Removal of bromide from surface waters using silver impregnated activated carbon

The main objectives of this study were to develop an understanding of silver impregnated activated carbon (SIAC) preparation for enhanced bromide (Br⁻) removal from water, and to investigate the impact of aqueous background composition on the Br⁻removal. Several SIACs were produced using various combinations of oxidation and silver impregnation procedures and powdered activated carbons (ACs). Regardless of the preparation procedure, SIACs showed significantly Br⁻uptakes than the virgin ACs. The Br⁻removal efficiency was affected by (i) the background water composition (e.g. Cl⁻and NOM competition reduced the Br⁻uptake), (ii) silver impregnation process (e.g. silver content, pre-oxidation of virgin AC; silver impregnation largely increased the Br⁻removal, and the pre-oxidation of AC prior to silver impregnation was found to be important), and (iii) AC characteristics (e.g. surface area, oxygen content; SIACs with higher silver contents and larger surface areas exhibited higher degrees of Br⁻removal). The Br⁻removal by SIAC reduced the formation of brominated THMs. Jar test results showed that coagulation did not have an impact on Br⁻removal by SIAC.