Hierarchically-porous resin for the adsorption of organic matter in raffinate produced by solvent extraction from the vanadium industry

• Published in: Separation and purification technology 2025-06, Vol.358, p.130383, Article 130383
• Main Authors: Yuan, Ling, Wang, Changqing, Yang, Hailun, Ning, Pengge, Cao, Hongbin
• Format: Article
• Language: English
• Subjects: Hierarchically-porous adsorption resin; Mixed oil phase; Primary amine extractant; Raffinate; Regeneration
• ISSN: 1383-5866
• DOI: 10.1016/j.seppur.2024.130383

[Display omitted] •WS6108 resin achieved an excellent adsorption capacity and selectivity for OIVR.•WS6108 resin presented effective stability and good regeneration property.•The isotherm equations and kinetic models for OIVR adsorption were assessed.•WS6108 resin could effectively separate OIVR in real vanadium raffinate.•The adsorption mechanism of OIVR by WS6108 resin was illustrated. Solvent extraction wastewater contains high concentrations of organic pollutants and metal ions, making it difficult to treat. This paper presents a method of using hierarchically-porous adsorption resin to recover organics from raffinate and regenerate the resin, addressing secondary pollution in extraction processes. The chosen resin, WS6108, removes over 95 % of organics from raffinate, with high metal ion concentrations enhancing its adsorption efficiency. The article conducted an optimization experiment and mechanism study on WS6108 resin for adsorbing organic matter in vanadium raffinate (OIVR), followed by desorption and recycling tests. Results showed WS6108 resin achieved a 96.7 % adsorption efficiency at a solid–liquid ratio of 24 g/L after optimization. The chosen methanol desorbent achieves over 99 % desorption efficiency for the WS6108 cycle under specific conditions. The resin’s performance remains stable for up to 45 cycles. Adsorption isotherms and kinetic experiments indicate that OIVR adsorption by WS6108 resin is endothermic, non-spontaneous and entropy increasing. Moreover, the adsorption kinetics of OIVR by WS6108 resin followed a pseudo-second-order model, based on the activation energy, liquid film diffusion was considered the main rate-controlling step. A column experiment was conducted to verify that WS6108 resin can be used in real vanadium raffinate to remove organics. Density functional theory (DFT) revealed that strong hydrogen bonding, π-π stacking and excellent adsorption diffusion behavior drive OIVR adsorption. This study aims to increase the use of adsorption to treat oily wastewater generated by solvent extraction.