Enhanced oxidation of antibiotics by ferrate(VI)-sulfur(IV) system: Elucidating multi-oxidant mechanism
Enhanced oxidation of antibiotics by ferrate(VI)-sulfur(IV) system: Elucidating multi-oxidant mechanism
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DOI：
10.1016/j.cej.2018.01.112
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发表时间：
2018-06-01
影响因子：
15.1
通讯作者：
Sharma, Virender K.
中科院分区：
文献类型：
--
作者：
Feng, Mingbao;Sharma, Virender K.
高铁酸盐（VI）（（FeO 42-）-O-VI Fe-VI）通常在几秒钟的时间尺度上有效氧化各种抗生素，但一些难降解的抗生素如甲氧苄啶（TMP）和氟甲喹（FLU）需要更长的时间和更高剂量的Fe-VI才能从水中去除。目前的研究提出了Fe-VI-硫（IV）（或Fe-VI-亚硫酸盐/亚硫酸氢盐）系统，该系统可以几乎瞬时氧化这两种抗生素（20.0 μ M）（即，在15秒的时间尺度内），在比单独Fe-VI氧化所需的剂量更低的Fe-VI剂量（100.0 μ M）下。在好氧（空气饱和）和缺氧（氮饱和）条件下，在三种不同的pH值（7.0，9.0和11.0）下，进行了去除TMP的实验，作为S（IV）与Fe-VI（0.2-15.0）和Fe-VI与TMP（2.0-30.0 μ M）的摩尔比的函数。在相同条件下氧化FLU的情况下，在相同溶液pH下使用1.0（[S（IV）]：[Fen]）和5.0（[Fen：[FLU]）的摩尔比。这两种柠檬酸抗生素的去除取决于反应溶液中的pH和氧气量。缺氧条件下，Fe-VI-S（IV）体系对TMP的去除率明显低于好氧条件下的去除率。好氧和缺氧环境中TMP氧化产物的相对含量也不同。一组涉及通过Fe-VI-S（IV）体系氧化TMP的反应可以证明多氧化物种（Fe-V/Fe-VI，SO 3（中心点）（-），SO 4中心点-和中心点OH）参与从水中去除TMP。代表性阴离子和天然有机物对Fe-S（IV）技术去除水中TMP的干扰很小或没有显著影响。
Ferrate(VI) ((FeO42-)-O-VI Fe-VI) is usually effective in oxidizing a wide range of antibiotics on a time scale of seconds, but some recalcitrant antibiotics such as trimethoprim (TMP) and flumequine (FLU) require a longer time and higher dose of Fe-VI for their removal from water. The current study presents the Fe-VI-sulfur(IV) (or Fe-VI-sulfite/bisulfite) system, which could give near-instantaneous oxidation of these two antibiotics (20.0 mu M) (i.e., in 15 s time scale) at a lower dose of Fe-VI (100.0 mu M) than is needed with Fe-VI oxidation alone. Experiments on the removal of TMP were performed as a function of the molar ratios of S(IV) to Fe-VI (0.2-15.0) and Fe-VI to TMP (2.0-30.0 mu M) at three different pH values (7.0, 9.0 and 11.0) under both oxic (air saturated) and anoxic (nitrogen saturated) conditions. In case of oxidation of FLU under the same conditions, the molar ratios were used at 1.0 ([S(IV)]:[Fen) and 5.0 ( [Fen: [FLU]) under the same solution pH. Removal of these two recalcitrant antibiotics depended on the pH and the amount of oxygen in the reaction solution. Significantly, TMP was removed by Fe-VI-S(IV) system under anoxic condition, whereas the removal percentage was lower than that under oxic condition. The relative amounts of the oxidized products of TMP were also different in the oxic and anoxic environments. A set of reactions that were involved in the oxidation of TMP by the Fe-VI-S(IV) system may demonstrate the participation of multi-oxidizing species (Fe-V/Fe-VI, SO3(center dot)(-), SO4 center dot- and center dot OH) in the removal of TMP from water. Representative anions and natural organic matters had little or no significant interference on the removal of TMP by the Fe-S(IV) technique in water.