State‐of‐the‐Art of the Synthesis and Applications of Sulfonated Carbon‐Based Catalysts for Biodiesel Production: a Review

Abstract

Sulfonated carbon‐based catalysts (SCC) are favorable heterogeneous acids for acid‐catalyzed reactions including esterification and transesterification for biodiesel production. They are covalently functionalized with SO3H groups via CPhSO3H or CSO3H linkages with special carbon structures. To date, the types of SCC for biodiesel production ranges from biochar (BC), activated carbon (AC), graphene, graphite oxides, multiwalled carbon nanotubes, order mesoporous carbon, and graphitic carbon nitride. Lignocellulosic and biomass wastes are important carbon precursors for low‐cost BC and AC production. This review critically reviews and summarizes the most up‐to‐date research progress in the evolution of SCC for biodiesel production. Systematic discussions and comparisons on the different carbon materials, preparation methods, and sulfonation preparation parameters which directly affect the physicochemical attributes and catalytic performance are provided. The applications and reusability studies of these materials in biodiesel production are also included. Finally, the challenges to be addressed and future prospects of the research direction on the applications of SCC for biodiesel production are discussed.

Catalytic Esterification Using Solid Acid Carbon Catalysts Synthesized by Sustainable Hydrothermal and Plasma Sulfonation Techniques

“…Significantly lower activating agent to catalyst mass ratios were used to synthesize the materials, yet activity and stability was similar to a commercial catalyst (Amberlyst-15) derived from petroleum resources. For example, 0.62 to 1.75 mL/g was used in this work compared to 7–50 mL/g in the literature − and TOF’s greater than Amberlyst. If all activating agent ends up as waste, an E -factor (kg waste/kg product) 11–46× lower than those reported in the literature is estimated (e.g., E = 1.96 for GAC-HT-2M vs E = 91.5) .…”

“…Similarly, carbon fibers have been refluxed in concentrated H 2 SO 4 (50 mL H 2 SO 4 /g catalyst) for 12 h at 150 °C . A review of the postgrafting literature indicates sulfonation agent to carbon ratios (v/w, mL/g) from 7:1 to 50:1, with 10:1 suggested as optimum, and increasing the temperature to 250 °C was shown to increase acid site density in activated carbon. , These techniques utilize large quantities of acid, necessitating a more environmentally friendly preparation method for scale-up. Modifications to existing hydrothermal methods are essential to minimize activating agent consumption, reduce acidic waste, and ensure optimal sulfonation conditions.…”

Flake Graphene as an Efficient Agent Governing Cellular Fate and Antimicrobial Properties of Fibrous Tissue Engineering Scaffolds—A Review

“…Moreover, GO can be easily dispersed in water and some organic solvents [ 56 ]. GO presents high surface functionalization potential with other functional groups such as nitrogen, sulfur, and phosphorous [ 57 ]. For example, recent research suggests that sulfonated graphene oxide (graphene oxide with substituted sulfonic acid functional groups) presents possible use as a catalyst in esterification and transesterification reactions [ 58 , 59 ].…”

A Network of Processes for Biorefining Burdock Seeds and Roots

“…Sulfonated carbon catalysts are considered promising alternatives to conventional homogeneous acid catalysts because they are inexpensive, less corrosive, and have a low environmental impact [ 50 , 51 ]. They can be obtained by the sulfonation of a variety of carbon-based materials, including carbon nanotubes [ 52 ], graphene [ 53 ], mesoporous carbons [ 54 ], and polyaromatic molecules [ 55 ].…”