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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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    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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    Utilization of ionic liquids for the separation of organic liquids from industrial effluents
    (Sabinet, 2012) Mabaso, Mbongeni Hezekia; Redhi, Gan G.; Moodley, Kandasamy
    The recovery of aromatic organic solvents from mixtures containing aliphatic compounds has economic as well as environmental significance. This is so because viable methods have not been established for the recovery from mixtures in which the compo-nents of value are 20 % (v/v) or less. In the light of this, we investigated the efficacy of selected ionic liquids to recover aromatic solvents from prepared mixtures. We used 1-ethyl-3-methylimidazolium ethyl sulfate [EMIM][EtSO4] and 1-ethyl-3-methyl-pyridinium ethyl sulfate [EMpy][EtSO4] to separate and recover aromatic hydrocarbons (less than 10 % (v/v)) from aromatic/aliphatic hydrocarbon mixtures, namely, benzene, toluene, ethyl benzene and o-xylene (BTEX) from n-heptane at 40 °C. The same aromatic components were used with n-hexane as an alkane and 1-ethyl-3-methylpyridinium ethyl sulfate [EMpy][EtSO4] as an ionic liquid. The concentrations of the aromatic components used were in the range of 2.5–10 % (v/v) for the following multi-systems at 40 °C: Benzene + toluene + ethyl benzene + o-xylene + n-heptane + [EMIM][EtSO4]. The % removal of each aromatic, the ionic liquid selectivity trend, as well as its lifetime, and the distribution pattern of aromatic components in the ionic liquid obtained by gas chromatography were used to determine the capability of [EMIM][EtSO4] and [EMpy][EtSO4] as extracting solvents for low concentration BTEX.