- Title
- Optimising the uptake of [𝐈𝐫𝐂𝐥𝟔]𝟐− by a diammonium resin: HCl effect and resin performance
- Creator
- Ngayeka, Mbokazi Zizipho
- Subject
- Port Elizabeth (South Africa)
- Subject
- Eastern Cape (South Africa)
- Subject
- South Africa
- Date Issued
- 2021-04
- Date
- 2021-04
- Type
- Master's theses
- Type
- text
- Identifier
- http://hdl.handle.net/10948/54089
- Identifier
- vital:46284
- Description
- The separation of [IrCl6]2- from [RhCl5(H2O)]2- by silica microparticles functionalized with 1,10-diamindecane (C10) and quaternized with 4-nitrobenzylchloride (NO2Benz) in various hydrochloric acid mediums was investigated by continuous column studies. The sorbent materials were synthesized using three different routes: Synthesis route 1 (NaI catalyzed synthesis of diammonium functionalized silica microparticles), Synthesis Route 2 (via silylazation of silica followed by functionalization) and Synthesis Route 3 (silane-based sorbent material). The functionalized sorbent materials were characterized by NMR, Microanalysis, SEM-EDS, FT-IR, TGA and BET surface area. The separation efficiency of the quaternary diammonium cations was investigated under dynamic flow adsorption conditions. Preliminary ICP-OES runs were done, at 6 M HCl, to assess which synthesis route gave the best performing sorbent material. [IrCl6]2- selectivity of the sorbent materials was achieved by washing with an HCl solution to remove unadsorbed metal species, then stripping off the [RhCl5(H2O)]2- with 0.05 M of sodium chlorate and the iridium species was eluted with a 20% HCl solution. From the preliminary ICP-OES, loading capacities were calculated, and it was observed that the three sorbent materials from synthesis route 2 (13.89 mg/g for (4) SSC10NO2Benz-A, 1.44 mg/g for (5) SSC10NO2Benz-HoA, and 1.0859 mg/g for (6) SSC10NO2Benz-DoA) showed the highest uptake of [IrCl6]2- and route 1 (1.89 mg/g for (1) SSC10NO2Benz-A, 1.25 mg/g for (2) SSC10NO2Benz-HoA and 0.99 mg/g for (3) SSC10NO2Benz-DoA ) and Route 3 (0.55 mg/g for (7) SC10-AI and 0.755 mg/g for (8) SC10-ACl) materials did not perform efficiently enough, thus were not used further for the HCl study. Within synthesis route 2, three sorbent materials were evaluated, which had varying quantities of the cation: SSC10NO2Benz-A (having a quantity previously used in our research and denoted A), SSC10NO2Benz-HoA (having a quantity Half of A) and SSC10NO2Benz-DoA (having a quantity double of A). SSC10NO2Benz-A showed the highest loading capacity than SSC10NO2Benz-HoA and SSC10NO2Benz-DoA; HCl studies were carried out using SSC10NO2Benz-A. HCl solution having different concentrations (5, 5.5 , 6 , 6.6 and 6.8 M) were used to prepare the metal solutions. This was done to assess which HCl concentration gave the best metal solution containing high amounts of [IrCl6]2- and [RhCl5(H2O)]2-, which would result in a more efficient separation. An auto titrator was used to standardize the HCl concentrations, and the metal ion chloride species solutions were determined by UV-Vis, and their concentrations were confirmed with ICP-OES. Column sorption of iridium and rhodium on SSC10NO2Benz-A using these HCl solutions was carried out, and loading capacities of [IrCl6]2- were obtained. The loading capacities of the 5 M, 5.5 M, 6 M, 6,6 M and 6.8 M HCl solutions for [IrCl6]2- were 2.64, 4.01, 13.89, 18.15 and 7.23 mg/g, respectively. The optimum separation conditions were thus determined by investigating effective parameters such as the method of synthesis, silica to cation ratio, HCl concentration and flow rate. This thesis presents quaternary diammonium sorbent materials that could be applied in feed solutions from ore processing for iridium recovery.
- Description
- Thesis (MSc) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2021
- Format
- computer
- Format
- online resource
- Format
- application/pdf
- Format
- 1 online resource (189 pages)
- Format
- Publisher
- Nelson Mandela University
- Publisher
- Faculty of Science
- Language
- English
- Rights
- Nelson Mandela University
- Rights
- All Rights Reserved
- Rights
- Open Access
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| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | SOURCE1 | Ngayeka, Z.pdf | 6 MB | Adobe Acrobat PDF | View Details Download |