Experimental evaluation of nitrate reduction from water using synthesis nanoscale zero-valent iron (NZVI) under aerobic conditions

Abstract

The aim of this research was to study the potential of synthesized nanoscale zero-valent iron for nitrate reduction in aqueous solution. Batch technique was used to determine the kinetics and effective parameters. The effects of initial pH level, initial nitrate concentration and nanoscale Fe° concentration on nitrate reduction were studied. Nanoscale zero-valent iron was synthesized by chemical reduction method. The TEM image showed that synthesized nano Fe° has a size in the range of 40-120 nm. Experimental results exhibited that reduction efficiency of nitrate decreases with increasing initial pH and increases significantly due to increasing the concentration of zero-valent iron nanoparticles. Also, it was illustrates that initial concentration of nitrate has little effect on the nitrate reduction efficiency. Under acidic and neutral conditions, pH level of the reaction solution increased considerably after 60 min. However, under alkaline conditions, pH level of the reaction solution decreased. The reduction rate of nitrate reached 80% in 60 min with nanoscale Fe° dosage of 1.0 gl -1 and pH in4. The observed reaction rate constant was determined to be 0.0255 in min -1 for nanoscale concentration 1.0 gl -1. The experimental results indicated that the nitrate reduction with zero-valent iron nanoparticles do not comply the first-order reaction model with respect to nitrate concentration.