Preparation of a Novel Sorbent Based on Pickering Emulsions Polymerization Method for Encapsulating Extractants and the Adsorption of Indium in an Aqueous Solution

Abstract

The recovery of indium from impregnating resins in water is usually limited by the poor bonding of the extractant to the carrier resin. Pickering emulsion hydrogels (PEHGs) encapsulating extractant bis(2-ethylhexyl) phosphate are prepared by oil-in-water Pickering emulsions polymerization method using polyvinyl alcohol and sodium alginate as continuous phases and nano-SiO 2 and alkylphenol ethoxylates-10 (OP-10) as emulsifiers. PEHGs are used to recover trivalent In(III) from water to study its encapsulation and adsorption properties. Pickering emulsions are characterized by optical microscopy. PEHGs are characterized by Fourier transform infrared spectrometer and scanning electron microscopy. The results showed that the stabilization time of Pickering emulsions improved from 3 min to ≈14 days after the addition of 5 wt.% of OP-10. The internal structure of 4-Pickering emulsion hydrogels (4-PEHGs) prepared from Pickering emulsions co-stabilized by nano-SiO 2 and OP-10 is changed from core-shell to honeycomb structure and no oil phase leakage occurred. In(III) adsorption is carried out on 4-PEHGs. The results showed that the maximum adsorption of In(III) in water by 4-PEHGs is 18.03 mg g −1 . The adsorption process of In(III) is controlled by chemisorption. This study showed that 4-PEHGs can be used as an effective adsorbent for the recovery of indium in water.