Department of Polymer Technology and Engineering

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Competitive sorption of Cd2+ and Pb2+ from a binary aqueous solution by poly (methyl methacrylate)-grafted montmorillonite clay nanocomposite
(Applied Water Science, 2016-03-24) Tavengwa, Bunhu; Tichagwa, Lilian; Chaukura, Nhamo
Poly(methyl methacrylate)-grafted montmorillonite (PMMAgMMT) clay and sodium-exchanged montmorillonite (NaMMT) clay were prepared through in situ graft polymerisation and used to remove Cd2+ and Pb2+ from synthetic wastewater. The modification of adsorbent materials was confirmed by fourier transform infra-red spectroscopy (FTIR), thermogravimetric analysis (TGA) and X-ray powder diffraction (XRD) techniques. BET surface area measurements showed NaMMT had a higher surface area than PMMAgMMT. Batch experiments were used to assess the simultaneous uptake of Cd2+ and Pb2+ from a synthetic binary solution. Pb2+ was preferentially sorbed, exhibiting greater affinity for the sorbents compared to Cd2+ as shown by its relatively higher uptake onto the sorbents than Cd2+. The maximum sorption capacities for NaMMT and PMMAgMMT were 18.73 and 19.27 mg/g for Cd2+, and 30.03 and 34.25 mg/g for Pb2+, respectively. The sorption data obeyed the Langmuir model and the pseudo-second order kinetic model with R 2 of at least 0.9800 for both models. The sorbents could also be regenerated up to three cycles without a significant loss in the sorption capacity. FTIR measurements showed the presence of metal–oxygen bonds after sorption, confirming the occurrence of adsorption as one of the heavy metal removal processes. The work demonstrated the potential of using low-cost nanoscale composite material for the removal of Cd2+ and Pb2+ from aqueous solution.
EFFECTS OF POLYANILINE FILLER ON THE SHEAR STRENGTH OF SILVER-POLYANILINE-EPOXY ADHESIVE
(i-Manager's Journal on Material Science, 2015-10-30) Tafadzwa, Ziyambi; Muzata, Tanyaradzwa S
Electrically Conductive Adhesives (ECAs) are widely applied in electronic packaging such as solder less interconnections, heat dissipation and component repair. This research focuses on the effects of polyaniline filler percentage in the silver-polyaniline epoxy conductive adhesive. Conductive adhesives with different polyaniline filler concentrations were prepared, so as to check on how the different filler concentrations affect the shear strength of the ECAs. Silver concentration was kept constant, but the polyaniline concentration was varied between 3-10%. The shear strength of the adhesive was measured using the universal tensile machine and the results showed that, the more the filler loading is increased, the less the adhesive strength exhibited by the composite. The research also shows the synthesis of the main filler silver particles by chemical reduction method and also the synthesis of the co-filler polyaniline by chemical method and both UV (Ultraviolet) and SEM (Scanning Electron Microscope) characterizations were conducted.
Medical Imaging Technology
(HIT, 2025-11-21) HIT
Preparation and Structural Properties of Electrospun PAN Nanofibers Reinforced With ZnS Nanoparticles
(Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry, 2015-02-04) Onwudiwe, Damian C.; Strydom, Christien A.; Vala, Remy M. K.; Tichagwa, Lilian
Polymer nanocomposite fibers based on polyacrylonitrile (PAN), reinforced with different morphologies of ZnS nanoparticles at different percentage loadings were prepared using the electrospinning method. The thermal decomposition profile of the nanofibers was investigated using thermogravimetric analysis (TGA). The morphology and structure of the nanofibers were studied by scanning electron microscopy (SEM) and X-ray diffraction. TGA results indicated an enhanced thermal stability of the fibers after incorporation of the nanoparticles. SEM images indicated a linear relationship between the diameter of the PAN-ZnS fibers and the concentration of the hybrid composite solution. X-ray diffraction showed that the ZnS nanoparticles were in cubic phase.
Preparation of photo‑catalytic copolymer grafted asymmetric membranes (N‑TiO2‑PMAA‑g‑PVDF/PAN) and their application on the degradation of bentazon in water
(Iran Polymer and Petrochemical Institute, 2016-01-21) Mungondori, Henry Heroe; Tichagwa, Lilian; Katwire, David Meredith; Aoyi, Ochieng
Nitrogen-doped titanium dioxide (N–TiO2) was prepared and supported on a novel copolymer grafted membrane matrix to avoid the problems associated with the removal of spent photocatalyst from treated water. Membranes of poly (methacrylic acid) grafted onto poly (vinylidene difluoride) and blended with poly (acrylonitrile) (PMAA-g-PVDF/PAN) were prepared through a dry–wet phase inversion technique. Methacrylic acid side chains were grafted onto an activated PVDF backbone by the method of reversible addition fragmentation chain transfer polymerization and then the novel photocatalytic asymmetric membranes of N–TiO2–PMAA-g-PVDF/PAN were prepared. The casting solutions were blended with 1–5 % N–TiO2 before immersion into the coagulation bath. PVDF and PAN offer several advantages which include: mechanical strength and toughness, chemical resistance, unaffected by long-term exposure to UV radiation, low weight, and thermal stability. N–TiO2 was prepared through sol-gel synthesis. The photocatalytic membranes were evaluated by degradation process of herbicide bentazon in water. Photodegradation studies revealed that the optimum photocatalyst loading was 3 % N–TiO2 and the optimum pH was 7 for the degradation of bentazon in water. UV– Vis, TOC and LC–MS analyses confirmed the successful
Techno-economic assessment for biochar production from paper mill sludge
(Research and Intellectual Outputs 2016-Science, Engineering and Technology,, 2016-09-04) Manyuchi, M.M; Chaukura, N; Ruzvidzo, C
Sludge generated from the wastewater treatment plant of a pulp and paper factory was used as feedstock for the preparation of biochar using fast pyrolysis followed by chemical activation with NaOH to make activated biochar (ABC). A process utilising 300 kg/day of waste paper mill sludge (PMS) was designed with a plant utilisation of 80%. A pyrolysis temperature of 500 oC and residence time of 2 h was used in a limited oxygen pyrolysis reactor producing biochar at a yield of 40 %. The biochar was activated using NaOH and heated for an hour at 70 oC to enhance the sorption properties of the ABC. The resulting ABC had a BET surface area of 492.02 m 2 /g, had decolourising properties and a pH of 7, hence applicable in wastewater treatment. A capital investment of US$1 860 729.47 is required and the plant life is 20 years, with a net present value of US$ 1 832 445.94. The rate of return is 29.6 %, return on investment is 26.9% and a payback period of 3.7 years. The production of ABC from PMS is economically feasible, with a product selling price of $30.00/kg.