Rapid and long-effective removal of phosphate from iron in combination with hypochlorite (ZVI/NaClO)
Rapid and long-effective removal of phosphate from iron in combination with hypochlorite (ZVI/NaClO)
复制标题
与次氯酸盐 (ZVI/NaClO) 结合，快速、长效地去除铁中的磷酸盐
DOI：
10.1016/j.cej.2019.122835
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发表时间：
2020
影响因子：
15.1
通讯作者：
Ayalew Zinashbizu Mengesha
中科院分区：
文献类型：
--
作者：
Luo Xiaoyan;Guo Xuejun;Xia Xinghui;Zhang Xiangyuan;Ma Na;Leng Siwen;Ullah Sana;Ayalew Zinashbizu Mengesha
采用零价铁与次氯酸盐（ZVI/NaClO）联用，实现了对水中磷的快速、长效去除。试验了两种铁，钢铁（ZVI-S）和生铁（ZVI-P）。在好氧（缺氧）条件下，当初始磷浓度为0.5、1.0和5.0 mg/L时，ZVI-P对磷的去除率分别为94.2（94.2）%、96.5（88.3）%和76.2（33.8）%。NaClO与ZVI-P的组合显著提高了磷的去除率，达到94.8- 98.2%，而与初始磷浓度和曝气条件无关。初始磷浓度为5.0 mg/L时，ZVI-P与NaClO联用对磷的去除也达到了快速、长效的效果，12次循环的磷去除率为96.4-97.8%，在12 min的空床接触时间（EBCT）下，磷的残留浓度平均为0.04 mg/L。氧化剂NaClO使铁腐蚀迅速增加，这可能是元素碳和铁之间的微观电偶效应以及具有更多晶体缺陷的铁结晶度较低所致。然而，在氧气的存在下，观察到ZVI-S对P去除的有限增强，甚至掺入NaClO。结果表明，ZVI-S表面形成了一层稳定的钝化层，该钝化层由FePO 4和氧化铁组成，可以有效地阻挡溶解氧甚至NaClO的氧化侵蚀。
Rapid and long-effective removal of phosphate (P) from water was achieved by simply using zero-valent iron coupled with hypochlorite (ZVI/NaClO). Two irons, steel iron (ZVI-S) and pig iron (ZVI-P) were tested. The removal rate of P by ZVI-P alone was observed to 94.2 (94.2), 96.5 (88.3) and 76.2 (33.8) %, respectively, at 0.5, 1.0 and 5.0 mg/L of initial P concentrations under oxic (anoxic) conditions. The combination of NaClO with ZVI-P remarkably enhanced the percentages of P removal to 94.8–98.2%, regardless of initial-P concentrations and aeration conditions. At 5.0 mg/L of initial P, the coupling of ZVI-P and NaClO also achieved a rapid and long-effective removal of P, resulting in a 96.4–97.8% of P removal during 12 batch recycles, with residual concentration of P averaged at 0.04 mg/L during the long-term of column running with only 12 min of empty-bed contact time (EBCT). The oxidant, NaClO, drove a rapid increase in iron corrosion, which was probably favored by microscopic galvanic effect between elemental carbon and iron, and less degree of iron crystallinity with more crystal defects. However, a limited enhancement of P removal by ZVI-S was observed in presence of oxygen and even spiked with NaClO. The formation of a stable passivation layer composted of ferric oxides and FePO4on ZVI-S surface was strongly indicated, which might block the oxidative attack from dissolved O2and even NaClO.