Evaluation of commercial zerovalent iron sources in combination with solar energy to remove microcontaminants from natural water at circumneutral pH.

Abstract Solar zerovalent iron (ZVI) was studied at circumneutral pH in combination with hydrogen peroxide and persulfate for removal of imidacloprid as a model contaminant in natural water. Three commercial ZVI sources, steel wool (ZVI-SW) and two iron micro-powders (ZVI-MS and ZVI-S) were independently evaluated. First, different ZVI corrosion conditions were tested in contact with air, exposed to natural solar radiation and with addition of oxidants, such as H2O2 and S2O82−, demonstrating the importance of released iron. Then, the technical feasibilities of solar/H2O2/ZVI and solar/S2O82−/ZVI were assessed for the elimination of 1 mg/L of imidacloprid. In general, H2O2 concentrations and treatment times were high. Only ZVI-MS (1 mM) reached 80% imidacloprid degradation after 157 min and 3 mM (102 mg/L) of H2O2. Solar/S2O82−/ZVI performance was better, reaching >80% imidacloprid degradation in