Phenolic wastewater remediation employing nano zerovalent iron as a granular third electrode in an electrochemical reactor

Abstract

The rise in toxic industrial and domestic wastewater due to urbanization makes it necessary to pursue new, alternative routes for the removal of refractory pollutants. In this study, both unsupported nano zerovalent iron (NZVI) and silty clay-supported nano zerovalent iron (SC-NZVI) were employed as a granular third electrode (3-D) in an electrochemical reactor. The electrochemical system with two aluminum electrodes as anode and cathode was performed as a granular third electrode treatment process to degrade aqueous phenol. The maximum removal rate of phenol using the tow electrodes electrochemical process (2-D) was 82%. The optimum conditions in a 2-D electrode were as follows: pH = 4, electrolysis time = 30 min, current density = 50 mA/cm2, electrode distance = 4 cm, and phenol concentration = 0.5 g/L. It was concluded that the 3-D electrode system exhibited high efficiency in removing phenolic wastewater in a third electrode system. The optimum conditions were as follows: pH = 2, electrolysis time = 30 min, current density = 50 mA/cm2, electrode distance = 4 cm, and phenol concentration = 0.5 g/L. The maximum removal efficiencies of phenol in the presence of a 3-D electrode with doses of NZVI = 1 g/L or SC-NZVI = 1.25 g/L were 96.1 and 97.8%, respectively.