A quantitative study of the effects of particle' properties and environmental conditions on the electron efficiency of Pd and sulfidated nanoscale zero-valent irons
A quantitative study of the effects of particle' properties and environmental conditions on the electron efficiency of Pd and sulfidated nanoscale zero-valent irons
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颗粒性质和环境条件对Pd和硫化纳米零价铁电子效率影响的定量研究
DOI：
10.1016/j.scitotenv.2022.158469
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
He Feng
中科院分区：
文献类型：
--
作者：
Gong Li;Zhang Zaizhi;Xia Chenyun;Zheng Jing;Gu Yawei;He Feng
电子效率（或电子选择性）是零价铁处理有机卤化物污染地下水的重要定量指标。该定量研究的目的是系统地探索和比较Pd/Fe和S/Fe摩尔比（即，[Pd[S/Fe]和[S/Fe]）、三氯乙烯（TCE）浓度（[TCE]）、pH溶液、老化时间和水基质对Pd-nZVI和S-nZVI的影响。为此，我们使用TCE作为探针污染物。随着[S/Fe]的增大，Pd-nZVI的疏水性先增大后减小，而S-nZVI的疏水性则随着[S/Fe]的增大而增大。S-nZVI和Pd-nZVI的ε e随[TCE]的增加而增加。具体地，与[TCE]为10 ppm时的ε e相比，在[TCE]为200 ppm时S-nZVI和Pd-nZVI的ε e分别增加了24.9%和79.3%。由于析氢反应（HER）比TCE脱氯对表面钝化更敏感，S-nZVI和Pd-nZVI在碱性条件下的ε e比在碱性条件下的ε e高，pH 10时的ε e比pH 6时的ε e分别提高了11.7%和37.8%。S-nZVI和Pd-nZVI粒子的ε e也随着老化时间的延长而增加，老化30 d时，ε e分别比新鲜粒子增加了27.2%和59.6%。两种颗粒在人工地下水（AGW）中的粒径均大于在真实的地下水（RGW）中的粒径。对于所有批次实验，S-nZVI的ε e随反应时间增加并且倾向于优于Pd-nZVI的ε e，即使在TCE脱氯的初始阶段Pd-nZVI的ε e高于S-nZVI的ε e，从而证明S-nZVI的寿命。
Electron efficiency (or electron selectivity,ɛe) is an important quantitative criterion for zero-valent iron treatment of organohalide contaminated groundwater. The aim of this quantitative study was the systematic exploration and comparison of the effects of the Pd/Fe and S/Fe molar ratios (i.e., [Pd/Fe] and [S/Fe]), trichloroethylene (TCE) concentrations ([TCE]), pH solution, aging time, and water matrices on theɛeof Pd-nZVI and S-nZVI. To this end, we used TCE as a probe contaminant. Theɛeof Pd-nZVI increased and then decreased with [Pd/Fe], while that of S-nZVI increased with [S/Fe], as more hydrophobic FeS2was formed on S-nZVI at higher [S/Fe]. Theεeof S-nZVI and Pd-nZVI increased with increasing [TCE]. Specifically, theεeof S-nZVI and Pd-nZVI at [TCE] of 200 ppm increased by 24.9 % and 79.3 %, respectively, compared with that at [TCE] of 10 ppm. As the H2evolution reaction (HER) was more sensitive to surface passivation than TCE dechlorination, theεeof S-nZVI and Pd-nZVI under alkaline conditions was higher than that under basic conditions, and increased by 11.7 % and 37.8 %, respectively, at pH 10 relative to that at pH 6. Theεealso increased with the aging time of the S-nZVI and Pd-nZVI particles; the increase was by 27.2 % and 59.6 %, respectively, at aging time of 30 d compared with that of the fresh ones. Theɛeof both particles were higher in artificial groundwater (AGW) than in real groundwater (RGW). For all batch experiments, theεeof S-nZVI increased over the reaction time and tended to outperform that of Pd-nZVI, even though theεeof Pd-nZVI was higher than that of S-nZVI at the initial stage of TCE dechlorination, thereby justifying the longevity of S-nZVI.