Synergistic formulation for reactive dyes extraction using benign based emulsion liquid membrane

Abstract

Dye loaded in the wastewater is considered as a pollutant due to its toxicity and carcinogenic effect. Hence, the removal of dyes from wastewater is highly demanded. There are many methods introduced for the extraction of dyes but they consume high energy and chemicals. Emulsion liquid membrane (ELM) extraction is one of the promising techniques to simultaneously extract and recover solute from wastewater solution. However, it has some drawbacks such as slow extraction rate, low loading capacity and use of non-friendly based diluent. In this research, emulsion liquid membrane was studied as an alternative method to extract and recover the dye from wastewater. The aims of this study are to formulate a synergistic extractant liquid membrane on extraction of dye (Orange 3R) using palm oil as a diluent, to study the mechanism of Orange 3R extraction and stripping process and optimization of ELM extraction of Orange 3R. The liquid membrane formulation was investigated on the selection of the extractant and synergist extractant using liquid-liquid extraction process. The mechanism of extraction and stripping process was determined by selection of extractant and synergist extractant concentration, extraction kinetic of dyes and selection of stripping agents and its concentration using liquid-liquid extraction process. ELM process was optimized using response surface methodology for four parameters which were surfactant concentration, treat ratio, agitation speed, and extraction time. The important parameter affecting the recovery process of dye which is initial feed concentration was investigated. Results showed that the liquid membrane formulation was determined using Tricaprylmethylammonium Chloride (Aliquat 336) as an extractant and Di-(2-ethylhexyl)phosphoric acid (D2EHPA) as a synergist extractant. The extraction and stripping process was performed at 0.08 M D2EHPA, 0.1 M Aliquat 336, and 0.1 M NaOH, where 86 and 100% of dyes has been extracted and stripped respectively in liquid-liquid extraction process. The optimum condition for ELM extraction performance was achieved at 3.2 % (w/v) of surfactant concentration (Span 80), 12000 rpm of homogenizer speed, 12 minutes of extraction time, 1:9.8 of treat ratio, and 413 rpm of agitation speed. At this condition, 90 % of dye was extracted and 28% was stripped. Almost 10 times of wastewater volume can be treated by a single volume of emulsion liquid membrane. Therefore, ELM process is a promising technology to separate dye from wastewater while solving environmental problems simultaneously.