Use of Co/Fe-Mixed Oxides as Heterogeneous Catalysts in Obtaining Biodiesel

Abstract

Catalyst-type mixed metal oxides with different compositions and Co/Fe ratios were obtained from layered double hydroxides to be used as heterogeneous catalysts in the production of biodiesel. The effect of the Co/Fe ratio on the precursors of the catalysts was analyzed, considering their thermal, textural and structural properties. The physicochemical properties of the catalysts were determined by thermogravimetric analysis (differential scanning calorimetry and thermogravimetric), X-ray diffraction, Fourier-transform infrared spectroscopy, Scanning Electron Microscopy-Energy Dispersive X-ray spectroscopy and N2-physisorption. The conversion to biodiesel using the different catalysts obtained was determined by diffuse reflectance infrared Fourier-transform spectroscopy and 1H-Nuclear magnetic resonance spectroscopy, allowing us to correlate the effect of the catalyst composition with the catalytic capacity. The conditions for obtaining biodiesel were optimized by selecting the catalyst and varying the percentage of catalyst, the methanol/oil ratio and the reaction time. The catalysts reached yields of conversion to biodiesel of up to 96% in 20 min of reaction using only 2% catalyst. The catalyst that showed the best catalytic activity contains a mixture of predominant crystalline and amorphous phases of CoFe2O4 and NaxCoO2. The results suggest that cobalt is a determinant in the activity of the catalyst when forming active sites in the crystalline network of mixed oxides for the transesterification of triglycerides, with high conversion capacity and selectivity to biodiesel.

Advances in Nanocatalysts Mediated Biodiesel Production: A Critical Appraisal

“…However, Di Serio et al [93] claimed that calcined Li/Al hydrotalcites were most active in the glycerolysis of fatty acid than Mg/Al material due to high Lewis basicity. Similarly, Gutiérrez-Ortega et al [94] reviewed the role of Co/Fe-mixed oxides as heterogeneous catalysts in the production of biodiesel. In this article, authors mentioned that all the different kinds of nanohydrotalcite including Co/Fe-mixed oxides can be effectively used for transesterification of various oils.…”

A green approach for enhancing the hydrophobicity of UiO-66(Zr) catalysts for biodiesel production at 298 K

“…Recently, heterogeneous catalysts have been introduced to solve the aforementioned problems because of their many advantages, including easy separation from the reaction mixture, environmental friendliness and good reusability. 13,14 Various types of heterogeneous catalysts, such as ion-exchange resins, 15 alkoxides, 16,17 Mg-Al hydrotalcites, [18][19][20] metal oxides and hydroxides, [21][22][23][24] are used in biodiesel production by the alcoholysis of vegetable oils, animal fats or various fatty acids. Heterogeneous base catalysts are more efficient in activating the reaction than acid catalysts.…”

Biodiesel-Derived Glycerol Obtained from Renewable Biomass—A Suitable Substrate for the Growth of Candida zeylanoides Yeast Strain ATCC 20367

“…The triglycerides from vegetal or animal sources can be efficiently converted into biodiesel through a variety of procedures, such as direct mixtures with solvents, micro-emulsions, pyrolysis, and transesterification [23,24,25,26]. The biodiesel phase consisting of fatty acids methyl/ethyl esters is mostly achieved through transesterification using various catalysts [27].…”

“…The biodiesel phase consisting of fatty acids methyl/ethyl esters is mostly achieved through transesterification using various catalysts [27]. The transesterification reaction and the quality of the final products depend significantly on the catalyst type (alkaline (sodium hydroxide, sodium methoxide, potassium hydroxide) vs. acidic (sulfuric acid, sulphonic acid, hydrochloric acid) vs. enzymatic (lipase)) and its concentration [20,24,28,29,30]. During transesterification, the ester bonds between fatty acids and glycerol break down, and the free fatty acids bind to other alcohol molecules present in the reaction medium.…”