title: Recovery and refining of Au by gold-cyanide ion biosorption using animal fibrous proteins.
abstract: Animal fibrous proteins (AFPs) such as egg-shell membrane (ESM), chicken feather (CF), wool, silk, or elastin are an intricate network of stable and water-insoluble fibers with high surface area and are abundant bioresources. Every AFP tested was found to accumulate gold-cyanide ion from aqueous solutions in high yield, depending on pH and some other parameters. Gold-cyanide ion is adsorbed by AFP at low pH range, with maximum binding observed at approx pH 2.0. Under the certain conditions, gold-cyanide ion was accumulated up to 8.6, 7.1, 9.8, 2.4, and 3.9% of dry weight on ESM, CF, wool, silk, and elastin, respectively. In the case of ESM, it was found that ESM removed gold-cyanide ion almost quantitatively and almost all the gold uptake by ESM was easily desorbed with 0.1 M NaOH. ESM can be used repeatedly for the process of gold adsorption-desorption. The gold-biosorptive capacity of ESM that was chemically modified with glutaraldehyde was higher than that of control. In column procedure, ESM packed on column removed gold-cyanide ion from the dilute aqueous solution to extremely low concentrations (nondetectable concentration of below 1 ppb).
authors.affiliation: Laboratory of Applied Biochemistry, Faculty of Agriculture, Tohoku University, Sendai, Japan. suyama@bios.yohoku.ac.jp
authors.forename: S
authors.initials: S
authors.lastname: Ishikawa
authors.forename: K
authors.initials: K
authors.lastname: Suyama
mesh_terms: D000327:Adsorption; D000818:Animals; D002645:Chickens; D003485:Cyanates; D003486:Cyanides / Q000737:chemistry*; D004527:Egg Proteins / Q000737:chemistry; D004549:Elastin / Q000737:chemistry; D005241:Feathers / Q000737:chemistry; D006046:Gold / Q000302:isolation & purification*; D017612:Gold Compounds / Q000737:chemistry*; D019476:Insect Proteins / Q000737:chemistry; D008566:Membranes / Q000737:chemistry; D011506:Proteins / Q000737:chemistry*; D047011:Silk; D012972:Sodium Hydroxide; D014935:Wool / Q000737:chemistry
chemical_list: D003485:Cyanates; D003486:Cyanides; D004527:Egg Proteins; D017612:Gold Compounds; D019476:Insect Proteins; D011506:Proteins; D047011:Silk; C043041:gold cyanide; D012972:Sodium Hydroxide; D006046:Gold; D004549:Elastin