Biomass‐based heterogeneous catalysts for biodiesel production: A comprehensive review

Abstract

Summary Biodiesel is one of the most widely used alternative fuels to reduce exhaust emissions and the use of conventional fossil fuels. It can be synthesized from a transesterification reaction from vegetable oils or animal fats in the presence of homogeneous or heterogeneous catalysts. Some drawbacks of using homogeneous catalysts increased attention to heterogeneous catalysts for biodiesel production. Recently, heterogeneous catalysts derived from biomass have risen to the forefront of biodiesel production due to their sustainability, economical and eco‐friendly nature. In addition, they are easily recovered and constitute an alternative to eliminate biomass residues. This review highlights several biomass sources used as precursors for the production of heterogeneous catalyst. Furthermore, methods for preparing heterogeneous catalysts, the reaction mechanisms, catalyst advantages and drawbacks, their performance in biodiesel production, as well as the methodologies developed for their effective recovery are discussed in detail. Among lignocellulosic biomass‐based precursors, the paper takes into account those based on biochar, ash, carbonaceous substrate, and seed oil cake. Those catalysts obtained by both preparation methods (calcination and activation) have good catalytic activity for waste cooking oil or neat oils. Biomass ash or biochar‐based catalysts are also promising routes in biodiesel synthesis, but significant reductions in catalyst load, reaction time, temperature, and methanol‐to‐oil ratio must be reached.

Pyrolysis of lignocellulosic and algal biomasses in a fixed‐bed reactor: A comparative study on the composition and application potential of bioproducts

“…Biochar has diverse applications because of its unique properties, such as high carbon content, specific surface area, cation exchange capacity, nutrient retention capacity, and stable structure 76,77 . Based on these features, the biochar has been used as air, water, and soil decontamination, 78,79 additive in organic solid waste composting, 80 fuel alternatives, 81 catalyst, and support, 82,83 electrode, battery, and supercapacitor 84,85 …”

“…Biochar has diverse applications because of its unique properties, such as high carbon content, specific surface area, cation exchange capacity, nutrient retention capacity, and stable structure. 76,77 Based on these features, the biochar has been used as air, water, and soil decontamination, 78,79 additive in organic solid waste composting, 80 fuel alternatives, 81 catalyst, and support, 82,83 electrode, battery, and supercapacitor. 84,85 Investigating the functional groups on the biochar surface, measuring the surface area, and understanding the distribution of pore sizes are critical because many biochar applications rely on interactions occurring at the biochar surface.…”

Preparation of Activated Carbon-Based Solid Sulfonic Acid and Its Catalytic Performance in Biodiesel Preparation

“…For the advantages of high acid density, good thermodynamic stability, excellent surface hydrophobicity, high chemical stability and other characteristics, carbon-based solid acids have gradually been developed into popular catalysts that attract the interest of many researchers ( Vakros, 2018 ; Tang and Niu, 2019 ; Tobío-Pérez et al, 2022 ). In addition, carbon-based solid acid catalysts can be prepared using inexpensive and renewable biomass and its derivatives as raw materials ( Rocha et al, 2019 ; Wilk et al, 2020 ), and the required production cost is low.…”

Biocatalysts Synthesized with Lipase from Pseudomonas cepacia on Glycol-Modified ZIF-8: Characterization and Utilization in the Synthesis of Green Biodiesel

“…In contrast to base catalysis in acid catalysis, the catalysis can be separated and recycled, separation protocols are reduced, and environmental impact problems are reduced [ 15 ]. Various heterogeneous catalysts have been used for the production of biodiesel from different raw materials [ 16 , 17 , 18 ]. The reuse of the heterogeneous catalyst mainly defines its economic viability.…”

“…Many studies have been performed on the synthesis of heterogeneous catalysts to reduce the problems of homogeneous catalysts in biodiesel synthesis. Among them are oxides and derivatives of alkali metals [ 6 , 21 ], alkaline earth metal oxides supported with copper oxide [ 22 ], ion exchange resins and sulfated oxides [ 16 , 23 ], heterogeneous catalysts based on waste materials [ 24 ], and heterogeneous catalysts based on enzymes [ 25 , 26 ]. In particular, the latter catalysts have awakened great interest in the scientific community [ 27 ], especially those resulting from the immobilization of enzymes on MOFs-type supports, because these supports confer greater catalytic activity, greater stability, and allow reuse [ 28 , 29 ] to the new structural configurations in relation to other types of supports.…”