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Selective recovery of Au(III) from wastewater by a recyclable magnetic Ni0.6Fe2.4O4 nanoparticels with mercaptothiadiazole: Interaction models and adsorption mechanisms

Zhao, Jiling, Wang, Chen, Wang, Shixing, Zhang, Libo, Zhang, Bing
Journal of cleaner production 2019 v.236 pp. 117605
adsorbents, adsorption, desorption, endothermy, gold, industry, ion exchange, magnetism, metal ions, models, nanogold, pH, social benefit, sorption isotherms, temperature, thermodynamics, wastewater
Gold is widely used in various industries. The recovery of Au(III) from wastewater has important economic and social benefits. In here, a new adsorbent (Ni0.6Fe2.4O4-MTD) was synthesized by functionalizing Ni0.6Fe2.4O4 with mercaptothiadiazole for selectively recovery of Au(III) from wastewater. The Ni0.6Fe2.4O4-MTD was characterized by FT-IR, TEM, ZETA, TGA and XPS. The optimum pH, kinetic, isotherm and thermodynamics were determined. The maximum adsorption capacity (283.9 mg/g) was obtained at pH 4 and 300 min. The mechanism was mainly ion exchange, complexation and reduction. The adsorption process submits to pseudo-secondary kinetics and Langmuir models because monolayer chemisorption is the rate-determining step. Adsorption and desorption experiments had shown that the adsorbent was reusable at least 4 cycles. In addition, Ni0.6Fe2.4O4-MTD can selectively separate Au(III) from laboratory wastewater containing various metal ions. The increase of temperature is favorable for Au(III) adsorption because adsorption processes were a spontaneous endothermic reaction. Since Ni0.6Fe2.4O4-MTD has high adsorption capacity and remarkable selectivity for Au(III), it becomes an ideal adsorbent for the recovery of Au(III) in wastewater.