Investigating the design parameters for a permeable reactive barrier consisting of nanoscale zero-valent iron and bimetallic iron/copper for phosphate removal

Abstract

There is a growing interest in deploying nanoscale zero valent iron (NZVI) in permeable reactive barriers (PRBs) for groundwater remediation. In the present study a series of packed-column experiments were conducted in order to investigate the effectiveness of phosphorus removal from groundwater using NZVI and bimetallic NZVI/Cu as reactive materials within PRBs. Seven sets of packed-column experiments were conducted in order to study the effect of different design parameters for PRB; including delivery approach of NZVI into porous media, PRB's configuration, coexisting groundwater ions and change in flowrate. Results implied that doping NZVI surface with copper had an anti-aggregation effect and enhanced its performance in terms of phosphorus removal 2.2 times higher than bare NZVI. Moreover, the lower flowrate (10 ml/min) demonstrated improved phosphorus removal by 22% compared with higher flowrate (60 ml/min). Additionally, groundwater ions barely interfered phosphorus removal process with only ±6%. Overall, geochemical properties and characteristics of the supporting materials were key parameters in the removal process of phosphorus by NZVI/Cu.