Optimization of methyl esters production from non-edible oils using activated carbon supported potassium hydroxide as a solid base catalyst

Abstract

The present investigation reports transesterification of non-edible oils, waste cooking oil (WCO) and waste fish oil (WFO) with methanol using activated carbon supported potassium hydroxide (KOH) as a solid base catalyst. Activated carbon was prepared from polyethylene terephthalate waste and loaded with KOH by wet impregnation method to prepare KOH/AC solid base catalyst. X-ray diffraction and Scanning Electron Microscopy (SEM) were utilized to characterize the resulting solid base catalyst. Retention method was utilized to measure the specific surface area of the activated carbon and its derived solid base catalyst, while Hammett indicator method was followed to determine the basic strength of the prepared solid base catalyst. The prepared catalyst has granular and porous structures with a high basicity and a superior catalytic performance for the transesterification reaction. Transesterification reaction variables were arranged to obtain the best biodiesel yield. The highest methyl ester yield from WCO (88.12% w/w with an ester content of 96.68% w/w) was obtained by employing 3.5 wt.% KOH/AC catalyst, 9:1 methanol to oil molar ratio, 65 C reaction temperature, the reaction time of 180 min and the stirring rate of 600 rpm, while maximum methyl ester yield from WFO (92.66% w/w with 96.98% w/w ester content) was produced with 3.0 wt.% KOH/AC catalyst, 9:1 methanol to oil molar ratio at 65 C for 150 minutes of the reaction and 600 rpm. The prepared solid base catalyst was recoverable and thermally stable giving a yield of 70 wt.% after the 5th cycle. The fuel properties of the raw oils were significantly enhanced after transesterification with methanol in the presence of KOH/AC, and were in conformity with the ASTM D 6751 limits as well. Therefore, the prepared KOH/AC composite may be considered as a promising solid base catalyst for transesterification of non-edible oils with methanol. ARTICLE HISTORY

Biodiesel production from Lipidium sativum L.seed oil by alkali-catalyzed transesterification with different alcohols: Evaluation and analysis of biodiesels

“…The GCSO has a lower RI than other NEO. Besides, its RI was within the established range stated for other NEO (1.466-1.470) [17,19]. The fatty acids composition of GCSO manifested its higher content of unsaturated fatty acids (UFA) than saturated fatty acids (SFA).…”

Polyethylene terephthalate waste‐derived activated carbon for adsorptive desulfurization of dibenzothiophene from model gasoline: Kinetics and isotherms evaluation

“…Several sets of experiments were accomplished at various temperature (450–950°C), different periods (30–150 min), and various particle size (0.841, 0.4, 0.25, 0.21, and 0.149 mm). Lastly, the activated samples were cooled to room temperature and stored in sealed PET bags for further identification 25 . The yield of the AC was calculated as follows: The iodine number (IN), which estimates the micropore content of 0‐20A°, was specified following AATM 1112‐01 2006 standard test method 26 .…”

“…Data were recorded at 40 kV and 70 mA, by transmission in the 2θ range 20 and 80°. Boehm titration method was employed in the determination of the numbers of oxygen acid groups 25 …”

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

“…The separation and purification process often produce large quantities of chemical wastewater, leading to pollution and environmental contamination (OA et al 2019 ). Saponification and emulsification during the transesterification process tend to increase the production cost and reaction time and reduce the overall yield (Fadhil et al 2018 ; Krishnamoorthi et al 2018 ; OA et al 2019 ). The significant drawbacks mentioned above have limited the scope for extended development and commercialization of biodiesel synthesized using homogeneous catalysts.…”