The usage of dried activated sludge and fly ash wastes in phenol biosorption/adsorption: Comparison with granular activated carbon

The potential of using dried activated sludge and fly ash as a substitute for activated carbon was examined in this study. The pollutant binding rate and capacity of each biosorbent/adsorbent for the removal of phenol was shown as a function of initial pH and initial phenol concentration. The maximum phenol loading capacity of each sorbent was found to be 91.0 mg/g for dried activated sludge, 27.9 mg/g for fly ash and 108.0 mg/g for granular activated carbon at 100 mg/l initial phenol concentration. The phenol sorption data when applied to the Freundlich, Langmuir and Redlich-Peterson isotherm equations, showed better correlation to the Freundlich model for all the sorbents over the entire concentration range. It was suggested that both the fly ash and dried activated sludge sorbents can be used successfully for phenol removal as an alternative to commercial activated carbon.