Dual-Surface-Modified Reverse-Selective Membranes

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• 作者：Rajinder Pal Singh ; Praveen Jha ; Kerem Kalpakci ; J. Douglas Way
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2007
• 出版时间：October 24, 2007
• 年：2007
• 卷：46
• 期：22
• 页码：7246 - 7252
• 全文大小：275K
• 年卷期：v.46,no.22(October 24, 2007)
• ISSN：1520-5045

文摘

The reverse selectivity of inorganic membranes can be enhanced by surface modification using longhydrocarbon chain silanes. Improvements in n-C₄H₁₀ selectivity of Vycor porous glass over N₂ and CH₄ wereobtained by sequentially modifying it with a C₁₈ monochlorosilane (OCS) followed by a C₁₈ trichlorosilane(ODS). The membranes were tested for pure and mixed gases at different feed pressures. The dual-modifiedmembranes have higher ideal, or pure-gas, selectivities than membranes modified using OCS alone. Then-C₄H₁₀/N₂ and n-C₄H₁₀/CH₄ ideal selectivities for the dual-modified membrane were 88 and 35, respectively,as compared to values of 13 and 7, respectively, for the OCS-modified membrane. Adsorption experimentsshowed an increase in the relative adsorption of n-C₄H₁₀ over N₂ and CH₄ after dual surface modification ofVycor glass. Nuclear magnetic resonance, X-ray photoelectron spectroscopy, and thermogravimetric analysistechniques were used to confirm the presence of silanes on the surface of the substrates. A high flux ofn-butane was measured for a dual-modified membrane fabricated using a 5 nm pore diameter -aluminaultrafilter substrate. The mixed-gas n-butane permeance for this membrane was 2 × 10^-4 cm³(STP) cm^-2 cmHg^-1 s^-1 (6.7 × 10^-8 mol m^-2 s^-1 Pa^-1).