Synergism between ionic liquid and ultrasound for greener extraction of geraniol: Optimization using different statistical tools, comparison and prediction

Abstract

A new-fangled concept of combining synthesized ionic liquid with ultrasound was executed for the isolation of geraniol, a generally recognized as safe (GRAS) terpene. Shortening the extraction time and lowering the solvent requirement along with maintaining the quality of the product were the frugal aspects of this technique. Solubilization study was performed using four different water soluble synthesized ionic liquids. N,N,N,N′,N′,N′-hexaethyl-propane-1,3-diammonium dibromide was found to be the most suitable solvent amongst the selected ionic liquids. Optimization of process parameters viz., ultrasound power, volume of ionic liquid solution, concentration of ionic liquid and extraction time was carried out with the help of the Taguchi method as well as Box–Behnken response surface design. Box–Behnken response surface design was found to be the superlative optimization technique with 1.73% (w/w) yield of geraniol under optimized conditions (250W ultrasound power, 40mL aqueous solution having 10% ionic liquid and 18min of extraction time). Conventional extraction involving organic solvents was also investigated and compared with the proposed extraction technique. Predictive modeling of the experimental data was also performed using the artificial neural network. The extraction mechanism was explicated by microscopic study to recognize the effect of ionic liquid and ultrasound. The current technique was turned out to be the sustainable extraction technique when compared in terms of yield, solvent consumption and extraction time. Energy efficiency and reduced environmental burden were the rewarding outcome of the study. The proposed technology incorporating ionic liquid and sonication in a single system can be studied in detail for industrial perspective.