Degradation of sulfamerazine by a novel CuxO@C composite derived from Cu-MOFs under air aeration.

Most metal-organic frameworks (MOFs) are synthesized from carboxylate and metal precursors by hydrothermal process, which will consume a large amount of solvent and carboxylate. To address this issue, a new strategy for Cu-based MOFs was developed, in which the Cu-based MOFs was obtained by using abundant natural polymer (tannic acid) as one of the precursors and using high-energy ball milling to achieve a self-assembly of tannic acid and copper sulfate. Based on this strategy, a novel Cu-based MOFs derivative (CuxO@C composite) was synthesized by high-temperature sintering of Cu-based MOFs and used for sulfamerazine (SMR) removal via O2 activation. The BET specific surface area and average pore size of CuxO@C composite were 110.34 m2 g-1 and 21.06 nm, respectively, which made CuxO@C composite had the maximum adsorption capacity (Qmax) for SMR of 104.65 mg g-1 and favored the subsequent degradation of SMR. The results from XRD and XPS indicated that CuxO@C composite contained a lot of Cu0 and Cu2O with the sizes of 76.6 nm and 9.8 nm, respectively, which led to its high performance of O2 activation. The removal efficiency of SMR and 90.2% TOC achieved 100% and 90.2%, respectively in the CuxO@C/air system at initial pH of 4.0, air flow rate of 100 mL min-1, CuxO@C dosage of 1 g L-1 and reaction time of 30 min. Reactive species, including H2O2, OH and O2- radicals were detected in the CuxO@C/air system, and OH and O2- were mainly responsible for the degradation of SMR.