Extraction of Ethylparaben by emulsion liquid membrane: Statistical analysis of operating parameters

Ethylparaben, alkyl esters of p-hydroxybenzoic acid, is an endocrine disruptor that interfere glandular activity and hormone production and even with considerable elimination of them using conventional treatment methods, it is still recognized in river water samples at high concentrations. In this study, Emulsion Liquid Membrane (ELM) consisted of trioctylamine (TOA) as carrier, n-heptane as diluent, Span 80 as surfactant and Na2CO3 as the stripping solution was used for the removal of ethylparaben (EP) from aqueous solution. Studies were conducted to analyse the effect of various operating parameters. Effect of factors like carrier concentration (C), stripping phase concentration (N), speed of homogenizer (H), surfactant concentration (S) on the extraction of EP were evaluated with Taguchi's method. Statistical analysis of variance (ANOVA) was applied to analyze the effect of each parameter and stripping phase concentration (0.5 N Na2CO3) followed by speed of homogenizer (13500 rpm) were found to be the most influencing parameters. Photomicrographs of emulsions and droplet size analyzer were used to study the impact of speed of homogenizer on emulsion droplet size and size distribution. Dispersion destabilization of the emulsion was detected by Turbiscan. Atomic force microscopy and Fourier transform infrared spectroscopy were used to analyse dimensions, shape of emulsion droplet and also to confirm bonding and the presence of different functional groups. Experimental design for multivariable optimization by Taguchi had also been implemented. Using a stable emulsion at optimum condition similar to 90% extraction of EP was achieved.