STUDIES OF MODIFIED BENTONITE FOR REMOVAL OF CR(VI) FROM AQUEOUS MEDIUMA.K Jha, S. Majumder, S. Verma, P. Kumari, S. Kumar and U. Sharma
Hexavalent chromium has been established as a human carcinogen through the route of water and air. This paper deals with the low cost and eco-friendly method of removal of Cr(VI) from aquatic environment using modified Bentonite. Bentonite having Montmorillonite unit with 2:1 octahedral structure, have emerged as an alternative to traditional methods. The ratio of SiO2 and AlO3 in bentonite composition is 4.125 having minor oxides of K, Na and Mn. Loss on ignition is 8.87% which resembles montmorillonite. Kinetic studies have been done by treating modified bentonite with FeCl3 solution with 100 ml 2 ppm Cr(VI) solution up to different intervals of time. Plot of Ct/qt Vs Ct indicates that Langmuir adsorption isotherm is followed. A plot of adsorbed amount Vs time shows that first order kinetics is obeyed. The removal percentage of Cr(VI) at pH 2,4 and 8 are 60.8, 70.5 and 55 respectively. The optimum pH for the removal of Cr(VI) is 4. Stacks of layers and aggregates in SEM images explain greater surface area for adsorption.