Department of Chemical Engineering, One University Place, Chester, PA 19013, USA.
Molecules. 2020 Jan 18;25(2):403. doi: 10.3390/molecules25020403.
Lead pollution in drinking water is one of the most common problems worldwide. In this research, sulfur and iron dual-doped mesoporous carbons are synthesized by soft-templating with sulfur content 4.4-6.1 atom% and iron content 7.8-9 atom%. Sulfur functionalities of the carbons are expected to enhance the affinity of the carbon toward lead whereas iron content is expected to separate the carbon from water owing to its magnetic properties. All the carbons were characterized by pore textural properties, x-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and energy dispersive x-ray (EDX). In order to study the Pb(II) removal efficiently of this carbon in competitive mode and to mimic the real-world use, one additional heavy-metal, including Cr(III), and four other commonly occurring metals-Na(I), K(I), Ca(II) and Fe (III)-are added with lead prior to adsorption experiments. It was observed that Pb(II) adsorption capacity of this carbon was not influenced by the presence of other metals. A highly elevated concentration of Na(I), K(I), Ca(II) and Fe(III) in the eluting solution compared to the initial dose suggested possible leaching of those metals from other salts as impurities, water source or even from the carbon itself, although the XPS analysis of the carbon confirmed negligible adsorption of those metals in carbon. From the equilibrium and kinetic data of adsorption, few parameters have been calculated, including distribution coefficient, diffusive time constant and pseudosecond order rate constant. The overall results suggest that these iron and sulfur dual-doped mesoporous carbons can serve as potential adsorbents for removal of lead from drinking water in the presence of other competing metals.
饮用水中的铅污染是全球最常见的问题之一。在这项研究中，通过软模板法合成了硫和铁双掺杂介孔碳，硫含量为 4.4-6.1 原子%，铁含量为 7.8-9 原子%。期望碳中的硫官能团增强碳对铅的亲和力，而铁含量由于其磁性将碳与水分离。所有碳均通过孔结构性质、X 射线光电子能谱（XPS）、扫描电子显微镜（SEM）和能量色散 X 射线（EDX）进行了表征。为了在竞争模式下有效地研究这种碳对 Pb(II)的去除，并模拟实际应用，在吸附实验之前，将另一种重金属 Cr(III)以及其他四种常见金属 Na(I)、K(I)、Ca(II)和 Fe(III)与铅一起添加。结果表明，其他金属的存在并不影响这种碳对 Pb(II)的吸附能力。洗脱溶液中 Na(I)、K(I)、Ca(II)和 Fe(III)的浓度比初始剂量高得多，这表明这些金属可能是从其他盐类（杂质、水源甚至碳本身）中浸出的，尽管碳的 XPS 分析证实碳对这些金属的吸附可以忽略不计。从吸附的平衡和动力学数据中，计算了几个参数，包括分配系数、扩散时间常数和拟二级速率常数。总体结果表明，这些铁和硫双掺杂介孔碳可作为在存在其他竞争金属的情况下从饮用水中去除铅的潜在吸附剂。
