Removal of bromate ion using powdered activated carbon

Bromate ion (BrO3-) removal from drinking water by powdered activated carbons (PACs) in bath mode was evaluated under various operational conditions Six kinds of PACs including wood-based carbon fruit-based carbon coal-based carbon and these three carbons thermally deoxidized in a nitrogen atmosphere were selected to investigate their capacity on BrO3- removal With the highest zeta potential value and being richly mesoporous, coal-based carbon had a high and an excellent BrO3- adsorption efficiency The removal content of BrO3- by per gram of coal-based carbon was 0 45 mg within 5 hr in 100 mu g/L bromate solution The surface characteristics of PACs and bromide formation revealed that both physical and chemical PACs properties simultaneously affected the adsorption reduction process Under acidic conditions PACs possessed high zeta value and adequate basic groups and exhibited neutral or positive charges promoting BrO3- adsorption-reduction on the carbon surface Interestingly, the PAC(s) thermally deoxidized in N-2 atmosphere optimized their properties e g increasing their zeta values and decreasing the oxygen content which accelerated the BrO3- removal rate The maximum adsorption capacity of fruit-based carbon was the highest among all tested carbons (99 6 mg/g) possibly due to its highest pore volume Remarkably the thermal regeneration of PACs in N2 atmosphere could completely recover the adsorption capacity of PACs The kinetic data obtained from carbons was analyzed using pseudo second-order and intraparticle diffusion models, with results showing that the intraparticle diffusion was the more applicable model to describe adsorption of BrO3- onto PACs