Application of Sawdust modified with m-DMDHEU/ Choline chloride for the removal of CrO_4~(2-) and H2AsO_4~- in water

摘要

This article studies the use of acacia auriculiformis wood sawdust modified with 4,5-dihydroxy-1,3-bis (methoxymethyl) imidazolidin-2-one (m-DMDHEU) and choline chloride for separating CrO_4~(2-) and H2AsO_4~- ions in water. NaOH 0.2N/ ethanol 70° solution was used to remove lignin from the raw material, the material was then immersed in m-DMDHEU/choline chloride aqueous solution for 24 hours, after that the material was activated at 140°C for one hour. The ability to adsorb and exchange ions of the material was examined using solutions containing CrO_4~(2-) and H2AsO_4~- ions in different conditions. The results suggested that the ability to separate CrO_4~(2-) and H2AsO_4~- ions of the modified material was better than that of anion resin at pH = 7.0; the chromate adsorption capacity was the highest in acidic condition; the presence of arsenate (V) anions had no effect on the ability to remove chromate. Lastly, the modified material was used to treat water samples containing concentrations of arsenic similar to groundwater in several arsenic-contaminated areas of Vietnam.