https://cris.library.msu.ac.zw//handle/11408/299 2026-04-11T05:13:05Z 2026-04-11T05:13:05Z Gudyanga, Ishekudzwai Blessed https://cris.library.msu.ac.zw//handle/11408/6852 2025-10-14T11:13:04Z 2023-01-01T00:00:00Z

Title: Crystal engineering of robust metal-organic frameworks for applications in capture of carbon dioxide Authors: Gudyanga, Ishekudzwai Blessed Abstract: The atmospheric concentration of carbon dioxide gas (CO2) is of global concern given its continued rise. Burning of fossil fuel has increased since the beginning of the industrial revolution, which then increased the atmospheric CO2 concentration to > 400 ppm from 280 ppm. CO2 has an effect of trapping the sun’s heat, and is believed to be one of the cardinal contributors of global warming. In order to make improvements to the CO2 problem, carbon capture techniques have been proposed. MOFs are porous structures constructed from the coordinative bonding between metal ions and organic linkers or bridging ligands. Thus, having an enormous choices of metal clusters and organic linkers, MOFs possess a wide range of surface area, pore volume and functionality, and this has contributed to the consideration of them being versatile materials for storage, separation, and catalysis, etc. Therefore, there is need to synthesise MOFs which capture CO2 and convert it into useful chemicals such as methanol and formic acid for industrial application. Linker 2,2’-bipyridine-5,5’ dicarboxylic acid and ceric metal salt Ce(NO3)3·6H2O were used in this study. Two MOFs were synthesised by solvothermal method. These were characterised by TGA, PXRD, FTIR, Potentiostat Galvanostat and Gas Sorption. The two MOFs MSU-3 and MSU-4 were thermally and chemically stable. The thermal and chemical stability observed in the MOFs emanated from the presence of the rod secondary building unit, which are linked by the pyridyl carboxylate linker to give three dimensional structures. CO2 adsorption studies of the MOFs revealed a low uptake of the gas in comparison to those MOFs reported literature. MSU-3a and MSU-4a was tested for electroactivity. Also, resistivity was tested using electrical impedance spectroscopy. It was found out that both MOFs had a lower interfacial electron transfer resistance.

2023-01-01T00:00:00Z Gudyanga, Ishekudzwai Blessed Nago, Anesuishe https://cris.library.msu.ac.zw//handle/11408/4140 2022-06-27T13:49:05Z 2017-01-01T00:00:00Z

Title: Paint formulation based on deodorizer distillate based alkyd resin and metallophthalocyanines Authors: Nago, Anesuishe Abstract: A novel study was carried on paint formulation based on alkyd resin and metallopthalocyanines. Alkyd Resin was synthesised using deodorizer distillate, which is a source of fatty acids that are included in the resin formulation. The distillate is generally cheaper as compared to soya bean oil that is being used at the moment. It is a by-product produced during the deodorization process of edible oil refineries. The resin reaction was stopped at an acid value of 9.6 mg of potassium hydroxide per gram of alkyd resin. Metallopthalocyanes, Copper(II)Phthalocyanine and Cobalt(II)Phthalocyanine were synthesised as pigments in paint formulation. All the synthesised products were characterised using Fourier Transform Infrared spectroscopy (FT-IR), Ultraviolet visible spectroscopy (UV- Vis) and thermal gravimetric analysis (TGA). The synthesised alkyd resin was linked covalently with cobalt(II)tetraamino phthalocyanine and non-covalently with copper(II) phthalocyanine. The pigments were dispersed in the resin with the aid of a solvent xylene in order to produce two paints based on the two different metallophthalocyanines. The formulated paint products were exposed to sunlight in solution form for photo degradation studies. The wavelength of highest absorbance was found to be 680 nm and no new bands were observed signifying the stability of the formulated paints.

2017-01-01T00:00:00Z Nago, Anesuishe Fusirai, Fadzanai https://cris.library.msu.ac.zw//handle/11408/3915 2022-06-27T13:49:05Z 2018-05-01T00:00:00Z

Title: Photocatalytic degradation of methylene blue dye from aqueous systems by HKUST-1 and CuO@HKUST-1 Authors: Fusirai, Fadzanai Abstract: High concentrations of methylene blue (MB) in aqueous environments have detrimental effects to both plants and animals and hence its removal is very important. Metal Organic Framework, HKUST-1 and composite, CuO@HKUST-1, were synthesized and characterised for their functional groups before and after degradation of methylene blue. Studies were done to optimize the degradation of methylene blue and to characterize the degradation system with respect to photocatalytic degradation kinetics. The optimum methylene blue degradation conditions were pH 4, catalyst dosage of 50 mg and contact time of 180 minutes for CuO@HKUST-1 and pH 6, catalyst dosage of 100 mg and contact time of 180 minutes for HKUST-1. The pseudo first order kinetics best described the data (R2 0.991 and 0.992 for HKUST-1 and CuO@HKUST-1 respectively). Methylene blue showed negligible self catalysis properties suggesting that it is very stable to light. CuO@HKUST-1 was found to have better photocatalytic degradation efficiency (95 %) as compared to HKUST-1 (75%). CuO@HKUST-1 proved to be an effective and stable catalyst which can be re used for 4 times producing a degradation efficiency of more than 80 %.

2018-05-01T00:00:00Z Fusirai, Fadzanai Miraso, Marvelous Nzwanai https://cris.library.msu.ac.zw//handle/11408/3730 2022-06-27T13:49:05Z 2019-01-01T00:00:00Z

Title: Photocatalytic degradation of methyl orange dye by ZnO/TiO2/CoFe2O4 trapped in alginate beads Authors: Miraso, Marvelous Nzwanai Abstract: Azo dyes have become an immerging and difficult pollutant to the environment. Industrial activities have resulted in disposal of these toxic dyes in effluent and among them is methyl orange (MO) dye. Proper effluent treatment schemes have become a necessity so as to be able to reduce the potential toxicity issues regarding plant and animal life due to the rise in demand for clean and safe water. Several methods have been applied for the removal and degradation of MO dye but have proven to be inadequate. The purpose of this work was photocatalytic degradation of MO by a novel composite catalyst ZnO/TiO2/CoFeO4. ZnO was synthesized by sol-gel and CoFe2O4 via the co-precipitation method ZnO, CoFe2O4 and commercial TiO2 was combined and trapped in alginate ZnO/TiO2/CoFe2O4 was characterized for functional groups, thermal stability, size, morphology and surface crystallinity. Successful fabrication was shown by the presence of the O-H stretching, C-H stretching and the M-O stretching vibrations on the FTIR spectrum. The composite was thermally stable and the photocatalysts constituted 9% of the composite. Optimum conditions were pH 8, 240 min and 0.2 g catalyst dosage. The effective initial concentration was 10 mg/L. Complete decolorisation of 10 mg/L under optimum conditions giving up to 98.4% degradation. The mechanism of photocatalysis was indirect. The composite was stable as there was no change in the percentage composition in terms of the catalysts added which were 1.9% ZnO and 6.7% CoFe2O4 in both the recycled and the fresh composite. The composite can be reused up to 5 cycles giving significant degradation.

2019-01-01T00:00:00Z Miraso, Marvelous Nzwanai