Characterization and stability study of pseudo-emulsion hollow fiber membrane: Separation of Ethylparaben

Abstract

Ethylparaben (EP), being one of the members of parabens family is an endocrine disrupting compound. Despite their efficient elimination in waste water treatment plants, parabens are still noticed in river waters. Studies were conducted by Pseudo-emulsion hollow fiber strip dispersion (PEHFSD) system using pseudo-emulsion comprised of Trioctylamine (carrier), n-heptane (solvent) and Na2CO3 (strippant) for EP elimination from aqueous feed phase. Influence of different operational factors like concentration of feed, carrier and stripping phase were studied for EP removal. 100% removal of EP was achieved by PEHFSD system. Permeability studies were conducted and mass transfer coefficient for aqueous and membrane phase were also evaluated at optimum conditions. Fourier transform infrared spectroscopy confirmed the bonding and existence of various functional groups in the membrane phase. Field emission scanning electron microscope revealed the pores on hollow fiber membrane surface. Droplet size distribution and backscattering profile of pseudo-emulsion at different impeller speed indicated instability of pseudo-emulsion and concentrated EP can be easily recovered. Multiple runs conducted with fresh feed solution and fresh pseudo-emulsion showed 100% removal of EP for five runs which indicated stability of membrane phase within the micropores for longer time. The recyclability of pseudo-emulsion phase was also studied by contacting the fresh feed with the previously used pseudo-emulsion phase. It was observed that removal of EP was 100%, 73% and 43% for 1st, 2nd and 3rd run respectively.