高温改性钢渣活化过硫酸盐降解甲基橙和苯酚的反应机制

Degradation mechanism of methyl orange and phenol by high-temperature modified steel slag activated peroxymonosulfate

采用高温改性钢渣活化过硫酸盐(peroxymonosulfate,PMS)降解甲基橙(methyl orange,MO)和苯酚(phenol,AR)。考察了改性钢渣投加量、PMS浓度、初始pH值、反应温度对MO和AR降解效果的影响。在改性钢渣质量浓度为9.0 g/L、PMS物质的量浓度为12.0 mmol/L、初始pH值为7.0、反应温度为25℃的条件下,反应90 min,30 mg/L MO和15 mg/L AR的降解率分别达到90.5%和100%。材料表征分析结果表明,高温改性钢渣比表面积增大、孔隙率高、催化氧化PMS性能好,且重复利用仍有较好的原位恢复性能。自由基淬灭和电子顺磁共振波谱实验说明,高温改性钢渣/PMS反应体系存在非自由基(1 O 2)和自由基(SO_(4)^(-)·和·OH),发挥了碱活化PMS和铁氧化物活化PMS的共同作用,最终将MO和AR降解为小分子物质。

In this study,high-temperature modified steel slag was used to activate peroxymonosulfate(PMS)for the degradation of methyl orange and phenol.The effects of steel slag dosages,PMS concentrations,initial pH values and reaction temperatures on the degradation efficiencies of methyl orange and phenol were investigated.The removal efficiencies of methyl orange and phenol reached to 90.5%and 100%after the treatment of 90 min,respectively,under the optimal conditions of 9.0 g/L steel slag,12.0 mmol/L PMS,initial pH 7.0 and reaction temperature 25℃.The characterization analysis showed that high-temperature modified steel slag had larger specific surface area and higher porosity,which contributed to preferable catalytic activity and reuse performance.Free radical quenching and EPR experiments confirmed that methyl orange and phenol were degraded by the way of non-free radical(1 O 2)and free radical(SO_(4)^(-)·and·OH)oxidation,and alkali activating PMS and iron oxide activating PMS played a synergistic effect in the catalytic system.