A review of biomass-derived heterogeneous catalyst for a sustainable biodiesel production
TL;DR: A review of bio-based heterogeneous catalysts utilized for sustainable biodiesel production and their suitability for industrial application is presented in this article, where the use of these biomass derived catalysts provides a greener synthesis route for biodiesel synthesis.
Abstract: Biodiesel production is commonly carried out through the process of transesterification reaction. The reaction is expedited with a suitable catalyst either homogeneous or heterogeneous. The selection of an appropriate catalyst depends on the amount of free fatty acids in the oil. Recently, homogeneous catalysts are widely chosen for biodiesel production in large scale operation. However, they are toxic, highly flammable and corrosive in nature. Furthermore, the use of homogeneous catalyst produced soaps as by-product and large amount of wastewater that required additional processing technologies and cost for proper disposal. On the contrary, heterogeneous catalysts are capable to overcome the problems faced by the former ones. However, they were mostly derived from non-renewable resources, highly expensive with low stability. Recently, heterogeneous catalysts derived from biological waste have gotten more attention. This type of catalysts offers several advantages, including renewable resources, non-toxic, reusable, high catalytic activity, stability in both acidic and basic conditions and high water tolerance properties, which depend on the amount and strengths of active acid or basic sites. Basic catalyst can be subdivided based on the type of metal oxides and their derivatives. Similarly, acidic catalyst can be subdivided depending upon their active acidic sites. In this article, efforts have been taken to review the bio-based heterogeneous catalyst utilized for sustainable biodiesel production and their suitability for industrial application. Catalyst generated from bio-waste and other biocatalysts, which are heterogeneous in nature and extensively reported in literature are also reviewed. The utilization of these biomass derived catalysts provides a greener synthesis route for biodiesel production.
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TL;DR: The most recent development of metal organic frameworks (MOFs) as precursors for the preparation of various nanostructures and their potential applications in energy-related devices and processes is presented in this article.
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TL;DR: In this paper, an organic-inorganic hybrid recyclable catalyst with both Bronsted and Lewis acid sites for the one-pot production of biodiesel from the low-cost acidic oil feedstocks is presented.
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TL;DR: In this article, the authors focus on the recent finding in transesterification of non-edible sources for biodiesel production as well as its economic aspects, fuel properties, and by-products applications.
213 citations
TL;DR: In this paper, a review of catalytic hydrodeoxygenation (HDO) catalysts for green bio-diesel is presented, including the sulfur-free noble metals, non-noble metals, metal phosphides, metal carbides and metal nitrides.
Abstract: Biodiesel as a substitute of traditional petroleum-derived liquid fuels has been put into use in recent years. However, the first generation biodiesel (fatty acid methyl esters) with high oxygen content is inconvenient for large-scale use due to its incompatible nature with fossil fuels. As a result, green biodiesel (the second generation biofuel) prepared from catalytic hydrodeoxygenation (HDO) of the first generation biodiesel has been gradually developed. The biodiesel after deoxygenation which has a great number of advantages is similar to petroleum fuel in composition, so it can be employed directly in fuel industry. To obtain the expected products, accessible production processes and suitable catalyst systems are needed. In this review, we first make an analysis on the pathways and processes of deoxygenation reactions including hydrodeoxygenation, decarboxylation and decarbonylation. Selectivity to reaction pathways has a close relationship with raw materials, catalysts or reaction conditions. The special goal of this review is to highlight the advances in the heterogeneous sulfur-free catalysts used for deoxygenation, including the sulfur-free noble metals, non-noble metals, metal phosphides, metal carbides and metal nitrides. We thoroughly discussed the different performances of these developed catalysts in the deoxygenation reactions, such as activity, selectivity and stability. Fundamental mechanisms over sulfur-free catalysts, including experimental comparison of different active phases and calculations by Density Function Theory (DFT), were also addressed. This review also involved effects of different support materials, composition, structure optimization, water and H2 pressure on the HDO activity and silectivity, and detailed information about catalyst deactivation. It is expected that this review can provide some new design and modification strategies for fabricating highly active,selective and durable earth-abundant HDO catalysts for the substainable production of green bio-diesel.
160 citations
TL;DR: A review of the latest synthesis routes of various types of catalysts (including acidic, basic, bifunctional and nanocatalysts) derived from different chemicals, as well as biomass is presented in this paper.
Abstract: An ever-increasing energy demand and environmental problems associated with exhaustible fossil fuels have led to the search for an alternative renewable source of energy. In this context, biodiesel has attracted attention worldwide as an eco-friendly alternative to fossil fuel for being renewable, non-toxic, biodegradable, and carbon-neutral. Although the homogeneous catalyst has its own merits, much attention is currently paid toward the chemical synthesis of heterogeneous catalysts for biodiesel production as it can be tuned as per specific requirement and easily recovered, thus enhancing reusability. Recently, biomass-derived heterogeneous catalysts have risen to the forefront of biodiesel productions because of their sustainable, economical and eco-friendly nature. Furthermore, nano and bifunctional catalysts have emerged as a powerful catalyst largely due to their high surface area, and potential to convert free fatty acids and triglycerides to biodiesel, respectively. This review highlights the latest synthesis routes of various types of catalysts (including acidic, basic, bifunctional and nanocatalysts) derived from different chemicals, as well as biomass. In addition, the impacts of different methods of preparation of catalysts on the yield of biodiesel are also discussed in details.
144 citations
References
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TL;DR: In this article, the transesterification reaction is aected by molar ratio of glycerides to alcohol, catalysts, reaction temperature, reaction time and free fatty acids and water content of oils or fats.
4,902 citations
TL;DR: In this article, the main factors affecting the yield of biodiesel, i.e. alcohol quantity, reaction time, reaction temperature and catalyst concentration, are discussed, as well as new new processes for biodiesel production.
2,207 citations
TL;DR: The most important variables affecting methyl ester yield during the transesterification reaction are the molar ratio of alcohol to vegetable oil and the reaction temperature as discussed by the authors, which is the commonly used alcohol in this process, due to its low cost.
1,798 citations
TL;DR: In this paper, a review of the alternative technological methods that could be used to produce this fuel is made, and advantages and disadvantages of technologies are listed and for all of them a kinetics model is introduced.
Abstract: Biodiesel production is a very modern and technological area for researchers due to the relevance that it is winning everyday because of the increase in the petroleum price and the environmental advantages. In this work it is made a review of the alternative technological methods that could be used to produce this fuel. Different studies have been carried out using different oils as raw material, different alcohol (methanol, ethanol, buthanol) as well as different catalysts, homogeneous ones such as sodium hydroxide, potassium hydroxide, sulfuric acid and supercritical fluids, and heterogeneous ones such as lipases. In this work advantages and disadvantages of technologies are listed and for all of them a kinetics model is introduced.
1,323 citations
TL;DR: In this paper, the authors reviewed the source of production and characterization of vegetable oils and their methyl ester as the substitute of the petroleum fuel and future possibilities of Biodiesel production.
Abstract: The world is confronted with the twin crises of fossil fuel depletion and environmental degradation. The indiscriminate extraction and consumption of fossil fuels have led to a reduction in petroleum reserves. Petroleum based fuels are obtained from limited reserves. These finite reserves are highly concentrated in certain region of the world. Therefore, those countries not having these resources are facing a foreign exchange crisis, mainly due to the import of crude petroleum oil. Hence it is necessary to look for alternative fuels, which can be produced from materials available within the country. Although vegetative oils can be fuel for diesel engines, but their high viscosities, low volatilities and poor cold flow properties have led to the investigation of its various derivatives. Among the different possible sources, fatty acid methyl esters, known as Biodiesel fuel derived from triglycerides (vegetable oil and animal fates) by transesterification with methanol, present the promising alternative substitute to diesel fuels and have received the most attention now a day. The main advantages of using Biodiesel are its renewability, better quality exhaust gas emission, its biodegradability and the organic carbon present in it is photosynthetic in origin. It does not contribute to a rise in the level of carbon dioxide in the atmosphere and consequently to the green house effect. This paper reviews the source of production and characterization of vegetable oils and their methyl ester as the substitute of the petroleum fuel and future possibilities of Biodiesel production.
1,250 citations