Synthesis of waste cooking oil based biodiesel via ferric-manganese promoted molybdenum oxide / zirconia nanoparticle solid acid catalyst: influence of ferric and manganese dopants

Biodiesel Production from Waste Cooking Oil Catalyzed by a Bifunctional Catalyst

The objective of this study was to prepare bifunctional catalysts based on iron and CaO and test them in the biodiesel production using waste cooking oil (WCO) as feedstock. Two iron precursors were studied, Fe₂O₃ and Fe(NO₃)₃·9H₂O. The identified crystalline phases were Ca₂Fe₂O₅ and CaFeO₃. Surface morphology and textural properties (distribution of active species, specific surface area, size, and pore volume) were also analyzed. Additionally, thermal stability was studied and 800 °C was established as the optimum calcination temperature. The density of both acidic and basic sites was higher with the catalyst prepared with Fe₂O₃ than with that prepared with Fe(NO₃)₃·9H₂O. The latter, however, leads to reach equilibrium in half of the time than with the former. This was ascribed to the ratio of acidic to basic sites, which is higher with the catalyst prepared with the precursor salt. This ratio not only affects the overall cost of the process by affecting the time at which equilibrium is reached but also by dictating the methanol/oil molar ratio at which the equilibrium is reached sooner. The prepared bifunctional catalyst allowed us to produce biodiesel with 90% of methyl ester content at atmospheric pressure, reaction temperature of 60 °C, reaction time of 2 h, with 12:1 M ratio of methanol/WCO, 10 wt % of Fe over CaO, and a catalyst loading of 5 wt %. This catalyst can be used at least 3 times. The so-obtained biodiesel met the European norm EN-14214 regarding viscosity and density.

Nano-sulfated zirconia catalyzed biodiesel production from tannery waste sheep fat

This study makes use of tannery waste to produce biodiesel using a nano-sulfated zirconia catalyst (ferric-manganese-doped sulfated zirconia). It was through a modified wetness impregnation method that the catalyst was prepared which was then characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The catalytic property of the synthesized catalyst was determined by using it to produce biodiesel from tannery waste sheep fat. A study was carried out to find the effect of the different parameters affecting the process. Optimized conditions of 15:1 methanol to fat molar ratio and catalytic loading of 8 wt% at 65 °C with a stirring rate of 400 rpm for a reaction duration of 300 min gave a maximum yield of 98.7 wt%. The performance of the catalyst during recycling was analyzed by conducting reusability study. The reused catalyst gives a maximum yield above 90 wt% up to five cycles with a catalyst recovery of 88 wt%. ASTM D6751 standard was used to compare the analyzed fuel properties of the biodiesel.

Widely used catalysts in biodiesel production: a review

An ever-increasing energy demand and environmental problems associated with exhaustible fossil fuels have led to the search for an alternative renewable source of energy. In this context, biodiesel has attracted attention worldwide as an eco-friendly alternative to fossil fuel for being renewable, non-toxic, biodegradable, and carbon-neutral. Although the homogeneous catalyst has its own merits, much attention is currently paid toward the chemical synthesis of heterogeneous catalysts for biodiesel production as it can be tuned as per specific requirement and easily recovered, thus enhancing reusability. Recently, biomass-derived heterogeneous catalysts have risen to the forefront of biodiesel productions because of their sustainable, economical and eco-friendly nature. Furthermore, nano and bifunctional catalysts have emerged as a powerful catalyst largely due to their high surface area, and potential to convert free fatty acids and triglycerides to biodiesel, respectively. This review highlights the latest synthesis routes of various types of catalysts (including acidic, basic, bifunctional and nanocatalysts) derived from different chemicals, as well as biomass. In addition, the impacts of different methods of preparation of catalysts on the yield of biodiesel are also discussed in details.

An ever-increasing energy demand and environmental problems associated with exhaustible fossil fuels have led to the search for an alternative energy. In this context, biodiesel has attracted attention worldwide as an alternative to fossil fuel.

Synthesis of nanomagnetic sulphonated impregnated Ni/Mn/Na2SiO3 as catalyst for esterification of palm fatty acid distillate

The deterioration of the environment due to anthropogenic disturbances has become a major concern to scientists and engineers. This study responds to the concern by developing a novel nanomagnetic carbonaceous solid acid catalyst using empty fruit bunches (EFBs) as a precursor. The EFB was sulphonated to obtain acidic EFBs (AEFBs). The impregnation method was performed to incorporate metal oxides, namely, NiO, MnO and Na₂SiO₃, on the AEFBs. This process resulted in three nanomagnetic catalysts, namely, Na₂SiO₃–NiO–MnO/AC, NiO–MnO/AC and NiO/AC. According to X-ray diffraction analysis, the crystal size of the NiO/AC, NiO–MnO/AC and Na₂SiO₃–NiO–MnO/AC catalysts were 13.87, 28.38 and 39.64 nm, respectively, whereas their Brunauer–Emmett–Teller surface areas were 23.78, 12.69 and 16.8 m² g⁻¹, respectively. To confirm the incorporation of active metallic species (Ni, Mn, Na and SiO) into the carbon surface, we performed X-ray photoelectron spectroscopy. TPD-NH₃ absorption showed that the Na₂SiO₃–Ni–MnO/AC catalysts substantially increased in the active sites and exhibited higher acidity. FESEM images showed the morphology of the surface, pore sizes and agglomeration of the catalysts. Moreover, the vibrating sample magnetometer depicted that the Na₂SiO₃–Ni–MnO/AC catalyst was ferrimagnetic with magnetisation and magnetic saturation values of 40.27 and 86.04 emu g⁻¹, respectively. The optimal reaction conditions were as follows: PFAD/methanol ratio of 16 : 1, 2 wt% mass of the catalyst, temperature of 120 °C and time of 4 h. Using the synthesised nanomagnetic catalyst exhibited 96% conversion of PFAD to methyl esters. Furthermore, the Na₂SiO₃–Ni–MnO/AC catalyst was easily separated from the reaction mixture using an external magnet and was recycled six times. The modified nanomagnetic catalyst could be an efficient catalyst for discarded feedstocks for biodiesel production.

The acidic EFB was doped with magnetic oxides to produce sulphonated nanomagnetic catalysts for biodiesel production from palm fatty acid distillate (PFAD).