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Research Publications (Engineering and Built Environment)

Permanent URI for this collectionhttp://ir-dev.dut.ac.za/handle/10321/215

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    Acetic acid adsorption onto activated carbon derived from pods of Acacia nilotica var astringens (Sunt tree) by chemical activation with ZnCl2
    (IISTE, 2015) Elhussien, Mutasim H.; Isa, Yusuf Makarfi
    The purpose of this study is to prepare and investigate the adsorption behavior of acetic acid onto two samples of activated carbon prepared from Acacia nilotica var astringens, Sunt tree,( SUNT-C1 and SUNT-C2). Applicability Langmuir, Freundlich, Temkin and Dubinin-Radushkevitch models of adsorptions isotherm have been tested, while acetic acid initial concentration varied between (0.010 – 0.300) mol/dm3. A comparative study of adsorption capacities of these samples was performed. The obtained data were compared and fitted well with the four models; there exist a correlation between physico- chemical properties of the activated carbons and the sorption processes. The maximum monolayer coverage (Qo) from Langmuir isotherm model was determined to be 1.016mg/g. Also from Freundlich Isotherm model, the sorption intensity (n) which indicates favourable sorption and the correlation value are 1.11 and 1.09 respectively.
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    Investigation of BTEX compounds adsorption onto polystyrenic resin
    (Institution of Chemical Engineers, 2017) Makhathini, Thobeka Pearl; Rathilal, Sudesh
    In this study, the adsorptive capacity of polystyrenic resin was evaluated for the removal of benzene, toluene, ethylbenzene and isomers of xylene (BTEX) from an aqueous solution. Batch studies were performed to evaluate the effects of various experimental parameters such as mixing strength, contact time, internal diffusion, adsorbates and initial concentration on the removal of the BTEX compounds. The equilibrium isotherms for the adsorption of the adsorbates on the PAD 910 polystyrenic resin were analyzed by the Langmuir and linearized Dubinin–Radushkevich models at pH of 5.86. The Langmuir model fitted the data adequately; is concluded that the latter is the most practical model in representing the adsorption of aromatic compounds. The Langmuir model indicated that resin has the highest adsorption capacity of 79.44 mg/g. At temperature of 25 °C, resin was found to adsorb 98% of benzene, 88% of toluene, 59% of ethylbenzene, 84% m-;p-xylene and 90% o-xylene at an initial concentration of 14.47 mg/l. The pseudo-second order rate model fitted better to the adsorption kinetics. The thermodynamic analysis resulted in a negative equilibrium enthalpy change suggesting an exothermic process.
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    Fouling mitigation on a woven fibre microfiltration membrane for the treatment of raw water
    (Institution of Chemical Engineers, 2017-06) Chollom, Martha Noro; Pikwa, Kumnandi; Rathilal, Sudesh; Pillay, Visvanathan Lingamurti
    The main source of drinking water in rural areas of South Africa is surface water. Improving drinking water and sanitation facilities alone does not completely solve the problem of waterborne diseases. A novel simple gravity driven filtration unit incorporated with the woven fibre microfiltration (WFMF) membranes was developed for the treatment of raw water for drinking purposes. However, these membranes are susceptible to fouling which reduces flux permeation. This paper focused on evaluating the fouling mitigation strategies to improve on performance of the woven fibre membrane filtration unit with respect to fouling and flux recovery. The study found that the WFMF membrane fouled both internally by pore plugging and externally by adsorption and deposition on the membrane. As a result, a single flux enhancement strategy proved insufficient to maintain high flux successfully. A combination of strategies gave the best optimum conditions for flux production. Backwashing with a combination of brushing yielded the highest recovery of 187%. Soaking the membranes in 0.2% hypochlorite for an hour and thereafter by brushing them yielded 93% flux recovery. Mechanical cleaning however yielded the best result with 97% flux recovery. It was concluded that the selected strategies were the most successful strategies to prevent a sharp decline in flux due to fouling and giving high average flux for the filtration period.