Sulfonated Orange Peel Catalysts for Biodiesel Production: Recent Advances and Future Directions

Recent advances in biodiesel production from agricultural products and microalgae using ionic liquids: Opportunities and challenges

Simultaneous esterification and transesterification of waste phoenix seed oil with a high free fatty acid content using a free lipase catalyst to prepare biodiesel

Guanidine post-functionalized crystalline ZIF-90 frameworks as a promising recyclable catalyst for the production of biodiesel via soybean oil transesterification

Biodiesel has the potential to contribute significantly to the elimination of the present global energy and climate change logjam, but its production and commercialization have been hindered by the diverse nature of the feedstocks used for production. This paper reviews the effectiveness of applying various types of crop and animal waste‐derived catalysts together with innovative feedstock hybridization as an economically viable technique for biodiesel production. Feedstock challenges, availability, and sustainability for large‐scale applications are addressed with a view to bridging the existing gaps. Challenges in the use of edible oils and algae oil sources and development remain, but the technique of feedstock hybridization appears to be very promising, innovative, and cost‐effective for biodiesel production. The present state of biodiesel production could be improved by the application of simple and cost‐effective technologies in the feedstock system. High free fatty acid (FFA) content is the major hurdle to the use of most oils, especially low‐grade/advanced oil feedstocks, in biodiesel production. This could be addressed through technological application of feedstock hybrids and biogenic waste‐derived heterogenous catalysts, and their biochemical modifications. Conventional technology for the large‐scale application of inorganically derived catalysts in biodiesel production with various characteristic differences is presented. Heterogenous catalysts derived from biogenic wastes and their modification could be used to overcome associated problems with the use of inorganic catalysts in biodiesel production. Biogenic waste‐derived heterogenous catalysts are renewable, available, eco‐friendly, and cost‐effective. Technological applications of heterogeneous catalysts derived from biogenic waste are outlined and reviewed, considering various materials and different modification techniques to identify appropriate options for scaling up development. This review also discusses fundamental considerations for the exploitation of feedstock hybrids to optimize biodiesel production and its sustainable development. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd

Solid acid as catalyst for biodiesel production via simultaneous esterification and transesterification of macaw palm oil

Magnetized ZIF-8 impregnated with sodium hydroxide as a heterogeneous catalyst for high-quality biodiesel production

Mesoporous polymeric solid acid as efficient catalyst for (trans)esterification of crude Jatropha curcas oil

Evaluation on feedstock, technologies, catalyst and reactor for sustainable biodiesel production: A review

The utilization of sustainable and renewable materials, specifically CaO derived from blood clam shells and SiO2 extracted from coconut fiber, as catalysts for biodiesel production not only promotes waste valorization but also enhances catalytic efficiency, providing an eco-friendly and effective solution for biodiesel synthesis. The present study was synthesized and characterized CaO-SiO2 catalysts using the impregnation method with SiO2 content at 3, 5, and 7 wt.%. Characterization included surface area (BET), crystallinity and crystal size (XRD), chemical composition (XRF), functional groups (FTIR), and acidity-basicity (pyridine adsorption and titration). The maximum biodiesel yield of 96.29% was achieved under optimized conditions: 2 wt.% catalyst loading, 90-min reaction time, 60 °C temperature, and a 1:9 oil-to-methanol molar ratio, determined using response surface methodology (RSM). The synthesized biodiesel was evaluated according to ASTM D6751 standards, and its purity and methyl ester composition were analyzed using GC-MS. The results showed that the CaO-SiO2 catalyst achieved a biodiesel purity of 97.44%, higher than that obtained with unmodified CaO. This research successfully modified the CaO-SiO2 heterogeneous catalyst, enhancing its surface area and acidity, which led to an increase in the purity and yield of biodiesel synthesized from crude palm oil with high free fatty acid content.

Economic and environmental reasons show a trend towards replacing fossil fuels with biofuels such as those from triglycerides. Biodiesel can be obtained from vegetable oils and animal fat through several processes such as transesterification, esterification, usually with methanol, ethanol or through pyrolysis, all of them in the presence of an acid or basis catalyst. The use of solid catalysts in biodiesel production has the following advantages: easy recovery and reuse, thus decreasing process costs and amount of waste generated. 1 Some of the problems in the use of solid catalysts are: low concentration of active sites, microporosity, and leaching of active sites. 2 Studies aiming at developing methodologies involving hydrated niobium oxide as catalyst in biodiesel production have been carried out by our research group. 3,4 Parameters such as the use of assistant solvent to increase the boiling point of the mixture (toluene, ethylene glycol, and DMSO), pre-thermal treatment (calcinations) and catalyst molar concentration were initially assessed in esterification, oleic acid, and methanol reactions. From these studies we could observe that high temperatures and excessive alcohol favor esterification reactions. The best reaction conditions were then used as models and employed in transesterification reactions of soybean oil. DMSO (Dimethyl sulfoxide) was the solvent used to increase the reaction medium temperature without evaporating all the methanol. Transesterification reactions were carried out with soybean oil (0.5 g), methanol (0.85 g), DMSO (2.50 ml), and hydrated niobium oxide as catalyst in ratios of 20% and 100% (in relation to oil mass). Catalyst was employed without pretreatment and after pretreatment at 115 °C, 300 °C, and 500 °C. The reactions occurred at 170 °C, under reflux for 48 hours. A reaction without a catalyst was also carried out. All the reactions have shown conversion using CCD and they have been determined by 1 H NMR spectroscopy.

The oleic acid solubility in methanol is low due to two phase separation, and this causes a slow reaction time in biodiesel production. Tetrahydrofuran as co-solvent can decrease the interfacial surface tension between methanol and oleic acid. The objective of this study was to investigate the effect of co-solvent, methanol to oleic acid molar ratio, catalyst amount, and temperature of the reaction to the free fatty acid conversion. Oleic acid esterification was conducted by mixing oleic acid, methanol, tetrahydrofuran and Amberlyst 15 as a solid acid catalyst in a batch reactor. The Amberlyst 15 used had an exchange capacity of 2.57 meq/g. Significant free fatty acid conversion increments occur on biodiesel production using co-solvent compared without co-solvent. The highest free fatty acid conversion was obtained over methanol to the oleic acid molar ratio of 25:1, catalyst use of 10%, the co-solvent concentration of 8%, and a reaction temperature of 60°C. The highest FFA conversion was found at 28.6 %, and the steady state was reached after 60 minutes. In addition, the use of Amberlyst 15 oleic acid esterification shows an excellent performance as a solid acid catalyst. Catalytic activity was maintained after 4 times repeated use and reduced slightly in the fifth use.

A cleaner approach with magnetically assisted reactor setup over CaO-zeolite/Fe3O4 catalyst in biodiesel production: Evaluation of catalytic performance, reusability and life cycle assessment studies

Food waste, including non-reusable materials like chicken bones, forms a significant portion of solid waste. In Malaysia, approximately 540,000 tons of waste cooking oil (WCO) is discarded annually without proper treatment. Chicken bones, rich in calcium, can be utilized as a heterogeneous catalyst in biodiesel production, addressing waste management issues. However, the use of chicken bone as a catalyst presents challenges such as the unmodified chicken bones often require a pre-treatment step to reduce high free fatty acid (FFA) content in WCO to prevent saponification, limiting their efficiency. Hence, this research endeavors to innovate by converting WCO into biodiesel via a transesterification reaction, leveraging waste chicken bones as a catalyst. The calcined waste chicken bone (CB) was modified to form 5 wt% Fe-CB, and 10 wt% Fe-CB. The catalysts were found to have similar physical characteristics in terms of the structure and surface morphology observed from XRD, N2 adsorption-desorption, and SEM analysis. Among the catalysts, 10 wt% Fe-CB, produced the highest yield of fatty acid methyl esters (FAME), reaching 72.52%, under mild reaction conditions (10:1 methanol-to-WCO molar ratio, 1 wt% catalyst loading, 60 oC reaction temperature and 4 h reaction time). The capability of 10 wt% Fe-CB to produce a higher fatty acid methyl esters (FAME) yield than 5 wt% Fe-CB and calcined CB was due to the presence of CaO with binary transition metal oxides providing both acidic and basic sites, allowing for more efficient WCO conversion.

Cocoa butter (CB) technological quality and financial value depend widely on the free fatty acids (FFA) content. Cocoa butter has to contain less than 1.75% free fatty acids (FFA, based on oleic acid) to be in compliance with the EU directive 2000/36/EC (2000) and needs to be free from off-flavours and rancidity from a sensory (taste, odour, colour) and technological point of view. Free fatty acids are carboxylic acids, generated from triglycerides via the hydrolysis of their ester bounds by enzymatic and/or chemical reactions. The present work reviews free fatty acids formation mechanisms in cocoa beans, the free fatty acids levels assay as well as possible reduction methods. Furthermore, the impact of high free fatty acids content on the technological and chemical qualities and on the health of consumer of cocoa derived products were described. The results highlighted that the free fatty acids formation in cocoa beans was ascribed to the endogenous and exogenous lipases activities. Excreted exogenous lipases by contaminated molds during poor post-harvest processing are most active for free fatty acids generation in cocoa beans. In addition, the germination, poor storage conditions such as high water activity and moisture content provoke high free fatty acids content in cocoa butter. Although alkalization, deodorization and other refining treatments are efficient methods for reduction of free fatty acids content, chocolate manufacturers recorded high losses in cocoa butter. It is important to eliminate the free fatty acids content of cocoa butter because excessive consumption of high- free fatty acids cocoa product induces pathologies.

Due to increasing concerns about global warming and dwindling oil supplies, the world’s attention is turning to green processes that use sustainable and environmentally friendly feedstock to produce renewable energy such as biofuels. Among them, biodiesel, which is made from nontoxic, biodegradable, renewable sources such as refined and used vegetable oils and animal fats, is a renewable substitute fuel for petroleum diesel fuel. Biodiesel is produced by transesterification in which oil or fat is reacted with short chain alcohol in the presence of a catalyst. The process of transesterification is affected by the mode of reaction, molar ratio of alcohol to oil, type of alcohol, nature and amount of catalysts, reaction time, and temperature. Various studies have been carried out using different oils as the raw material; different alcohols (methanol, ethanol, butanol); different catalysts; notably homogeneous catalysts such as sodium hydroxide, potassium hydroxide, sulfuric acid, and supercritical fluids; or, in some cases, enzymes such as lipases. This article focuses on the application of heterogeneous catalysts for biodiesel production because of their environmental and economic advantages. This review contains a detailed discussion on the advantages and feasibility of catalysts for biodiesel production, which are both environmentally and economically viable as compared to conventional homogeneous catalysts. The classification of catalysts into different categories based on a catalyst’s activity, feasibility, and lifetime is also briefly discussed. Furthermore, recommendations have been made for the most suitable catalyst (bifunctional catalyst) for low-cost oils to valuable biodiesel and the challenges faced by the biodiesel industry with some possible solutions.