Optimization Modeling of nFe0/Cu-PRB Design for Cr(VI) Removal from Groundwater

Abstract

Hexavalent chromium is one of the highly toxic heavy metals which could lead to severe health issues when it is discharged into aquifers as industrial wastewater. In the current study nFe0/Cu was successfully employed in PRB technology for Cr(VI) removal from groundwater. Batch and column experiments confirmed the high reactive performance of nFe0/Cu towards Cr(VI) removal by around 85% removal efficiency. The main pathways for Cr-species removal by nFe0/Cu were determined as the reduction of Cr(VI) to Cr(III) by both nFe0 and Cu0 and the precipitation/co-precipitation of Cr(III) with the released iron oxides on the nFe0/Cu surface. The developed 3D-surface response optimization model confirmed the reciprocal relation between the residence time, barrier thickness and hydraulic conductivity. The interaction and sensitivity analysis between the model’s parameters were significantly crucial for defining the optimal design conditions of the nFe0/Cu-PRB. Generally, the current study could represent a great contribution in scaling-up the PRB technology towards the real field applications.