ADSORPTION OF HEAVY-METALS ON TREATED AND UNTREATED LOW-GRADE BITUMINOUS COAL

Bituminous coal has been subjected to hydrothermal treatment to incorp orate additional functional groups and to effect changes in the colloi dal-chemical nature of the coal surface to enhance the adsorption of C u(II), Ni(II), Zn(II) and Cr(VI) from aqueous system. The effectivenes s of two such chemical pretreatments like hydrogen peroxide and mangan ese oxide impregnation has been investigated through adsorption of the se metals, separately at the same condition of pH, temperature, adsorb ent size and concentration. The rate of adsorption and capacity of bit uminous coal is found to be enhanced significantly. Lagergren equation and Langmuir model have been used to determine rate constants of adso rption and capacity of treated and untreated bituminous coal.