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The properties of biodiesel are completely dependent on the fatty acid profile of feedstock oils. Several feedstocks are not in use for biodiesel production because of the presence of unsuitable fatty acids in their oils. The present study was conducted to overcome this problem by the utilization of interesterification and hydrolysis processes. The present study reports biodiesel with much better cold flow properties than previous studies. Fatty acids present in Pongamia pinnata oil were optimized via interesterification and hydrolysis treatment of feedstock prior to alkali-catalyzed transesterification. The physiochemical properties of fuel were evaluated by standard test methods and the results were compared with EN 14214 and ASTM D6751 standards. Biodiesel composition was analyzed by a gas chromatographic analysis. The density, saponification and iodine values of the biodiesel derived from treated and non-treated oil were found to be within the range recommended by the international fuel standards. The acid values of biodiesel produced from non-treated and treated fractions were high (0.7–0.8 mg of KOH/g of oil), as compared to the biodiesel produced from non-treated and treated pure oil. The cloud points and pour points of biodiesel produced from hydrolyzed and interesterified oil were in the range of (8.1 to −9.6 °C) and (2.03 to −12.5 °C), respectively, while those of non-treated oil were in the range of (13.37 to −1.53 °C). These results indicate that treatments of oil specifically improved the low-temperature properties of biodiesel.

The adsorption process combined with electrocoagulation is a highly effective technique for dye removal. Calcinized and non-calcinized composites based on bentonite and sodium zeolite were prepared for adsorptive removal of Foron EBL blue, Terasil brown 2RFL, Torque blue PG, and Orange P3R dyes. Factors affecting the adsorption process, such as contact time, initial dye concentration, and temperature, were also explored in this study. Equilibrium data of natural clay composites was explained by Freundlich, Langmuir, Dubinin Radushkevich isotherm, Harkin Jura, and Temkin isothermal models. Harkin Jura isotherm model best fitted on the adsorption mechanism compared to Langmuir and Temkin isotherm model. Morphology of clay-based adsorbents and functional group arrangement were investigated by scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). The calcinized nano-composite material exhibited better adsorption capacity than non-calcinized nano-composite and could be employed as a low-cost alternative for dye removal.