A novel graphene oxide-dicationic ionic liquid composite for Cr(VI) adsorption from aqueous solutions

Jun Shang; Yanni Guo; Deliang He; Wei Qu; Yining Tang; Lei Zhou; Rilong Zhu

doi:10.1016/j.jhazmat.2021.125706

A novel graphene oxide-dicationic ionic liquid composite for Cr(VI) adsorption from aqueous solutions

J Hazard Mater. 2021 Aug 15:416:125706. doi: 10.1016/j.jhazmat.2021.125706. Epub 2021 Mar 23.

Authors

Jun Shang¹, Yanni Guo¹, Deliang He², Wei Qu¹, Yining Tang¹, Lei Zhou¹, Rilong Zhu¹

Affiliations

¹ College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China.
² College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China. Electronic address: delianghe@163.com.

PMID: 33813290
DOI: 10.1016/j.jhazmat.2021.125706

Abstract

A novel graphene oxide-dicationic ionic liquid composite (GO-DIL) was prepared by modifying graphene oxide (GO) with a dicationic ionic liquid (DIL), 3,3'-(butane-1,4-diyl) bis (1-methyl-1H-imidazol-3-ium) chloride ([C₄(MIM)₂]Cl₂). GO and GO-DIL were characterized by SEM, BET, FTIR, and XPS, and the materials were used for Cr(VI) adsorption. Batch adsorption studies showed that adsorption reached equilibrium within 40 min, and the optimal pH was 3, where the electrostatic attraction between GO-DIL and Cr(VI) was maximized. The maximum theoretical Cr(VI) adsorption capacity (q_m) was 271.08 mg g^-1, and q_m remained above 228.00 mg g^-1 after five cycles. The adsorption data were fitted well by both the pseudo-first-order kinetic model and the Langmuir model. Furthermore, thermodynamics calculations revealed that adsorption was a spontaneous endothermic process. Importantly, electrostatic attraction between Cr(VI) and the protonated imidazole N⁺ of GO-DIL played a critical role in Cr(VI) adsorption, and Cr(VI) was reduced to Cr(III). Thus, GO-DIL is predicted to be an effective adsorbent for Cr(VI) and other heavy metal ions in wastewater.

Keywords: Adsorption; Cr(VI); Dicationic ionic liquid; Graphene oxide; Imidazole.