Efficient Gallium Recovery from Aqueous Solutions Using Polyacrylonitrile Nanofibers Loaded with D2EHPA

Abstract

Centrifugal spinning was utilized in producing polyacrylonitrile (PAN) nanofibers loaded with extractant di-(2-ethylhexyl) phosphoric acid (D2EHPA) for efficient adsorption recovery of gallium from aqueous solutions. The adsorption experimental data were best fitted by a pseudo-second-order kinetic model and the BET equilibrium isotherm model. Optimal adsorption performance by the PAN/D2EHPA nanofibers exhibited an adsorption capacity of 33.13 mg g−1 for the recovery of gallium at pH 2.5 and 55 °C. The thermodynamic parameters demonstrated that adsorption was endothermic, spontaneous, and favorable. The stability and reusability of the nanofibers was assessed, demonstrating retention of structural and functional integrity for the nanofibers over five cycles of an adsorption/desorption process, whilst retaining adsorption efficiency. The results demonstrate that PAN/D2EHPA nanofibers have excellent potential for utilization in an efficient adsorption process for gallium recovery, offering significant positive environmental impact over conventional liquid–liquid extraction methods.