Adsorption Behavior of Cr (VI) From Aqueous Solution by Fe-Pillared Acid Activated Indonesian Bentonite

摘要

Hexavalent chromium is one of the most toxic pollutants released in the environment by various human activities. In this work, the removal of Cr (VI) from aqueous solution has been investigated using modified natural bentonite as the low-cost based material. Natural bentonite has been modified by two-step modifications, acid activation followed by iron pillarization. The bentonite products, before and after the modification have been characterized using X-ray diffraction and FT-IR in order to investigate the change of the bentonite properties. The further study of Cr (VI) adsorption on modified bentonite was explored by conducting a batch adsorption experiment in various operational parameter including adsorbent dosage, initial pH, contact time, initial Cr (VI) concentration, and temperature. The studied on the kinetics adsorption revealed that the Cr (VI) adsorption follows the pseudo-second-order model rather than the pseudo-first-order model. The investigation about the adsorption equilibrium at various initial Cr (VI) concentration apparently informed that the adsorption isotherm model is better interpreted with Langmuir model rather than Freundlich. The thermodynamic study on the Cr (VI) adsorption revealed that the adsorption process has endothermic behaviour and occurred spontaneously.