Evaluating Powdered Activated Carbon for Adsorption of Nitrogenous Organics in Water Using HDPairFinder

Abstract

Amino-containing compounds are key precursors to highly toxic nitrogenous disinfection byproducts (DBPs) and odorous DBPs, posing a critical challenge for drinking water utilities. This study systematically evaluated the adsorption performance of six commercial powdered activated carbons (PACs) for removing soluble amino-containing compounds using amino acids as model compounds. Among them, PHF and AN PAC demonstrated superior removal efficiencies for six tested amino acids, ranging from 77 to 98% for PHF PAC and 83 to 96% for AN PAC. Subsequent analysis focused on PHF, AN, and HB PACs to investigate adsorption kinetics and effects of water parameters, including initial amino acid concentration, pH, and natural organic matter (NOM) on removal efficiencies. Optimal removal efficiencies were observed for PHF and AN PACs at pH levels between 6 and 8, while increased NOM levels significantly reduced amino acid adsorption. Finally, a hydrogen/deuterium isotopic labeling-based nontargeted analysis was applied to evaluate the removal of amino-containing compounds from source water (represented by Suwannee River standard reference materials). PHF exhibited the highest removal efficiency, achieving a 47% reduction in the total ion chromatogram (TIC) intensity of labeled amino-containing features, followed by AN at 21% and HB at 19%. The decrease in the TIC intensity and number of labeled amino-containing features aligned with the trends observed in adsorption, establishes a consistent ranking of PHF > AN > HB PAC. PAC can be seamlessly integrated into existing drinking water treatment processes and applied on an as-needed basis. Our results could provide valuable guidance for its effective application in water treatment plants.