Removal of insoluble heavy metal sulfides from water.
The necessity of heavy metal removal from wastewater has led to increasing interest in absorbents. We have developed a new approach to obtain high metal adsorption capacity by precipitating metal sulfides with sodium sulfide on the surface of bentonite and adhere them to the absorbent. This method allowed to remove approximately 90% of cadmium as CdS from 10(-4)-10(-6) M CdCl2 solutions. Additional reactions are related to the removal of excess sodium sulfide by the release of hydrogen sulfide and oxidation to sulfur using carbogen gas (5% CO2, 95% O2) followed by aeration.
Banfalvi
Gaspar
G
Department of Animal Anatomy and Physiology, University of Debrecen, 1 Egyetem Street, Debrecen 4010, Hungary. bgaspar@delfin.unideb.hu
D000327:Adsorption; D001546:Bentonite / Q000737:chemistry*; D002245:Carbon Dioxide; D011232:Chemical Precipitation; D019216:Metals, Heavy / Q000032:analysis*; D010084:Oxidation-Reduction; D010100:Oxygen; D012995:Solubility; D012996:Solutions; D013440:Sulfides / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods*
D019216:Metals, Heavy; D012996:Solutions; D013440:Sulfides; D014874:Water Pollutants, Chemical; D001546:Bentonite; D002245:Carbon Dioxide; C011700:carbogen; D010100:Oxygen