Evaluation of Menthol:Lauric Acid Hydrophobic Deep Eutectic Solvent in The Removal of Malachite Green from Water

Abstract

Dye-containing wastewater is a significant source of water pollution if discharged without proper treatment. Liquid-liquid extraction can effectively remove dyes from wastewater. However, conventional organic solvents such as hexane and kerosene are volatile and toxic, thus necessitating greener alternatives. Hydrophobic deep eutectic solvents (HDESs) have emerged as promising solvents due to their tunable properties and synthesis from natural compounds. The study investigated Menthol:Lauric Acid (2:1 molar ratio) HDES as solvent for the removal of malachite green (MG) dye from water. Laboratory-scale extraction experiments were conducted using synthetic MG dye solutions to evaluate the effects of pH of dye solution, initial dye concentration, and solution-to-HDES ratio on dye extraction. Extraction efficiencies exceeding 93% were achieved at pH 5–9 and solution-to-HDES ratios of 3–12 mL/g, while initial dye concentration had minimal influence. These findings demonstrate the strong potential of Menthol:Lauric Acid HDES as an alternative solvent for efficient dye removal from water.