Role of the physico-chemical factors in the purification process of water from surface-active matter by biosorption

Activated carbon adsorption with attached microorganisms (biosorption) has been studied. The approaches. available do not account for an efficient role of activated carbon under a steady state of purification, considering it (carbon) as a carrier of biofilm only. This paper considers the role of physico-chemical, factors in order to clear up and assess a contribution of both physical adsorption and biodegradation (influencing effectiveness of the biosorption process) into the cumulative effect of the biosorption. The nonionic and anionic surfactants as well as phenol were used as sorbates. The impact of such essential physico-chemical factors of the adsorption process as the change in the Gibbs free energy (-DeltaG(a)(0)) and the porous structure of the activated carbon on the effectiveness of the biosorption process has been established. The lower the contribution of the biological degradation into the biosorption process, the higher the -DeltaG(a)(0). a result of the biodegradation process, products differing in their -DeltaG(a)(0) are generated on the active carbon. Separation of the biodegradation products characterized by different -DeltaG(a)(0) in the biosorption column filled by active carbon results in redistribution of contributions of physical adsorption and biodegradation into a cumulative effect. The micropores of the active carbon in the course of the biosorption/bioregeneration process are occupied by adsorbed molecules and are not subjected to biological regeneration. (C) 2002 Elsevier Science Ltd. All rights reserved.