| Abstract |
| The removal characteristics of As ion from aqueous solution by octadecyl trimethyl ammonium bromide impregnated bentonite (OTABr-BT) was investigated under various conditions of contact time, pH and temperature. When the pH is 6, the zeta potential value of bentonite (BT) is - 50 ㎷ and on the other hand, the zeta potential value of the OTABr-BT is +38 ㎷. It can be seen that the overall increase of about 88 ㎷. The increase of the (+) potential value expected that anionic heavy metals are better adsorbed as the surface of the absorbent shows a much stronger positive charge. The kinetic study shows that As ion was adsorbed onto the OTABr-BT within the first 60 min, while equilibrium was arrived within 100 min for As ion. The experimental data was analyzed using equilibrium isotherm and kinetic models. The isotherm data was well described by Langmuir isotherm model and Temkin model. The maximum adsorption capacity was found to be 9.57 mg/g for As ion from the Langmuir isotherm model at 25℃. The kinetic data was tested using pseudo first and second order models. The results indicated that adsorption fitted well with the pseudo-second order kinetic model. The mechanism of the adsorption process showed that adsorption was dependent on intra particle diffusion model according to two step diffusion. Adsorption reaction of anionic heavy metals is judged to be the physisorption process from the Temkin B value. |
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| Key Words |
| OTABr-Impregnated Bentonite, Isotherm Model, Adsorption, Kinetic Model, Intra Particle Diffusion Model, Liquid Film Diffusion Model |
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