Screening,optimization and kinetics of Jatropha curcas oil transesterification with heterogeneous catalysts

This work investigates the production of fatty acid methyl esters (FAME) from Jatropha curcas oil using a variety of heterogeneous catalysts: resins, zeolites, clays, hydrotalcites, aluminas and niobium oxide. For this purpose, a catalyst screening was first conducted in a batch reactor at the following operating conditions: oil to methanol molar ratio of 1:9, 6 h of reaction, 5 wt% catalyst, at 333 and 393 K. From the screening step, KSF clay and Amberlyst 15 catalysts were selected to carry out a 2³ full factorial central composite rotatable design so as to elucidate the effects of process variables on FAME yield. The optimum reaction conditions for both catalysts were found to be oil to methanol molar ratio of 1:12, 5 wt% of catalyst, 433 K and 6 h of reaction with a FAME yield of about 70 wt%. A kinetic study was then experimentally performed and a semi-empirical model was built to represent the experimental data. Finally, catalyst re-utilization in five successive batch experiments was evaluated at the optimized conditions.     

Biodiesel production from soybean and Jatropha oils using cesium impregnated sodium zirconate as a heterogeneous base catalyst

Cesium modified sodium zirconate (Cs-Na₂ZrO₃) was prepared by ionic exchange from sodium zirconate (Na₂ZrO₃), which was synthesized via a solid state reaction. Both ceramics, i.e., pristine Na₂ZrO₃ and the Cs-Na₂ZrO₃, were used as basic heterogeneous catalysts in biodiesel production. Soybean and Jatropha oils were used as triglyceride sources for transesterification reactions. Parameters, such as catalyst concentration (between 0.5 and 3 wt%), reaction time, different methanol/vegetable oil molar ratios, and temperature of the reaction, were evaluated. The cesium cation influence was evaluated from the basic transesterification reactivity. The results showed that the introduction of cesium significantly modified the catalytic activity in biodiesel production. Cs enhanced the reaction kinetics in obtaining biodiesel and reduced the reaction time in comparison with pristine Na₂ZrO₃. The results showed that Cs-Na₂ZrO₃ as a basic heterogeneous catalyst exhibited the best fatty acid methyl esters (FAME) conversion for soybean oil (98.8%) at 1 wt%, 30:1 methanol/oil ratio, 65 °C, and 15 min. The best conditions for Jatropha oil (90.8%) were 3 wt%, 15:1 methanol/oil ratio, 65 °C, and 1 h. The impregnation of Na₂ZrO₃ with cesium represents a very exciting alternative heterogeneous base catalyst for biodiesel production.     

Transesterification of canola oil as biodiesel over Na/Zr-SBA-15 catalysts: Effect of zirconium content

A series of mesoporous Zr-SBA-15-supported Na catalysts was prepared and applied to the heterogeneous catalysis of canola oil transesterification. The effects of Si/Zr ratio, reaction time, and percentage of Na loading on the conversion to fatty acid methyl esters (FAME) were studied. The dependence of the textural structure and chemical properties of Zr-SBA-15 supports on Zr content was investigated using small-angle X-ray diffraction, Brunauer–Emmett–Teller analysis, transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. The results obtained from FTIR and TEM indicate that the incorporation of Zr atoms into the SBA-15 structure facilitated the formation of Brönsted acid sites and decreased the particle size of Na species. Catalysts with a higher Zr content enhanced the FAME yield. The optimum conditions determined were as follows: reaction temperature of 70 °C, 15 wt.% Na, reaction time of 6 h, and 12% catalyst content (wt.% oil) with a methanol/oil molar ratio of 6:1. The optimum conditions resulted in a FAME yield of up to 99%.     

Effects of water on the esterification of free fatty acids by acid catalysts

To maximize the production of biodiesel from soybean soapstock, the effects of water on the esterification of high-FFA (free fatty acid) oils were investigated. Oleic acid and high acid acid oil (HAAO) were esterified by reaction with methanol in the presence of Amberlyst-15 as a heterogeneous catalyst or sulfuric acid as a homogeneous catalyst. The yield of fatty acid methyl ester (FAME) was studied at oil to methanol molar ratios of 1:3 and 1:6 and reaction temperatures of 60 and 80 °C. The rate of esterification of oleic acid significantly decreased as the initial water content increased to 20% of the oil. The activity of Amberlyst-15 decreased more rapidly than that of sulfuric acid, due to the direct poisoning of acid sites by water. Esterification using sulfuric acid was not affected by water until there was a 5% water addition at a 1:6 molar ratio of oil to methanol. FAME content of HAAO prepared from soapstock rapidly increased for the first 30 min of esterification. Following the 30-min mark, the rate of FAME production decreased significantly due to the accumulation of water. When methanol and Amberlyst-15 were removed from the HAAO after 30 min of esterification and fresh methanol and a catalyst were added, the time required to reach 85% FAME content was reduced from 6 h to 1.8 h.     

Optimization of biodiesel production from camelina oil using orthogonal experiment

Camelina oil is a low-cost feedstock for biodiesel production that has received a great deal of attention in recent years. This paper describes an optimization study on the production of biodiesel from camelina seed oil using alkaline transesterification. The optimization was based on sixteen well-planned orthogonal experiments (OA₁₆ matrix). Four main process conditions in the transesterification reaction for obtaining the maximum biodiesel production yield (i.e. methanol quantity, reaction time, reaction temperature and catalyst concentration) were investigated. It was found that the order of significant factors for biodiesel production is catalyst concentration > reaction time > reaction temperature > methanol to oil ratio. Based on the results of the range analysis and analysis of variance (ANOVA), the maximum biodiesel yield was found at a molar ratio of methanol to oil of 8:1, a reaction time of 70 min, a reaction temperature of 50 °C, and a catalyst concentration of 1 wt.%. The product and FAME yields of biodiesel under optimal conditions reached 95.8% and 98.4%, respectively. The properties of the optimized biodiesel, including density, kinematic viscosity, acid value, etc., were determined and compared with those produced from other oil feedstocks. The optimized biodiesel from camelina oil meets the relevant ASTM D6571 and EN 14214 biodiesel standards and can be used as a qualified fuel for diesel engines.     

Utilization of waste freshwater mussel shell as an economic catalyst for biodiesel production

An economic and environmentally friendly catalyst derived from waste freshwater mussel shell (FMS) was prepared by a calcination-impregnation-activation method, and it was applied in transesterification of Chinese tallow oil. The as-prepared catalyst exhibits a “honeycomb” -like structure with a specific surface area of 23.2 m² g⁻¹. The newly formed CaO crystals are major active phase of the catalyst. The optimal calcination and activity temperature are 900 °C and 600 °C, respectively. When the reaction is carried out at 70 °C with a methanol/oil molar ratio of 12:1, a catalyst concentration of 5% and a reaction time of 1.5 h, the FMS-catalyst is active for 7 reaction cycles, with the biodiesel yield above 90%. The experimental results indicate that the FMS can be used as an economic catalyst for the biodiesel production.     

Biodiesel from palm oil via loading KF/Ca–Al hydrotalcite catalyst

The solid base catalyst KF/Ca–Al hydrotalcite was obtained from Ca–Al layered double hydroxides and successfully used in the transesterification of methanol with palm oil to produce biodiesel. With the load of KF, the activity of Ca–Al mixed-oxides had been improved much. For the mass ratio 80 wt.%(KF·6H₂O to Ca–Al mixed-oxides) catalyst, under the optimal condition: 338 K, catalyst amount 5%(wt./wt. oil) and methanol/oil molar ratio 12:1, after 5 h reaction, the fatty acid methyl esters yield could reach 97.98%; for the mass ratio 100 wt.%(KF·6H₂O to Ca–Al mixed-oxides) ones, under the same reaction condition, only needed 3 h to get the FAME yield of 99.74%, and even only reacted 1 h, the FAME yield could obtain 97.14%.     

Biodiesel production using gel‐type cation exchange resin at different ionic forms

In this study, a strong acidic‐type cation exchange resin was used in the transesterification of corn oil to fatty acid methyl esters (FAME). The gel‐type cation exchange resin (Purolite‐PD206) was used in H⁺ and Na⁺ forms to utilize ion‐exchange resin as effective heterogeneous catalyst in the production of biodiesel. Effect of ionic forms of ion exchange resin on free fatty acid (FFA) conversion and composition was investigated by using different amounts of ion exchange resin (12, 16, and 20 wt%), various mole ratios of methanol to oil (1:6, 1:12, and 1:18 mol/mol), reaction temperatures (63, 65, and 67°C), and reaction time (24, 36, and 48 h) during transesterification reaction. The highest FFA conversions of 73.5% and 79.45% were obtained at conditions of 20 wt% of catalyst, 65°C of reaction temperature, 18:1 as methanol to oil ratio, and 48 h of reaction time for H⁺ and Na⁺ forms of ion exchange resin, respectively. These results were obtained from regression equations established by using analysis of variance (ANOVA) model according to the experimental results of selected parameters. Gas chromatography analysis revealed that FAME is mainly composed of C16:0 (palmitic), C18:1 (oleic), and C18:2 (linoleic) acids of methyl ester.     

Manufacturing of zeolite based catalyst from zeolite tuft for biodiesel production from waste sunflower oil

In the present work, zeolite based catalyst was prepared from zeolite tuft by impregnation methods. The zeolite tuft was initially treated with hydrochloric acid (16%) and then several KOH/zeolite catalysts were prepared by impregnation in KOH solutions. Various solutions of KOH with different molarities (1–6 M) were used. Further modification for the catalyst was performed by a 2nd step impregnation treatment by heating and stirring the KOH/zeolite to 80 °C for 4 h. The zeolite tuft and the prepared catalysts were characterized by several analytical techniques in order to explore their physicochemical properties. These tests include: X-Ray Fluorescence (XRF), Scanning Electron Microscopy (SEM), Zero point of Charge (PHzpc), Fourier Transform Infrared (FT-IR), Energy-dispersive X-Ray analysis (EDX) and X-Ray Diffraction (XRD). The catalysts were then used for transesterification of waste sunflower vegetable oil in order to produce biodiesel. Among the different catalysts prepared, the 1–4M KOH/TZT catalyst provided the maximum biodiesel yield of 96.7% at 50 °C reaction temperature, methanol to oil molar ratio of 11.5:1, agitation speed of 800 rpm, 335 μm catalyst particle size and 2 h reaction time. The physicochemical properties of the produced biodiesel comply with the EN and ASTM standard specifications.     

Biodiesel synthesis from Hevea brasiliensis oil employing carbon supported heterogeneous catalyst: Optimization by Taguchi method

The present work illustrates the parametric effects on biodiesel production from Hevea brasiliensis oil (HBO) using flamboyant pods derived carbonaceous heterogeneous catalyst. Activated carbon (AC) was prepared maintaining 500 °C for 1 h and steam activated at optimised values of activation time 1.5 h and temperature 350 °C. Carbonaceous support was impregnated with KOH at different AC/KOH ratios. The transesterification process was optimized and significant parameters affecting the biodiesel yield was identified by Taguchi method considering four parameters viz. reaction time, reaction temperature, methanol to oil ratio and catalyst loading. The physicochemical properties of Hevea brasiliensis methyl ester (HBME) were examined experimentally at optimised condition and found to meet the global American standards for testing and materials (ASTM). The optimum condition observed to yield 89.81% of biodiesel were: reaction time 60 min, reaction temperature 55 °C, catalyst loading 3.5wt% and methanol to oil ratio 15:1. Contribution factor revealed that among four parameters considered, catalyst loading and methanol to oil ratio have more prominent effect on biodiesel yield. The cost for preparing carbonaceous catalyst support was estimated and observed to be fairly impressive. Thus, Hevea brasiliensis oil (HBO) could be considered as suitable feedstock and flamboyant pods derived carbon as effective catalyst for production of biodiesel.     

Biodiesel production from mixed soybean oil and rapeseed oil

The biodiesel (fatty acid methyl esters, FAME) was prepared by transesterification of the mixed oil (soybean oil and rapeseed oil) with sodium hydroxide (NaOH) as catalyst. The effects of mole ratio of methanol to oil, reaction temperature, catalyst amount and reaction time on the yield were studied. In order to decrease the operational temperature, a co-solvent (hexane) was added into the reactants and the conversion efficiency of the reaction was improved. The optimal reaction conditions were obtained by this experiment: methanol/oil mole ratio 5.0:1, reaction temperature 55 °C, catalyst amount 0.8 wt.% and reaction time 2.0 h. Under the optimum conditions, a 94% yield of methyl esters was reached ∼94%. The structure of the biodiesel was characterized by FT-IR spectroscopy. The sulfur content of biodiesel was determined by Inductively Coupled Plasma emission spectrometer (ICP), and the satisfied result was obtained. The properties of obtained biodiesel from mixed oil are close to commercial diesel fuel and is rated as a realistic fuel as an alternative to diesel. Production of biodiesel has positive impact on the utilization of agricultural and forestry products.     

Alkaline catalyzed biodiesel production from moringa oleifera oil with optimized production parameters

The utilization of non-edible feedstock such as moringa oleifera for biodiesel production attracts much attention owing to the issue with regards to avoiding a threat to food supplies. In this study, the optimization of biodiesel production parameters for moringa oleifera oil was carried out. The free fatty acid value of moringa oil was found to be 0.6%, rendering the one step alkaline transesterification method for converting moringa fatty acids to their methyl esters possible. The optimum production parameters: catalyst amount, alcohol amount, temperature, agitation speed and reaction time were determined experimentally and found to be: 1.0 wt% catalyst amount, 30 wt% methanol amount, 60 °C reaction temperature, 400 rpm agitation rate and 60 min reaction time. With these optimal conditions the conversion efficiency was 82%. The properties of the moringa biodiesel that was produced were observed to fall within the recommended international biodiesel standards. However, moringa biodiesel showed high values of cloud and pour points of 10 °C and 3 °C respectively, which present a problem as regards use in cold temperatures.     

Production of biodiesel from castor oil using iron (II) doped zinc oxide nanocatalyst

The depletion of fossil fuels has caused the price of petroleum to rise remarkably and created need for alternative energy such as biodiesel. In the present study, the biodiesel was produced from castor oil using ferromagnetic zinc oxide nanocomposite as heterogeneous catalyst for transesterification reaction. Single phase of nanocatalyst were confirmed by X-Ray Diffraction analysis. The spherical shape of the aggregated nanocatalyst was observed in Scanning Electron Microscopy. Magnetic properties were analysed using vibrating sample magnetometer. Atomic Force Microscopic analysis revealed the larger surface area and roughness of nanocatalyst. The biodiesel yield of 91% (w/w) was obtained in 50 min at 55 °C with 14 wt % catalyst loading and 12:1 methanol/oil ratio and was confirmed by Gas chromatograph with Mass Spectrometer. The result showed that the iron (II) doped ZnO nanocatalyst is a promising catalyst for the production of biodiesel via heterogeneous catalytic transesterification under milder reaction conditions.     

Optimization of biodiesel production from waste fish oil

The present study deals with the production of biodiesel using waste fish oil. The research assesses the effect of the transesterification parameters on the biodiesel yield and its properties, including temperature (40–60 °C), molar ratio methanol to oil (3:1–9:1) and reaction time (30–90 min). The experimental results were fitted to complete quadratic models and optimized by response surface methodology. All the biodiesel samples presented a FAME content higher than 93 wt.% with a maximum, 95.39 wt.%, at 60 °C, 9:1 of methanol to oil ratio and 90 min. On the other hand, a maximum biodiesel yield was found at the same methanol to oil ratio and reaction time conditions but at lower temperature, 40 °C, which reduced the saponification of triglycerides by the alkaline catalyst employed. Adequate values of kinematic viscosity (measured at 30 °C) were obtained, with a minimum of 6.30 mm²/s obtained at 60 °C, 5.15:1 of methanol to oil ratio and 55.52 min. However, the oxidative stability of the biodiesels produced must be further improved by adding antioxidants because low values of IP, below 2.22 h, were obtained. Finally, satisfactory values of completion of melt onset temperature, ranging from 3.31 °C to 3.83 °C, were measured.     

Synthesis of glycerol-free fatty acid methyl ester using interesterification reaction based on solid acid carbon catalyst derived from low-cost biomass wastes

The current research was aimed to corroborate as well as compare the feasible applicability of waste banana peel and empty fruit bunch (EFB) in synthesising high-performing heterogeneous catalysts. The solid acid catalysts originated from biomass wastes were employed for the synthesis of glycerol-free fatty acid methyl ester (FAME) using catalytic interesterification process pathway. Acetic acid was produced as the by-product instead of glycerol. The heterogeneous acid catalysts were synthesised utilising sulphuric acid through direct sulfonation with thermal treatment. The concentration of the sulphuric acid was manipulated from 2 to 13 mol L^?1 to investigate its effects on the resulting FAME yield while maintaining the sulfonating ratio at 10 mL g^?1. The catalytic performances of the as-synthesised catalysts were studied under reaction conditions of 12 wt % catalyst loading, 50:1 methyl acetate to oleic acid molar ratio for a duration of 8 hours at 60°C. The catalyst produced by activated carbon derived from EFB and sulfonated with 13 mol L^?1 sulphuric acid exhibited the highest FAME yield at 44.3%. The parameter studies on reactant ratio (45:1-70:1), reaction temperature (90°C-130°C) and time (4-24 hours) of interesterification reaction discovered a general increasing trend in the FAME yield up to 52.3% with the optimum conditions of 50:1, 110°C and 8 hours, respectively. The catalyst was recyclable with 82% of the catalytic performance retained after five successive cycles with catalyst reactivation. This study confirmed that the renewable heterogeneous catalyst derived from biomass waste could catalyse the glycerol-free interesterification process via an environmentally benign and promising approach for green fuel production.     

Mixed and ground KBr-impregnated calcined snail shell and kaolin as solid base catalysts for biodiesel production

Mixed and ground activated snail shell and kaolin catalysts impregnated with KBr were investigated. The snail shell and kaolin were calcined, mixed, and ground prior to immersion with KBr solution and subsequent activation at 500 °C for 3 h. The precursor and catalysts were characterized by thermal gravimetric analysis, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and Brunauer–Emmett–Teller surface area. The catalytic performance of the prepared catalysts was evaluated by transesterification of soybean oil with methanol. The effects of various parameters on biodiesel yield were investigated. A biodiesel yield of 98.5% was achieved using the catalyst prepared by 40% KBr-immersed, mixed, and ground snail shell and kaolin, which were activated at 500 °C. The transesterification conditions were as follows: reaction temperature, 65 °C; reaction time, 2 h; methanol-to-soybean oil molar ratio, 6:1; and catalyst amount (relative to the weight of soybean oil), 2.0 wt%. The solid catalyst could be reused for four times, and biodiesel yield remained over 73.6% for the fourth time.     

A comparative study of KOH/Al2O3 and KOH/NaY catalysts for biodiesel production via transesterification from palm oil

The transesterification of palm oil to methyl esters (biodiesel) was studied using KOH loaded on Al₂O₃ and NaY zeolite supports as heterogeneous catalysts. Reaction parameters such as reaction time, wt% KOH loading, molar ratio of oil to methanol, and amount of catalyst were optimized for the production of biodiesel. The 25 wt% KOH/Al₂O₃ and 10 wt% KOH/NaY catalysts are suggested here to be the best formula due to their biodiesel yield of 91.07% at temperatures below 70 °C within 2–3 h at a 1:15 molar ratio of palm oil to methanol and a catalyst amount of 3–6 wt%. The leaching of potassium species in both spent catalysts was observed. The amount of leached potassium species of the KOH/Al₂O₃ was somewhat higher compared to that of the KOH/NaY catalyst. The prepared catalysts were characterized by using several techniques such as XRD, BET, TPD, and XRF.     

Ethanolysis of waste cottonseed oil over lithium impregnated calcium oxide: Kinetics and reusability studies

A series of Li/CaO catalysts has been prepared by impregnating 0.5–5.0 wt% Li in CaO by wet chemical method. Prepared Li/CaO catalysts have been characterized by powder X-ray diffraction, scanning electron and transmission electron microscopy and Brunauer–Emmett–Teller (BET) surface area studies, in order to establish the structure and surface morphology of the catalyst. Hammett indicator test study was performed to determine the basic strength of the Li/CaO catalysts. The prepared Li/CaO catalysts have been employed as a heterogeneous catalyst for the transesterification of waste cottonseed oil (having 2.8 wt% free fatty acid contents) with ethanol. Under optimal reaction conditions viz., ethanol/oil molar ratio of 12:1, catalyst to oil weight fraction of 5% and 65 °C reaction temperature, 98% fatty acid ethyl ester yield was obtained in 2.5 h of reaction duration. Under the optimized reaction conditions, the pseudo first order constant and Arrhenius activation energy were found to be 0.03 min⁻¹ and 70.0 kJ mol⁻¹, respectively. Further Li/CaO catalyst was also found to be effective for the ethanolysis and methanolysis of vegetable oils having up to 3.4 wt% free fatty acids. The use of 3-Li/CaO catalyst is advantageous considering that it not only utilizes waste cottonseed oil as a feedstock, but also renewable and nontoxic alcohol, ethanol, for the biodiesel production.     

Preparation, characterization and application of heterogeneous solid base catalyst for biodiesel production from soybean oil

A solid base catalyst was prepared by neodymium oxide loaded with potassium hydroxide and investigated for transesterification of soybean oil with methanol to biodiesel. After loading KOH of 30 wt.% on neodymium oxide followed by calcination at 600 °C, the catalyst gave the highest basicity and the best catalytic activity for this reaction. The obtained catalyst was characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Thermogravimetric analysis (TGA), N₂ adsorption-desorption measurements and the Hammett indicator method. The catalyst has longer lifetime and maintained sustained activity after being used for five times, and were noncorrosive and environmentally benign. The separate effects of the molar ratio of methanol to oil, reaction temperature, mass ratio of catalyst to oil and reaction time were investigated. The experimental results showed that a 14:1 M ratio of methanol to oil, addition of 6.0% catalyst, 60 °C reaction temperature and 1.5 h reaction time gave the best results and the biodiesel yield of 92.41% was achieved. The properties of obtained biodiesel are close to commercial diesel fuel and is rated as a realistic fuel as an alternative to diesel.     

Alkaline-catalyzed transesterification of Silurus triostegus Heckel fish oil: Optimization of transesterification parameters

The present work reports the production of biodiesel from Silurus triostegus Heckel fish oil (STFO) through alkaline-catalyzed transesterification by using potassium hydroxide (KOH) as an alkaline catalyst with methanol. Chemical and physical properties of the extracted oil were determined. It was found that STFO has a low acid value (1.90 mg KOH/g oil); hence no pre-treatment such as acid esterification is required to produce the biodiesel. The influence of the experimental parameters such as KOH concentration (0.25–1.0% w/w of oil), methanol to oil molar ratio (3:1, 6:1, 9:1 and 12:1), reaction temperature (32, 45 and 60 °C), reaction duration (30, 60, 90 and 120 min), type of the catalyst (potassium or sodium hydroxide) and step multiplicity (single- and two-step transesterification) on the yield of the biodiesel were investigated. The maximum biodiesel yield (96%) was obtained under the optimized parameters of the transesterification (KOH 0.50% w/w, 6:1 methanol to oil, at 32 °C for 60 min). The properties of the produced biodiesel were found to conform with the ASTM standard, indicating its suitability for internal combustion engines. Blending of the produced biodiesel with petro diesel with various volume percentages was investigated as well.