COMPARATIVE SORPTION KINETIC-STUDIES OF PHENOLIC-COMPOUNDS ON FLY-ASHAND IMPREGNATED FLY-ASH

The factors affecting the rate processes involved in the removal of ph enolic compounds, e.g. initial phenol concentration, particle size, im pregnation of fly ash (IFA), pH and temperature have been studied. The removal rate of phenols varied in the order p-nitrophenol > m-nitroph enol > o-nitrophenol > p-cresol > phenol > m-cresol > o-cresol. The pr ocess followed first order rate kinetics. The sorption data generally fit the Lagergren equation and the intraparticle diffusion rate equati on from which adsorption rate constants, diffusion rate constants and diffusion coefficients were determined. Intraparticle diffusion was fo und to be the rate-limiting step. These kinetic parameters were compar ed for various phenols under different conditions using fly ash (FA) a nd impregnated fly ash (IFA).