pH-dependent degradation of p-nitrophenol by sulfidated nanoscale zerovalent iron under aerobic or anoxic conditions
pH-dependent degradation of p-nitrophenol by sulfidated nanoscale zerovalent iron under aerobic or anoxic conditions
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硫化纳米零价铁在有氧或缺氧条件下对硝基苯酚的 pH 依赖性降解
DOI：
10.1016/j.jhazmat.2016.07.042
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发表时间：
2016-12-15
影响因子：
13.6
通讯作者：
Zhou, Yaoyu
中科院分区：
文献类型：
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作者：
Tang, Jing;Tang, Lin;Zhou, Yaoyu
硫化纳米零价铁（S-NZVI）因其易于制备和对污染物的高反应性而受到广泛关注。研究了优化后的S-NZVI （Fe/S摩尔比为6.9）与原始纳米级零价铁（NZVI）在不同pH（6.77 ~ 9.11）条件下对硝基酚（PNP）在好氧和缺氧条件下的反应性。研究表明，与NZVI相比，优化的硫化程度可以完全提高PNP的降解能力。批量试验结果表明，在缺氧S-NZVI体系中，降解速率常数随pH值的增加而增大，pH值达到7.60时，降解速率常数先增大后减小。然而，在好氧S-NZVI以及缺氧或好氧NZVI系统中，它随着pH的增加而降低。结果表明，缺氧S-NZVI体系在弱碱性溶液中表现较好，而好氧S-NZVI体系在酸性溶液中表现较好。在pH为6.77的好氧S-NZVI体系中，PNP的TOC去除率最高（17.59%），说明在微酸性条件下，氧促进了过量羟基自由基对PNP的降解，在中酸性条件下，TOC去除率有望进一步提高。醋酸是一种无毒的开环副产物，这证实了S-NZVI系统对于含硫离子的工业废水是一种很有前途的处理方法。(C) 2016 Elsevier B.V.版权所有
Sulfidated nanoscale zerovalent iron (S-NZVI) is attracting considerable attention due to its easy production and high reactivity to pollutants. We studied the reactivity of optimized S-NZVI (Fe/S molar ratio 6.9), comparing with pristine nanoscale zerovalent iron (NZVI), at various pH solutions (6.77-9.11) towards p-nitrophenol (PNP) under aerobic and anoxic conditions. Studies showed that the optimized extent of sulfidation could utterly enhance PNP degradation compared to NZVI. Batch experiments indicated that in anoxic S-NZVI systems the degradation rate constant increased with increasing pH up to 7.60, and then declined. However, in aerobic S-NZVI, and in anoxic or aerobic NZVI systems, it decreased as pH increased. It was manifested that anoxic S-NZVI systems preferred to weaker alkaline solutions, whereas aerobic S-NZVI systems performed better in acidic solutions. The highest TOC removal efficiency of PNP (17.59%) was achieved in the aerobic S-NZVI system at pH 6.77, revealing that oxygen improved the degradation of PNP by excessive amounts of hydroxyl radicals in slightly acidic conditions, and the TOC removal efficiency was supposed to be further improved in moderate acidic solutions. Acetic acid, a nontoxic ring opening by-product, confirms that the S-NZVI system could be a promising process for industrial wastewater containing sulfide ions. (C) 2016 Elsevier B.V. All rights reserved.