Significant enhancement in treatment of salty wastewater by pre-magnetization Fe0/H2O2 process

Abstract

Nowadays, Fenton (Fe2+/H2O2) process is increasingly applied to wastewater treatment, however, the treatment efficiency would be inhibited largely when treated salty wastewater. To overcome this limitation, pre-magnetization (pre-magn-Fe0)/H2O2 process was investigated to treat salty wastewater, which could enhance the degradation rate of organic pollutants (1.2–171.2 folds enhancement) and reduce reagents dosage (save 75% H2O2) in salty system compared with Fe0/H2O2 process, using Orange G as the target pollutant and Na2SO4 as the model salty system. The characterizations by SEM, XRD and XPS and the intensity of DMPO–OH adduct signals in different processes confirmed this enhancement attributed to the increase of corrosion of Fe0 inducing fast catalysis of H2O2 and generation of hydroxyl radicals. Pre-magn-Fe0/H2O2 process could also have 5.9, 26.4 and 93.7 folds enhancement in NaCl, NaNO3 and Na2HPO4 salty system, respectively. Meanwhile, pre-magn-Fe0/H2O2 process could keep close performance in Na2SO4 and NaCl salty systems and have better performance in NaNO3 and Na2HPO4 salty systems than Fenton process. Pre-magn-Fe0/H2O2 process also had remarkable improvement (1.1–5.3 folds) on the removal of many refractory contaminants in salty system. Furthermore, it could also keep good performance in real reverse osmosis concentrated wastewater and petrochemical wastewater. Therefore, pre-magn-Fe0/H2O2 process is a more cost-effective process to treat salty wastewater, which could have not only improved performance than conventional system and Fe0/H2O2 process, but also good performance as Fenton process.