Efficient degradation of sulfamethazine via activation of percarbonate by chalcopyrite

In this work, the novel application of chalcopyrite (CuFeS2) for sodium percarbonate (SPC) activation towards sulfamethazine (SMT) degradation was explored. Several key influencing factors like SPC concentration, CuFeS2 dosage, reaction temperature, pH value, anions, and humic acid (HA) were investigated. Experimental results indicated that SMT could be effectively degraded in the neutral reaction media by CuFeS2/SPC process (86.4%, 0.054 min(-1) at pH = 7.1). The mechanism of SPC activation by CuFeS2 was elucidated, which was discovered to be a multiple reactive oxygen species (multi-ROS) process with the co existence of hydroxyl radical ((OH)-O-center dot), carbonate radical (CO3 center dot-), superoxide radical (O-2(center dot-)), and singlet oxygen (O-1(2)), as evidenced by quenching experiments and electron spin resonance (ESR) tests. The generated (OH)-O-center dot via the traditional heterogeneous Fenton-like process would not only react with carbonate ions to yield other ROS but also involve in SMT degradation. The abundant surface-bound Fe(II) was deemed to be the dominant catalytic active sites for SPC activation. Meanwhile, it was verified that the reductive sulfur species, the interaction between Cu(I) and Fe(III) as well as the available O(2)(center dot-)derived from the activation of molecular oxygen and the conversion of (OH)-O-center dot favored the regeneration of Fe(II) on CuFeS2 surface. Furthermore, the degradation intermediates of SMT and their toxicities were evaluated. This study presents a novel strategy by integrating transition metal sulfides with percarbonate for antibiotic-contaminated water treatment.

Automated summary

In this study, the novel application of chalcopyrite for sodium percarbonate activation towards sulfamethazine degradation was explored. The mechanism of SPC activation by CuFeS2 was elucidated to involve multiple reactive oxygen species processes, with hydroxyl radical playing a key role in SMT degradation.