School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China.
Department of Chemistry and Environmental Science, School of Science, Tibet University, Lhasa, 850000, China.
Environ Sci Pollut Res Int. 2021 Feb;28(6):7261-7270. doi: 10.1007/s11356-020-11084-5. Epub 2020 Oct 7.
Drinking water sludge (DWS) contains organic carbon and metal ions with the potential to prepare adsorbents. In this research, DWS was separated into two parts by acid leaching, i.e., an acid leaching carbonization sludge (ALCS) and an acid leaching solution. Iron and aluminum were extracted from the acid leaching solution and loaded onto ALCS by sedimentation and liquid-phase reduction to prepare a carbon/AlO/nZVI magnetic adsorption material (ALCS-Al-Fe). The optimum arsenic removal conditions, adsorption kinetics, and isotherm were determined, and the characteristics of the adsorbent ALCS-Al-Fe were investigated. The results showed that the composite exerted a favorable arsenic removal effect due to the electrostatic adsorption of nanometer zero-valent iron as well as ion exchange and complexation between the OH groups on the surface of ALCS-Al-Fe and As(V). The pH change had a slight effect on the adsorption capacity, while the common anions SO and SiO showed obvious inhibitory effects. Considering that alkalinity is beneficial to arsenic ion desorption, NaOH was used in desorbing to conduct 6 cycles of regeneration experiments, and the final removal rate could still reach 90.5%. Therefore, the concept of green development of preparing magnetic adsorbents by using whole component of DWS is significant to the exploitation of sludge recycling.
饮用水污泥（DWS）含有有机碳和金属离子，具有制备吸附剂的潜力。在这项研究中，通过酸浸将 DWS 分离成两部分，即酸浸碳化污泥（ALCS）和酸浸溶液。通过沉淀和液相还原从酸浸溶液中提取铁和铝，并将其负载到 ALCS 上，制备出碳/AlO/nZVI 磁性吸附材料（ALCS-Al-Fe）。确定了最佳的砷去除条件、吸附动力学和等温线，并研究了吸附剂 ALCS-Al-Fe 的特性。结果表明，由于纳米零价铁的静电吸附以及 ALCS-Al-Fe 表面的 OH 基团与 As(V)之间的离子交换和络合作用，该复合材料表现出良好的砷去除效果。pH 值变化对吸附容量的影响较小，而常见的阴离子 SO 和 SiO 则表现出明显的抑制作用。考虑到碱度有利于砷离子解吸，因此使用 NaOH 进行脱附，进行了 6 次再生实验，最终去除率仍可达 90.5%。因此，利用 DWS 全组分制备磁性吸附剂的绿色发展理念对于污泥回收的开发具有重要意义。
