Adsorption removal of Entrapped LIX 984N from acidic copper sulfate electrolyte using Nano-Porous silica aerogel

Abstract

Entrapment of organic solvents in the aqueous phase is the main drawback of hydrometallurgical extraction of copper, which leads to lower quality of the produced cathodes in the electrowinning (EW) process. To address this challenge, a synthesized hydrophobic nano-porous silica aerogel was utilized to selectively eliminate the organic solvent in the ppm range, namely commercial LIX984N (a mixture of 5-nonyl salicylaldoxime (C₁₆H₂₅NO₂) and 2-hydroxy-5-nonyl acetophenone (C₁₄H₁₃NO₂) at the same volume, which is diluted in kerosene) from the acidic copper sulfate electrolyte. The effects of adsorbent characteristics and process parameters on the adsorption performance of the organic solvent were investigated and discussed in detail. The optimum conditions of the adsorption process were also identified using the response surface methodology (RSM) based on central composite design (CCD). ANOVA analysis revealed a linear-quadratic model for organic solvent elimination, with significant adsorption factors including contact time, initial organic solvent concentration, and sol pH. A second-order model was proposed to predict the adsorption behavior of organic solvent using silica aerogel, and the optimized process parameters, including contact time, sol pH, and initial concentration of adsorbate, were obtained 120 min, pH = 4, and 20 ppm, respectively. The efficiency of organic solvent removal using the synthesized hydrophobic nano-porous silica aerogel was obtained by about 90 %.