title: Extraction of gold(III) from hydrochloric acid solutions by CTAB/n-heptane/iso-amyl alcohol/Na2SO3 microemulsion.
abstract: The extraction of Au(III) from hydrochloric acid solutions by microemulsion was studied. The extraction experiments were carried out using cetyltrimethylammonium bromide (CTAB) as surfactant and iso-amyl alcohol as co-surfactant. Au(III) was found to be extracted into the microemulsion phase due to ion pair formation such as AuCl(4)(-)CTAB(+). The influence of temperature on the extraction of Au(III) has been investigated at temperatures ranging from 288 to 313 K. Temperature was found to decrease the distribution of Au(III). Thermodynamic parameters like enthalpy and entropy of the extraction, calculated by applying Van't Hoff equation, were -36.76 kJ mol(-1) and -84.87 J mol(-1) K(-1), respectively. Furthermore, the influence of the concentrations of hydrogen ion and chloride anion on the extraction efficiency (E%) were verified. Au(III) was extracted quantitatively (E%>99%) and selectively at the whole range of HCl concentrations (0.2-5 M). Recovery of gold from electrical waste and treatment of CTAB wastewater generated from the extraction were also discussed. Thus, the extraction of Au(III) from hydrochloric acid solutions by microemulsion is an effective approach.
authors.affiliation: Key Laboratory for Special Functional Aggregated Materials of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China.
authors.forename: Wenjuan
authors.initials: W
authors.lastname: Lu
authors.forename: Yanmin
authors.initials: Y
authors.lastname: Lu
authors.forename: Fei
authors.initials: F
authors.lastname: Liu
authors.forename: Kai
authors.initials: K
authors.lastname: Shang
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Yanzhao
authors.initials: Y
authors.lastname: Yang
mesh_terms: D000465:Algorithms; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry*; D002712:Chlorides / Q000737:chemistry; D004581:Electronics; D004655:Emulsions; D006046:Gold / Q000302:isolation & purification*; D006536:Heptanes / Q000737:chemistry*; D006851:Hydrochloric Acid / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry; D007202:Indicators and Reagents; D007220:Industrial Waste / Q000032:analysis; D007501:Iron / Q000737:chemistry; D010084:Oxidation-Reduction; D000439:Pentanols / Q000737:chemistry*; D012996:Solutions; D013447:Sulfites / Q000737:chemistry*; D013696:Temperature
chemical_list: D002593:Cetrimonium Compounds; D002712:Chlorides; D004655:Emulsions; C045076:Fenton's reagent; D006536:Heptanes; D007202:Indicators and Reagents; D007220:Industrial Waste; D000439:Pentanols; D012996:Solutions; D013447:Sulfites; C028618:n-heptane; D006046:Gold; D006861:Hydrogen Peroxide; C029683:isopentyl alcohol; D007501:Iron; D006851:Hydrochloric Acid; C025026:sodium sulfite; D000077286:Cetrimonium