Polyvinylidene Fluoride Hollow Fiber Membrane Contactor Incorporating Surface Modifying Macromolecule for Carbon Dioxide Stripping from Water

Abstract

Porous surface modified polyvinylidene i‌‚uoride (PVDF) hollow fiber membranes are fabricated through a dry-wet phased inversion process. Surface modifying macromolecules (SMM) (1 wt. %) are used as additives in the spinning dope. The performance of the surface modified membrane in contactor application for CO2 stripping from water is assessed through the fabricated gas–liquid membrane contactor modules. It is found that the liquid phase resistance is dominant in the stripping flux experiments. The results indicate that the surface modified PVDF membrane out performs control PVDF membrane. By applying surface modified membrane in a CO2 stripping process at the liquid flow rate of 200 ml.min-1, the maximum CO2 stripping flux and efficiency of 1.78 × 10-3 and 65 % are achieved, respectively. Enhancement of gas flow rate increased the CO2 desorption flux, while this changing is negligible. By increasing the liquid temperature from 80 to 90 oC, the CO2 stripping flux increases from 1.78×10−3 to 2.18 ×10−3 mol.m-2.s-1 at 200 ml.min-1 liquid velocity. Consequently, the liquid phase temperature has a significant effect on the stripping flux in membrane contactor application. In a long-term stability study, CO2 stripping flux decreases about 16.4 % by using surface modified PVDF membrane during 130 h operation.