Kinetics of endosulfan sorption on to wood charcoal

A part of the research work conducted to evaluate the efficiency of a local ly available low cost wood charcoal in removing endosulfan, an organochlori ne insecticide, has been presented here in this paper. In the batch experim ents conducted at 1 mg/l initial concentration of endosulfan, it was found that wood charcoal could remove endosulfan from water up to 95%. Kinetic pr ofiles were developed for various conditions and they followed second order kinetic reactions. Adsorption equilibrium time was determined by two diffe rent approaches namely rough estimate and 2% slope criteria. The equilibriu m time was found to be 5 hrs. Forward, reverse, and overall reaction rate c onstants were determined by approximating the kinetic data to the first ord er reversible kinetic model. Rate constants increased with increasing initi al concentration of endosulfan Rate limiting process was determined by usin g kinetics data and further confirmed by the multiple interruption test. Po re and film diffusion coefficients were determined from the half time equat ions. Film diffusion appeared to be the rate limiting which was further sup ported by the multiple interruption test.