Study of activated carbon absorption for bromate removal in drinking water treatment

Granular activated carbon was modified with HNO3, HCl, NaOH and NH3, respectively. Bromate (BrO3-) ion removal from drinking water by granular activated carbon (GAC) was evaluated in bath mode. The characteristics of granular activated carbon, such as the particle size, the pore size distribution and the changing of functional group, to influence the adsorption of BrO3- was studied by performing the adsorption kinetic and adsorption isotherm tests. The results show that the pseudo-second-order and intraparticle diffusion models are applicable to describe adsorption of BrO3-on GAC. The process of inner diffusion exists, and it is the key factor to control the adsorption rate on GAC. The adsorption capacity of GAC is independent of GAC's particle size. However, the initial adsorption rate decreases as the increasing of particle size. Surface area of GAC is not the main factor for controlling adsorption capacity of GAC. Activated carbons with high pHpzc values and many basic groups are conducive to the adsorption of BrO3-on GAC.