EDTA enhanced removal of sulfamethazine by pre-magnetized Fe0 without oxidant addition

This study presents a novel pre-magnetized Fe 0 /ethylenediaminetetraacetic acid/air (pre-Fe 0 /EDTA/air) Fenton-like system to remove sulfamethazine (SMT). SMT removal only reached 10.6% in pre-Fe 0 /air system (0.2 g L −1 , SMT 3 mg L −1 , pH 5) while reached 88.5% in pre-Fe 0 /EDTA/air system within 1 h (0.2 g L −1 , SMT 3 mg L −1 , EDTA 2 mM, pH 5). EDTA could combine with Fe II or Fe III to keep iron soluble in the solution and the fast activation of molecular oxygen by Fe-EDTA complex could induce the fast and more production of H 2 O 2 . It was found that much more H 2 O 2 (5.1 mg L −1 ) and OH radical (26.4 μM) were produced in the pre-Fe 0 /EDTA/air system than in the pre-Fe 0 /air system (0.06 mg L −1 , 0.6 μM) within 1 h. The degradation rate of SMT (1 0  3 ) in pre-Fe 0 /EDTA/air system (38.4 min −1 ) was also 2.3 times as large as that in the Fe 0 /EDTA/air system (17.0 min −1 ), owing to the fast corrosion rate of pre-Fe 0 . 81.5 mgL −1 total Fe ions could be generated in pre-Fe 0 /EDTA/air while 53.6 mg L −1 in Fe 0 /EDTA/air. Fe 0 dosage (0.05–0.8 g L −1 ) and EDTA dosage (0–8 mM) were optimized and the optimal dosage for Fe 0 and EDTA was 0.2 g L −1 and 2 mM, respectively. The degradation rate of SMT in pre-Fe 0 /EDTA/air system were 1.6–2.9 times at different initial pH (3–6) and 2.3–3.1 times in the presence of inorganic ions (SO 4 2− , Cl − and HCO 3 − ) and natural organic matter (NOM) compared with Fe 0 /EDTA/air system. Decrease of Fe 0 contact angle in the presence of magnetization and EDTA enhanced the corrosion rate of Fe 0 . Accordingly, pre-Fe 0 /EDTA/air system would be a cost-effective and promising eco-friendly alternative for removal of SMT.