Chaoqun Tan,Wangqi Yu,Hong Mei,Kaiyang Chen,Tianhui Xu,Huiming Xiang,Yiming Feng,Lin Deng
In this study, Fe(III) catalyzed calcium peroxide (CaO 2 , CP) Fenton-like process assisted by crystal boron (C-boron) was applied for in situ chemical oxidation. Flunixin meglumine (FMME), aspirin (ASA), nitrobenzene (NB) and benzoic acid (BA) were selected as target contaminants. Pollutants decomposition by the CP/Fe(III) and C-boron/CP/Fe(III) systems was proposed in terms of diverse parameters, including C-boron dosage, pH, and temperature, with regard to the pseudo-first-order kinetic model (R 2 > 0.95). About 26.8% of 20 μM FMME was removed by 0.5 mM CP and 0.5 mM Fe(III) after 20 min at pH 4.0, whereas 90.4% of FMME was decomposed in the C-boron/CP/Fe(III) system with 100 mg/L C-boron. The removal rates of the other three pollutants were also improved to varying degrees. The k obs of the C-boron/CP/Fe(III) system for these four pollutants degradation at pH 4.0 was approximately 4.1 ∼ 5.3 times higher compared to the CP/Fe(III) system. Electron paramagnetic resonance and quenching experiments indicated that OH, O 2 − and 1 O 2 were present in both systems and contribution of OH was 71.3% at initial pH 4.0 in C-boron/CP/Fe(III) system, suggesting that it was the main reactive oxygen species for the contaminants elimination. Furthermore, experiments on the characterization of C-boron showed great reactivity and stability. This work manifested the promotion mechanism of pollutant degradation in the C-boron/CP/Fe(III) system.
Haiying Gao,Hui Yu,Jun Yu,Tianhui Xu,Yiming Feng,Yan Wang,Jun Qian,Chaoqun Tan
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.
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