Department of Municipal Engineering, School of Civil Engineering, Southeast University, Nanjing, Jiangsu, 210096, China.
Chemosphere. 2023 Aug;332:138835. doi: 10.1016/j.chemosphere.2023.138835. Epub 2023 May 2.
Nanoscale zero-valent iron (NZVI) has been widely used in rapid remediation of contaminants. However, several obstacles such as aggregation and surface passivation hampered NZVI from further application. In this study, sulfurized nanoscale-zero valent iron supported by biochar (BC-SNZVI) was successfully synthesized and utilized for highly efficient 2,4,6-trichlorophenol (2,4,6-TCP) dechlorination in aqueous solution. SEM-EDS analysis revealed the even distribution of SNZVI on the surface of BC. FTIR, XRD, XPS and N Brunauer-Emmett-Teller (BET) adsorption analyses were carried out to characterize the materials. Results showed that BC-SNZVI with S/Fe molar ratio of 0.088, NaSO as sulfurization agent, and pre-sulfurization as the sulfurization strategy exhibited the superior performance for 2,4,6-TCP removal. The overall removal of 2,4,6-TCP was well described with the pseudo-first-order kinetics (R > 0.9), and the observed kinetics constant K was 0.083 min with BC-SNZVI, which was one order of magnitude higher than that of BC-NZVI (0.0092 min) and SNZVI (0.0042 min), and two orders of magnitude higher than that of NZVI (0.00092 min). Moreover, the removal efficiency of 2,4,6-TCP reached 99.5% by BC-SNZVI with dosage of 0.5 g L, initial 2,4,6-TCP concentration of 30 mg L and initial solution pH of 3.0 within 180 min. The removal of 2,4,6-TCP by BC-SNZVI was acid-promoted and the removal efficiencies of 2,4,6-TCP decreased with the increase of initial 2,4,6-TCP concentrations. Furthermore, more extensive dechlorination of 2,4,6-TCP was achieved with BC-SNZVI and complete dechlorination product phenol became predominant. The facilitation of sulfur for Fe utilization and electron distribution in the presence of biochar remarkably enhanced the dechlorination performance of BC-SNZVI for 2,4,6-TCP. These findings provide insights into BC-SNZVI as an alternative engineering carbon based NZVI material for treating chlorinated phenols.
纳米零价铁（NZVI）已被广泛应用于污染物的快速修复。然而，团聚和表面钝化等几个障碍阻碍了 NZVI 的进一步应用。本研究成功合成了负载在生物炭上的硫化纳米零价铁（BC-SNZVI），并将其用于水溶液中高效去除 2,4,6-三氯苯酚（2,4,6-TCP）。SEM-EDS 分析表明 SNZVI 在 BC 表面均匀分布。FTIR、XRD、XPS 和 N Brunauer-Emmett-Teller（BET）吸附分析用于对材料进行表征。结果表明，S/Fe 摩尔比为 0.088、以 NaSO 作为硫化剂、采用预硫化策略的 BC-SNZVI 对 2,4,6-TCP 的去除效果最佳。2,4,6-TCP 的去除过程可以很好地用准一级动力学（R>0.9）来描述，用 BC-SNZVI 观察到的动力学常数 K 为 0.083 min，比 BC-NZVI（0.0092 min）和 SNZVI（0.0042 min）高一个数量级，比 NZVI（0.00092 min）高两个数量级。此外，当 BC-SNZVI 的用量为 0.5 g/L、初始 2,4,6-TCP 浓度为 30 mg/L、初始溶液 pH 为 3.0 时，2,4,6-TCP 的去除效率在 180 min 内达到 99.5%。BC-SNZVI 对 2,4,6-TCP 的去除是受酸促进的，随着初始 2,4,6-TCP 浓度的增加，2,4,6-TCP 的去除效率降低。此外，BC-SNZVI 可实现更广泛的 2,4,6-TCP 脱氯，完全脱氯产物苯酚成为主要产物。生物炭的存在促进了硫对 Fe 利用和电子分布的作用，显著提高了 BC-SNZVI 对 2,4,6-TCP 的脱氯性能。这些发现为 BC-SNZVI 作为一种替代工程碳基 NZVI 材料用于处理氯化酚类化合物提供了新的见解。
