Simultaneous removal of arsenic and nitrate from actual water by catalytic ozonation process with nanoparticles of zero-valent iron/optimization via Taguchi model

In the current research, the performance of catalytic ozonation with zero-valent iron nanoparticles (nZVI) in the simultaneous removal of arsenic (As) and nitrate (NO3), two potentially harmful elements (PHEs) from actual drinking water sources in Hamedan province, located in the west of Iran, was investigated. Contact time (5–30) min, pH (6.8–7.8), initial concentration of As (20–100) μg/L, initial concentration of NO3 (50–150) mg/L and adsorbent dosage (0–1.25) g/L were investigated as various operating effects on the catalytic removal of arsenic and nitrate from water through various experimental tests. The characteristics of zero-valent iron nanoparticles were determined through X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and Brunauer–Emmett–Teller (BET) analysis. The results showed that the optimal parameters are: primary concentration of arsenic (60 μg/L), initial concentration of nitrate (100 mg/L), nanoparticle dose 0.75 g/L, and pH (7.4). The concurrent removal efficiency of As and NO3 in optimal conditions was 81.9%. The process cost analysis showed that it should be assessed to be about $0.05 per liter of safe drinking water. This research illustrates that the efficiency of catalytic ozonation with nZVI in the concurrent catalytic elimination of As and NO3 is hopeful.