Re-utilization of spent Cu2+-immobilized MgMn-layered double hydroxide for efficient sulfamethoxazole degradation: Performance and metals synergy

MgMn-layered double hydroxide (MgMn-LDH) was fabricated by a homogeneous co-precipitation method. MgMn-LDH exhibited excellent Cu2+ immobilization with the maximum removal capacities of 668 mg·g−1. Based on the outstanding fixation ability, the feasibility of re-utilization of spent Cu-MgMn-LDH as catalyst for drug degradation was investigated. Calcination in muffle furnace at 300 °C strengthen the stability of spent Cu-MgMn-LDH and obtained CuO-MgMn-LDO-300. As-obtained CuO-MgMn-LDO-300 consisted of CuO, Mg2MnO4 and MgO. CuO-MgMn-LDO-300 exhibited superior catalytic performance, almost 97% of sulfamethoxazole (SMX) was removed within 30 min. The TOC removal for CuO-MgMn-LDO-300 reached to 76%, while that of MgMn-LDO-300 was only 5%. These were profit from convenient electronics transfer due to oxygen vacancy and synergism between Cu and Mn. Therefore, CuO-MgMn-LDO-300 could effective activate persulfate (PS) to generate 1O2 and SO4– for SMX degradation. The performance showed good adaptability in a wide pH (from 3 to 9), low dissolution of Cu and Mn verified the security of re-utilization. Moreover, more than 95% of ciprofloxacin (CIP), tetracycline (TC) and sulfadiazine (SD) could also be degraded by the obtained materials. The catalysis system of CuO-MgMn-LDO-300 was also effective applied in lake and river water contaminated by SMX. Hence, the re-utilization strategy of spent Cu-MgMn-LDH was feasible and obtained an excellent catalytic material for antibiotics degradation.