Investigation the efficiency of emulsion liquid membrane process for malachite green dye separation from water

The main aim of this work is to remove the cationic malachite green dye (MG) from wastewater using the emulsion liquid membrane (ELM) process. The used emulsion liquid membrane contains n-hexane as a diluent and a surfactant (Span 80) as an emulsion stabilizer, 0.5 M nitric acid (HNO3) solution as a stripping phase, and MG dye solution as a feed phase. Amongst the main factors that affect the separation of dyes, treat ratio, agitation speed, surfactant concentration, agitation time, emulsification time, phase ratio, and initial dye concentration have been investigated. The results showed that almost 100% of the cationic MG dye in the feed phase were separated under the best experimental circumstances. These conditions are a 1:2 treat ratio, 350 rpm agitation speed, 2% surfactant (Span 80), 3 min agitation time, 30 s emulsification time, 1:2 phase ratio, and 20 mg/L initial dye concentration. The ELM revealed a highly efficient and straight forward method for removing cationic dye from water.