Department of Biology, Chemistry, and Environmental Sciences, American University of Sharjah, Sharjah, P.O. Box 26666, United Arab Emirates.
Center for the Management, Utilization, and Protection of Water Resources, Department of Chemistry, Tennessee Technological University, Cookeville, TN 38505, United States; EnviroChem Services, 224 Windsor Drive, Cookeville, TN 38506, United States.
Sci Total Environ. 2015 Jul 15;521-522:293-304. doi: 10.1016/j.scitotenv.2015.03.090. Epub 2015 Apr 3.
Humic substances (HSs) are precursors for the formation of hazardous disinfection by-products (DBPs) during chlorination of water. Various surrogate parameters have been used to investigate the generation of DBPs by HS precursors and the removal of these precursors by activated carbon treatment. Dissolved organic carbon (DOC)- and ultraviolet absorbance (UVA254)-based isotherms are commonly reported and presumed to be good predictors of the trihalomethane formation potential (THMFP). However, THMFP-based isotherms are rarely published such that the three types of parameters have not been compared directly. Batch equilibrium experiments on activated carbon were used to generate constant-initial-concentration sorption isotherms for well-characterized samples obtained from the International Humic Substances Society (IHSS). HSs representing type (fulvic acid [FA], humic acid [HA]), origin (aquatic, terrestrial), and geographical source (Nordic, Suwannee, Peat, Soil) were examined at pH6 and pH9. THMFP-based isotherms were generated and compared to determine if DOC- and UVA254-based isotherms were good predictors of the THMFP. The sorption process depended on the composition of the HSs and the chemical nature of the activated carbon, both of which were influenced by pH. Activated carbon removal of THM-precursors was pH- and HS-dependent. In some instances, the THMFP existed after UVA254 was depleted.
腐殖质物质（HSs）是水中氯化过程中形成有害消毒副产物（DBPs）的前体。已经使用了各种替代参数来研究 HS 前体生成 DBPs 的情况，以及用活性炭处理去除这些前体的情况。基于溶解有机碳（DOC）和紫外线吸光度（UVA254）的等温线通常被报道，并被认为是三卤甲烷生成潜力（THMFP）的良好预测因子。然而，很少有基于 THMFP 的等温线被发表，因此这三种类型的参数尚未被直接比较。在 pH6 和 pH9 条件下，使用活性炭批量平衡实验，为从国际腐殖质物质学会（IHSS）获得的具有良好特征的样品生成恒定初始浓度的吸附等温线。考察了代表类型（富里酸[FA]、腐殖酸[HA]）、来源（水生、陆生）和地理来源（北欧、苏万尼、泥炭、土壤）的 HSs。生成了基于 THMFP 的等温线，以确定基于 DOC 和 UVA254 的等温线是否是 THMFP 的良好预测因子。吸附过程取决于 HSs 的组成和活性炭的化学性质，这两者都受 pH 的影响。活性炭对 THM 前体的去除取决于 pH 和 HS。在某些情况下，UVA254 耗尽后仍存在 THMFP。
