SPECTROSCOPIC STUDY OF ALUMINIUM SPECIATION IN REMOVING HUMIC SUBSTANCES BY AI COAGU LATION

摘要

Removal of humic substances (HS) isolated from swamp water, surface soil, peat and brown coal by aluminium (AI) coagulation under different conditions was studied using the jar test method and spectrosscopic techniques.At lower pHs <4.5, humic substances formed soluble complexes with substances. Maximum removal of the humic substances was found to occur in the PH range from 5.0 to 7.0, due to the adsorption of humic substances on the surface of AI(OH)3(s.) crystal. Sequential extraction of the humic substances adsorbed on AI(OH)3(s) using the Soxhlet technique with different solvents showed that the adsorption forces involved were great. The effects of humic substances on the AI speciation are discussed and a model is proposed to explain the mechanism for the removal of humic substances during the AI coagulation process.