Bromide (Br-) is a non-toxic halogen found in surface water at concentrations from 14-200 µg/L. During the water disinfection process, however, the oxidants that are added cause cyto- and genotoxic disinfection by-products (DBPs) to form. Current Br- removal technologies are non-specific and costly. We investigated a new alternative: a silver-impregnated graphene oxide nanocomposite. Silver ions can precipitate bromide as insoluble AgBr salts with higher selectivity than traditional adsorbents; however, the cost of silver reduces its applicability. The objective of this project was to reduce the amount of silver needed for efficient bromide removal. Graphene oxide (GO) was impregnated with ionic silver (Ag) or nanoparticulate silver (nAg) to obtain two different nanocomposite materials. Particle size and silver content were assessed for material optimization. The GO-Ag with high silver content removed 73-84% Br-, while the low-silver content GO-Ag removed 48-55%. The GO-nAg nanocomposite removed up to 90% of the Br- with 100 times less silver, indicating that silver nucleation to nanoparticles promotes Br- removal compared to the ionic form. The GO-nAg with bigger nanoparticles reduces Br- more than that with smaller particles (90% vs 58%)

Comparison of graphene oxide impregnated with ionic or nano silver for bromide removal from surface waters

256th National Meeting (2018)

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