Removal of p-nitrophenol from aqueous solution by membrane-supported solvent extraction

• Published in: Journal of membrane science 1992-12, Vol.75 (3), p.277-292
• Main Authors: TOMPKINS, C. J, MICHAELS, A. S, PERETTI, S. W
• Format: Article
• Language: English
• Subjects: Chemistry; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; Mathematical models; Membranes; Phenols; Q1; Solvent extraction
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/0376-7388(92)85069-U

p-Nitrophenol was extracted from aqueous solution into 1-octanol via membrane solvent extraction, using a hydrophobic, microporous-wall, polypropylene hollow fiber module. The system was operated with the aqueous phase flowing through the fiber lumens and the octanol flowing through the shell space. The overall mass transfer coefficient for the extraction was measured and analyzed in terms of individual resistances to mass transfer. The average value for the overall mass transfer coefficient was 6.5 x 10 super(-4) cm/sec. The resistances to mass transfer of the tube-side boundary layer and membrane were found to be controlling, while the shell-side boundary layer resistance was negligible. The tube-side boundary layer resistance measured in these experiments agreed well with a prediction based on the Sherwood number correlation for well developed laminar flow in tubes. The experimentally measured membrane permeability to solute transport was substantially smaller than that predicted for solute diffusion through octanol occupying the membrane pores; flow maldistribution and channeling of solvent in the shell space is believed to be the most probable cause of this disparity. The results support the belief that membrane solvent extraction may be a technically and economically feasible means for selectively removing organic solutes from very dilute aqueous waste streams characteristic of many chemical plant effluents.