The key role of crystal boron in enhanced degradation of refractory contaminants using heterogeneous Fe3+/SPC system

An origin Fenton-like system was discussed for the abatement of refractory contaminants. Sodium percarbonate (SPC) was utilized as the source of H 2 O 2 and crystal boron ( C -boron) was applied to enhance the activation of H 2 O 2 . Under the conditions of 0.50 mM Fe 3+ , 0.34 mM SPC, and heterogeneous catalysis using 100 mg L −1   C -boron, four target pollutants, at the initial concentrations of 20 μM, could be efficiently degraded by the Fenton-like system, with a degradation rate within 20 min up to 81.1% (aspirin, ASA), 92.8% (nitrobenzene, NB), 94.7% (flunixin meglumine, FMME), and 94.3% (benzoic acid, BA) respectively and total organic carbon removal up to 25.0%. The increase of Fe 2+ concentration indicated that the conversion of Fe 2+ /Fe 3+ was remarkably promoted by C -boron. Degradation reactions at acidic pH were comparatively fast, with pH-dependent k obs of 9.9 × 10 −2 min −1 (ASA), 1.5 × 10 −1 min −1 (NB), 1.7 × 10 −1 min −1 (FMME), and 1.9 × 10 −1 min −1 (BA), whereas those at neutral and alkaline pH were slower. Furthermore, reactive oxygen species including · OH, 1 O 2 , and O 2 · − were identified by in-situ electron paramagnetic resonance tests. The contribution ratios of · OH turned out to be about 71.3–86.7% for the decomposition of four contaminants. The elimination of natural organic matter and the performance of material recycling highlighted the potential for its application in water treatment . The inhibition rate of Chlorella pyrenoidosa reached 211.9% in the C -boron/Fe 3+ /SPC system. The relatively high algae toxicity limited its application scope, which requires additional research to resolve.