EDTA enhanced pre-magnetized Fe-0/H2O2 process for removing sulfamethazine at neutral pH

摘要

Ethylenediaminetetraacetic acid (EDTA) was used to enhance pre-magnetized Fe-0/H2O2 process for sulfamethazine (SMT) removal at neutral pH. Only 19.4% SMT was removed in pre-Fe-0/H2O2 within 60 min at neutral pH while 90.6% SMT was removed after addition of 0.1 mM EDTA. Meanwhile, k (10(3)) value for SMT removal in pre-Fe-0-EDTA/H2O2 was 1.3 folds larger than in Fe-0-EDTA/H2O2. Single-factor experiments and response surface methodology (RSM) were used to optimize the system for SMT removal. Maximum k (10(3)) value was 81.4 mol(-1) obtainning at conditions of Fe-0 0.28 g L-1, EDTA 0.13 mM, and H2O2 36.2 mu M. The presence of EDTA and magnetization could inhibit the generation of iron oxides, reduce the contact angle of Fe-0, and improve the recovery of surface Fe-II which induced a faster catalytic decomposition of H2O2. The system could still achieve good performance for removing SMT after six consecutive reaction cycles. These results demonstrated that pre-Fe-0-EDTA/H2O2 system has the potential application for wastewater treatment.