Novel low viscosity ammonium-based ionic liquids with carboxylate anions: Synthesis, characterization, and thermophysical properties

Hydrophobic ammonium based ionic liquids for efficient extraction of textile dyes from aqueous media: Extraction study and antibacterial evaluation

Alizarin red S (ARS) extraction from aqueous medium was carried out using hydrophobic ionic liquids (ILs) containing trioctylammonium cation paired with 4-tert-butylbenzoate ([TOA][Butbenz] (IL1), 4-phenylbutanoate ([TOA][PheBut] (IL2), 3-4-dimethylbenzoate ([TOA][DMbenz] (IL3), naphthoate, ([TOA][Naph]) (IL4), salicylate ([TOA][Sali]) (IL5) and nonanedioate ([TOA]2[Nona]) (IL6). The findings demonstrated that all of the tested ILs were efficient for extracting ARS, however, [TOA]2[Nona] was more effective than others. For the extraction of ARS from the aqueous phase, the effects of various parameters including the initial pH of the dye solution, contact time, ILs to dye volume ratio (VIL:VW), dye concentration, temperature, and salt effect were investigated. The spontaneity of the liquid-liquid extraction of ARS from the aqueous phase to the IL phase was confirmed by thermodynamic parameters. More than 90% of the ARS was extracted from the aqueous phase to the IL phase throughout all experiments. Interaction of selected IL with dyes were confirmed using FTIR analysis. The standard bacterial strains of Escherichia coli (E. coli) ATCC BAA-2471 (gram negative) and Methicillin-resistant Staphylococcus (MRSA) ATCC 43300 (gram positive) were used for evaluating antibacterial activity. The lower dose (250 ppm), the ILs1, 2, 3, 4, 5, and 6 inhibited 0.40, 1.50, 6.50, 1.50, 2.50, and 0.50 mm growth of E. coli, and 4.0, 2.0, 16.50, 0.40, 5.0, and 3.50 mm growth of MRSA, respectively. The experimental findings confirmed that the present ILs can be utilized as an effective solvent for ARS and other dyes extraction from aqueous media.

Amine-Based Deep Eutectic Solvents for Alizarin Extraction from Aqueous Media

Alizarin dye is toxic and has a negative influence on human life and the environment. Consequently, the scientific community faces a difficult issue in developing efficient approaches for removing alizarin from water streams. Six distinct deep eutectic solvents (DESs) containing different hydrogen bond acceptors (HBAs), namely trioctylphosphine, trioctylamine and trihexylamine, and two hydrogen bond donors (HBDs), namely salicylic acid and malonic acid, were used to rapidly remove alizarin from high concentration solutions up to 2000 mg/L at room temperature using the liquid–liquid micro-extraction method (LLE). DES-3 had the highest extraction efficiency for alizarin among the other synthesized DESs. The effect of process variables such pH, contact time, dye initial concentration, volume ratio, temperature and salt on alizarin extraction efficiency from water stream was explored, optimized and reported. Statistical analysis was conducted to ensure the accuracy of values for the optimized parameters. For a 1000 mg/L solution of alizarin with a DES/alizarin volume ratio of 1:10 at room temperature, the maximum elimination of 98.02 percent was achieved in 5 min. FTIR was used to analyze the structural properties of DES and the interaction between DES and alizarin. The thermal stability of DES-3 was determined using thermogravimetric analysis (TGA) and indicated that DES-3 has excellent thermal stability up to 320 °C. Human saline was used to test the toxicity of the synthesized DES in vitro. It was determined that synthesized DES is less harmful and more effective at removing alizarin.