Dehydration of Industrial Byproduct Solutions for Recycling via Pervaporation-Adsorption Hybrid Process


INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, vol.57, no.6, pp.2277-2286, 2018 (SCI-Expanded) identifier identifier


Dehydration of used solvents in the printing and packaging industry is required in order to reuse or increase the commercial value of the solvents. In this study, a pervaporation-liquid-phase adsorption hybrid process for dehydration of a low-value byproduct solution obtained from a real operation was examined. The byproduct solution contained water varying in the range of 1-11.5 wt %, and the majority of the rest is ethanol and isopropanol with minor components such as ethyl acetate and methoxy propanol. We measured the flux and separation factor of two commercial membranes as a function of process parameters such as feed and membrane module temperature, feed flow rate, and permeate side pressure in addition to the feedwater and ethyl acetate concentration. We observed higher flux and separation factors at high temperatures and low permeate side pressures. PERVAP 2201 membranes showed higher flux with a reasonable separation factor toward water. PERVAP 2211 showed higher water separation factor but lower flux compared to PERVAP 2201. We performed concentrated-mode experiments to simulate a long-term use (similar to week) of the membranes, which clearly demonstrated a successful removal of water from the byproduct solution below 98.5 wt %. Finally, application of liquid-phase adsorption on the predried solution (using pervaporation) revealed a successful dehydration to 0.04 wt % water.