Department of Dermatology, Second Xiangya Hospital, Central South University, Changsha 410011, PR China; College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, PR China; Center of Research Excellence in Renewable Energy and Power Systems, Center of Excellence in Desalination Technology, Department of Mechanical Engineering, Faculty of Engineering-Rabigh, King Abdulaziz University, Jeddah 21589, Saudi Arabia.
Center of Research Excellence in Renewable Energy and Power Systems, Center of Excellence in Desalination Technology, Department of Mechanical Engineering, Faculty of Engineering-Rabigh, King Abdulaziz University, Jeddah 21589, Saudi Arabia.
Sci Total Environ. 2022 Oct 20;844:156835. doi: 10.1016/j.scitotenv.2022.156835. Epub 2022 Jun 21.
Polluted stormwater (PSW) treatment is becoming increasingly important because of the existence of multiple pollutants from non-point pollution sources. Alfalfa biochar loaded with Mg/Fe layered double hydroxide (AF-LDH) was successfully synthesized to remove trace metal(loid)s from stormwater. The adsorption kinetics and isotherms of metal(loid)s in a mono-component system and the reusability of the composite materials was investigated in this study. The result showed that the maximum removal efficiency for Pb(II), Cu(II), Zn(II), Cd(II), As(V), and Cr(VI) were 98.98 %, 98.11 %, 97.88 %, 97.71 %, 98.81 %, and 50.89 %, respectively, when added calcined AF-LDH (AF-LDO) composite material to the multi-component solution. The AF-LDH and AF-LDO could efficiently remove trace pollutants (10-100 μg/L) from multi-component solution, especially for AF-LDO, which could completely remove the tested six trace metal(loid)s. Furthermore, Fourier transform infrared spectra and X-ray diffraction characterizations supported the Mg/Fe layered double hydroxide reconstruction. The main mechanisms of Pb(II), Cu(II), Zn(II), and Cd(II) (cationic metals) removal were ion exchange and surface precipitation, whereas As(V) and Cr(VI) (anionic metals) were mainly dislodged through the formation of surface complexation, electrostatic attraction, and interlayer anion exchange, concerning the -OH and -COOH of AF-LDH. Importantly, the results of the column experiment demonstrated that AF-LDO was superior to AF-LDH for anionic metal removal from stormwater. In this study, we synthesized AF-LDH and AF-LDO for trace metal(loid) removal and proposed a new and practical approach for stormwater purification.
受非点源多污染物存在的影响，受污染的雨水（PSW）处理变得越来越重要。成功合成了负载 Mg/Fe 层状双氢氧化物（AF-LDH）的苜蓿生物炭，用于去除雨水中的痕量金属（loid）。本研究考察了金属（loid）在单一组分体系中的吸附动力学和等温线以及复合材料的可重复使用性。结果表明，当向多组分溶液中添加煅烧 AF-LDH（AF-LDO）复合材料时，Pb（II）、Cu（II）、Zn（II）、Cd（II）、As（V）和 Cr（VI）的最大去除效率分别为 98.98%、98.11%、97.88%、97.71%、98.81%和 50.89%。AF-LDH 和 AF-LDO 可有效去除多组分溶液中的痕量污染物（10-100μg/L），尤其是 AF-LDO 可完全去除六种测试痕量金属（loid）。此外，傅里叶变换红外光谱和 X 射线衍射特性支持 Mg/Fe 层状双氢氧化物的重构。Pb（II）、Cu（II）、Zn（II）和 Cd（II）（阳离子金属）的主要去除机制是离子交换和表面沉淀，而 As（V）和 Cr（VI）（阴离子金属）主要通过表面络合、静电吸引和层间阴离子交换来去除，这与 AF-LDH 的-OH 和-COOH 有关。重要的是，柱实验的结果表明，AF-LDO 比 AF-LDH 更有利于从雨水中去除阴离子金属。在本研究中，我们合成了 AF-LDH 和 AF-LDO 以去除痕量金属（loid），并提出了一种新的实用的雨水净化方法。
