Valorisation of corncob residues to functionalised porous carbonaceous materials for the simultaneous esterification/transesterification of waste oils

Towards carbon efficient biorefining: Multifunctional mesoporous solid acids obtained from biodiesel production wastes for biomass conversion

“…The morphology was distinctly different for the hydrothermal MACHT and the chemically activated sulfonated carbons MACS, PACS and JACS. The non-activated catalyst, MACHT closely resembled the corncob derived sulfonated carbons reported by Arancon et al [15]. While, the highly textured surface morphology and appearance of well developed mesopores in the chemically activated sulfonated carbons were in good agreement with the results of N 2 physisorption ( Table 3).…”

“…The single P2p peak at 133.5 ± 1 eV in the phosphoric acid activated carbons also suggested the existence of pentavalent tetracoordinated phosphate compounds (PO 4 or polyphosphates) in their structure (Table 2) [31]. Generally, the S2p photoelectron peak (163-168 eV) is of particular significance in the sulfonated materials and has been used to confirm the presence of SO 3 H groups [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Here, XPS surface analysis also revealed the effects of preparation method on catalyst surface structure.…”

“…But since the sulfonation step is carried out with large amounts of concentrated acids at a high temperature (150-250 • C), the process may not be reasonably called an eco-friendly. In addition, H 2 SO 4 is reported to be ineffective for sulfonating aromatized, ordered and rigid carbon materials such as graphite, activated carbons (AC) or carbons prepared by high temperature treatment [4,5,8,9,14,15]. Hence, by applying the conventional H 2 SO 4 sulfonation it is very difficult to sulfonate ACs, in other words to prepare catalysts simultaneously possessing high porosity (large pore size, pore volume, specific surface area) and SO 3 H density, vital features when considering catalytic applications in conversion of large biomass molecules.…”

“…Over the years, although a large number of manuscripts detailing preparation and applications of these sulfonic acid functionalized materials have been reported. The preparation has been seldom based on a method pioneered by Hara et al [4] involving sulfonation of an incompletely pyrolysed carbonaceous material obtained from sources such as: sucrose [7], glucose [4,8], starch [9], glycerol [10], biochar [11], wood [12], oil pitch [13], canola meal [14], corncob [15] and to name others. Similar, catalysts have also been prepared from more expensive carbon precursors such as phenolic resins [16], carbon foams [17] graphene [18] and OMCs [19,20].…”

Biomass ash-based heterogeneous catalysts to produce fatty acid methyl esters from waste cooking oil.

“…Heterogeneous catalysts have been used in a wide number of studies, to further decrease product cleaning costs and steps to neutralize homogeneous catalyst at the end o f the process (Borges et al 2011;Kim et al 2011;Arancon et al 2011;Olutoye and Hameed 2013;Balakrishnan, Olutoye, and Hameed 2013).…”