‘Who? what?’: an uninducted view of towards a new psychology of women from post-Apartheid South Africa
- Authors: Macleod, Catriona I
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6251 , http://hdl.handle.net/10962/d1007869 , http://journals.sagepub.com/doi/abs/10.1177/0959353508092088
- Description: From the text: Towards a New Psychology of Women (TPNW) promises a new psychology of “women”. On the cover of the second edition, the Toronto Globe and Mail is cited as acclaiming the book as “nothing short of revolutionary” as it “set out to recognize, re-define and understand the day-to-day experience of women”. But when we take a closer look at these “women” we discover that they are in fact “white”, (for the most part) middle-class women living in heterosexual relationships in a liberal democracy. This kind of exclusionary inclusion, in which the use of the generic term “woman” disguises the normative assumptions made about the race, class, sexual orientation and location of women, replicates the phallocentrism evidenced in the normalising masculinist terms “mankind” or “Man”. By now, of course, these kinds of critiques of “white” Western feminism by African American writers (e.g. Collins, 1999) postcolonial feminists (e.g. Mohanty, 1991), African feminists (e.g. Ogundipe-Leslie, 1994; Mangena, 2003), and queer theorists (e.g. Jackson, 1999) are well known.
- Full Text:
- Date Issued: 2008
- Authors: Macleod, Catriona I
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6251 , http://hdl.handle.net/10962/d1007869 , http://journals.sagepub.com/doi/abs/10.1177/0959353508092088
- Description: From the text: Towards a New Psychology of Women (TPNW) promises a new psychology of “women”. On the cover of the second edition, the Toronto Globe and Mail is cited as acclaiming the book as “nothing short of revolutionary” as it “set out to recognize, re-define and understand the day-to-day experience of women”. But when we take a closer look at these “women” we discover that they are in fact “white”, (for the most part) middle-class women living in heterosexual relationships in a liberal democracy. This kind of exclusionary inclusion, in which the use of the generic term “woman” disguises the normative assumptions made about the race, class, sexual orientation and location of women, replicates the phallocentrism evidenced in the normalising masculinist terms “mankind” or “Man”. By now, of course, these kinds of critiques of “white” Western feminism by African American writers (e.g. Collins, 1999) postcolonial feminists (e.g. Mohanty, 1991), African feminists (e.g. Ogundipe-Leslie, 1994; Mangena, 2003), and queer theorists (e.g. Jackson, 1999) are well known.
- Full Text:
- Date Issued: 2008
Xylem as well as phloem sustains severe damage due to feeding by the Russian wheat aphid
- Saheed, S A, Liu, Lin, Jonsson, L M V, Botha, Christiaan E J
- Authors: Saheed, S A , Liu, Lin , Jonsson, L M V , Botha, Christiaan E J
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6541 , http://hdl.handle.net/10962/d1005983
- Description: Investigation of comparative effects of feeding damage by the Russian wheat aphid (RWA, biotype SA1, Diuraphis noxia Mordvilko) on leaf blades of susceptible and resistant wheat cultivars (Triticum aestivum L. var Betta and Betta-Dn1 respectively) were carried out to establish the level of ultrastructural damage caused by this aphid and the possible limitation of damage induced which could be ascribed to the resistance gene Dn1 over the susceptible cultivar. Ultrastructurally, Betta-Dn1 sustained less damage to the vascular tissue as well as to the mesophyll during the experimental period. Both inter- and intracellular probes resulted in considerable saliva deposition as the aphids probed for suitable feeding sites. Salivary tracks were observed between and within mesophyll, bundle sheath cells as well as the vascular tissue, including the xylem. Disruption of organelles and cytoplasm resulted from cell probing and sheath deposition. Cell and organelle damage was more evident in the non-resistant Betta cultivar. The aphids probed for and fed from thin-walled sieve tubes preferentially. Few thick-walled sieve tubes showed evidence of either aphid probing or feeding-related damage. Saliva was deposited when the aphids probed inter- and intracellularly for feeding sites. The aphids appeared preferentially to probe for and feed from thin-walled sieve tubes, as few thick-walled sieve tubes showed evidence of damage. Vessels, apparently probed for water, contained watery saliva that encased the secondary walls and sealed pit membranes between probed vessels and xylem parenchyma. The xylem probed by the RWA was rendered non-functional, probably contributing to symptoms of leaf roll, chlorosis and necrosis, which were observed within two weeks of infestation in the susceptible Betta cultivar. This damage was limited in the resistant Betta-Dn1 cultivar during the same time frame.
- Full Text:
- Date Issued: 2007
- Authors: Saheed, S A , Liu, Lin , Jonsson, L M V , Botha, Christiaan E J
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6541 , http://hdl.handle.net/10962/d1005983
- Description: Investigation of comparative effects of feeding damage by the Russian wheat aphid (RWA, biotype SA1, Diuraphis noxia Mordvilko) on leaf blades of susceptible and resistant wheat cultivars (Triticum aestivum L. var Betta and Betta-Dn1 respectively) were carried out to establish the level of ultrastructural damage caused by this aphid and the possible limitation of damage induced which could be ascribed to the resistance gene Dn1 over the susceptible cultivar. Ultrastructurally, Betta-Dn1 sustained less damage to the vascular tissue as well as to the mesophyll during the experimental period. Both inter- and intracellular probes resulted in considerable saliva deposition as the aphids probed for suitable feeding sites. Salivary tracks were observed between and within mesophyll, bundle sheath cells as well as the vascular tissue, including the xylem. Disruption of organelles and cytoplasm resulted from cell probing and sheath deposition. Cell and organelle damage was more evident in the non-resistant Betta cultivar. The aphids probed for and fed from thin-walled sieve tubes preferentially. Few thick-walled sieve tubes showed evidence of either aphid probing or feeding-related damage. Saliva was deposited when the aphids probed inter- and intracellularly for feeding sites. The aphids appeared preferentially to probe for and feed from thin-walled sieve tubes, as few thick-walled sieve tubes showed evidence of damage. Vessels, apparently probed for water, contained watery saliva that encased the secondary walls and sealed pit membranes between probed vessels and xylem parenchyma. The xylem probed by the RWA was rendered non-functional, probably contributing to symptoms of leaf roll, chlorosis and necrosis, which were observed within two weeks of infestation in the susceptible Betta cultivar. This damage was limited in the resistant Betta-Dn1 cultivar during the same time frame.
- Full Text:
- Date Issued: 2007
The use of response surface methodology to evaluate the impact of level 2 SUPAC–IR changes on the in vitro release of metronidazole and ranitidine from a fixed-dose combination tablet
- King’ori, Loti D, Walker, Roderick B
- Authors: King’ori, Loti D , Walker, Roderick B
- Date: 2012
- Language: English
- Type: text , Article
- Identifier: vital:6391 , http://hdl.handle.net/10962/d1006313
- Description: The purpose of this study was to evaluate the effect of different levels of disintegrant (croscarmellose sodium, CCS), binder (polyvinylprrolidone K30, PVP–K30), and lubricant (magnesium stearate) on the in vitro release of metronidazole (MTZ) and rantidine (RTD) from a solid oral fixed-dose combination tablet. The excipient levels investigated were Level 2 changes in component and composition described in the Scale-Up and Post Approval Changes for Immediate Release (SUPAC–IR) guidance (1). Batches of tablets (1000 units) were manufactured by wet granulation using a Saral high-shear mixer granulator and a Manesty B3B rotary tablet press. Weight uniformity, friability, and disintegration of all tablets were assessed, and all batches complied with compendial specifications. The amount of drug released (Q) at ten minutes was dependent on the levels of CCS in the formulation, and the effect of PVP–K30 and magnesium stearate was dependent on the levels of CCS. Synergistic interactions between independent variables were observed for the Q10 value for RTD, whereas PVP–K30 and magnesium stearate exhibited an antagonistic effect on the Q10 values for MTZ and RTD. The use of response surface methodology facilitated an investigation into the effect of Level 2 component and composition changes, as described in SUPAC–IR, on the in vitro release of MTZ and RTD from a fixed-dose combination (FDC) solid oral dosage form (SODF).
- Full Text:
- Date Issued: 2012
- Authors: King’ori, Loti D , Walker, Roderick B
- Date: 2012
- Language: English
- Type: text , Article
- Identifier: vital:6391 , http://hdl.handle.net/10962/d1006313
- Description: The purpose of this study was to evaluate the effect of different levels of disintegrant (croscarmellose sodium, CCS), binder (polyvinylprrolidone K30, PVP–K30), and lubricant (magnesium stearate) on the in vitro release of metronidazole (MTZ) and rantidine (RTD) from a solid oral fixed-dose combination tablet. The excipient levels investigated were Level 2 changes in component and composition described in the Scale-Up and Post Approval Changes for Immediate Release (SUPAC–IR) guidance (1). Batches of tablets (1000 units) were manufactured by wet granulation using a Saral high-shear mixer granulator and a Manesty B3B rotary tablet press. Weight uniformity, friability, and disintegration of all tablets were assessed, and all batches complied with compendial specifications. The amount of drug released (Q) at ten minutes was dependent on the levels of CCS in the formulation, and the effect of PVP–K30 and magnesium stearate was dependent on the levels of CCS. Synergistic interactions between independent variables were observed for the Q10 value for RTD, whereas PVP–K30 and magnesium stearate exhibited an antagonistic effect on the Q10 values for MTZ and RTD. The use of response surface methodology facilitated an investigation into the effect of Level 2 component and composition changes, as described in SUPAC–IR, on the in vitro release of MTZ and RTD from a fixed-dose combination (FDC) solid oral dosage form (SODF).
- Full Text:
- Date Issued: 2012
The trade in medicinal plants in the Eastern Cape Province, South Africa
- Dold, Anthony P, Cocks, Michelle L
- Authors: Dold, Anthony P , Cocks, Michelle L
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6512 , http://hdl.handle.net/10962/d1005940
- Description: A study of the trade in medicinal plants in the Eastern Cape Province of South Africa undertook to document the species traded, to determine the quantities harvested annually, and to assess the economic value of the trade. All the participants involved at the different levels of the trade were included in the survey, that is, informal street hawkers, owners of amayeza esiXhosa stores, traditional healers, and consumers of traditional medicines. In total, 282 questionnaires were administered in six urban centres. It was found that poorly educated black middle-aged women of low economic standing dominate the trade. A minimum of 166 medicinal plant species were traded at the study sites alone, providing 525 tonnes of plant material valued at approximately R27 million annually. Plants were harvested from a diverse range of vegetation types including Valley Thicket, Afromontane Forest, Coastal Forest and Moist Upland Grassland, the most frequently sold species differing significantly from those documented in similar studies in other regions. The Forest Biome was the vegetation type found to be most threatened by over-harvesting. Of the species documented, 93% were being harvested unsustainably and 34 species have been prioritised for conservation management.
- Full Text:
- Date Issued: 2002
- Authors: Dold, Anthony P , Cocks, Michelle L
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6512 , http://hdl.handle.net/10962/d1005940
- Description: A study of the trade in medicinal plants in the Eastern Cape Province of South Africa undertook to document the species traded, to determine the quantities harvested annually, and to assess the economic value of the trade. All the participants involved at the different levels of the trade were included in the survey, that is, informal street hawkers, owners of amayeza esiXhosa stores, traditional healers, and consumers of traditional medicines. In total, 282 questionnaires were administered in six urban centres. It was found that poorly educated black middle-aged women of low economic standing dominate the trade. A minimum of 166 medicinal plant species were traded at the study sites alone, providing 525 tonnes of plant material valued at approximately R27 million annually. Plants were harvested from a diverse range of vegetation types including Valley Thicket, Afromontane Forest, Coastal Forest and Moist Upland Grassland, the most frequently sold species differing significantly from those documented in similar studies in other regions. The Forest Biome was the vegetation type found to be most threatened by over-harvesting. Of the species documented, 93% were being harvested unsustainably and 34 species have been prioritised for conservation management.
- Full Text:
- Date Issued: 2002
The South African sugar industry
- Authors: Lewis, Colin A
- Date: 1990
- Language: English
- Type: Article
- Identifier: vital:6695 , http://hdl.handle.net/10962/d1006730
- Description: The sugar industry was established in Natal in the mid-nineteenth century. By the 1980s, South Africa produced c. 2 million metric tons of sugar per annum and, directly or indirectly, the industry supported almost one million people. Exports, which amounted for almost half the sugar produced in the 1970s, declined during the 1980s and low prices together with American and Canadian sanctions have forced the industry to consider alternative uses for sugar cane.
- Full Text: false
- Date Issued: 1990
- Authors: Lewis, Colin A
- Date: 1990
- Language: English
- Type: Article
- Identifier: vital:6695 , http://hdl.handle.net/10962/d1006730
- Description: The sugar industry was established in Natal in the mid-nineteenth century. By the 1980s, South Africa produced c. 2 million metric tons of sugar per annum and, directly or indirectly, the industry supported almost one million people. Exports, which amounted for almost half the sugar produced in the 1970s, declined during the 1980s and low prices together with American and Canadian sanctions have forced the industry to consider alternative uses for sugar cane.
- Full Text: false
- Date Issued: 1990
The myth of authenticity : folktales and nationalism in the 'new South Africa'
- Authors: Naidu, Samantha
- Date: 2001
- Language: English
- Type: Article , text
- Identifier: vital:26378 , http://hdl.handle.net/10962/54047 , https://orcid.org/0000-0001-9456-8657
- Description: Folktales texts are published in glorious, polychromatic, innovative forms that promote the texts as both culturally educational and entertaining.
- Full Text: false
- Date Issued: 2001
- Authors: Naidu, Samantha
- Date: 2001
- Language: English
- Type: Article , text
- Identifier: vital:26378 , http://hdl.handle.net/10962/54047 , https://orcid.org/0000-0001-9456-8657
- Description: Folktales texts are published in glorious, polychromatic, innovative forms that promote the texts as both culturally educational and entertaining.
- Full Text: false
- Date Issued: 2001
The honeybees, Apis mellifera Linnaeus (Hymenoptera: Apidae) of woodland savanna of southeastern Africa
- Radloff, Sarah E, Hepburn, H Randall, Villet, Martin H
- Authors: Radloff, Sarah E , Hepburn, H Randall , Villet, Martin H
- Date: 1997
- Language: English
- Type: Article
- Identifier: vital:6829 , http://hdl.handle.net/10962/d1012341
- Description: The morphometric characters and sting pheromones of worker honeybees, Apis mellifera Linnaeus, were analysed by multivariate methods to identify discrete populations in the southeastern woodland savanna of Africa. A discrete population in Mozambique is classified as A. m. litorea Smith, a second in Zimbabwe as A. m. scutellata Lepeletier and a third group in southwestern Zambia as A.m. adansonii Latreille. A zone of introgression between the last two subspecies occurs in south-central Zambia and in the Zambezi Valley.
- Full Text:
- Date Issued: 1997
- Authors: Radloff, Sarah E , Hepburn, H Randall , Villet, Martin H
- Date: 1997
- Language: English
- Type: Article
- Identifier: vital:6829 , http://hdl.handle.net/10962/d1012341
- Description: The morphometric characters and sting pheromones of worker honeybees, Apis mellifera Linnaeus, were analysed by multivariate methods to identify discrete populations in the southeastern woodland savanna of Africa. A discrete population in Mozambique is classified as A. m. litorea Smith, a second in Zimbabwe as A. m. scutellata Lepeletier and a third group in southwestern Zambia as A.m. adansonii Latreille. A zone of introgression between the last two subspecies occurs in south-central Zambia and in the Zambezi Valley.
- Full Text:
- Date Issued: 1997
The Educational Journal
- Date: 1964-09
- Subjects: Education –- South Africa , South Africa -- Politics and government , Government, Resistance to -- South Africa
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/10948/34702 , vital:33421 , Bulk File 7
- Description: The Educational Journal was the official organ of the Teachers' League of South Africa and focussed on education within the context of a racialized South Africa.
- Full Text: false
- Date Issued: 1964-09
- Date: 1964-09
- Subjects: Education –- South Africa , South Africa -- Politics and government , Government, Resistance to -- South Africa
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/10948/34702 , vital:33421 , Bulk File 7
- Description: The Educational Journal was the official organ of the Teachers' League of South Africa and focussed on education within the context of a racialized South Africa.
- Full Text: false
- Date Issued: 1964-09
Stuffed birds on trees: an historical review of avian systematics in southern Africa
- Authors: Craig, Adrian J F K
- Date: 2000
- Language: English
- Type: Article
- Identifier: vital:6931 , http://hdl.handle.net/10962/d1011949
- Description: Avian systematics in southern Africa has been heavily dependent on a small number of museum-based specialists. They produced bird checklists which prescribed the names to be used by other scientists. After an initial phase of cataloguing the avifauna, a major preoccupation was the description of geographical variation, which was documented in an extensive subspecific nomenclature. Until recent years, few African ornithologists have been involved in systematics as a biological discipline. This historical overview considers the contribution of particular individuals from Andrew Smith to Phillip Clancey.
- Full Text: false
- Date Issued: 2000
- Authors: Craig, Adrian J F K
- Date: 2000
- Language: English
- Type: Article
- Identifier: vital:6931 , http://hdl.handle.net/10962/d1011949
- Description: Avian systematics in southern Africa has been heavily dependent on a small number of museum-based specialists. They produced bird checklists which prescribed the names to be used by other scientists. After an initial phase of cataloguing the avifauna, a major preoccupation was the description of geographical variation, which was documented in an extensive subspecific nomenclature. Until recent years, few African ornithologists have been involved in systematics as a biological discipline. This historical overview considers the contribution of particular individuals from Andrew Smith to Phillip Clancey.
- Full Text: false
- Date Issued: 2000
South African music libraries : collegial, institutional and geographic isolation, an examination
- Authors: Still-Drewett, F
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6984 , http://hdl.handle.net/10962/d1006723
- Description: Music libraries are relatively recent additions to South African library collections and attempts at forming a music library association have been thwarted through a number of financial and historical societal limitations. Consequently, many South African music librarians feel isolated from the field. This paper examines the effects of this isolation and the benefits that closer association for the librarian could bring. Future outlooks for music libraries in South Africa are discussed and suggestions made for a more positive future. Les bibliothèques de musique sont des additions relativement récentes aux collections des bibliothèques en Afrique du sud. Les tentatives de création d'une aßociation de bibliothécaires de musique ont été contrariées pour des raisons financières, historiques et sociales. Par conséquent, beaucoup de bibliothécaires de musique se sentent isolés du milieu. Cet article examine les effets de cette isolation et les bénéfices que pourrait apporter une aßociation qui rapproche les bibliothécaires. Il aborde des discußions sur des perspectives futures et émet des suggestion afin d'appréhender un avenir plus positif. Musikbibliotheken sind eine relativ neue Erscheinung im Bibliothekswesen Südafrikas. Die Gründung einer musikbibliothekarischen Vereinigung ist aus finanziellen und anderen Gründen heraus immer wieder gescheitert. Daher fühlen sich viele südafrikanische Musikbibliothekare beruflich isoliert. Der Artikel untersucht die Auswirkungen dieser Isolation und die Vorteile, die ein engerer Zusammenschluß den Bibliothekaren bringen könnte. Er wagt einen Ausblick in und macht Vorschläge für die Zukunft südafrikanischer Musikbibliotheken.
- Full Text:
- Date Issued: 2009
- Authors: Still-Drewett, F
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6984 , http://hdl.handle.net/10962/d1006723
- Description: Music libraries are relatively recent additions to South African library collections and attempts at forming a music library association have been thwarted through a number of financial and historical societal limitations. Consequently, many South African music librarians feel isolated from the field. This paper examines the effects of this isolation and the benefits that closer association for the librarian could bring. Future outlooks for music libraries in South Africa are discussed and suggestions made for a more positive future. Les bibliothèques de musique sont des additions relativement récentes aux collections des bibliothèques en Afrique du sud. Les tentatives de création d'une aßociation de bibliothécaires de musique ont été contrariées pour des raisons financières, historiques et sociales. Par conséquent, beaucoup de bibliothécaires de musique se sentent isolés du milieu. Cet article examine les effets de cette isolation et les bénéfices que pourrait apporter une aßociation qui rapproche les bibliothécaires. Il aborde des discußions sur des perspectives futures et émet des suggestion afin d'appréhender un avenir plus positif. Musikbibliotheken sind eine relativ neue Erscheinung im Bibliothekswesen Südafrikas. Die Gründung einer musikbibliothekarischen Vereinigung ist aus finanziellen und anderen Gründen heraus immer wieder gescheitert. Daher fühlen sich viele südafrikanische Musikbibliothekare beruflich isoliert. Der Artikel untersucht die Auswirkungen dieser Isolation und die Vorteile, die ein engerer Zusammenschluß den Bibliothekaren bringen könnte. Er wagt einen Ausblick in und macht Vorschläge für die Zukunft südafrikanischer Musikbibliotheken.
- Full Text:
- Date Issued: 2009
Should active recruitment of health workers from sub-Saharan Africa be viewed as a crime?
- Mills, E J, Schabas, W A, Volmink, J, Walker, Roderick B, Ford, N, Katabira, E, Anema, A, Joffres, M, Cahn, P, Montaner, J
- Authors: Mills, E J , Schabas, W A , Volmink, J , Walker, Roderick B , Ford, N , Katabira, E , Anema, A , Joffres, M , Cahn, P , Montaner, J
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6392 , http://hdl.handle.net/10962/d1006314
- Description: (Conclusion) When the international community permits for-profit companies to actively entice overworked and often underpaid workers away from the most vulnerable populations, it is contributing to the deterioration of essential health-care delivery. Improvement of the health of the world’s poor is a challenge that the international community is failing to adequately address. Current international treaties and commitments are severely compromised if we are unwilling to adhere to their principles and prevent obvious harms to poor people. Clear, enforced regulation is needed to prevent recruitment companies from enticing health workers away from their local work, and developed countries should adequately compensate less-developed countries for the human resources they have lost and continue to lose.
- Full Text:
- Date Issued: 2008
- Authors: Mills, E J , Schabas, W A , Volmink, J , Walker, Roderick B , Ford, N , Katabira, E , Anema, A , Joffres, M , Cahn, P , Montaner, J
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6392 , http://hdl.handle.net/10962/d1006314
- Description: (Conclusion) When the international community permits for-profit companies to actively entice overworked and often underpaid workers away from the most vulnerable populations, it is contributing to the deterioration of essential health-care delivery. Improvement of the health of the world’s poor is a challenge that the international community is failing to adequately address. Current international treaties and commitments are severely compromised if we are unwilling to adhere to their principles and prevent obvious harms to poor people. Clear, enforced regulation is needed to prevent recruitment companies from enticing health workers away from their local work, and developed countries should adequately compensate less-developed countries for the human resources they have lost and continue to lose.
- Full Text:
- Date Issued: 2008
Selective removal of chromium (VI) from sulphates and other metal anions using an ion-imprinted polymer
- Pakade, V, Cukrowska, E, Darkwa, J, Torto, N, Chimuka, L
- Authors: Pakade, V , Cukrowska, E , Darkwa, J , Torto, N , Chimuka, L
- Date: 2011
- Language: English
- Type: Article
- Identifier: vital:6588 , http://hdl.handle.net/10962/d1004171
- Description: A linear copolymer was prepared from 4-vinylpyridine and styrene. An ion-imprinted polymer (IIP) specific for Cr (VI) adsorption was prepared by copolymerisation of the quaternised linear copolymer (quaternised with 1,4-chlorobutane), 2-vinylpyridine functional monomer and ethylene glycol dimethacrylate (EGDMA), as the cross-linking monomer, in the presence of 1,1’-azobis(cyclohexanecarbonitrile) as initiator. Ammonium dichromate and aqueous methanol were used as a template and porogenic solvent, respectively. Leaching of the chromate template from the polymer particles was achieved with successive stirring of the ion-imprinted polymer (IIP) particles in 4 M HNO3 solutions to obtain leached materials, which were then used for selective rebinding of Cr (VI) ions from aqueous solutions. Similarly, the non-imprinted polymer/ control polymer (NIP/CP) material was also prepared under exactly the same conditions as the IIP but without the chromate anion template. Various parameters, such as solution pH, initial concentration, aqueous phase volume, sorbent dosage, contact time and leaching solution volumes, were investigated. Scanning electron microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy, BET surface area and pore size analysis were used for the characterisation of IIP (both unleached and leached) and CP materials. Optimal parameters were as follows: solution pH, 3; contact time, 120 min; eluent, 20 mℓ of 0.1 M NaOH; and sorbent amount, 125 mg. Maximum retention capacity of IIP and CP was 37.58 and 25.44 mg∙g-1, respectively. The extraction efficiencies of the IIP and CP were compared using a batch and SPE mode of extraction. In the absence of high concentrations of ions, especially sulphate ions, both CP and IIP demonstrated no differences in binding of Cr (VI), which was almost 100%. However, in the presence of high concentrations of sulphate ions, the selectivity on the CP completely collapsed. The study clearly demonstrates the suitably of the developed IIP for selective extraction of Cr (VI) in complex samples such as those from acid mine drainage. The selectivity was also compared by direct injection of the real-world sample, both spiked and non-spiked, into that obtained after IIP selective extraction. Despite the method’s very low detection limits for direct injection (below 1 μg∙ℓ-1), no Cr (VI) was obtained. However, after IIP selective extraction, spiked Cr (VI) was detected in the spiked sample.
- Full Text:
- Date Issued: 2011
- Authors: Pakade, V , Cukrowska, E , Darkwa, J , Torto, N , Chimuka, L
- Date: 2011
- Language: English
- Type: Article
- Identifier: vital:6588 , http://hdl.handle.net/10962/d1004171
- Description: A linear copolymer was prepared from 4-vinylpyridine and styrene. An ion-imprinted polymer (IIP) specific for Cr (VI) adsorption was prepared by copolymerisation of the quaternised linear copolymer (quaternised with 1,4-chlorobutane), 2-vinylpyridine functional monomer and ethylene glycol dimethacrylate (EGDMA), as the cross-linking monomer, in the presence of 1,1’-azobis(cyclohexanecarbonitrile) as initiator. Ammonium dichromate and aqueous methanol were used as a template and porogenic solvent, respectively. Leaching of the chromate template from the polymer particles was achieved with successive stirring of the ion-imprinted polymer (IIP) particles in 4 M HNO3 solutions to obtain leached materials, which were then used for selective rebinding of Cr (VI) ions from aqueous solutions. Similarly, the non-imprinted polymer/ control polymer (NIP/CP) material was also prepared under exactly the same conditions as the IIP but without the chromate anion template. Various parameters, such as solution pH, initial concentration, aqueous phase volume, sorbent dosage, contact time and leaching solution volumes, were investigated. Scanning electron microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy, BET surface area and pore size analysis were used for the characterisation of IIP (both unleached and leached) and CP materials. Optimal parameters were as follows: solution pH, 3; contact time, 120 min; eluent, 20 mℓ of 0.1 M NaOH; and sorbent amount, 125 mg. Maximum retention capacity of IIP and CP was 37.58 and 25.44 mg∙g-1, respectively. The extraction efficiencies of the IIP and CP were compared using a batch and SPE mode of extraction. In the absence of high concentrations of ions, especially sulphate ions, both CP and IIP demonstrated no differences in binding of Cr (VI), which was almost 100%. However, in the presence of high concentrations of sulphate ions, the selectivity on the CP completely collapsed. The study clearly demonstrates the suitably of the developed IIP for selective extraction of Cr (VI) in complex samples such as those from acid mine drainage. The selectivity was also compared by direct injection of the real-world sample, both spiked and non-spiked, into that obtained after IIP selective extraction. Despite the method’s very low detection limits for direct injection (below 1 μg∙ℓ-1), no Cr (VI) was obtained. However, after IIP selective extraction, spiked Cr (VI) was detected in the spiked sample.
- Full Text:
- Date Issued: 2011
Seasonal phenology of the diamondback moth, Plutella xylostella (L.), (Lepidoptera: Plutellidae), and its parasitoids on canola, Brassica napus (L.), in Gauteng province, South Africa
- Mosiane, S M, Kfir, R, Villet, Martin H
- Authors: Mosiane, S M , Kfir, R , Villet, Martin H
- Date: 2003
- Language: English
- Type: text , Article
- Identifier: vital:6856 , http://hdl.handle.net/10962/d1011139
- Description: Canola, Brassica napus L. (Brassicaceae), is a relativelynewcrop in SouthAfrica. Several insect pests, including diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), that attack cruciferous vegetables, also attack canola. The aims of this study were to determine the seasonal phenology of P. xylostella populations on canola, and the composition, relative abundance and seasonal phenology of parasitoids attacking P. xylostella on this crop. Diamondback moth adults were monitored with synthetic sex-pheromone traps. Larval and pupal populations of P. xylostella were monitored weekly for three years at Bapsfontein and Rietondale in Gauteng province. Samples of diamondback moth larvae, pupae and parasitoid cocoons were collected and transported to the laboratory. Parasitoids that emerged were identified and their incidence recorded. Berlese funnel catches were used as an indicator of the accuracy of the visual counts. The infestation level of P. xylostella larvae was high from May to August at Rietondale, while at Bapsfontein it was high from September to December. There was a high correlation (r=0.79, P<0.001) between pheromone trap catches and subsequent larval infestations at Bapsfontein. The pheromone traps indicated that diamondback moth adults were present throughout the year. Berlese funnel catches indicated that a large number of larvae, especially first instars, were overlooked during visual plant scouting. Parasitism rates were often very high, reaching 90–100 %. The following parasitoids were recorded from field-collected P. xylostella: the larval parasitoids Cotesia plutellae (Kurdjumov) (Hymenoptera: Braconidae) and Apanteles halfordi Ullyett (Hymenoptera: Braconidae), the larval/pupal parasitoids Diadegma mollipla (Holmgren) (Hymenoptera: Ichneumonidae) and Oomyzus sokolowskii (Kurdjumov) (Hymenoptera: Eulophidae), the pupal parasitoid Diadromus collaris (Gravenhorst) (Hymenoptera: Ichneumonidae), and the hyperparasitoids Mesochorus sp. (Hymenoptera: Ichneumonidae) and Pteromalus sp. (Hymenoptera: Pteromalidae). Cotesia plutellae was the most abundant parasitoid throughout the study.
- Full Text:
- Date Issued: 2003
- Authors: Mosiane, S M , Kfir, R , Villet, Martin H
- Date: 2003
- Language: English
- Type: text , Article
- Identifier: vital:6856 , http://hdl.handle.net/10962/d1011139
- Description: Canola, Brassica napus L. (Brassicaceae), is a relativelynewcrop in SouthAfrica. Several insect pests, including diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), that attack cruciferous vegetables, also attack canola. The aims of this study were to determine the seasonal phenology of P. xylostella populations on canola, and the composition, relative abundance and seasonal phenology of parasitoids attacking P. xylostella on this crop. Diamondback moth adults were monitored with synthetic sex-pheromone traps. Larval and pupal populations of P. xylostella were monitored weekly for three years at Bapsfontein and Rietondale in Gauteng province. Samples of diamondback moth larvae, pupae and parasitoid cocoons were collected and transported to the laboratory. Parasitoids that emerged were identified and their incidence recorded. Berlese funnel catches were used as an indicator of the accuracy of the visual counts. The infestation level of P. xylostella larvae was high from May to August at Rietondale, while at Bapsfontein it was high from September to December. There was a high correlation (r=0.79, P<0.001) between pheromone trap catches and subsequent larval infestations at Bapsfontein. The pheromone traps indicated that diamondback moth adults were present throughout the year. Berlese funnel catches indicated that a large number of larvae, especially first instars, were overlooked during visual plant scouting. Parasitism rates were often very high, reaching 90–100 %. The following parasitoids were recorded from field-collected P. xylostella: the larval parasitoids Cotesia plutellae (Kurdjumov) (Hymenoptera: Braconidae) and Apanteles halfordi Ullyett (Hymenoptera: Braconidae), the larval/pupal parasitoids Diadegma mollipla (Holmgren) (Hymenoptera: Ichneumonidae) and Oomyzus sokolowskii (Kurdjumov) (Hymenoptera: Eulophidae), the pupal parasitoid Diadromus collaris (Gravenhorst) (Hymenoptera: Ichneumonidae), and the hyperparasitoids Mesochorus sp. (Hymenoptera: Ichneumonidae) and Pteromalus sp. (Hymenoptera: Pteromalidae). Cotesia plutellae was the most abundant parasitoid throughout the study.
- Full Text:
- Date Issued: 2003
Regulation within the supracellular highway - plasmodesma are the key
- Botha, Christiaan E J, Cross, Robin H M
- Authors: Botha, Christiaan E J , Cross, Robin H M
- Date: 2001
- Language: English
- Type: Article
- Identifier: vital:6500 , http://hdl.handle.net/10962/d1005918
- Description: Plasmodesmal connections are unique, highly dynamic intercellular structures that are lined by the plasmamembrane. They are believed to be a vital intercellular communication channel between living cells, linking numbers of living cells into interconnected, highly specialised cellular domains, thus enabling the plant to act as an integrated organism. Their evolution in the higher plant was inevitable. It is accepted that cell heterogeneity rather than cell divergence pressurised developing plant systems along a route that led to the development of intercellular passages and connections. With time these connections have evolved to allow some degree of regulation and traffic control. This paper explores some of the structure/function relationships in plasmodesmata. Attention is focused on the potential role of the neck region of these remarkable structures and discusses models which may explain the processes involved in regulating the movement of substances from cell to cell.
- Full Text: false
- Date Issued: 2001
- Authors: Botha, Christiaan E J , Cross, Robin H M
- Date: 2001
- Language: English
- Type: Article
- Identifier: vital:6500 , http://hdl.handle.net/10962/d1005918
- Description: Plasmodesmal connections are unique, highly dynamic intercellular structures that are lined by the plasmamembrane. They are believed to be a vital intercellular communication channel between living cells, linking numbers of living cells into interconnected, highly specialised cellular domains, thus enabling the plant to act as an integrated organism. Their evolution in the higher plant was inevitable. It is accepted that cell heterogeneity rather than cell divergence pressurised developing plant systems along a route that led to the development of intercellular passages and connections. With time these connections have evolved to allow some degree of regulation and traffic control. This paper explores some of the structure/function relationships in plasmodesmata. Attention is focused on the potential role of the neck region of these remarkable structures and discusses models which may explain the processes involved in regulating the movement of substances from cell to cell.
- Full Text: false
- Date Issued: 2001
Re-examining local and market-orientated use of wild species for the conservation of biodiversity
- Authors: Shackleton, Charlie M
- Date: 2001
- Language: English
- Type: Article
- Identifier: vital:6655 , http://hdl.handle.net/10962/d1007071
- Description: The hypothesis of attaching and realising market values as one means of conserving biodiversity has gained ground over the last decade. This has been challenged recently after examination of a number of case studies, largely from tropical Amazonia, on high value logging, marketing of non-timber forest products, and bioprospecting. The conclusion was that market-orientated conservation has seldom generated the financial returns envisaged, and as such cannot be used as an incentive to prevent land transformation. This paper reviews the basis of the challenge to market-orientated conservation on a number of grounds, drawing on examples largely from southern Africa. It concludes that generalizations from tropical Amazonia regarding the failure of market-orientated conservation are probably premature, and that it should remain an option, amongst a number of options, for conservation of biodiversity. Additionally, the prerequisite criteria identified as necessary to create an enabling framework for the success of market-orientated conservation are insufficient. Case studies are presented where the prerequisites do not apply, yet current extraction for market purposes is sustainable. Other potential prerequisites are also considered. There is a need for multivariate analysis, based on a large sample size drawn from across a range of environments and resources, of which factors are important prerequisites for successful market-orientated conservation, and under which circumstances.
- Full Text:
- Date Issued: 2001
- Authors: Shackleton, Charlie M
- Date: 2001
- Language: English
- Type: Article
- Identifier: vital:6655 , http://hdl.handle.net/10962/d1007071
- Description: The hypothesis of attaching and realising market values as one means of conserving biodiversity has gained ground over the last decade. This has been challenged recently after examination of a number of case studies, largely from tropical Amazonia, on high value logging, marketing of non-timber forest products, and bioprospecting. The conclusion was that market-orientated conservation has seldom generated the financial returns envisaged, and as such cannot be used as an incentive to prevent land transformation. This paper reviews the basis of the challenge to market-orientated conservation on a number of grounds, drawing on examples largely from southern Africa. It concludes that generalizations from tropical Amazonia regarding the failure of market-orientated conservation are probably premature, and that it should remain an option, amongst a number of options, for conservation of biodiversity. Additionally, the prerequisite criteria identified as necessary to create an enabling framework for the success of market-orientated conservation are insufficient. Case studies are presented where the prerequisites do not apply, yet current extraction for market purposes is sustainable. Other potential prerequisites are also considered. There is a need for multivariate analysis, based on a large sample size drawn from across a range of environments and resources, of which factors are important prerequisites for successful market-orientated conservation, and under which circumstances.
- Full Text:
- Date Issued: 2001
Racial segregation in East London, 1836-1948
- Authors: Nel, Etienne L
- Date: 1991
- Language: English
- Type: Article
- Identifier: vital:6717 , http://hdl.handle.net/10962/d1006790
- Description: Urban racial segregation in East London has a distinctive heritage, making the city one of South Africa's most segregated in the pre-Union era. Segregation was initiated by the British military in the then colony of British Kaffraria, and was later enhanced by successive municipal councils. Municipal ordinances ensured exceptionally high levels of segregation in the city during the 19th century. The enforcement of Asian segregation in this era is noteworthy. Urban planning in the 20th century resulted as much from local as national considerations and legislation. Segregation was a reality in East London prior to the passage of the Group Areas Act. The deteriorating social circumstances in the long-segregated African areas in particular receive special mention, as do government attempts to rectify the situation through the institution of state commissions.
- Full Text: false
- Date Issued: 1991
- Authors: Nel, Etienne L
- Date: 1991
- Language: English
- Type: Article
- Identifier: vital:6717 , http://hdl.handle.net/10962/d1006790
- Description: Urban racial segregation in East London has a distinctive heritage, making the city one of South Africa's most segregated in the pre-Union era. Segregation was initiated by the British military in the then colony of British Kaffraria, and was later enhanced by successive municipal councils. Municipal ordinances ensured exceptionally high levels of segregation in the city during the 19th century. The enforcement of Asian segregation in this era is noteworthy. Urban planning in the 20th century resulted as much from local as national considerations and legislation. Segregation was a reality in East London prior to the passage of the Group Areas Act. The deteriorating social circumstances in the long-segregated African areas in particular receive special mention, as do government attempts to rectify the situation through the institution of state commissions.
- Full Text: false
- Date Issued: 1991
Quantity and significance of wild meat off-take by a rural community in the Eastern Cape, South Africa
- Kaschula, Sarah A H, Shackleton, Charlie M
- Authors: Kaschula, Sarah A H , Shackleton, Charlie M
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6638 , http://hdl.handle.net/10962/d1006864
- Description: When compared to tropical forest zones in west and central Africa, off-take of wild meat from savannah and grassland biomes by local rural communities has not been well assessed. This case study of wild meat collection activities within a rural community in the Mount Frere region of the Eastern Cape (South Africa) uses last-catch records derived from 50 wild meat gatherers to calculate average off-take of taxa, species and fresh mass of wild meat per collection event. When per-event off take is overlaid onto household hunting frequency data, annual off-take would be 268.6 kg km−2 yr−1 or 3 kg person−1 yr−1 presuming constant off-take over an annual period. Monetary value of off-take would be South African R 307 (US$ 39) per household annually. For some species, off-take weight per km2 shows similar values to data from tropical forest zones, but high human population densities tend to dilute off-takes to less nutritionally significant amounts at the per person scale. However, unlike many tropical zones, none of the species harvested can be considered high-priority conservation species. Even densely populated and heavily harvested communal lands appear to offer high wild meat off-takes from low conservation priority species.
- Full Text:
- Date Issued: 2009
- Authors: Kaschula, Sarah A H , Shackleton, Charlie M
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6638 , http://hdl.handle.net/10962/d1006864
- Description: When compared to tropical forest zones in west and central Africa, off-take of wild meat from savannah and grassland biomes by local rural communities has not been well assessed. This case study of wild meat collection activities within a rural community in the Mount Frere region of the Eastern Cape (South Africa) uses last-catch records derived from 50 wild meat gatherers to calculate average off-take of taxa, species and fresh mass of wild meat per collection event. When per-event off take is overlaid onto household hunting frequency data, annual off-take would be 268.6 kg km−2 yr−1 or 3 kg person−1 yr−1 presuming constant off-take over an annual period. Monetary value of off-take would be South African R 307 (US$ 39) per household annually. For some species, off-take weight per km2 shows similar values to data from tropical forest zones, but high human population densities tend to dilute off-takes to less nutritionally significant amounts at the per person scale. However, unlike many tropical zones, none of the species harvested can be considered high-priority conservation species. Even densely populated and heavily harvested communal lands appear to offer high wild meat off-takes from low conservation priority species.
- Full Text:
- Date Issued: 2009
Preliminary observations on the effects of hydrocortisone and sodium methohexital on development of Sarcophaga (Curranea) tibialis Macquart (Diptera: Sarcophagidae), and implications for estimating post mortem interval
- Musvasva, E, Williams, K A, Muller, W J, Villet, Martin H
- Authors: Musvasva, E , Williams, K A , Muller, W J , Villet, Martin H
- Date: 2001
- Language: English
- Type: text , Article
- Identifier: vital:7075 , http://hdl.handle.net/10962/d1009532
- Description: Larvae of Sarcophaga (Curranea) tibialis (S. tibialis) were reared at constant temperature on chicken liver treated with a steroid or a barbiturate at concentrations that would be lethal, half-lethal and twice-lethal doses for humans. Trends to greater mortality at higher drug concentrations were not statistically significant. Larvae exposed to either drug took significantly longer to reach pupation compared to those in the control, while larvae exposed to sodium methohexital passed through pupation significantly faster than those in the control. No systematic relationship was found between drug concentration and development time of larvae or pupae. The total developmental period from hatching to eclosion did not differ between treatments, implying that estimates of post mortem intervals- (PMI) based on the emergence of adult flies will not be affected by the involvement of these drugs in a case. On the other hand, anomalous pupation spans may indicate the presence of barbiturates. These findings are compared with patterns found in another fly fed other contaminants.
- Full Text:
- Date Issued: 2001
- Authors: Musvasva, E , Williams, K A , Muller, W J , Villet, Martin H
- Date: 2001
- Language: English
- Type: text , Article
- Identifier: vital:7075 , http://hdl.handle.net/10962/d1009532
- Description: Larvae of Sarcophaga (Curranea) tibialis (S. tibialis) were reared at constant temperature on chicken liver treated with a steroid or a barbiturate at concentrations that would be lethal, half-lethal and twice-lethal doses for humans. Trends to greater mortality at higher drug concentrations were not statistically significant. Larvae exposed to either drug took significantly longer to reach pupation compared to those in the control, while larvae exposed to sodium methohexital passed through pupation significantly faster than those in the control. No systematic relationship was found between drug concentration and development time of larvae or pupae. The total developmental period from hatching to eclosion did not differ between treatments, implying that estimates of post mortem intervals- (PMI) based on the emergence of adult flies will not be affected by the involvement of these drugs in a case. On the other hand, anomalous pupation spans may indicate the presence of barbiturates. These findings are compared with patterns found in another fly fed other contaminants.
- Full Text:
- Date Issued: 2001
Preliminary observations on the effects of hydrocortisone and sodium methohexital on development of Sarcophaga (Curranea) tibialis Macquart (Diptera: Sarcophagidae), and implications for estimating post mortem interval
- Musvasva, E, Williams, K A, Muller, Wilhelmine J, Villet, Martin H
- Authors: Musvasva, E , Williams, K A , Muller, Wilhelmine J , Villet, Martin H
- Date: 2001
- Language: English
- Type: text , Article
- Identifier: vital:6920 , http://hdl.handle.net/10962/d1011898
- Description: Larvae of Sarcophaga (Curranea) tibialis (S. tibialis) were reared at constant temperature on chicken liver treated with a steroid or a barbiturate at concentrations that would be lethal, half-lethal and twice-lethal doses for humans. Trends to greater mortality at higher drug concentrations were not statistically significant. Larvae exposed to either drug took significantly longer to reach pupation compared to those in the control, while larvae exposed to sodium methohexital passed through pupation significantly faster than those in the control. No systematic relationship was found between drug concentration and development time of larvae or pupae. The total developmental period from hatching to eclosion did not differ between treatments, implying that estimates of post mortem intervals- (PMI) based on the emergence of adult flies will not be affected by the involvement of these drugs in a case. On the other hand, anomalous pupation spans may indicate the presence of barbiturates. These findings are compared with patterns found in another fly fed other contaminants.
- Full Text:
- Date Issued: 2001
- Authors: Musvasva, E , Williams, K A , Muller, Wilhelmine J , Villet, Martin H
- Date: 2001
- Language: English
- Type: text , Article
- Identifier: vital:6920 , http://hdl.handle.net/10962/d1011898
- Description: Larvae of Sarcophaga (Curranea) tibialis (S. tibialis) were reared at constant temperature on chicken liver treated with a steroid or a barbiturate at concentrations that would be lethal, half-lethal and twice-lethal doses for humans. Trends to greater mortality at higher drug concentrations were not statistically significant. Larvae exposed to either drug took significantly longer to reach pupation compared to those in the control, while larvae exposed to sodium methohexital passed through pupation significantly faster than those in the control. No systematic relationship was found between drug concentration and development time of larvae or pupae. The total developmental period from hatching to eclosion did not differ between treatments, implying that estimates of post mortem intervals- (PMI) based on the emergence of adult flies will not be affected by the involvement of these drugs in a case. On the other hand, anomalous pupation spans may indicate the presence of barbiturates. These findings are compared with patterns found in another fly fed other contaminants.
- Full Text:
- Date Issued: 2001
Pre-concentration of toxic metals using electrospun amino-functionalized nylon-6 nanofibre sorbent
- Darko, G, Sobola, A, Adewuyi, Sheriff, Okonkwo, J O, Torto, N
- Authors: Darko, G , Sobola, A , Adewuyi, Sheriff , Okonkwo, J O , Torto, N
- Date: 2012
- Language: English
- Type: Article
- Identifier: vital:6571 , http://hdl.handle.net/10962/d1004134
- Description: This paper presents a new approach for pre-concentrating toxic metals (As, Cd, Ni and Pb) in aqueous environments using an amino-functionalized electrospun nanofibre sorbent. The sorbent, composed of nanofibres of average diameter 80 ± 10 nm and specific surface area of 58m2 g–1, exhibited fast adsorption kinetics (<20 min) for As, Cd, Ni and Pb. The optimalpHfor the uptake of As, Cd, Ni and Pb were 5.5, 6.0, 6.5 and 11, respectively. The adsorption process best fitted the Freundlich isothermand followed the first-order kinetics. The highest pre-concentration achieved using the sorbent was 41.99 (Ni in treated wastewater). The capacity of the sorbent to pre-concentrate the toxic metals was compared with those of aqua regia and HNO3+H2O2 digestions. The pre-concentration factors achieved for Cd in river water samples can be ranked as aqua regia digestion (0.73) > adsorption (0.34)>HNO3+H2O2 (0.23) digestion.Asimilar trend was observed for Ni in river water as well as Ni andCdin tap water samples. Pb ions in the river water samples were pre-concentrated slightly better using the two digestion methods pre-concentration factors ~22) compared to adsorption method (pre-concentration factor ~21). The use of the electrospun amino-functionalized nanofibre sorbent presentsanefficientand cost-effective alternative for pre-concentration of toxic metals inaqueousenvironments.
- Full Text:
- Date Issued: 2012
- Authors: Darko, G , Sobola, A , Adewuyi, Sheriff , Okonkwo, J O , Torto, N
- Date: 2012
- Language: English
- Type: Article
- Identifier: vital:6571 , http://hdl.handle.net/10962/d1004134
- Description: This paper presents a new approach for pre-concentrating toxic metals (As, Cd, Ni and Pb) in aqueous environments using an amino-functionalized electrospun nanofibre sorbent. The sorbent, composed of nanofibres of average diameter 80 ± 10 nm and specific surface area of 58m2 g–1, exhibited fast adsorption kinetics (<20 min) for As, Cd, Ni and Pb. The optimalpHfor the uptake of As, Cd, Ni and Pb were 5.5, 6.0, 6.5 and 11, respectively. The adsorption process best fitted the Freundlich isothermand followed the first-order kinetics. The highest pre-concentration achieved using the sorbent was 41.99 (Ni in treated wastewater). The capacity of the sorbent to pre-concentrate the toxic metals was compared with those of aqua regia and HNO3+H2O2 digestions. The pre-concentration factors achieved for Cd in river water samples can be ranked as aqua regia digestion (0.73) > adsorption (0.34)>HNO3+H2O2 (0.23) digestion.Asimilar trend was observed for Ni in river water as well as Ni andCdin tap water samples. Pb ions in the river water samples were pre-concentrated slightly better using the two digestion methods pre-concentration factors ~22) compared to adsorption method (pre-concentration factor ~21). The use of the electrospun amino-functionalized nanofibre sorbent presentsanefficientand cost-effective alternative for pre-concentration of toxic metals inaqueousenvironments.
- Full Text:
- Date Issued: 2012