Efficient mercury removal from aqueous solutions using carboxylated Ti3C2T MXene
Efficient mercury removal from aqueous solutions using carboxylated Ti3C2T MXene
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使用羧化 Ti3C2T MXene 从水溶液中高效去除汞
DOI：
10.1016/j.jhazmat.2022.128780
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发表时间：
2022
影响因子：
13.6
通讯作者：
Soroush, Masoud
中科院分区：
文献类型：
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作者：
Isfahani, Ali Pournaghshband;Shamsabadi, Ahmad A.;Alimohammadi, Farbod;Soroush, Masoud
受重金属污染的供水是一个全球性的问题。MXene具有使其对于从水中去除金属离子具有吸引力的特性。这项工作提出了一个简单的一步法的Ti 3C 2 Tx羧化，涉及使用的螯合剂与线性结构，提供强的羧酸基团具有高流动性。羧基化在2.0-8.5的pH范围内使Ti 3C 2 Tx的zeta-电位降低约16至约18 mV，并且在分子氧存在下提高了Ti 3C 2 Tx的稳定性。pH在2-6范围内对Ti_3C_2Tx和COOH-Ti_3C_2 Tx的吸附量影响不大。与Ti_3C_2Tx相比，COOH-Ti_3C_2 Tx具有稍高且快得多的汞吸收，并且从COOH-Ti_3C_2 Tx中浸出的汞离子浓度较低。对于Ti 3C 2 Tx和COOH-Ti 3C 2 Tx，浸出的汞离子浓度远低于美国标准。EPA最高水平。当Hg 2+初始浓度为50 ppm，pH为6时，COOH-Ti 3C 2 Tx的平衡吸附容量为499.7 mg/g，在1 min内去除95%的Hg 2+。此外，其具有5分钟的平衡时间，这显著短于Ti 3C 2 Tx的平衡时间（约60分钟）。最后，其汞离子吸收能力高于文献中报道的市售吸附剂。其除汞主要通过化学吸附和单分子层吸附。
Water supplies contaminated with heavy metals are a worldwide concern. MXenes have properties that make them attractive for the removal of metal ions from water. This work presents a simple one-step method of Ti3C2Txcarboxylation that involves the use of a chelating agent with a linear structure, providing strong carboxylic acid groups with high mobility. The carboxylation decreases the zeta-potential of Ti3C2Txby ~16 to ~18 mV over a pH range of 2.0–8.5 and improves Ti3C2Txstability in the presence of molecular oxygen. pH in the range of 2–6 has a negligible effect on the adsorption capacity of Ti3C2Txand COOH–Ti3C2Tx. Compared to Ti3C2Tx, COOH–Ti3C2Txhas a slightly higher and much faster mercury uptake, and the concentration of mercury ions leached out from COOH-Ti3C2Txis lower. For both Ti3C2Txand COOH–Ti3C2Tx, the leached mercury ion concentration is far below the U.S.-EPA maximum level. At an initial Hg2+concentration of 50 ppm and pH of 6, COOH–Ti3C2Txhas the equilibrium adsorption capacity of 499.7 mg/g and removes 95% of Hg2+in less than 1 min. Moreover, it has an equilibrium time of 5 min, which is significantly shorter than that of Ti3C2Tx(~ 60 min). Finally, its mercury-ion uptake capacity is higher than commercially available adsorbents reported in the literature. Its mercury removal is mainly via chemisorption and monolayer adsorption.