Removal of As(III) from Synthetic Groundwater Using Fe-Mn Bimetal Modified Kaolin Clay: Adsorption Kinetics, Isotherm and Thermodynamics Studies
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The removal efficiency of As(III) by kaolin clay modified by Fe-Mn bimetal oxides was successfully evaluated. Modification of kaolin clay by Fe-Mn oxides increased the surface area of the kaolin clay from 19.2 to 29.8 m2/g and further decreased the pore diameter from 9.54 to 8.5 nm. As(III) removal efficiency was optimum at pH < 8 and was inhibited at pH >8. The adsorption isotherm data fitted well to Langmuir adsorption isotherm model with a maximum adsorption capacity of 2.93 mg/g at initial As(III) concentration range of 1 to 30 mg/L. The adsorption kinetics data was described better by pseudo-second order of reaction kinetics indicating that As(III) sorption occurred via chemisorption. Thermodynamics studies revealed that As(III) adsorption occurs spontaneously and the reaction is exothermic in nature. Compared to other reported adsorbents, Fe-Mn bimetal kaolin showed higher adsorption capacity making it a suitable candidate for As(III) removal from groundwater.
KeywordsAdsorption Arsenic Kaolin clay Kinetics Isotherms Thermodynamics
An initial version of the paper has been presented in the “International Conference on Protection and Restoration of the Environment XIV”, July 3rd to 6th, 2018, Thessaloniki, Greece. Authors would like to acknowledge the financial assistance from NRF-South Africa, Sasol Inzalo Foundation and University of Venda RPC.
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Conflict of Interest
The authors declare no conflict of interest.
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