Ethical issues pertaining to sustainable biodiesel synthesis over trans/esterification process

There is a global search for renewable energy sources because of the increasing unpredictability of petroleum supplies and the related environmental problems from the use of fossil fuels. Cur-rently, biodiesel has gained a major momentum of interest as an environmentally benign alterna-tive fuel for compression ignition engines and a majority of the world has been proffering a po-tential drive for its viable application. It can be made from renewable sources employing cost -competitive and energy-efficient trans/esterification process and is compatible with existing in-frastructure. Biodiesel production process encompasses various steps viz. feedstock assortment, crude oil extraction, catalyst development, feedstock processing, trans/esterification of feed-stock, product purification, ecological toxicity, and land-use pattern. Hence, for biodiesel produc-tion especially on a large-scale, everyone must be aware of the activities which could not exhibit any deleterious impacts or create secondary problems for the environment. This article aims to outline a review by exploring various ethical issues related to biodiesel production that one may encounter while pursuing biodiesel research. The major ethical issues pertaining to the selection of feedstock are food vs. fuel trade-off, problems with land acquisition for biodiesel, and societal impacts of the global biodiesel trade. Other ethical concerns examine the effects on the environ-ment, specifically deforestation and other (indirect) land-use changes that affect greenhouse gas emissions. Moreover, this review paper also highlights one significant ethical question related to the purification and water washing of biodiesel that cause the presence of oil spills in water, which results in environmental degradation in the form of ecological toxicity.