Structure and Separation Performance of Carbon Membranes from Lignin-based Materials

Abstract

Carbon membranes were prepared by pyrolyzing lignocresol derived from wood using high frequency induction heating. The pore structure of the carbon membrane was studied by adsorption measurements and XPS. Gas adsorption measurements indicated that lignin carbon membrane has micropores in the range of 0.6-0.5 nm. C1s peak of XPS spectra of the lignin carbon membranes clearly showed that there are several hydrophilic functional groups, containing oxygen groups, on the surface of the membranes. Gas permeation rates through the membranes were also measured at 35°C. Carbon membranes from lignin-based materials have higher performance than conventional polymer membranes and provide a promising new class of separation membranes.

Review on the preparation of carbon membranes derived from phenolic resins for gas separation: From petrochemical precursors to bioresources

“…This phenolic fraction was mixed with methyl ethyl ketone and used to coat the outer face of an alumina tube. After pyrolysis, the supported CMSM showed separation performances above Robeson's upper bound for the gas pairs O 2 /N 2 , CO 2 /CH 4 , and H 2 /CO 2 .In fact, the membrane carbonised at 700 °C stands out from the rest for any gas pair; for example, the permeabilities to O 2 and CO 2 are 17 and 57 Barrer, respectively, and the permselectivities to O 2 /N 2 and CO 2 /CH 4 are 12 and 260, respectively[184,185].CMSMs were produced from liquefied larch sawdust by Zhao et al[186,187], using formaldehyde (which could be replaced by a more benign or sustainable aldehyde) and Pluronic F127 in the synthesis. The latter was used as a pore-forming agent to obtain an ordered mesoporous carbon.…”

“…although it may open up a space for new research. In this sense, lignocresols, as polyphenolic extracts of lignocellulose and other liquefied wood products, represented an approach to synthesise CMSMs for gas separation [182][183][184][185][186][187]. Pyrolysis of these precursors was carried out over a temperature range of 400-800 °C and under vacuum or N 2 atmosphere.…”

“…In the works of the research group of Kita et al and Koga et al[182][183][184][185], a lignocresol fraction was extracted from a lignin matrix by a phase-separation treatment with p-cresol and sulphuric acid. This phenolic fraction was mixed with methyl ethyl ketone and used to coat the outer face of an alumina tube.…”