Mechanical and metal adsorption properties of emulsion gel adsorbents composed of PEGDA-co-PEG hydrogels and tri-n-octylamine

• Published in: Polymer bulletin (Berlin, Germany) Vol. 75; no. 4; pp. 1597 - 1606
• Main Authors: Tokuyama, Hideaki, Nakahata, Yu, Sato, Ryuichi, Nagatsu, Yuichiro, Ban, Takahiko
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.04.2018; Springer Nature B.V
• Subjects: Adsorbents; Adsorption; Aqueous solutions; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Complex Fluids and Microfluidics; Copolymers; Crosslinking; Deformation; Diffusion rate; Emulsions; Free radicals; Hydrogels; Mechanical properties; Organic Chemistry; Original Paper; Physical Chemistry; Polyethylene glycol; Polymer Sciences; Polymerization; Soft and Granular Matter; Solvent extraction; Solvent extraction processes; Pegden; Trioctylamine (TOA); Solvent Extraction Method; Emulsion Gel; Organic Phase Extraction
• ISSN: 0170-0839; 1436-2449
• DOI: 10.1007/s00289-017-2116-x

A novel type of emulsion gel adsorbent consisting of a polymeric hydrogel containing randomly distributed oil microdroplets of an extractant was developed for metal separation. A copolymer hydrogel composed of poly(ethylene glycol) diacrylate (PEGDA; cross-linking monomer) and polyethylene glycol (PEG), i.e., a PEGDA- co -PEG hydrogel, was developed; the hydrogel with PEGDA = 500 mol/m 3 and PEG = 50 kg/m 3 possessed improved flexibility and strength. The emulsion gel containing an amine extractant, tri- n -octylamine, successfully adsorbed Zn(II) ions. The metal–extractant complexation process and its pH dependence in the emulsion gel were comparable to those of the solvent extraction method. Investigation of the metal adsorption kinetics revealed that diffusion of the solute in the hydrogel phase is fast, and diffusion (accumulation) in the organic extractant phase is the rate-determining step.