title: Trihalomethane formation potential of aquatic and terrestrial fulvic and humic acids: Sorption on activated carbon.
abstract: 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.
authors.affiliation: Department of Biology, Chemistry, and Environmental Sciences, American University of Sharjah, Sharjah, P.O. Box 26666, United Arab Emirates.
authors.forename: Mohamed Y Z
authors.initials: MY
authors.lastname: Abouleish
authors.affiliation: 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. Electronic address: info@envirochemservices.net.
authors.forename: Martha J M
authors.initials: MJ
authors.lastname: Wells
mesh_terms: D001578:Benzopyrans / Q000737:chemistry*; D002606:Charcoal; D004203:Disinfection; D006812:Humic Substances / Q000032:analysis*; D008956:Models, Chemical; D022882:Trihalomethanes / Q000032:analysis* / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry; D018508:Water Purification
chemical_list: D001578:Benzopyrans; D006812:Humic Substances; D022882:Trihalomethanes; D014874:Water Pollutants, Chemical; D002606:Charcoal; C005023:fulvic acid
keywords: Chlorination; Disinfection by-products; Dissolved organic carbon; Drinking water treatment; Factorial analysis; Isotherms