Heterogenous catalysts for transesterification from snail, crustacean and mollusc shells

In biodiesel synthesis, the process of catalytic transesterification of vegetable oil with alcohols is applied. Among heterogeneous catalysts, calcium oxide is more promising, which can be obtained from various natural compounds and waste. Waste generated in the food industry – shells of land snail, Arthropod crustaceans, and molluscs - contains calcium carbonate, which decomposes into calcium oxide when heated at high temperatures. Such prepared shells can be used in biodiesel synthesis. The article reviews the possibilities presented in the scientific literature of using snail, crustaceans, and mollusc shells in biodiesel synthesis. The objectives if review was to analyse catalyst preparation processes focusing on the activity of catalysts depending on calcination conditions. The possibilities of using catalysts in the transesterification process and the properties of biodiesel depending on the transesterification conditions with great attention paid to biodiesel yield are analysed. The catalyst regeneration process is discussed and its reuse possibilities are analysed. The article presents the physical and chemical properties of biodiesel specified by various authors and their compliance with the requirements of EN 14214 and ASTM standards. Prospects for the preparation and use of heterogeneous catalysts obtained from shells for biodiesel synthesis and their economic and environmental advantages. • Land snails, Arthropod crustaceans, and molluscs could be used as catalysts for biodiesel production. • Preparation methods of the shell are reviewed. • Optimal transesterification conditions are presented. • Possibilities of catalyst regeneration and reuse are discussed. • Biodiesel properties are analysed.