Gold recovery from precious metals in acidic media by using human hair waste as a new pretreatment-free green material

Insights into the Applications of Natural Fibers to Metal Separation from Aqueous Solutions

“…The studies on the behavior of protein biofibers in the uptake of metal ions from poly-metal aqueous synthetic solutions are by no means numerous. Those that already exist followed two lines of investigation: (i) description of the competitive effects in multicomponent systems of biosorption [243][244][245][246][247]; (ii) evaluation of the industrial applicability of biosorbents based on wool fibers through studies on simulated industrial effluents containing different ions [126,134,[248][249][250]. From the first category, the recent studies on the competitive biosorption of Cr(III) and Cu(II) from binary solutions on electron beam-irradiated sheep wool are of particular importance [243,244].…”

“…In another work, the significant effects of competing cations on the uptake of Cr(III) and Cu(II) from binary solutions on electron beam irradiated wool were highlighted by comparing the biosorption isotherms [244]. On the other hand, the decrease in the uptake of Au(III) from multi-metal solutions on human hair waste because of the biosorption of Ag(I), Pd(II), and Pt(IV) was up to a level where the selectivity for Au(III) is still predominant [247]. From the other perspective, amidoximated wool fibers displayed a high U uptake capacity (25-35 mg/g) for biosorption of uranyl ions (102.8 mg/L) from simulated nuclear industry effluents, which also contained Cd(II) (89.05 mg/L); Ce(III) (100.1 mg/L); Eu(III) (97.95 mg/L); Co(II) (93.7 mg/L); La(III) (99.7 mg/L); Mn(II) (101.7 mg/L) and Ni(II) (85.85 mg/L); and Sm(III) (102 mg/L), at pH = 4 [126].…”