Immobilisation of phosphonium-based ionic liquid in polysulfone capsules for the removal of phenolic compounds, with an emphasis on 2,4-dichlorophenol, in aqueous solution

Phosphonium-based ionic liquid immobilised in polysulfone capsules were prepared by the phase inversion technique for the adsorption of different phenolic compounds from aqueous solution. Some techniques, including Scanning Electron Microscopy (SEM), surface analysis by Brunauer-Emmett-Teller (BET), Fourier Transform Infrared Spectroscopy (FT-IR) and Thermogravimetric Analysis (TGA), were used to characterize the capsule and indicated that trihexyltetradecylphosphonium decanoate (ionic liquid) was successfully immobilised in polysulfone, the immobilisation was determined to be 63.29%. Adsorption tests showed that the developed capsules have the potential to remove varied phenolic compounds. For compounds 2,4-dichlorophenol (2,4-DCP) the best removal was achieved between pH 3.0 and 9.0. Temperature variation (25-70 degrees C) and sodium chloride concentration (0-1000 mg.L-1) had no significant changes in adsorption, demonstrating the scope for using this adsorbent with real effluents. Adsorption kinetics demonstrated the mechanism occurs in second order, the Weber-Morris model delimited the intraparticle diffusion as the adsorption limiter. The Redlich-Peterson model was the isothermal analysis that best suited the experimental data, with a beta value equal to 0.821 approaching the Langmuir model, which obtained a q(max) of 404.50 mg.g(-1). Consequently, these results demonstrate that these capsules have potential application in the treatment of environmental pollution caused by phenolic compounds.

Automated summary

Phosphonium-based ionic liquid immobilised in polysulfone capsules prepared by the phase inversion technique showed potential for adsorbing various phenolic compounds, with a successful immobilisation rate of 63.29%. The capsules demonstrated efficient removal of phenolic compounds, especially 2,4-dichlorophenol, under different pH conditions, temperature variations, and salt concentrations, showing promise for real effluent treatment. Adsorption kinetics indicated a second-order mechanism with intraparticle diffusion as the limiting factor, and the Redlich-Peterson model best fit the experimental data with a q(max) of 404.50 mg.g(-1), suggesting these capsules have potential for environmental pollution treatment caused by phenolic compounds.