Application of Liquid Membrane in Removal of Dyes

Abstract

Textile industries are major sources of residual dyes and organic pollutants that are released into natural water resources. Treatment of this waste water and its recycling is essential because of higher grades of impurities for example pigments, auxiliary chemicals and heavy metals,etc.). Dyeing process causes a loss of 10-25% of the textile dyes,out of which 2-20% are removed as aqueous effluents causing harm to environment. Removal of effluents constituting dyes inside water bodies are unwanted due to their color,& because many of them breakdown into products which are poisonous. To re-use the materials obtained from the waste products,Liquid membrane techniques evolved over other separation techniques due to its high selectivity,recovery,increased fluxes,and reduced investment and operating cost. It combines extraction and stripping in a single unit operation. Removal of dyes by liquid membranes using organic solvents was found to be toxic and costlier. So vegetables oils are used instead of organic solvents in liquid membranes for extraction of different types of dyes and different parameters are optimized based on the extraction percentage. This thesis focuses on the extraction of Methylene Blue using bulk liquid membrane from its aqueous phase. The feed phase was aqueous solution of Methylene Blue and the strip phase was sulfuric acid solution. Solvent was Sunflower Oil for the liquid membrane phase and phenol acted as carrier. 95% MB extraction was achieved from feed phase to organic phase whereas only 90% of MB was recovered from organic phase to the receiving phase. Optimum value for strip phase concentration parameter was 1.25 N and similarly for carrier concentration 1M of carrier is most favorable for the transport process when optimum 12 pH of feed phase if maintained increases the efficiency. Even stirring speed conditions affects the extraction and recovery to great extent and when all the three phase are stirred at 300 rpm it gives the best results.