Effective and Selective Recovery of Precious Metals by Thiourea Modified Magnetic Nanoparticles

International Journal of Molecular Sciences

Tai-Lin Lin¹ 

[1] Department of Civil and Environmental Engineering, National University of Kaohsiung, Kaohsiung City 811, Taiwan; E-Mail

关键词: magnetic nanoparticle;    thiourea;    precious metals;    reuse;    recycle;    green material;    adsorption;    nanotechnology;   

DOI  :  10.3390/ijms14059834

来源: mdpi

【 摘 要 】

Adsorption of precious metals in acidic aqueous solutions using thiourea modified magnetic magnetite nanoparticle (MNP-Tu) was examined. The MNP-Tu was synthesized, characterized and examined as a reusable adsorbent for the recovery of precious metals. The adsorption kinetics were well fitted with pseudo second-order equation while the adsorption isotherms were fitted with both Langmuir and Freundlich equations. The maximum adsorption capacity of precious metals for MNP-Tu determined by Langmuir model was 43.34, 118.46 and 111.58 mg/g for Pt(IV), Au(III) and Pd(II), respectively at pH 2 and 25 °C. MNP-Tu has high adsorption selectivity towards precious metals even in the presence of competing ions (Cu(II)) at high concentrations. In addition, the MNP-Tu can be regenerated using an aqueous solution containing 0.7 M thiourea and 2% HCl where precious metals can be recovered in a concentrated form. It was found that the MNP-Tu undergoing seven consecutive adsorption-desorption cycles still retained the original adsorption capacity of precious metals. A reductive adsorption resulting in the formation of elemental gold and palladium at the surface of MNP-Tu was observed.

【 授权许可】

CC BY   
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