Carbon molecular sieve membranes from cellophane paper

International Journal of Hydrogen Energy

Mendes

2015

The influence of carbonization temperature on the permeation properties and aging of thin (4 m) supported carbon molecular sieve membranes (c-CMSM), prepared from in house synthesized novolac phenolic resin loaded with boehmite nanoparticles, were studied. Just after membrane carbonization (fresh membrane), high permeance to N2 and O2 and low O2/ N2 permselectivities were observed; the highest permeations were observed for carbonization end temperatures between 500 o C and 700 o C. After leaving the c-CMSM 1 day in the air, a large decrease in the permeation and considerable increase in the permselectivity were observed due to the reduction of the pore size by oxygen chemisorption and water physical adsorption; the permeability to H2 and H2/N2 ideal permselectivity for a mem-brane carbonized at 550 o C are close to palladium membranes for low temperature (<100 o C). The effect of the permeation characteristics of the membranes carbonized at various temperatures and the removal of water adsorbed in the pores by heat treatment were studied.

Section: Discussionmentioning

confidence: 99%

“…Campo et al [52] prepared CMSM from cellophane paper using a single pyrolysis step and found that the permeability reached a maximum at 550 o C, without compromising the selectivity. The Robeson upper bound was overtaken regarding H2/N2 separation with a permselectivity of 390.…”

Section: Introductionmentioning

confidence: 99%

Composite-alumina-carbon molecular sieve membranes prepared from novolac resin and boehmite. Part II: Effect of the carbonization temperature on the gas permeation properties

International Journal of Hydrogen Energy

Mendes

2015

“…The heating protocol was reported elsewhere [20,32], and can be summarized as follows: temperature rises from room temperature up to 110 o C to remove all humidity, followed by a rise up to 950 o C under N2, and a final burning step at 950…”

Section: Thermogravimetric Analysis (Tga)mentioning

confidence: 99%

“…In addition, one of the most important factors to obtain high performance CMSM is the choice of the precursor. CMSM based on polyimide [11,13], phenolic resin [14e18], polyfurfuril alcohol [19] and cellulose [20,21], have been previously reported.…”

Section: Introductionmentioning

confidence: 99%

Composite-alumina-carbon molecular sieve membranes prepared from novolac resin and boehmite. Part I: Preparation, characterization and gas permeation studies

International Journal of Hydrogen Energy

Rodrigues

et al. 2015

Supported composite alumina-carbon molecular sieve membranes (c-CMSM) were prepared from in house prepared novolac phenolic resin loaded with boehmite nanoparticles in a single dipping-drying-carbonization step. A porous a-alumina tube support was dipped into a N-methyl-2-pyrrolidone solution containing polymerized novolac resin loaded with boehmite, subsequently dried at 100 o C and carbonized at 500 o C under nitrogen environment. The structure, morphology and performance of the membranes were examined by scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), carbon dioxide adsorption and permeation of N2, O2, He, H2 and CO2. SEM showed carbon membranes with a thin and very uniform layer with a thickness of ca. 3 m CO2 adsorption isotherms indicated that the produced carbon membranes presented a micro-porous structure. The c-CMSM exhibited good gas separation properties. The permselectivity surpass the Robeson upper bound for polymeric membranes, especially regarding ideal permselectivities of pairs H2/N2 = 117, and He/O2 = 49. Aging effects were observed after membrane exposure to ambient air.However with a thermal treatment under nitrogen atmosphere the permeance of nitrogen increases.

“…The selection and modification of porous stainless steel for supported CMSMs conducted by Acharya and Merrit [83,84] could lead to building a large module because welding can be used to seal between supports and module shells. [73], (b) Bux [74], (c1) Llosa [51], (c2) Llosa [51], (d) Hosseini [70], (e) McCarthy [75], and (f) Campo [68].…”

Section: Carbon Molecular Sieve Membrane Modulesmentioning

confidence: 99%

Recent Advances on Carbon Molecular Sieve Membranes (CMSMs) and Reactors

2016

Processes

Carbon molecular sieve membranes (CMSMs) are an important alternative for gas separation because of their ease of manufacture, high selectivity due to molecular sieve separation, and high permeance. The integration of separation by membranes and reaction in only one unit lead to a high degree of process integration/intensification, with associated benefits of increased energy, production efficiencies and reduced reactor or catalyst volume. This review focuses on recent advances in carbon molecular sieve membranes and their applications in membrane reactors.