Highly effective removal of lead and cadmium ions from wastewater by bifunctional magnetic mesoporous silica
Highly effective removal of lead and cadmium ions from wastewater by bifunctional magnetic mesoporous silica
复制标题
双功能磁性介孔二氧化硅高效去除废水中的铅、镉离子
DOI：
10.1016/j.seppur.2021.118341
复制
发表时间：
2021-02-26
影响因子：
8.6
通讯作者：
Zhang, Yongfang
中科院分区：
文献类型：
--
作者：
Li, Shuangli;Li, Shiqi;Zhang, Yongfang
采用凝胶-溶胶和湿法浸渍的方法在室温下合成了表面固定有硫醇和纳米零价铁的双功能化磁性介孔二氧化硅（NZVI-SH-HMS）材料，并成功用于去除水溶液中的铅和镉离子。 SEM、TEM 图像和 FTIR 光谱表明硫醇和 NZVI 稳定且均匀地分散在 HMS 表面。 N2吸附-解吸等温线表明NZVI-SH-HMS具有良好的多孔性能，具有较大的比表面积（312.84 m2/g）和适当的孔径（2.56 nm）。 XRD和XPS结果证实该材料具有超顺磁性，去除重金属的主要过程是Pb3(CO3)2(OH)2、PbS、CdxFe(1-x)(OH)2和Cd(OH)2的形成。 NZVI-SH-HMS的理论最大吸附容量分别为487.8 mg Pb(II)/g和330.0 mg Cd(II)/g。吸附等温线和动力学数据完全符合Langmuir等温线模型并遵循伪二级动力学。批量实验表明，主要吸附机制可能是重金属离子与吸附剂之间的沉淀/共沉淀和表面络合。此外，NZVI-SH-HMS在各种模拟废水（地表水、自来水、污水厂废水和生活废水）中表现出优异的吸附能力和吸附可回收性，在实际水环境中显示出去除重金属离子的良好能力。这些结果表明，NZVI和硫醇的协同作用极大地提高了双功能化磁性介孔二氧化硅材料的吸附性能。
A bifunctionalized magnetic mesoporous silica (NZVI-SH-HMS) material with thiol and nanometer zero-valent iron immobilized on the surface was synthesized at ambient temperature by gel-sol and wet impregnation methods, which was successfully used to remove lead and cadmium ions from aqueous solution. SEM, TEM images and FTIR spectra showed that thiol and NZVI were stable and evenly dispersed onto the surface of HMS. N2 adsorption?desorption isotherms indicated NZVI-SH-HMS owned good porous properties with a large specific surface area (312.84 m2/g) and proper pore size (2.56 nm). XRD and XPS results confirmed the material was superparamagnetic and the main process for removing heavy metals was the formation of Pb3(CO3)2(OH)2, PbS, CdxFe(1-x)(OH)2 and Cd(OH)2. The theoretical maximum adsorption capacity of NZVI-SH-HMS was 487.8 mg Pb (II)/g and 330.0 mg Cd(II)/g, respectively. Adsorption isotherm and kinetics data fitted perfectly to Langmuir isotherm model and followed the pseudo-second-order kinetics. Batch experiments indicated that the main adsorption mechanisms could be precipitation/co-precipitation and surface complexation between the heavy metal ions and the adsorbents. Additionally, NZVI-SH-HMS exhibited excellent adsorption capacities and sorption recyclability in various simulated wastewater (the surface water, tap water, sewage plant wastewater and domestic wastewater), which showed the promising capabilities for the removal of heavy metal ions in actual water environment. These results suggested that the synergistic effects of NZVI and thiol greatly improved the adsorption performance of the bifunctionalized magnetic mesoporous silica materials.