Inverse gas chromatography for natural fibre characterisation: Identification of the critical parameters to determine the Brunauer–Emmett–Teller specific surface area

• Published in: Journal of Chromatography A Vol. 1425; pp. 273 - 279
• Main Authors: Legras, A., Kondor, A., Heitzmann, M.T., Truss, R.W.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 18.12.2015
• Subjects: Brunauer–Emmett–Teller theory; Cellulose - analysis; Chromatography, Gas - methods; Flax - chemistry; Hibiscus - chemistry; Inverse gas chromatography; Natural fibres; Specific surface area; Surface Properties; Inverse gas chromatography; Specific surface area; Natural fibres; Brunauer–Emmett–Teller theory
• ISSN: 0021-9673; 1873-3778
• DOI: 10.1016/j.chroma.2015.11.033

•BET specific surface areas were determined by inverse gas chromatography for samples of flax, kenaf and cellulose fibres.•The effect of experimental conditions on the BET surface area values were investigated.•Bast fibres showed a large variability within a batch compared to synthesised cellulose fibres.•An experimental procedure to determine the BET surface area values for natural fibres is proposed. Inverse gas chromatography (IGC) is an alternative technique to determine the specific surface area of natural fibres. Natural fibres have a complex surface chemistry and unique microstructure that challenge the current capabilities to perform surface characterisation. This study investigated the influence of multiple parameters on the measured Brunauer–Emmett–Teller (BET) specific surface area for samples of flax, kenaf and BioMid® cellulose fibres using IGC. The BET surface area of kenaf and flax differed with 0.51m2g−1 and 1.35m2g−1 respectively, the former being similar to the cellulose fibres (0.54m2g−1). The data was calculated under conditions where the BET equation showed good linearity (R2⩾0.995). Repeatability was excellent so that two runs sufficed to obtain representative BET surface area values. The findings showed the choice of solvent was important for all specimens to avoid any misleading data comparison due to molecular orientation effects that impact the adsorbent–adsorbate interactions. The higher surface area of the flax sample, and its higher variability, was correlated with a higher surface roughness observed under optical microscopy. Packing the chromatography column with long or chopped fibres produced results that were statistically insignificant.