Extruded Catalysts with Magnetic Properties for Biodiesel Production

Abstract

The aim of this work was to evaluate the performance of different extruded catalysts containing K2CO3as active phase and adding convenientlyγ-Al2O3and/or sepiolite and magnetic particles on the biodiesel production from sunflower oil by the ethanolic route. Firstly, the content of the Fe3O4on the catalyst (0.1, 0.2, 0.3, and 0.4 g Fe3O4/g of K2CO3/γ-Al2O3), after calcination step, was evaluated to verify the separation facility of the catalysts with magnetic properties from reactional medium, using an external magnetic field, at the end of biodiesel synthesis. After that, three different catalysts were considered for comparative purposes: (a) K2CO3/γ-Al2O3; (b) K2CO3/γ-Al2O3/Fe3O4; (c) K2CO3/γ-Al2O3/Sepiolite/Fe3O4and subsequently characterized by dynamometry, TGA, SEM, VSM, BET, and XRD to determine their mechanical, structural, magnetic, and textural properties. However, their catalytic activities were determined through biodiesel production that was carried out in a glass volumetric reactor during 4 h, under magnetic stirring with 5% wt. of the catalyst and oil : ethanol molar ratio (1 : 12) at 80°C reaction temperature. The best result, i.e., around 88% of biodiesel conversion, was obtained with catalyst K2CO3/γ-Al2O3/Sepiolite/Fe3O4which showed also satisfactory textural and mechanical strength properties comparatively with the other catalytic derivatives. In addition, no agglomeration of the particles was observed during the reaction, and the magnetic property of this catalytic system was satisfactory for adequate separation from reactional medium seeking further reuse. The attained results are attractive for possible implementation at industrial scale and can be considered to mitigate drawbacks which resulting by using of homogeneous catalysts in the conventional processes.

Crystal phase evolution of high temperature annealed Fe3O4‐CaO catalysts for biodiesel production

“…Using magnetic catalysts, 70-100% conversion has been achieved; however, stability is still problematic and reusability is still low. [18][19][20] The low reusability is usually attributed to particle agglomeration, and solubility of the ferric sulfate in methanol and water media produced, especially during the esterification reaction. 20 Oxides of iron alone cannot significantly promote a high yield of BD in transesterification reactions because of their poor basicity.…”

Development of a Reusable CaO/Fe3O4 Heterogeneous Catalyst for Biodiesel Production

“…Also, they have low resistance to mass transfer due to the small particle size. Using magnetic catalysts, 70-100% conversion has been achieved; however, the stability is still problematic and number of reusability is still low [11][12][13]. The low reusability was attributed to particle agglomeration, and solubility of the ferric sulphate in methanol and water media produced especially during esteri cation reaction [13].…”

“…Several catalytic materials have been developed over the years to propagate the BD synthesis. These catalysts mainly include homogeneous catalysts of acidic (H 2 SO 4 ) and alkaline (NaOH, KOH) origin [8-10], Enzymes (lipases) [11][12][13], and heterogeneous catalysts. Heterogeneous catalysts are widely attractive because of its easy separation, reusability and less corrosion tendencies compared to homogeneous catalysts.…”

Effect of single metal loading on CaO/AL2O3 pellet catalyst for biodiesel production

“…However, the solid catalysts for biodiesel production are still required the development of shaping catalyst instead of using small and fine particle size as presented in the numerous researches. The small and fine particle catalyst could be limited for using in industry scale [45]. The utilization of pellet catalyst is one of a practical choice to powder catalyst due to easy to separation from reaction mixture and minimize pressure drop for the continuous process.…”

“…In some report, metal oxide doped can promote the stability of catalyst. Silverira et al [45] used potassium (K) on the extruded alumina support in biodiesel production. The mechanical strength was increased when amount of potassium (K) was increased from 15 to 35 wt.% including the bimetallic catalyst using iron (Fe) to promote the stability of catalyst [76].…”