Produção de nanofibras de poliacrilonitrila modificadas com Cyanex 272 na recuperação de gálio

Abstract

The objectives of this work were to develop polyacrylonitrile (PAN) nanofibers modified with the commercial Cyanex 272 extractor (bis-2,4,4-trimethylpentyl phosphinic acid) and apply them for the recovery of gallium present in aqueous solution. The nanofibers were produced using the centrifugation technique, employing Forcespinning® equipment. The average nanofiber diameter ranged from 530 to 840 nm. The highest adsorption of gallium was achieved at pH 2.5, with the pseudo-second order kinetic model and the Freundlich equilibrium isotherm model providing the best fits of the experimental data. The thermodynamic parameters showed that the adsorption was spontaneous, favorable, and endothermic. The maximum capacity of the PAN/Cyanex 272 nanofibers for the recovery of gallium was 38.93 mg g-1. In successive reuse cycles, the nanofibers showed a small decrease of the adsorption capacity for the metal after the first cycle, while the efficiency remained constant in the subsequent cycles, indicating good stability of the material. The findings demonstrated that PAN/Cyanex 272 nanofibers have excellent potential for use as adsorbents, providing good capacity for the recovery of gallium and satisfactory stability during reuse in five cycles.