Review of biodiesel production using various feedstocks and its purification through several methodologies, with a specific emphasis on dry washing

Renewable biomass fuels are gaining attention as a cleaner energy alternative to fossil-based resources. Biodiesel, derived from biological sources, is particularly attractive due to its renewable and ecological benefits. Researchers are actively exploring various methodologies to convert biomass into gaseous and liquid fuels, similar to petroleum products. To optimize production and accommodate different feedstock sources, biodiesel production through different routes is becoming popular. The purification of biodiesel is an important step, and current methods involving water usage are being replaced with more sustainable alternatives. Adsorption and ion exchange, known as dry washing methods, are widely used for biodiesel purification worldwide. These processes use an adsorbent to selectively remove impurities from the liquid phase, offering advantages such as easy integration, shorter purification time, reduced water consumption, and minimal effluent generation. This review focuses on biodiesel production and purification methods, highlighting the advantages of adsorption over traditional wet washing methods.