Arsenic removal by periphytic biofilm and its application combined with biochar

A biochar and periphyton-based system (BPS) comprising of a biochar column and a periphyton bioreactor was designed to avoid the toxicity issue associated with removing As(III) from wastewater. Results showed that the periphyton can grow when As(III) is less than 5.0 mg L-1. The BPS obtained a high As (III) removal rate (similar to 90.2-95.4%) at flow rate = 1.0 mL min(-1) and initial concentration of As(III) = 2.0 mg L-1. About 60% of the As(III) was pre-treated (adsorbed) in the biochar column and the removal of the remaining As(III) was attributed to the periphyton bioreactor. The As(III) removal process by periphytic biofilm in the initial stage fits a pseudo-second-kinetic model. The calcite in the periphytic biofilm surfaces and the -OH and -C=O groups were responsible for the As(III) removal. This study indicates the feasibility of the BPS for As(III) removal in practice. (C) 2017 Elsevier Ltd. All rights reserved.