Biodiesel is a long-chain fatty acid ester made from renewed and biological raw materials such as used cooking, animal fat, vegetable oil, and algae. Biodiesel is a renewable and clean fuel as it reduces carbon monoxide, carbon dioxide, hydrocarbons, and particulate matter emissions compared with petroleum-based diesel fuel. Production of biodiesel from renewable resources is done through the transesterification reaction at which the organic group (alkyl) of alcohol is substituted with the organic group of a triglyceride– the main component of the feedstock –producing fatty acid alkyl ester (biodiesel) and crude glycerol. Biodiesel can be used in pure form (B100) or may be blended with petroleum diesel at any concentration if its specifications is identical to the international standard specifications provided by American standard for testing materials (ASTM) or EN14214 in the European Union for alternative fuels. In this paper, the different types of biodiesel feedstocks, feedstocks treatment methods, and biodiesel production technologies are reviewed and discussed.

CoFe₂O₄–SiO₂–TiO₂core–shell–shell magnetic nanocomposites have been prepared by coating cobalt ferrite nanoparticles with double layers of SiO₂–TiO₂.

Approximately 50% of global plastic wastes are produced from plastic packaging, a substantial amount of which is disposed of within a few minutes of its use. Although many plastic types are designed for single use, they are not always disposable. It is now widely acknowledged that the production and disposal of plastics have led to a plethora of negative consequences, including the contamination of both groundwater and soil resources and the deterioration of human health. The undeniable impact of excessive plastic manufacturing and waste generation on the global plastic pollution crisis has been well documented. Therefore, degradable polymers are a crucial solution to the problem of the non-degradation of plastic wastes. The disadvantage of degradable polymers is their high cost, so blending them with natural polymers will reduce the cost of final products and maximize their degradation rate, making degradable polymers competitive with industrial polymers that are currently in use daily. In this work, we will delineate various degradable polymers, including polycaprolactone, starch, and cellulose. Furthermore, we will elucidate several aspects of polyvinyl alcohol (PVA) and its blends with natural polymers to show the effects of adding natural polymers on PVA properties. This paper will study cost-effective and ecologically acceptable polymers by combining inexpensive natural polymers with readily accessible biodegradable polymers such as polyvinyl alcohol (PVA).