• SOURAV MAJUMDER

Bentonite deposits of major importance occur in association with volcanic rocks, tuffs and tuffaceous sediments of Miocene and Oligocene age, the bentonite layers and veins indicate the bentonization of the tuff having 1-2 m thickness of the beds. The chemical composition of bentonites is SiO2 (50-60%), Al2O3 17%, Fe2O3, FeO, MgO, CaO, Na2O, K2O and traces of TiO2 and cation exchange capacity value of bentonites are around 98 meq/100g. Due to the presence of exchangeable cations, the important applications are decolourising oil, manufacture of catalyst, production of oil well drilling muds softening of hard water and suitability of decontamination of radioactive wastes. Bentonites have been found a good adsorbent of hexavalent chromium and arsenic up to permissible limit. Maximum removal of Cr (vi) takes place at 120 min. First order kinetics is followed in the case of adsorption of Cr (vi) and As (iii) by bentonites. This can be exploited on large scale in industry for decontamination of water pollutants. In view of individual properties, characterization of bentonite has been done using P.X.R.D., T.G.A., DSC and IR studies. In the OH-stretching region obtained from FTIR, the bands (3600-3690 cm-1) represent surface OH and inner OH. Investigations on thermal behaviour presented a total weight loss of 14.4953%, 19.2160%, 9.8243% and 3.6774% for different samples showing loss of molecular water and dihydroxylation P.X.R.D. analysis important for the clay minerals make understand the diffraction characteristics of bentonites. The proportion of montmorillonite layers is abundant in the inner part, but at the margin the layers of Kaolin are present shown in RHB5, RHB6, RB8, RB9 and RB10 samples. The chemical formula has been obtained as (Na, Ca)0.3 (Al, Mg)2 SiO4 O10 (OH)2 nH2O unit indicating montmorillonite

Bentonite, P.X.R.D., T.G.A., Adsorbent, cation exchange capacity

"Adsorption and Kinetic Study of Rajmahal & Hazaribagh Bentonite", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.6, Issue 4, page no.628-646, April-2019, Available :http://www.jetir.org/papers/JETIR1904B93.pdf

"Adsorption and Kinetic Study of Rajmahal & Hazaribagh Bentonite", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.6, Issue 4, page no. pp628-646, April-2019, Available at : http://www.jetir.org/papers/JETIR1904B93.pdf