The interaction of disinfectants with bromide/iodide ions and natural organic matter (NOM) generates brominated/iodinated disinfection byproducts (Br/I-DBPs), known for their heightened cytotoxicity and genotoxicity relative to chlorinated DBPs. This study investigated Br/I-DBP formation during sodium hypochlorite (NaClO) disinfection of lignin-containing synthetic water by quantifying adsorbable organic halogens (AOX) and trihalomethanes (THMs). Disinfection of bromide-containing water yielded a bromide ion (Br⁻) to adsorbable organic bromine (AOBr) conversion rate of approximately 60%, with bromine within THMs accounting for about 30% of the total AOBr, indicating significant brominated DBP formation where THMs represent a major fraction. Conversely, iodide ion (I⁻) conversion to adsorbable organic iodine (AOI) is minimal, suggesting negligible iodinated DBP formation under NaClO disinfection. Examination of key parameters revealed that brominated THM (Br-THM) formation decreased with increasing lignin concentration, while iodinated THM (I-THM) formation increased. The effect of chlorine dose differed: Br-THM formation exhibited an initial increase followed by a decrease at higher doses, whereas I-THM formation consistently decreased. Both Br-THM and I-THM formation increased with higher bromide or iodide ion concentration and with increasing pH. These results highlight the distinct pathways and influencing factors governing brominated versus iodinated DBP formation in lignin-containing waters disinfected with hypochlorite.

Odorous metabolites produced by algae in source water pose severe threats to drinking water safety. Compared with conventional powdered activated carbon (PAC), in situ surface-amplified PAC exhibits superior adsorption capacity and favorable anti-interference performance in simplified aqueous systems containing selected inorganic ions for the removal of 2-methylisoborneol (2-MIB) and geosmin (GSM). This study systematically investigated the influences of PAC dosage, initial contaminant concentration, air exposure duration, inorganic anion and cation concentration, pH, and temperature on the adsorption behavior of 2-MIB and GSM onto surface-amplified PAC. Kinetic analyses reveal that the adsorption process follows the pseudo-second-order kinetic model (R² ≥ 0.98): the rate-limiting step is governed by liquid film diffusion at low concentrations, while intraparticle diffusion dominates adsorption under high-concentration conditions. Satisfactory fitting results of the Freundlich isotherm model (R² > 0.99) indicate heterogeneous energy distribution of surface active sites, demonstrating that heterogeneous adsorption characteristics serves as the main adsorption pathway. The relatively high adsorption energy (E) obtained from the Dubinin–Radushkevich (D-R) model suggests a possible contribution of micropore-related adsorption for both pollutants. Thermodynamic results prove that the adsorption is spontaneous (ΔG < 0) with a possible endothermic tendency (ΔH > 0). Active adsorption sites are distributed across both internal pore channels and external surfaces of PAC. This work provides a solid theoretical basis and experimental data for odor pollution remediation by the structural optimization of PAC.