Granular activated carbon as an adsorbent for simultaneous removal of nitrosodipropylamine (NDPA) and nitrosodibutylamine (NDBA) from water

Nitrosodipropylamine (NDPA) and nitrosodibutylamine (NDBA) are two representative nitrosamines that are known as emerging nitrogenous disinfection by-products in water with potent mutagenicity, teratogenicity, and carcinogenicity. In this study, laboratory-scale studies were carried out to concurrently remove both NDPA and NDBA from water. Key factors affecting the removal rate and adsorption capacity were studied. The treatment performance was heavily influenced by granular activated carbon (GAC) types, initial solution pH, reaction temperature, and water matrices, but appeared to be affected by initial concentration slightly. Within 48 h, 0.1 g/L cocoanut GAC (YK), advantageous over nutshell GAC (GK), and coal-based GAC (MZ), adsorbed >90% of 0.20 mg/L NDPA and NDBA at pH = 7 and 298 K. The adsorption kinetics and isotherm patterns could be well-described by pseudo-first-order reaction kinetics model and the Langmuir model. Thermodynamics analysis validated that the adsorption processes for both NDPA and NDBA were spontaneous and endothermic. Results showed that GAC might be an excellent agent to prevent water pollution caused by nitrosamines.