Phosphorus removal from aqueous solution by nanoscale zero valent iron in the presence of copper chloride

Abstract

This study investigates the adsorption of phosphorus by nanoscale zero valent iron (NZVI) in the presence of copper chloride. The NZVI used for the experiments was synthesized under optimum conditions using the chemical reduction method. The NZVI was characterized by transmission electron microscopy, X-ray diffraction, Brunauer–Emmett–Teller surface characterization and particle size analysis. Batch experiments were performed under different conditions to study the effect of parameters such as initial phosphorus concentration, copper chloride load, aerobic, anaerobic, pH and recovery. The results indicated that the presence of copper chloride effectively enhanced the adsorption capacity of phosphorus as it produced copper ferrite spinel on NZVI particles’ surface which can adsorb phosphorus and increase its rate of adsorption, and also it stimulated NZVI corrosion. The adsorption capacity of phosphorus reached 50mg PO43−-P/g NZVI in the presence of copper chloride while NZVI without copper chloride reached the maximum adsorption capacity of 28mg PO43−-P/g NZVI. Phosphorus recovery batch experiments results showed that the maximum phosphorus recovery achieved at pH 12 was 60%. But the recovery of phosphorus increased by increasing the molarity of the alkaline medium (NaOH) solution used for recovery. A complete recovery of phosphorus was gained using 1M NaOH solution.