Polysaccharide‐Derived Carbons for Polar Analyte Separations

Abstract

Highly mesoporous (Brunauer–Emmett–Teller surface area, SBET > 200 m2 g−1; mesopore volume > 1 cm3 g−1) carbonaceous materials are prepared in a truly sustainable manner, from the naturally occurring polysaccharide alginic acid. This approach yields large mesoporous materials (pore diameter > 14 nm) significantly without the use of a template or carbonization catalyst. The direct thermal decomposition of mesoporous forms of the acidic polysaccharide allows for an extremely flexible material preparation strategy. Materials can be prepared at any desired carbonization temperature (e.g., 200–1000 °C), possessing similar textural properties, but progressively presenting more uniform surface functionality through this temperature range, from more oxygenated surfaces at low temperatures to increasingly aromatic/graphitic‐like surfaces. The high‐temperature material (i.e., 1000 °C), while predominantly amorphous, presents some short range (turbostratic) ordering, providing sufficiently polarizable surfaces on which to perform challenging liquid phase separations of polar sugar analytes.

Polysaccharide‐Based Porous Materials

“…These types of stationary phases were found to be particularly efficient at separating the sugars, for example, glucose (monosaccharide), sucrose (disaccharide), and raffinose (trisaccharide). The resultant ion chromatograms had good peak shape and near-baseline resolution (White et al, 2010a).…”

“…These foams were formed after displacing water within an aquagel matrix with ethanol and then drying to form a low-density mesoporous solid (a type of microcellular foam). Continued research within this area has found that this technology can be applied to other polysaccharide and nonpolysaccharide sources such as alginic acid (White et al, 2010a), pectin (White et al, 2010b), and poly(vinyl alcohol) (PVA) (Hunt et al, 2009). The understanding of why some polymers and not others can form these types of porous solids has not yet been definitively concluded, but the general rationale is that if the linear chain fragment of polymers can form a helical type arrangement, then porous solids may result.…”

Functional carbons and carbon nanohybrids for the catalytic conversion of biomass to renewable chemicals in the condensed phase

“…The final product has a variable structure, stability, and chemistry that ranges from starch-like amorphous carbon to commercially available activated carbons [87]. The three-step carbonization process yields materials with high surface areas ranging from 150 m 2 /g to approximately 600 m Depending on the synthesis procedure, these biomass-derived carbons have a wide range of applications that include the separation of polar analytes [91], CO2 capture [92], and heterogeneous catalysis [93][94][95][96][97][98][99][100]. Sulfonated starbons have catalyzed the esterification of succinic, fumaric, itaconic and levulinic acids to their respective diesters in the presence of water [93,94,96].…”

Investigating the structure of biomass-derived non-graphitizing mesoporous carbons by electron energy loss spectroscopy in the transmission electron microscope and X-ray photoelectron spectroscopy

“…These samples represent respectively materials prepared using the same pyrolysis temperature as White et al [11] and the pyrolysis temperature more recently favoured for the preparation of Starbon ® material [14].…”

“…has been shown to be effective in the LC separation of low mass carbohydrates [11], with retention comparable to that on a commercial PGC column [12]. Synthesis of alginic acidderived Starbon ® involves the expansion of an alginic acid hydrogel in water, followed by solvent exchange with ethanol and supercritical CO 2 drying to produce an aerogel precursor, which is then subjected to pyrolysis at up to 1000 o C under an inert atmosphere.…”