Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
Water Res. 2020 Jul 1;178:115797. doi: 10.1016/j.watres.2020.115797. Epub 2020 Apr 26.
In this study, the adsorption capacities of two common odor compounds, 2-methylisoborneol (2-MIB) and dimethyl disulfide (DMDS), onto nine common types of powdered activated carbon (PAC) were comprehensively compared to screen the critical surface chemical properties affecting the adsorption performance. The results showed that the adsorption capacities of all the PACs for DMDS were generally lower than those for 2-MIB. The Spearman's rank correlation analysis indicated that the adsorption capacity for 2-MIB did not have any correlation with the PAC surface sites, while the DMDS adsorption capacity was positively related to the number of basic sites. The effect of the PAC basic sites on the DMDS adsorption was further verified by density functional theory (DFT) calculation in two adsorption modes (facial mode and edge mode). The graphene structure in the edge mode was the most favorable for DMDS adsorption with the lowest adsorption enthalpy, followed by the ketone-doped structure under the facial mode. An independent gradient model indicated that van der Waals forces were dominant in the DMDS adsorption. Moreover, thermal modification was conducted to further prove the relationship between the basic sites and the DMDS adsorption. After thermal modification, the PAC with more basic sites and graphene structures was found to be more effective for DMDS adsorption. Overall, this study could offer guidance for water treatment plants with respect to the selection of PAC to solve the odor problems caused by various compounds (e.g., DMDS or 2-MIB), and the modification of PAC, aiming at more efficient odor removal.
在这项研究中，综合比较了两种常见气味化合物（2-甲基异莰醇（2-MIB）和二甲基二硫醚（DMDS））在九种常见类型粉末活性炭（PAC）上的吸附能力，以筛选影响吸附性能的关键表面化学性质。结果表明，所有 PAC 对 DMDS 的吸附能力普遍低于对 2-MIB 的吸附能力。Spearman 秩相关分析表明，2-MIB 的吸附能力与 PAC 表面位点无关，而 DMDS 的吸附能力与碱性位点数呈正相关。通过两种吸附模式（面模式和边缘模式）的密度泛函理论（DFT）计算进一步验证了 PAC 碱性位对 DMDS 吸附的影响。在边缘模式下，具有石墨烯结构的吸附最有利于 DMDS 吸附，其吸附焓最低，其次是面模式下的酮掺杂结构。独立梯度模型表明，范德华力在 DMDS 吸附中占主导地位。此外，还进行了热改性实验，以进一步证明碱性位与 DMDS 吸附之间的关系。经过热改性后，发现具有更多碱性位和石墨烯结构的 PAC 更有利于 DMDS 吸附。总的来说，这项研究可以为污水处理厂在选择 PAC 以解决由各种化合物（如 DMDS 或 2-MIB）引起的气味问题，以及 PAC 的改性，以实现更高效的除味提供指导。
