Removal of nitrate from aqueous solution using nano zerovalent iron‐reduced graphene oxide composite: optimization of parameters

Abstract

AbstractIn this study, nitrate removal from aqueous solution was performed using nano zerovalent iron–reduced graphene (nZVI‐rGO) composite. The effect of operational parameters including initial nitrate concentration, composite dosage, solution pH, and contact time on the removal process was examined using design expert software. Our investigation revealed that the nitrate‐contaminated water can be easily treated by applying the synthesized composite within the short contact time of 1 min. In the presence of nZVI‐rGO composite, about 96% of nitrate reduced to nitrogen gas (~64%) and small amounts of ammonium (~32%) and nitrite (~0.3%) were released. The kinetics results confirmed that the adsorption and chemical reduction of nitrate by the composite are well fitted to the pseudo‐second‐order and pseudo‐first‐order kinetic models, respectively. The thermodynamic results showed that the removal of nitrate by the composite is a spontaneous and endothermic process.