Optimization of Biodiesel Production from Waste Cooking Oil Using S–TiO2/SBA-15 Heterogeneous Acid Catalyst

Abstract

The aim of this research was to synthesize, characterize, and apply a heterogeneous acid catalyst to optimum biodiesel production from hydrolyzed waste cooking oil via an esterification reaction, to meet society's future demands. The solid acid catalyst S-TiO 2 /SBA-15 was synthesized by a direct wet impregnation method. The prepared catalyst was evaluated using analytical techniques, X-ray diffraction (XRD), Scanning electron microscopy (SEM) and the Brunauer-Emmett-Teller (BET) method. The statistical analysis of variance (ANOVA) was studied to validate the experimental results. The catalytic effect on biodiesel production was examined by varying the parameters as follows: temperatures of 160 to 220 • C, 20-35 min reaction time, methanol-to-oil mole ratio between 5:1 and 20:1, and catalyst loading of 0.5%-1.25%. The maximum biodiesel yield was 94.96 ± 0.12% obtained under the optimum reaction conditions of 200 • C, 30 min, and 1:15 oil to methanol molar ratio with 1.0% catalyst loading. The catalyst was reused successfully three times with 90% efficiency without regeneration. The fuel properties of the produced biodiesel were found to be within the limits set by the specifications of the biodiesel standard. This solid acid catalytic method can replace the conventional homogeneous catalyzed transesterification of waste cooking oil for biodiesel production.

Biodiesel Production Using Homogeneous, Heterogeneous, and Enzyme Catalysts via Transesterification and Esterification Reactions: a Critical Review

“…Transesterification/esterification is a chemical conversion of lipids such as vegetable oils and animal fats reacting with alcohol to form fatty acid alkyl esters (FAAE). In the esterification process, the free fatty acid (FFA) reacts with alcohol to produce FAAE and water [ 4 ]. In transesterification, triglycerides react with alcohol and produce FAAE and glycerol.…”

“…Biodiesel is referred to as fatty acid monoesters derived from the transesterification of triglycerides and esterification of free fatty acids with alcohol [ 3 , 4 ]. Various acyl acceptors are used in biodiesel production, such as methanol, ethanol, propanol, and butanol.…”

Nanoferrites heterogeneous catalysts for biodiesel production from soybean and canola oil: a review

“…Additionally, heterogeneous catalysts allow high molecular weight alcohols to be used and often prove efficient in reactions where homogeneous catalysts are generally inactive. The solid-base heterogeneous catalysts have been extensively studied by researchers as their catalytic activity is greater than that of the solid-acid heterogeneous catalysts, and they offer higher conversion rates at lower reaction temperatures (Hossain et al 2019 ; Vasić et al 2020 ). A suitable heterogeneous catalyst must be highly stable, mesoporous, inexpensive, and benign (Changmai et al 2020 ).…”

Biodiesel Production Using Solid Acid Catalysts Based on Metal Oxides

“…The catalyst exhibited 90% efficiency for three recycles, without regeneration. A purification step is unnecessary for such a catalyst, which simplifies the process and leads to no generation of wastewater, which makes such a catalyst an environmentally friendly replacement of conventional catalysts [91]. Li 2 TiO 3 was used for the transesterification of soybean oil into biodiesel and prepared through a solid-state reaction that involved mixing and grinding TiO 2 and Li 2 CO 3 , followed by calcination at 1073.15 K for 2 h. A biodiesel conversion rate of 98.5% was obtained under optimal reaction conditions of a methanol-oil molar ratio of 24:1, catalyst amount of 6 wt.…”