The process of selective nitrate removal from drinking water by means of ion exchange was studied. A commercial strong base anion exchanger with triethylammonium (−N+Et3) functional groups was used in the bicarbonate (HCO3−) and carbonate (CO32−) form. The aim of this study was to optimize ion‐exchanger regeneration in view of the sub‐ sequent electrochemical reduction of nitrates in the spent regenerant so‐ lution. The effects of ion‐exchanger form, concentration of regenerant solution, and presence of nitrates, chlorides, and sulphates in the regenerant solution were studied. The strong base anion exchanger in HCO3− form that was investigated was able to treat 270 bed volumes of model water solution containing 124 mg dm−3 nitrates. To achieve adequate regeneration of the saturated anion exchanger, it is necessary to use approximately 30 bed volumes of fresh 1‐M sodium bicarbonate (NaHCO3) regenerant solution. The presence of residual 50‐mg dm−3 nitrates in the regenerant solution, treated by electrolysis, resulted in an increase in the dose of regenerant solution to 35 bed volumes and a decrease in the subsequent sorption run of approximately 13%. The volume of applied regenerant solution was high, but the consumption of NaHCO3 for regeneration was low.
Molybdate was adsorbed onto ion exchange resin based on poly (styrene-co-divinyl benzene) matrix with diethanolamine and 1-deoxy-1-(methylamino)-D-glucitol functional groups. The maximum sorption capacity was determined from Langmuir isotherms and breakthrough capacity from dynamic column sorption. The effects of pH, the initial form of the ion exchange resin, and of competitive sorption of sulphates and chlorides onto sorption capacities were determined. Ion exchange resin having 1-deoxy-1-(methylamino)-D-glucitol functional group showed higher breakthrough capacity and higher tolerance to competitive sorption of sulphates and chlorides than ion exchange resin having diethanolamine functional group. Molybdate was easily stripped from both ion exchange resins with 10 bed volumes of 1 mol/L NaOH solution.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.