|Biodiesel is a renewable and biodegradable alternative green fuel for petroleum-based diesel. The major obstacle for the production of biodiesel at an industrial scale is the high production cost, which is related to the relative high price of the conventional “1st generation feedstocks” (refined vegetable oils) used. This problem can be addressed by using low cost feedstocks such as waste oils and fats. However, these feedstocks contain high amounts of free fatty acids (FFA) which cannot be used for the production of biodiesel using a traditional homogeneous alkali-catalyzed transesterification process. Furthermore, there is a great need to develop a green process which can be used for multiple feedstocks. This shows the universal ability of the process to be adopted as per availability of local feedstock. In this study, a single-step second generation heterogeneous-catalyzed process is developed to produce biodiesel from multi-feedstocks.
Due to an increase in the commercial use of biodiesel and biodiesel blends, both ASTM D6751 and EN 14214 include the acid number (AN) as an important quality parameter. Currently, ASTM D974 and D664 analytical methods for acid number analysis of biodiesel are time consuming, expensive, and environmentally not friendly. Therefore, ASTM D974 has been modified and a green analytical method has been developed. This extensive study has demonstrated that this new method is a reliable method for the determination of AN and could be used for establishing the specifications of AN for biodiesel and biodiesel blends ranging from B1 to B20 in quality standards. The ASTM reference standard method D664, has major problems such as the use of excess toxic solvents, large sample size, mediocre reproducibility, tedious process for cleaning electrodes, and relatively long analysis time. Therefore, a new proposed method based on green chemistry approaches, has been developed to determine the acid number of biodiesel and biodiesel blends using small sample size and reduced toxic titration solvent. This proposed green analytical method could be used for the determination of AN of biodiesel and biodiesel blends in R&D as well as industrial quality control laboratories as a simple, time-efficient, cost effective and environmentally friendly method.