ABSTRACT
4Malachite green (MG) is a poisonous dye which must be removed from wastewater before disposal. In the present study silicahydrogel which had a porous structure and might be formed in any shape by gelation of silica hydro sol was employed for the adsorption of MG from water. A transparent silica hydrogel in slab form was obtained from aqueous sodium silicate and sulfuric acid and purified by water. The equilibrium and kinetics of MG adsorption was investigated by in situ measurements with a conventional and fiberoptic spectrophotometer respectively. Adsorption equilibrium and kinetic models in both linear and nonlinear forms were applied. It was shown that nonlinear forms of these models fitted to the experimental data more thoroughly than their linear forms by giving evenly distributed errors.
