Studies on selective removal of mercury using tri n butyl phosphate based liquid Membranes

Abstract

Mercury is a non-degradable, mobile, persistent, and toxic heavy newlinemetal whose concentration even in traces can cause harmful health effects to newlinehumans and the aquatic ecosystem. The development of techniques to monitor newlineand selectively separate traces of mercury from water bodies has become newlinecrucial due to escalating emissions of the metal. Liquid membranes are a newlinepromising technique for selective separation of mercury in the aqueous newlineenvironment, which is quite challenging. In this laboratory-scale study, newlineselective removal of mercury using supported liquid membrane (SLM) and newlinepolymer inclusion membrane (PIM) with tri n-butyl phosphate as a carrier has newlinebeen attempted. Batch experiments were carried out in the membrane reactor newlinesetup at room temperature. The effect of process parameters such as feed newlinephase acid concentration, strip phase alkali concentration, carrier newlineconcentration, soaking time of SLM in the carrier, stirring speed, and newlinethickness of PIM was determined. The Taguchi method was used to design newlinethe removal experiments with four factors (feed phase acid concentration, newlinestrip phase alkali concentration, the concentration of carrier, and feed phase newlinemercury concentration) for determining the most significant factor in the newlinetransport process. Removal efficiency for each experiment was calculated newlinefrom the concentration of mercury in the feed phase using a cold vapor atomic newlinefluorescence spectrophotometer. newlineHCl was found to be the suitable feed phase acid for both PIM and newlineSLM studies aimed for the removal of mercury from aqueous solutions. newlineMaximum removal efficiency of 97% and above under optimum conditions newlinewas achieved for feed phase mercury concentration of 0.01 to 10 mgL-1 by newlineboth the systems. newline