Pectin-derived porous materials.

Porous forms of pectin, a major industrial waste biomass polysaccharide, have been prepared by aqueous phase expansion routes (S(BET)>200 m(2) g(-1); V(pore)>0.80 cm(3) g(-1)). It was demonstrated that the aqueous phase acidity crucially influenced the properties of the porous pectin form. Preparation route selection allows direction of material textural and morphological properties, thought to be the result of polysaccharide configuration, and methyl ester group hydrolysis, believed to alter the lowest energy accessible metastable polysaccharide state during gel recrystallisation. The resulting low density amorphous powders or mouldable monoliths (rho(powder) approximately 0.20 g cm(-3)/rho(monolith) approximately 0.07 g cm(-3)) can be directly transformed by thermal carbonisation into low density mesoporous carbonaceous materials (e.g. rho approximately 0.27 g cm(-3) (T(p)=550 degrees C)), which possess textural and nanoscale material morphology reflective of the porous pectin precursor employed. Acidic gelation promotes methyl ester groups hydrolysis of the polysaccharide structure, generating carbons with unusual interdigitated rod-like nanoscale morphology. Importantly, the materials presented herein are produced directly from the parent porous pectin material, without the need for additive catalyst (or template) to yield highly mesoporous products (e.g. V(meso) > or = 0.45 cm(3) g(-1); polydispersity (PD)>10 nm), with accessible tuneable functionally rich surfaces. Due to the high mesoporosity (>85%), materials have potential application in chromatography, heterogeneous catalysis and large molecule adsorption strategies.