The utilization of citric acid:choline chloride (1:1) Deep eutectic solvent as a promising draw solute in forward osmosis exhibiting significant potential for efficient dye removal application

Abstract Citric acid: Choline chloride (1:1) (CACC) deep eutectic solvent (DES) was utilized as a Draw Solute (DS) in different concentrations for forward osmosis (FO) with Thin film composite (TFC) FO membrane. The water flux value of 7.5 (± 0.02) L m −2 h −1 for 1%, 10.1 (± 0.9) L m −2 h −1 for 5% and 17.5 (± 0.3) L m −2 h −1 for 10% concentrations (v/v) were observed. Reverse solute flux values were calculated with the conductivity calibration curve method which was found out to be low (for 10% 85 ppm for 4 h). The Congo Red dye-water separation was carried out with the solution of 100 ppm Congo Red solution as Feed solution and 10% CACC DES solution as a draw solution with TFC FO membrane. The membrane was characterized by field emission scanning electron microscopy analysis for the surface morphology and Contact angle for hydrophilicity which gave good results. CACC DES was characterized using Infrared Spectroscopy for structural identification, and thermogravimetric analysis for thermal stability. The low energy-consuming chilling method was used for the DS recovery which gives clear separation at -3 ℃. The data strongly agrees with the potential of CACC DES for FO applications and for dye-water separation applications.