing of their farm produce effectively to avoid wastage, get more value, and bridge the gap between themselves and urban commercial farmers. This challenge includes food wastage, untimely information, and market accessibility due to distance restraint. ICT can beused to bring a functional platform to assist this challenge. In this context, communal farmers have a challenge. The aim of this research was to design and develop an easy-to-use mobilebased e-marketing application for marketing farm products for communal farmers in Alice community, South Africa. Before design and development, review of challenges of farmers on the reception and communication of sensitive information pertaining to food security. Effective communication of farm produce baseline information on awareness and adaptation of mobile ICT technology of communal farmers was investigated. A mixed method was used through reviews of literature and as well distribution of questionnaires to get an understanding of the present state of communal farmers’ marketing problems. Furthermore, a prototyping methodology was used in the development of the mobile-based application for this research. The result of this research demonstrated the need for communal farmers to market their farm products at their convenience. An easy-to-use mobile-based e-market application was then developed; the application is an android application that will assist communal farmers in marketing their farm products as soon as they are available to avoid food wastage. The application performance and evaluation assessment indicated that the tool would maximize farm productivity and profitability and, facilitate concise and effective access to the market, as well as eliminate the need for an intermediary. , Thesis (MSci) -- Faculty of Science and Agriculture, 2023
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- Date Issued: 2023-02
Design of a Traffic Surveillance Application using iFogSim
- Authors: Sinqandu, Mluleki
- Date: 2020
- Subjects: Cloud computing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/18676 , vital:42705
- Description: __iFogSim is a toolkit to model, simulate and evaluate networks of Fog computing, Edge computing and Internet of Things (IoT). This framework provides the capabilities of analysing and evaluating the performance of applications and resource management policies in Fog/IoT environments, based on which designers can model and test their applications. This thesis proposes a novel application model of a traffic surveillance vehicular network application through smart cameras using iFogSim, where the scenario of multiple vehicles tracking is considered. The effectiveness of the proposed application model is assessed and validated by simulations using a modified application model inherited from a case study of intelligent surveillance through distributed camera networks introduced. Simulations are conducted using the iFogSim tool and performance evaluation is done. The comparison between one vehicle and multiple vehicle tracking is done and the results demonstrate that the multiple vehicle application model achieves a better performance in terms of average latency and data transfer rate
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- Date Issued: 2020
Design, construction and performance evaluation of an agitated portable biogas digester under greenhouse-regulated temperature
- Authors: Mutungwazi Asheal
- Date: 2017
- Subjects: Sewage -- Purification -- Anaerobic treatment Green technology Renewable energy sources
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/9055 , vital:34222
- Description: Biogas yield in anaerobic digesters is negatively affected by low temperatures during cold seasons and nights, temperature fluctuations and inefficient agitation. Electrical heating and underground digester installations have been used to help minimise these effects but the high cost of electrical heating, infeasibility of underground installations in some terrains, inefficient agitation and difficult maintenance continue to be major set-backs to high biogas yields. In this study a 100 ℓ, agitated, portable carbon steel digester housed within a greenhouse, whose operation temperature is automatically maintained at an optimum of 35 ± 1 oC by means of an ON/OFF electronic circuit for ventilation control through a suitably sized window and insulation offered by an air film trapped in-between a double layer of polyethylene plastic covering of the greenhouse, was designed. Cow dung from a dairy farm at the University of Fort Hare with total solids (TS), volatile solids (VS), chemical oxygen demand (COD) and ammonia nitrogen content of 162348.67 mg/ℓ, 116543.98 mg/ℓ, 37 879 mg/ℓ and 128 - 235 mg/ℓ respectively was used for the performance evaluation of the digester. Analysis of the biogas produced starting from day 6 of the 31-day retention period showed a specific biogas yield of 0.036 m3/kgVSadded and a methane yield of 55percent. The optimum pH maintained was 7.2 and the COD reduction achieved during the digestion period was 61percent. This simple, easy to construct, inexpensive yet efficient design will lead to improved biogas yields and quality and faster dissemination of the biogas technology.
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- Date Issued: 2017
Detection and antibiogram profile of members of the vibrio species in Umzimvubu, Swartkops and Buffalo rivers the Eastern Cape province, South Africa
- Authors: September, Dolly Thandeka
- Date: 2017
- Subjects: Vibrio -- South Africa -- Eastern Cape Water -- Fluoridation -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/15221 , vital:40255
- Description: Freshwaterbodies are often recipients of a wide array of infectious agents yet they serve as immediate sources of water supply. Brackish and freshwater rivers support the growth of Vibrio species, which are the leading cause of diarrheal infections in the world. Their occurrence in these environments is detrimental to the health and well-being of many communities. Hence, this study aimed at assessing the occurrence and antibiogram profile of Vibrio species in Swartkops, UMzimvubu and Buffalo rivers. The rivers are important sources of freshwater supplies for some communities around the Eastern Cape Province, and water samples were collected once off from each of the sites, using standard membrane filtration method to concentrate the samples. Cultivation was carried out on Thiosulfate Citrate-Bile Salt Sucrose (TCBS) agar, were typical yellow/green colonies were enumerated as presumptive Vibrio species and expressed as CFU/100mL. Presumptive Vibrio counts ranged from 0 to 1.67 × 103 CFU/100mL, 0 to 6.42 ×102 CFU/100mL and 0 to 3.28×103 CFU/100ml in the uMzimvubu, Swartkops and Buffalo rivers respectively. Polymerase Chain Reaction was employed for molecular identification of the Vibrio isolates. Two hundred (200) presumptive Vibrio species were screened for molecular identification, and 185 isolates confirmed positive as belonging to the Vibrio genus. Antibiotic susceptibility profile of the confirmed isolates was determined using a panel of 12 commercial test antibiotics. All the confirmed Vibrio species showed 98 to 100percent multiple antibiotic resistance against all the test antibiotics from the three study sites. The most predominant phenotypic pattern of multidrug resistance displayed by the isolates was CAZ-PEN-AMP-CIP-AK-AZM-TET-CAM-CTX-STX-GEN-IPM showing 100percent resistance to all 12 antibiotics. The multiple antibiotic resistance index (MARI) on average was 1 for all the three rivers assessed. This finding suggest high possibility of antibiotic pollution and usage around the study areas, and occurrence of potentially pathogenic Vibrio species carrying antibiotic resistant genes, which is a major public and environmental health concern.
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- Date Issued: 2017
Determinants and contribution of participation in farming to rural households’ welfare in Nyandeni Local Municipality, Eastern Cape Province of South Africa
- Authors: Qange, Siphesihle
- Date: 2020-06
- Subjects: Agricultural systems , Rural development , Community development
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/20849 , vital:46634
- Description: Participation in farming has been the main livelihood strategy for, especially in rural areas, where homesteads used to produce the majority of their basic food basket. Participation in farming is one of the strategies that can be used to address the food insecurity and poverty in rural areas. Participating in farming seems to be key in the improvement of rural households’ livelihoods, especially in the developing countries, however nowadays, participation in farming is declining from year to year. Rural households tend to invest more of their time in non-agricultural activities. Rural homesteads now behave like their urban counterparts; they purchase more food from the markets than they produce for themselves. Consequently, there are high levels of poverty and food insecurity in rural areas. Government and non-governmental organisations implemented a variety of agricultural projects with the intention of empowering subsistence farmers in rural areas. Despite these interventions, farming in rural areas has continued to decrease as rural dwellers have realised other livelihood strategies. Moreover, the decline in farming activities results in increased unemploymentrates, hunger, and food insecurity in rural areas, resulting in the depreciation of the economy. Therefore, the objective of the study is to investigate the determinants and contribution of participating in farming to the welfare of rural households. The study was conducted in Nyandeni Local Municipality in the Eastern Cape Province of South Africa. A multi-stage sampling procedure was employed in the survey and the data was obtained from 176 rural households comprising both those who participate in farming and those who do not. The study employed a cross-sectional research design, and purposive sampling was used to select the sample prior to the data collection. Data was collected and captured in Excel and then analysed using the Stata version 15. Descriptive statistics were used to profile the socio-economic characteristics of rural households, the probit model was used to determine the factors affecting farming in rural areas and Two stage least squares was used to determine the contribution of farming to the welfare of rural households. In reference to the descriptive statistics, the results indicated that 62 percent of the rural households were headed by females and 51 percent of the household heads were married. The average age of the household heads was 55 years old and above, and the average household comprised 5 persons. Moreover, 50 percent of the rural households had only obtained primary education and 55 percent were unemployed. The average farming experience was 12 years and 12 percent of the households confirmed that they receive extension services from the Government. The probit model was fitted to estimate the factors affecting rural households’ participation in farming. The empirical results indicated that education level, income and Participation in Agric. Project a negative influence on the participation of household in farming and they were significant at 0.01 and 0.05 significance level respectively. Access to extension services had a positive influence on households’ participation in farming and were significant at 5 percent. Farming experience had a positive influence on household participation in farming and was significant at 5 percent and farming experience had a positive influence on participation in farming and was significant at 1 percent significancelevel. Two stage least squares regression was used to measure factors affecting the contribution of household farming to rural household welfare. The study measured the contribution of household farming in terms of income generated from farming. The results indicated that Educational level, Household size and Condition of Infrastructure indicate a positive significant effect on income. The remaining variables, Age, Marital status, Participation in Agric. Project and Access to extension services have a negative significant effect on income. The study concluded that households headed by married individuals fared better than households headed by single individuals. Educated individuals have easy access to various sources of information that could help them with income-generating farming skills. Employment, more especially formal employment, results in higher income, and it is stated that the higher the income the better the welfare of the household. Therefore, the study recommends that Government must promote farming in rural areas through the initiation of support programmes and agricultural community projects. Rural households have the potential to succeed in farming but they lack input and proper equipment, and therefore it is recommended that Government should put more focus on household farming rather than their current primary focus on commercial farming. , Thesis (MSc) (Agricultural Economics) -- University of Fort Hare, 2021
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- Date Issued: 2020-06
Determinants of adaptation to climate variability:A case study of crop farming households in Tyhume Valley communities Eastern Cape,South Africa.
- Authors: Mtintsilana, Olona
- Date: 2020
- Subjects: Climatic changes Sustainable agriculture Climatic changes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/18789 , vital:42733
- Description: Climate variability affects rural households and agricultural productivity, yet it is just one of many stresses that vulnerable rural households have to cope with. Climate variability is not as noticeable as weather variability, because it happens over seasons and years. It is the manner in which climate fluctuates above or below a long-term average value. Without measures at local and national level to adapt to climate variability, risk of food insecurity will continue to increase at household level. The objective of the study was to determine factors affecting adaptation to climate variability. Purposive sampling was used to identify households who participated because of un-availability of sampling frame. Information was elicited from the selected households with the aid of a semi-structured questionnaire. The study utilised a cross-sectional survey of 205 farming households in Tyhume Valley communities. Data gathered was subjected to descriptive statistics, Cross tabulations and Binary logit model. The results indicate that rural households from Tyhume Valley communities practiced coping adaptation through use of the following adaptation strategies; crop rotation, planted drought resistant crops, changed planting dates and used indigenous strategies such as using ash to kill mule (intuku). Most of the households used irrigation as the coping strategy to adapt to climate variability. However, heatwave, high winds, employment status, cell phones, age and gender of the rural households’ heads have effects on households’ adaptation to climate variability in Tyhume Valley. In view of the research findings, a large number of farming households are old and are females, there is a need for development of labour saving technologies and extension services to increase the likelihood of adaptation of climate variability by vulnerable farmers such as women and elderly farmers.The study also recommends that there must be a development of infrastructure for farmers as they are negatively affect by high winds due to low infrastructural development.The study also shows that farming households who have access to cellphones are more likely to adapt to climate variability, therefore the study recommends that communication of farming households must be improved.Adapting to climate variability is an increasingly important issue in agriculture and one that is likely to persist for many years.
- Full Text:
- Date Issued: 2020
Determinants of smallholder vegetable farmers' participation on post-harvest practices and market access : evidence from Mashonaland East Province of Zimbabwe
- Authors: Mukarumbwa, Peter
- Date: 2017
- Subjects: Farms, Small -- Zimbabwe Vegetables -- Zimbabwe -- Marketing Vegetable trade -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/8703 , vital:33431
- Description: Smallholder vegetable production is very vital in enhancing livelihoods in Zimbabwe’s rural areas. Vegetable production generates household income and improves household food security. Despite this, smallholder vegetable farmers in Zimbabwe suffer huge post-harvest losses which reduce their profits and market competiveness. Post-harvest losses of vegetables are a major dilemma faced by smallholder farmers. They not only represent waste of scare resources such as farm inputs but they also entail wasted investment in terms of time, human effort and food. Furthermore, there are also a myriad of other challenges which constrain smallholder vegetable farmers in Zimbabwe from accessing lucrative markets. The broad objective of the study was to assess smallholder vegetable farmers` preferred post-harvest practices for value addition as well as factors that condition their selection choices, adoption and product market access. The study was conducted in four districts: Seke, Goromonzi, Murehwa and Mutoko, in the Mashonaland East Province of Zimbabwe. A multistage sampling procedure was adopted in the selection of villages and households. A total of 385 smallholder vegetable farmers were interviewed. The survey was undertaken from August–October 2016. Descriptive statistics were employed to analyse the socio-economic and demographic characteristics of households that were sampled in Mashonaland East Province. Age of household head, gender, educational level, household size, farming experience, main sources of income, land ownership, main vegetables produced and main causes of post-harvest losses were some of the statistics that were analysed. The average age of the farmers varied significantly across districts and it was generally high (average of 50 years). Moreover, the average household size was about six (6) individuals, which is an indication of high dependency ratio. The study also revealed the major causes of post-harvest losses across all vegetables predominantly cultivated in the study area were pests and diseases, followed by decay. Most of the underlying causes of huge post-harvest losses were within the control of the farmer. Therefore, the study recommends strategies from policymakers and Non-Governmental Organisations (NGOs) which enhance post-harvest management. These can result in substantial reduction in losses which can increase farmers’ income without necessarily expanding land under cultivation. The Poisson count regression model (PCRM) was used to analyse factors influencing number of post-harvest techniques adopted by smallholder vegetable farmers in the study area. The results of the PCRM revealed that the following variables were significant in influencing number of post-harvest practices adopted by smallholder vegetable growers: gender, education level, household size, age, farming experience, distance to market, market information, group membership, credit, and hired labour. The study recommends concerted efforts through public private partnerships (PPP) to provide active extension about post-harvest education. This will promote the adoption of simple, uncomplicated and innovative low-cost technologies for post-harvest management. The binary logit model was employed to analyse factors that influence smallholder vegetable farmers’ decisions to select a specific post-harvest practice for value addition. This was based on the three major post-harvest practices which were mainly being adopted by smallholder vegetable farmers’ in the study area which were drying, grading and washing. The results of the binary model showed that nine (9) variables were significant in influencing smallholder vegetable farmers’ decisions to select post-harvest practice for value addition. These were: gender, land size, distance to market, market information, family labour, training, target market, quantity produced and storage facilities. Policymakers and other stakeholders need to provide productive resources such as inputs to improve productivity and ultimately selection of basic post-harvest management techniques along the vegetable supply chain. The multinomial logit model was used in the study to analyse factors that influence market channel choice of smallholder vegetable farmers in the study area. The results from the multinomial logistic regression model revealed that distance to market, group membership, adding value, road infrastructure and quantity produced influenced participation in informal markets. On the other hand, gender, distance to market, market information, group membership, producer price, adding value, road infrastructure, quantity produced and market infrastructure influenced farmers’ participation in formal markets. Policies aimed at assisting resources for improved productivity of vegetables should be gender sensitive. Establishment of irrigation schemes as well as provision of credit for smallholder vegetable production are vital interventions. In the same way, crafting of appropriate policies and programmes which foster collective action amongst smallholder vegetable farmers are required. This will enable them to produce larger volumes as well as participate in more lucrative markets. Finally, smallholder vegetable farmers’ transaction costs can be reduced by investment in infrastructure such as roads.
- Full Text:
- Date Issued: 2017
Determination of acaricide resistance profiles, and geographic range of boophilid Rhipicephalus tick spp. (Acari: Ixodidae), and sero-status of tick-borne pathogens on communal cattle in the north-eastern regions of the Eastern Cape Province, South Africa
- Authors: Yawa, Mandla https://orcid.org/0000-0002-2402-298X
- Date: 2021-09
- Subjects: Cattle -- Diseases , Ticks as carriers of disease , Ticks
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/21590 , vital:49356
- Description: Cattle industry improves livelihoods for many developing farmers in South Africa, however, ticks and tick-borne diseases (TBDs) pose a detriment impact on cattle success; this is due to their resistance to acaricide application. Thus, this study was conducted to determine the extent of acaricide resistance, serostatus of tick-borne pathogens, and geographic range of boophilid ticks in communal grazing cattle in the north-eastern regions of the Eastern Cape Province (ECP), South Africa. A total of 160 structured questionnaires were prepared and randomly administered to cattle farmers to investigate their knowledge, attitudes, and practice on ticks and TBDs affecting cattle, tick control methods used, and their knowledge of acaricide resistance. Engorged visible cattle ticks were collected seasonally from 10 randomly selected cattle from the community cattle herds during dipping days between October 2018 and September 2019, and stored into the labelled test tubes containing 70 percent ethanol. For TBDs determination, a total of 240 cattle from Elundini and Senqu Municipalities were seasonally used to investigate the prevalence of ticks and TBDs, packed cell volume (PCV), and body condition scores (BCS). Shaw Larval Immersion Test (SLIT) method was used to determine the resistance of Rhipicephalus decoloratus larvae to various acaricides such as amidines, organophosphate, and synthetic pyrethroids. This study indicates that approximately 59 percent of the interviewed cattle farmers had no knowledge of the effect of TBDs affecting cattle production, and 78 percent of respondents considered ticks are the major challenge to the success of their cattle farming. Pour-on (61 percent) was the most commonly used acaricidal treatment system with fortnightly (40 percent and 31percent) treatment frequencies during the summer and winter seasons respectively. Synthetic pyrethroids (73 percent) were the most used acaricide compounds to control ticks. Moreover, approximately 85 percent of respondents perceived that they do not practice acaricide rotation, and 88 percent of the respondents had no knowledge of acaricide resistance. Interestingly, the current study record Rhipicephalus microplus for the first time at Elundini, Senqu, and Walter Sisulu. Based on the morphological traits, a total of 6176 ticks belonging to two boophilid tick species of Rhipicephalus were identified: R. decoloratus (98 percent) and R. microplus (2 percent). Rhipicephalus decoloratus was significantly higher (P<0.05) in Elundini during the hot-dry (3.37±0.121) and hot-wet (3.35±0.121) seasons compared to other localit ies. In Senqu, R. microplus had high counts (P<0.05) during the post-rainy season (1.06±0.027) compared to other localities. From this present study, it was observed that Ehrlichia ruminantium was the most prevalent at Elundini (16 percent) and (14 percent) during post-rainy and hot-dry seasons respectively and 15 percent at Senqu during the post-rainy season. Babesia bigemina was more frequent at Elundini (18 percent) and Senqu (16 percent) during the post-rainy season and hot-wet season, respectively. Cattle BCS were significantly negatively correlated with E. ruminantium (P<0.01; r = -0.203), B. bovis (P<0.01; r = -0.125), and A. marginale (P < 0.01; r = -0.122). On the other hand, PCV was significantly negatively correlated with B. bigemina (P<0.01; r =-0.138). E. ruminantium was strongly positively correlated with Amblyomma hebraeum (P<0.05; r = 0.112), while B. bovis (P<0.05; r = 0.134) and B. bigemina (P<0.05; r = 0.188) were strong positively correlated with Rhipicephalus microplus infestation and B. bigemina (P<0.05; r = 0.077) with Rhipicephalus decoloratus. During acaricide resistance testing, Shaw Larvae Immersion Testing (SLIT) was only performed on R. decoloratus larvae as engorged R. microplus ticks could not meet the required sample size for resistance testing. The current study found that the majority of the tick were susceptible at exposure to differe nt acaricide field concentrations of amidines (49 percent at 250ppm), organophosphates (33 percent and 47 percent at 300ppm and 500ppm, respectively), and synthetic pyrethroids (44 percent and 23 percent at 150ppm and 300ppm, respectively). In conclusion, less knowledge of cattle farmers on the threat pose by ticks on their cattle production results in the spatio-temporal spread of boophilid tick from region to region and from season to season thus increases incidence and risk for tick resistance. , Thesis (PhD) -- Faculty of Science and Agriculture, 2021
- Full Text:
- Date Issued: 2021-09
Determination of physiochemical properties and metal levels in soil, water, and plant from Alice landfill site
- Authors: Maphuhla, N G
- Date: 2017
- Subjects: Heavy metals -- Environmental aspects Soil pollution Water -- Pollution
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/6224 , vital:29521
- Description: The state of soil is of great significance because it is a common medium for plant growth, which provides important nutrients to plants. Water pollution is the build-up of harmful substances in water bodies to the level that results in health problems for people and animals. Heavy metal pollution (of soil, water, and plants) and their health effects on people is a persistent social issue, and several types of research have recognized health risks of residents living close to open dumpsites. Dump sites are sources of heavy metal impurity and toxicity to the surrounding environment. Analyses were done on water and soil samples for temperature, pH, Electrical conductivity (EC), Total dissolved solids (TDS), alkalinity, organic matter, organic carbon and total hardness. The pH results range from slightly acidic (6.79) to neutral soil pH (7.09), and have been recorded within the normal range from WHO. All the determined physicochemical properties in soil and water have been recorded within the normal range, except for EC in water which was found to be above the permissible limits by WHO. The heavy metals concentration was determined using the AAS technique. The results obtained shows that the dumpsite‘s soil consists of high metal concentration when compared to control site. The concentration in dumpsites ranges between 1.2783 ± 0.83 mg/kg to 26.3213 ± 6.37 mg/kg. The descending order for selected metal concentrations were in this following order Mn> Cu>Hg>Pb. The Pb and Hg mean concentration was recorded above permissible limits, while the Mn and Cu were within the normal range suggested by WHO. In both water and Acacia karroo samples the Cu was not detected. The trend of metal concentration in water sample was found to be in this order Hg> Mn > Pb> Cu, while in Acacia karroo metal concentration is Hg> Mn> Pb> Cu. The one-way ANOVA test was used to compare the mean concentration of selected metals in each sampling site. The results show that there is a statistically significant difference between the mean concentrations of selected metals; this is supported by the value of F-static and p-value (p <0.05)
- Full Text:
- Date Issued: 2017
Determining and analysing the emergent behaviour from context-aware devices
- Authors: Bandason, Vivian
- Date: 2017
- Subjects: Context-aware computing Mobile computing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/7907 , vital:30805
- Description: With the continued miniaturization of technology and the incorporation of Moore’s law, smartphones are more powerful. These mobile devices contain technologies that add other functionalities to them. Technologies such as sensors constantly provide information to the device. The constant stream of information from these sensors often leads to information overload of relevant and irrelevant information. To work towards solving this problem context-aware computing was introduced. Our major concern is that context information in context aware computing is not completely being utilized. The aggregation of context information could unlock more possibilities. This research seeks to aggregate the context of multiple devices such that, through analysis, some emergent behaviour can be observed. In this research context information from the sensors of devices is collected using an Android application and a central Server. The context information is used for pattern analysis. A pattern analysis algorithm is designed and used to observe patterns throughout the data set. It shows patterns that are similar within the dataset. In the case that the pattern observed has no similar pattern or few similar patterns this behaviour can be stated as emergent in the dataset. Further study of this emergent behaviour can be performed were a classifier can be used to give the exact activities that were being performed at that time. The research found this was possible and has many uses. One of these is in disaster prevention were the behaviour of a group of individuals may be monitored to observe any random changes such as masses running at the same time. This could be used as a first warning to natural disasters.
- Full Text:
- Date Issued: 2017
Developing a Machine Learning Algorithm for Outdoor Scene Image Segmentation
- Authors: Zangwa, Yamkela
- Date: 2020
- Subjects: Computational intelligence Computer science
- Language: English
- Type: Thesis , Masters , MSc (Computer Science )
- Identifier: http://hdl.handle.net/10353/12087 , vital:39150
- Description: Image segmentation is one of the major problems in image processing, computer vision and machine learning fields. The main reason for image segmentation existence is to reduce the gap between computer vision and human vision by training computers with different data. Outdoor image segmentation and classification has become very important in the field of computer vision with its applications in woodland-surveillance, defence and security. The task of assigning an input image to one class from a fixed set of categories seem to be a major problem in image segmentation. The main question that has been addressed in this research is how outdoor image classification algorithms can be improved using Region-based Convolutional Neural Network (R-CNN) architecture. There has been no one segmentation method that works best on any given problem. To determine the best segmentation method for a certain dataset, various tests have to be done in order to achieve the best performance. However deep learning models have often achieved increasing success due to the availability of massive datasets and the expanding model depth and parameterisation. In this research Convolutional Neural Network architecture is used in trying to improve the implementation of outdoor scene image segmentation algorithms, empirical research method was used to answer questions about existing image segmentation algorithms and the techniques used to achieve the best performance. Outdoor scene images were trained on a pre-trained region-based convolutional neural network with Visual Geometric Group-16 (VGG-16) architecture. A pre-trained R-CNN model was retrained on five different sample data, the samples had different sizes. Sample size increased from sample one to five, to increase the size on the last two samples the data was duplicated. 21 test images were used to evaluate all the models. Researchers has shown that deep learning methods perform better in image segmentation because of the increase and availability of datasets. The duplication of images did not yield the best results; however, the model performed well on the first three samples.
- Full Text:
- Date Issued: 2020
Developing logit calibration model for wildfire smoke characterization based on sentinel-2 multispectral data and machine learning techniques
- Authors: Sali, Athule
- Date: 2023-07
- Subjects: Wildfires -- Prevention and control -- Contracting out , Smoke plumes , Remote-sensing images
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/28467 , vital:74338
- Description: Wildfires are complicated incidents that arise as results of both natural causes and anthropological activities. They have long been regarded as the most devastating phenomena globally. Wildfires are considered a powerful natural factor which has detrimental effect on the global environment. This study was aimed at developing logit calibration models for wildfire smoke prediction based on Sentinel-2 multispectral data and machine learning techniques. Remotely sensed data, in the form of the Sentinel-2 imagery, was used as the base from which wildfire smoke plumes were spectrally characterized and distinguished from clouds and flame using endmember selection. The Smoke Detection Index (SDI) was generated to detect the relative abundance of smoke from the imagery. The Cloud Detection Index (CDI) was also generated from Sentinel-2 imagery to detect the relative abundance of clouds. The bi-level thresholding technique was also used to characterize wildfire smoke from the imagery. The logit models were developed through multilayer perceptron (MLP) neural network to predict wildfire smoke plumes. The Relative Operator Characteristic - Area Under the Curve (ROC-AUC) metrics was used to evaluate the logit models performance. The spectral signature pattern from endmembers revealed that wildfire smoke behaves different across Sentinel-2 multispectral channels with shortwave 1 channel (SWIR-1) exhibiting the highest radiance value. The signature patterns from endmember selection also revealed the distinctive spectral characterization of smoke from those of clouds. The findings showed that whilst smoke exhibited high radiance value on SWIR-1 channel, clouds exhibited high radiance value in the near infrared (NIR), signifying that smoke and cloud are spectrally separatable in the NIR. The smoke-containing pixels from bi-level thresholding were characterized by SDI values that ranged between 0.089 and 0.561. Suggesting that pixels associated with wildfire smoke are limited to this range of values. The logit models developed showed that smoke is predicted in SWIR-2. The ROC-AUC value obtained by this model was 0.77. The Implications emerging from the ROC-AUC results revealed that MLP model employed on the SWIR-2 band present a viable and accurate prediction of wildfire smoke plume. The findings of this study suggest that wildfire smoke is efficiently predicted at the shortwave channels of the electromagnetic spectrum. The wildfire smoke can be spectrally distinguished from cloud in the near infrared channel. , Thesis (MSc) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-07
Development & evaluation of modified lignocellulose-clinoptilolite composites for water treatment
- Authors: Vala, Mavula Kikwe Remy
- Date: 2012-12
- Subjects: Lignocellulose , Lignocellulose -- Biotechnology
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/24521 , vital:63051
- Description: Municipalities, mining, textile and many other industries release wastewater into water bodies. Thus, the entire ecosystem (biota and abiota) including drinking water is affected by polluted effluents. The growing environmental concern over water pollution (due to inorganic and persistent organic compounds) attracts a significant amount of research in the removal of pollutants from water. In this study, lignocellulose and clinoptilolite were modified for the preparation of composites, with high adsorption properties, suitable for the removal of pollutants. Grass (Kikuyu grass) material was first treated with boiling water in order to remove soluble compounds and then with sulfuric acid in order to free functional groups within lignocellulose. The lignocellulose obtained was then chemically modified with three different siloxanes (3-aminopropyl-terminated poly (di)methylsiloxanes) of different molecular weights. For clinoptilolite, impurities were removed by reflux in hydrochloric acid before chemical modification with siloxanes. Grafting of siloxanes onto lignocellulose and clinoptilolite as well as the preparation of composites were successfully achieved by means of dibutyltin dilaurate (catalyst) after reflux under nitrogen. The modified materials were characterized by FT-IR, XRD, SEM and TGA and results confirmed successful modification of the materials. Solid state 29Si and 13C NMR were used to investigate the nature of the composite prepared with siloxane NH40D (CNH40D). The investigation revealed a possible bond between the modified lignocellulose and the modified clinoptilolite in the composite. The sorptive and/or ion exchange properties of the materials prepared for the removal of pollutants from water were then investigated. Phenol red, used motor (engine) oil and cyanide were used (with regard to textile, oil spill and gold mining effluents respectively) to simulate water pollution in the laboratory. It was found that adsorption properties of lignocellulose were significantly increased after sulfuric acid treatment, suggesting the availability of lignocellulose functional groups as adsorption sites. When further modified with siloxanes, lignocellulose showed less efficiency in adsorbing phenol red. The general mechanism of phenol red uptake onto lignocellulose and clinoptilolite modified with siloxane or composites was: rapid initial adsorption, slow uptake, small rate increase and then equilibrium. The mechanism of phenol red uptake could be well represented by the pseudo second-order kinetic model with equilibrium being reached after a period of time, ranging between 1-5 hours. The linear Langmuir model was the best model for describing adsorption of phenol red onto lignocellulose modified with siloxanes and composites while the Freundlich model appeared to be best for clinoptilolite modified with siloxanes. The general mechanism of used motor oil uptake onto lignocellulose and clinoptilolite modified with siloxane or composites was: rapid uptake, equilibrium and the process occurs over a short period (10 min). The pseudo second-order kinetic model appeared to be the best representation of this adsorption. The linear Langmuir isotherms are the best fitted model for used motor oil uptake onto the adsorbents prepared. Adsorption of cyanide occurred very quickly (10 to 30 min). For lignocellulose and clinoptilolite modified with siloxanes, desorption occurred soon after adsorption and thus no kinetic model nor isotherms of adsorption were deduced. However, adsorption of cyanide onto composites could be represented by the pseudo second-order kinetic model. Nanofibres were fabricated by electrospinning of the modified lignocellulose and composites by blending them with PAN in a solvent mixture of DMF-DMSO. Nanofiltration was achieved by packing the nanofibres prepared into a pipette and filtering polluted water. Nanofiltration was assessed by measurement of the turbidity of water which dropped from 63 NTU for polluted water to 3.06 NTU for filtered water. , Thesis (PhD) -- Faculty of Science and Agriculture, 2012
- Full Text:
- Date Issued: 2012-12