Beijing Climate Change Response Research and Education Center, Collaborative Innovation Center of Energy Conservation & Emission Reduction and Sustainable Urban-Rural Development in Beijing, Beijing University of Civil Engineering and Architecture, Beijing, 100044, 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.
Environ Res. 2023 Dec 1;238(Pt 1):117072. doi: 10.1016/j.envres.2023.117072. Epub 2023 Sep 9.
Powdered activated carbon (PAC) adsorption is regarded as an efficient method for removing odorants from drinking water. However, in eutrophic aquatic environments, the presence of algal organic matter (AOM) produced by cyanobacteria considerably impedes the adsorption of odorous compounds by activated carbon. This study focused on investigating the adsorption characteristics of three representative odorants: 2-methylisoborneol (2-MIB), β-cyclocitral (β-cyclo), and butyl sulfide (BS) by PAC and the effects of AOM on the PAC adsorption of odorants. The removal of the three odorants reached 83.5-97.5% at a PAC dosage of 10 mg/L after 12 h of exposure in a competition-free scenario. The adsorption kinetics demonstrated higher conformity (R > 0.9) with the pseudo-second-order model, whereas the adsorption capacity exhibited stronger conformity (R > 0.9) with the Freundlich model. The presence of AOM resulted in varying levels of competition for PAC for the adsorption of the three odorants. As the concentration of AOM increased from 0 to 5 mg C/L, the removal of 2-MIB was the most affected (from 83.5% to 10.0%), followed by β-cyclo (from 86.6% to 55.0%), and BS (from 97.5% to 92.0%). The competitive adsorption of AOM at the molecular level was studied using density functional theory (DFT). The DFT results suggested that odorants with higher and more uniformly distributed electrostatic potentials exhibited a heightened affinity for PAC adsorption and a diminished susceptibility to disruption caused by AOM. This study provides valuable insights into the mitigation of odorous compounds during drinking water purification.
粉末状活性炭（PAC）吸附被认为是去除饮用水中嗅味物质的有效方法。然而，在富营养化的水生环境中，蓝藻产生的藻源有机物（AOM）会极大地阻碍活性炭对臭味化合物的吸附。本研究主要考察了三种代表性嗅味物质（2-甲基异莰醇、β-环柠檬醛和丁基硫醚）在无竞争条件下，通过 PAC 的吸附特性以及 AOM 对 PAC 吸附嗅味物质的影响。在 12 h 的暴露时间内，当 PAC 投加量为 10 mg/L 时，三种嗅味物质的去除率达到 83.5%-97.5%。吸附动力学更符合准二级模型（R > 0.9），而吸附容量更符合 Freundlich 模型（R > 0.9）。AOM 的存在会导致 PAC 对三种嗅味物质的吸附产生不同程度的竞争。随着 AOM 浓度从 0 增加到 5 mg C/L，2-MIB 的去除率受影响最大（从 83.5%降至 10.0%），β-环柠檬醛次之（从 86.6%降至 55.0%），BS 受影响最小（从 97.5%降至 92.0%）。采用密度泛函理论（DFT）研究了 AOM 在分子水平上的竞争吸附。DFT 结果表明，静电势更高且分布更均匀的嗅味物质与 PAC 吸附的亲和力更强，受 AOM 干扰的可能性更小。本研究为饮用水净化过程中嗅味物质的去除提供了有价值的见解。
