Preparation of Water-Selective Polybutadiene Membranes and Their Use in Drying Alcohols by Pervaporation and Vapor Permeation Technologies

Abstract

Separating azeotrope-forming solvent−water mixtures by conventional distillation poses technical, economic, and environmental challenges. Pervaporation and vapor permeation membrane technologies using water-permselective membranes provide an efficient alternative for water removal from solvents. We present here new water-selective materials, based on 1,2polybutadiene, that address two problems reported for traditional hydrophilic membrane materials under high water activities: swelling and hydrolysis. Exposure to UV radiation and/or heat converted portions of the vinyl groups in the polybutadiene to cross-links and hydrophilic functional groups, including alcohols, ketones, and carboxylic acids. In testing with a series of alcohols, such materials displayed high water permeabilities and stable performance over several months even at the extremes of 100% water, low water (2%), and an ethanol/water vapor at 115 °C and 2.5 bar.

Pervaporation separation of an azeotropic mixture of a tetrahydrofuran–water system with nanostructured polyhedral oligomeric silsesquioxane embedded poly(vinyl alcohol)

“…The success of the pervaporation process depends on the morphology of membrane and its properties. Membranes with good selectivity (α wt ) and high permeability are desirable for the better separation of solvent mixtures . Recently, silica–polymer hybrid membranes are found to be useful in the drug release and separation of azeotropic liquid mixtures because of their unique transport properties, which are not present in the individual components …”

Membrane condenser as emerging technology for water recovery and gas pre-treatment: current status and perspectives

“…Long-term stability of the membrane which is important from an economic point of view for increasing the membrane life-time and for reducing membrane maintenance and operating costs. [41,42]). -Possibility to control the liquid water vapor composition by opportunely tuning the operating conditions.…”

Free volume defects and transport properties of mechanically stable polyhedral oligomeric silsesquioxane embedded poly(vinyl alcohol)‐poly(ethylene oxide) blend membranes

“…Chemical and physical interactions between permeating molecules and polymer can enhance the penetrant solubility. The diffusivity of penetrants is affected by the presence of free volume defects or holes present between the chains of polymers, where diffusing molecules can be situated . The interaction between polymer chains and nanofillers may interrupt polymer chain packing and improve the diffusivity of penetrants.…”