Abstract：
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 (R2 > 0.9) with the pseudo-second-order model, whereas the adsorption capacity exhibited stronger conformity (R2 > 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.
摘要：
粉末活性炭（PAC）吸附被认为是去除饮用水中气味的有效方法。然而,在富营养化的水生环境中，蓝细菌产生的藻类有机物（AOM）的存在极大地阻碍了活性炭对有气味化合物的吸附。本研究的重点是研究三种代表性气味的吸附特性：2-甲基异冰片（2-MIB），β-环cycitral(β-cyclo),通过PAC和丁基硫醚（BS）以及AOM对PAC吸附气味剂的影响。在无竞争的情况下，暴露12小时后，在10mg/L的PAC剂量下，三种气味的去除率达到83.5-97.5％。吸附动力学表现出较高的一致性（R2>0.9）与伪二阶模型，而吸附能力与Freundlich模型表现出较强的一致性(R2>0.9)。AOM的存在导致对PAC的不同程度的竞争以吸附三种气味剂。随着AOM的浓度从0增加到5mgC/L，2-MIB的去除受影响最大(从83.5%到10.0%)，其次是β-环(从86.6%到55.0%)，和BS（从97.5％到92.0％）。利用密度泛函理论(DFT)研究了AOM在分子水平上的竞争吸附。DFT结果表明，具有更高，更均匀分布的静电势的气味剂对PAC吸附的亲和力增强，对AOM引起的破坏的敏感性降低。这项研究为饮用水净化过程中减轻气味化合物提供了有价值的见解。
