钠基海藻酸钠插层镁铝层状双氢氧化物对 Cu(II)、Pb(II)和 Cd(II)的有效去除：吸附性能和机理研究。

Effective removal of Cu(II), Pb(II) and Cd(II) by sodium alginate intercalated MgAl-layered double hydroxide: adsorption properties and mechanistic studies.

机构信息

School of Water Conservancy and Environment, University of Jinan, Jinan 250022, China E-mail:

Shandong Province Water Supply and Drainage Monitoring Center, Jinan 250101, China.

出版信息

Water Sci Technol. 2021 Feb;83(4):975-984. doi: 10.2166/wst.2021.013.

DOI:10.2166/wst.2021.013

PMID:33617502

Abstract

To improve the adsorption efficiency of layered double hydroxides (LDHs) for heavy metals, a novel sodium alginate (SA) intercalated MgAl-LDH (SA-LDH) was synthesized in this work. SA-LDH was characterized by XRD, FTIR, XPS and employed as adsorbent for Cd(II), Pb(II), Cu(II) elimination. Adsorbent dosage, initial pH and contact time, which are regarded as several key parameters, were optimized. The results showed that SA-LDH exhibited better adsorption performance compared with the pristine MgAl-LDH. The maximum adsorption capacities of SA-LDH for Cu(II), Pb(II) and Cd(II) reached 0.945, 1.176 and 0.850 mmol/g, respectively. The possible mechanisms were analyzed by XPS, XRD and FTIR. The results showed that Cd(II), Pb(II) and Cu(II) may be removed by SA-LDH via (i) bonding or complexation with Sur-OH or Sur-O- of SA-LDH, (ii) precipitation of metal hydroxides or carbonates, (iii) isomorphic substitution, and (iv) chelation with -COO in the interlayers. This work provides an effective method for the development of LDH-based adsorbent and the treatment of wastewater containing heavy metals.

摘要

为了提高层状双氢氧化物（LDHs）对重金属的吸附效率，本工作合成了一种新型海藻酸钠（SA）插层 MgAl-LDH（SA-LDH）。通过 XRD、FTIR、XPS 对 SA-LDH 进行了表征，并将其用作 Cd(II)、Pb(II)、Cu(II)去除的吸附剂。吸附剂用量、初始 pH 值和接触时间是几个关键参数，对其进行了优化。结果表明，SA-LDH 的吸附性能优于原始的 MgAl-LDH。SA-LDH 对 Cu(II)、Pb(II)和 Cd(II)的最大吸附容量分别达到 0.945、1.176 和 0.850 mmol/g。通过 XPS、XRD 和 FTIR 分析了可能的机制。结果表明，SA-LDH 可能通过以下几种方式去除 Cd(II)、Pb(II)和 Cu(II)：(i)与 SA-LDH 的 Sur-OH 或 Sur-O-键合或络合，(ii)金属氢氧化物或碳酸盐的沉淀，(iii)同晶取代，和 (iv)层间 -COO 的螯合。本工作为 LDH 基吸附剂的开发和含重金属废水的处理提供了一种有效的方法。