title: Uptake and recovery of gold ions from electroplating wastes using eggshell membrane.
abstract: The animal byproduct, hen eggshell membrane (ESM), was evaluated for its ability to sorb gold ions (dicyanoaurate(I) and tetrachloroaurate(III)) from solutions and electroplating wastewater. The gold uptake was dependent on pH, temperature and co-ions present in the solutions, with pH 3.0 being the optimum value. The equilibrium data followed the Langmuir isotherm model with maximum capacities of 147 mg Au(I)/g dry weight and 618 mg Au(III)/g, respectively. Desorption of sorbed gold(I) with 0.1 mol/l NaOH resulted in no changes of the biosorbent gold uptake capacity through five consecutive sorption/desorption cycles. In column experiments, selective recovery of gold from electroplating wastewater containing various metal ions was noted. The affinity of metal sorption was in the order Au > Ag > Co > Cu > Pb > Ni > Zn.
authors.affiliation: Department of Applied Bioorganic Chemistry, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan.
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Ishikawa
authors.forename: Kyozo
authors.initials: K
authors.lastname: Suyama
authors.forename: Keizo
authors.initials: K
authors.lastname: Arihara
authors.forename: Makoto
authors.initials: M
authors.lastname: Itoh
mesh_terms: D000818:Animals; D002645:Chickens; D004528:Egg Shell; D006046:Gold / Q000737:chemistry / Q000302:isolation & purification*; D007220:Industrial Waste; D014867:Water / Q000737:chemistry*
chemical_list: D007220:Industrial Waste; D014867:Water; D006046:Gold