Nitrilotriacetic acid/Fe0/H2O2 system enhanced by magnetic field and visible light promoted DMP degradation and high-salt wastewater treatment

Fe 0 -based heterogeneous Fenton process has been increasingly developed for organic pollutants removal. However, the reaction activity of Fe 0 catalyst is easily weakened due to the formation of dense oxide layer or the precipitation of iron hydroxides on the surface. Herein, the effect and mechanism of magnetic field (MF), visible light (Vis), nitrilotriacetic acid (NTA) and inorganic salt ions on the Fe dissolution and dimethyl phthalate (DMP) degradation in the Fe 0 /H 2 O 2 system were investigated. The results showed that the magnetic field (100 mT), NTA and inorganic salt ions effectively enhanced the dissolution of Fe from the surface of iron filings, and visible light significantly accelerated the Fe 3+ /Fe 2+ cycle in the aqueous phase, which promoted the decomposition of H 2 O 2 by Fe 2+ to generate •OH and further enhanced the degradation of DMP. DMP was nearly completely degraded within 60 min in the pH range of 3.0–9.0, indicating the MF/Vis/NTA/Fe 0 /H 2 O 2 system effectively broadened the pH range of Fenton-like system. The iron sand column tests proved that the MF/solar/NTA/Fe 0 /H 2 O 2 system was effective for the treatment of waste leachate reverse osmosis concentrate as a typical actual high-salt wastewater, in which the removal rates of chemical oxygen demand and humic acid reached 84.5 and 90.6%, and the chromaticity was almost completely removed. Generally, the activation mechanism of Fe 0 -based heterogeneous photo-Fenton system was set up and an effective method for organic pollutant removal and high-salt wastewater treatment was provided.