Sulfonation of Natural Carbonaceous Bentonite as a Low-Cost Acidic Catalyst for Effective Transesterification of Used Sunflower Oil into Diesel; Statistical Modeling and Kinetic Properties

Abstract

Bentonite sample enriched in organic matters (oil shale) was functionalized with −SO3H sulfonated carbonaceous bentonite (S-CB) by sulfonation process as a low-cost and effective acidic catalyst for the transesterification spent sunflower oil (SFO). The sulfonation effect was followed by several analytic techniques including X-ray diffraction, Fourier transform infrared, and scanning electron microscopy analysis. The catalytic performance of the sulfonated product was evaluated based on a statistical design which was built according to the response surface methodology and the central composite rotatable design. Using the S-CB acidic catalyst in the transesterification of spent SFO resulted in an actual biodiesel yield of 96% at studied conditions of 85 min at reaction interval, 50 °C as temperature,15:1 as methanol/oil ratio, and 3.5 wt % as S-CB loading. Moreover, the optimization function suggested enhancement to obtained yield up to 97.9% by selecting the values of temperature at 62 °C, the time at 98.5 min, the methanol/SFO ratio at 14.4:1, and S-CB loading at 3.4 wt %. The technical evaluation of the SFO biodiesel reflected the suitability of the product to be used as biofuels according to international standards. The kinetic behavior of the SFO transesterification reaction over S-CB is of pseudo-first order properties and of low activation energy. Finally, the synthetic S-CB as a solid acidic catalyst is of significant reusability and was reused five times with remarkable biodiesel yields.

Kinetic, Thermodynamic, and Mechanistic Studies on the Effect of the Preparation Method on the Catalytic Activity of Synthetic Zeolite-A during the Transesterification of Waste Cooking Oil

“…Based on the determination coefficient values (R 2 > 0.95) of the plotted kinetic graphs, the methanolysis and the transesterification of waste cooking oil over DH.ZA and H.ZA occurred according to the kinetic properties of the pseudo-first-order kinetic model. Therefore, the adsorptionsurface reaction-desorption processes are the essential operating mechanisms that control the transesterification of waste cooking oil by both DH.ZA and H.ZA, which is in agreement with the suggested mechanism based on the FT-IR findings [43,48]. Moreover, the increase in the rate constant with temperature and their higher values during the applications of DH.ZA as compared to H.ZA is in agreement with the experimental findings regarding the impact of temperature and the higher catalytic activity of DH.ZA than H.ZA.…”

“…The determined FAME conversion efficiencies using H.ZA and DH.ZA increased at remarkable rates with the experimental increase in the methanol contents, which corresponded to the molar ratios of 14:1 (95.8% FAME yield) and 12:1 (96.8% FAME yield), respectively (Figure 4E). This was assigned to the reducing effect of the excess in the menthol content on the viscosity and immiscibility properties between the reactants as well as the mass transfer resistance [6,43]. Additionally, the excess in the methanol concentration significantly accelerates the interaction between the zeolite-A particles and the present triglycerides up to a certain extent [34].…”

Microwave-assisted biodiesel production using bio-waste catalyst and process optimization using response surface methodology and kinetic study

“…S2 g,h) of BP-SO 3 H which shows agglomeration of dense particles leading to a spherical structure. This possibly could be due to sulfonation using H 2 SO 4 which might be the effect of the acid in oxidizing organic matters and dissolving impurities 32 . The EDX analysis results also support the observation, as the S content was found to be 4.62 wt% (1.4437 mmol g −1 ) (Fig.…”

“…Shang et al 30 used agricultural byproduct peanut shell, Kumawat, and Rokhum 31 used orange peel waste for simultaneous carbonization and sulfonation with H 2 SO 4 as a reagent. Hassan et al 32 revealed that using H 2 SO 4 for sulfonation is of low cost and provides high acidity to the carbonaceous Bentonite catalyst. Ngaosuwan et al 33 predicted that these sulfonated-carbon catalysts in industries for catalytic reactions like esterification, transesterification, nitration, and cellulose hydrolysis could soon replace homogeneous H 2 SO 4 catalyst.…”