Novel reusable hydrogel adsorbents for precious metal recycle

A novel polyethylene glycol diacrylate-allylthiourea (ATU-PEGDA) hydrogel was simply synthesized through photo-reaction. Modified thiourea simultaneously employed chelation and electrostatic force to selectively recycle Ag(I) and Pd(II) from electrolytic wastewater. Sorption efficiency was nearly 10...

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Bibliographic Details
Published in:Scientific reports 2021-10, Vol.11 (1), p.19577-19577, Article 19577
Main Authors: Dharmapriya, Thakshila N., Lee, Ding-Yang, Huang, Po-Jung
Format: Article
Language:English
Subjects:
639/301/923/1027
639/638/911/406
Adsorption
Chelation
Desorption
Electrostatic properties
Heavy metals
Humanities and Social Sciences
Hydrogels
Industrial applications
multidisciplinary
Polyethylene glycol
Science
Science (multidisciplinary)
Thiourea
Wastewater
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Summary:A novel polyethylene glycol diacrylate-allylthiourea (ATU-PEGDA) hydrogel was simply synthesized through photo-reaction. Modified thiourea simultaneously employed chelation and electrostatic force to selectively recycle Ag(I) and Pd(II) from electrolytic wastewater. Sorption efficiency was nearly 100% for Ag(I) and Pd(II), which occurred at initial pH of 1 within 300 min. The adsorption characteristics of ATU-PEGDA followed Langmuir isotherm model and the maximum adsorption capacity of Ag(I) and Pd(II) achieved 83.33 and 152.81 mg g −1 sorbent, respectively where Pseudo-first order model demonstrate the adsorption kinetics. In the presence of other heavy metals, ATU-PEGDA performed high selectivity, 0.89 and 1.31 towards Ag(I) and Pd(II). ATU-PEGDA can be completely regenerated within 120 min using 0.5 M thiourea—0.001 M HNO 3 and 1 M thiourea—4 M HCl after the adsorption of Ag(I) and Pd(II), respectively. Thiourea-branched structure was created after regeneration, improving the adsorption capacity. Compared to initial hydrogel, the adsorption capacity of Ag(I) and Pd(II) increased 31.83 ± 3.08% and 75.12 ± 11.02%, respectively. Over 10 consecutive adsorption–desorption cycles, ATU-PEGDA performed 111.34 and 263.79 mg g −1 sorbent in adsorption capacity of Ag(I) and Pd(II). Chromism of ATU-PEGDA hydrogel was a benefit to determine adsorption saturation and completely desorption of Ag(I) and Pd(II). Potentially, ATU-PEGDA can be extended to industrial applications.
ISSN:2045-2322
2045-2322
DOI:10.1038/s41598-021-99021-5