Pushing membrane stability boundaries with HybSi® pervaporation membranes

To overcome the limitations of currently available commercial polymer and zeolite membranes for pervaporation applications, a hybrid silica membrane (HybSi®) has been developed. In this paper the unprecedented stability of HybSi® membrane technology for the dehydration of organic solvents is reported. It is shown that the HybSi® membranes are suitable for demanding separations using pervaporation at temperatures up to at least 190 °C, in aggressive aprotic solvents including N-methyl-2-pyrrolidone (NMP), and down to a pH value of ∼2. The high hydrothermal and chemical stability was proven in continuous measurements that lasted for periods of months to several years. The longest test, on the dehydration of n-butanol at 150 °C, lasted for 1000 days. The high stability parallels high fluxes and selectivities that meet current industrial demands and expectations. After a period of stabilization, fluxes and selectivities become constant. The presented results show that HybSi® membranes are widely applicable in the dehydration of organic solvents by pervaporation.

Figure optionsDownload high-quality image (104 K)Download as PowerPoint slideHighlights▶ We study the long term performance of HybSi® pervaporation membranes. ▶ The maximum application temperature is at least 190 °C. ▶ These membranes can be applied in the range ∼2 < pH < 8. ▶ The organic–inorganic hybrid structure can withstand aprotic solvents like NMP.