Mass transfer kinetics and mechanisms of phosphate adsorbed on waste mussel shell

Abstract

An excessive amount of phosphate (PO43−) released from domestic wastewater treatment plant effluent (DWTPE) may trigger eutrophication of water causing a degradation of healthy aquatic ecosystem. Even though the PO43− ions can be removed from aqueous solution with an adsorption technique using the low-cost adsorbent, the adsorption kinetics of PO43− removal must be understood. The bed depth service time (BDST), Thomas and modified mass transfer factor (MMTF) models were used to investigate the adsorption kinetics of PO43− removed from DWTPE onto the waste mussel shell (WMS) applied to hybrid plug flow column reactor (HPFCR). Dynamic adsorption capacity of WMS described by the new modified BDST model is shown to increase with increasing of the plug flow column (PFC) bed. The analysis of mass transfer behavior described using the Thomas model is able to predict the performance of HPFCR at certain depths of the PFC bed. The use of the MMTF models could be useful to describe the real difference between the behaviors of film mass transfer and porous diffusion. The resistance of PO43− mass transfer depending on porous diffusion has been verified to provide a contribution in the development of advanced WMS adsorbent for enhancing the HPFCR performance in the future.