Biodiesel production from castor oil using heterogeneous Ni doped ZnO nanocatalyst

Research on the castor oil pressing extraction mechanism based on multi-physics coupling simulation

Castor oil has been widely used in various fields due to its properties, leading to large attention for its extraction mechanism. To research the castor oil extraction mechanism during pressing, a self-developed uniaxial compression device combined with an in situ observation is established. The effects of pressure, loading speed, and creep time are investigated, and a finite element model coupling with multi-physics is established for castor oil pressing extraction, verified by the seed cake experimental compression strain matching with numerical simulation under the same condition. Simulation results indicated that the pressing oil extraction process can be divided into two stages, Darcy's speed shows the first sharp decreasing stage and the second gradual increasing stage during porosity and pressure interaction. In the first stage, porosity is dominant on Darcy's speed. With porosity decreasing, the pressure effect on Darcy's speed exceeds porosity in the second stage. With seed thickness increasing, Darcy's speed first increases and then decreases. With loading speed increasing, Darcy's speed increases. Darcy's speed decreases constantly with creep time increasing. This study can provide basic theoretical and practical guidance for oil extraction.

Effect of different configurations of hybrid nano additives blended with biodiesel on CI engine performance and emissions

The use of nano additives to improve the cold properties of biodiesel is encouraged by its drawbacks and incompatibility in cold climate. Waste cooking oil (WCO) was transesterified to create biodiesel. A 20% by volume was used for combination of diesel and methyl ester. Current study aims to evaluate diesel engine emissions and performance. TiO2, alumina, and hybrid TiO2 + Al2O3 nanoparticles are added to WCO biodiesel mixture at 25 mg/liter. When B20 combined with nano materials such as TiO2, Al2O3, and hybrid nano, the highest declines in brake specific fuel consumption were 4, 6, and 11%, respectively. As compared to biodiesel blend, the largest gains in thermal efficiency were 4.5, 6.5, and 12.5%, respectively, at maximum engine output power. Introduction of TiO2, Al2O3, and hybrid nano particles to B20 at 100% load resulted in the highest decreases in HC concentrations up to 7, 13, and 20%, and the biggest reductions in CO emissions, up to 6, 12, and 16%. Largest increases in NOx concentrations at full load were about 7, 15, and 23% for B20 + 25TiO2, B20 + 25 Al2O3, and B20 + 25TiO2 + 25 Al2O3, respectively. Up to 8, 15, and 21% less smoke was released, correspondingly, which were the largest reductions. Recommended dosage of 25 ppm alumina and 25 ppm TiO2 achieved noticeable improvements in diesel engine performance, combustion and emissions about B20.

Application of Response Surface Methodology (RSM) in the statistical evaluation of biodiesel production from the neutral lipids of the Coelastrella-Nannochloropsis consortium

The paramount challenge in economically workable microalgal biodiesel production is the selection of a competent catalyst to improve the fatty acid methyl ester yield with desirable fatty acid composition. Though countless researchers have explored different homogeneous and heterogeneous catalysts to improve the transesterification efficacy, achieving greater biodiesel production from the neutral lipids of the microalgal consortium using a statistical tool, response surface methodology is scarce. Thus, the present study applied Response surface methodology to statistically analyze the biodiesel production from the neutral lipids of the indigenous Coelastrella-Nannochloropsis consortium (CNC) on the way to commercial feasibility. Onset of the study, the neutral lipids and acid value of the CNC were determined to be 18.74% and 2.73%, respectively. The transesterification of the neutral lipids of CNC was optimized through the coded factors in the RSM for various reaction parameters as combined influence viz., (i) Catalyst dose: methanol volume, (ii) Catalyst dose: reaction time; (iii) Catalyst dose: reaction temperature, (iv) Time: temperature, (v) time: methanol volume, (vi) temperature: methanol volume. Based on the ANOVA, coefficient determination, 2% KOH, 2 h time, 70 °C temperature, and 9 mL methanol volume were ascertained to be optimal values to accomplish 92% biodiesel production. Further, the biodiesel has desirable palmitic, palmitoleic, stearic, oleic, linoleic, and linolenic acids, with palmitic acid as the prevalent fatty acid contributing 16-18%. In addition, the tested fuel properties of CNC biodiesel satisfy international biodiesel standards.

Comparative life cycle cost analysis of bio-valorized magnetite nanocatalyst for biodiesel production: Modeling, optimization, kinetics and thermodynamic study

An active, high surface area, recyclable, magnetic, basic, iron oxide-based nanocatalyst was developed from banana leaves waste and used for microwave-assisted transesterification of soybean oil to biodiesel. According to the Hammett indicator, the catalyst has a high total basicity of 15 < H < 18.4. After optimization through the response surface methodology, the reaction allows 96.5 % biodiesel yield in the presence of 24:1 methanol to soybean oil molar ratio, 6 wt% BLW@Fe3O4, 0.5 h at 65 °C. The magnetic nature of the catalyst improves reusability for up to 6 cycles. Thermodynamic analyses showed that transesterification of soybean oil to biodiesel is an endothermic reaction. Moreover, the catalyst has the potential to reduce biodiesel production costs by utilizing abundant biomass waste materials. The calculated cost for 1 kg of catalyst is $1.14, while the biodiesel's cost per kg produced in this work is merely $1.05, showing high commercial viability.

Research on microstructural-mechanical and shearing properties of castor seed during mechanical extraction

Castor seed oil, as an important biomass fuel, has attracted extensive attention worldwide due to inclusive applications. Castor seed screw mechanical extraction is in fact seed shear damage and oil output. Seed shearing mechanism has been investigated with a developed tribometer. Influences of pressing load, shearing speed, roller roughness were analyzed. Castor seed structural damage was in-situ observed with optical microscope, and in-depth analyzed with Scanning Electron Microscopy and Energy Dispersive Spectroscopy. The results reveal that shear interaction can be divided into three stages: coat damage, transition shearing and endosperm oil output. Seed shear mechanism includes coat peeling, endosperm plowing, tissue transferring and oil lubrication. High pressing load leads to more damage of coat and endosperm, causing more oil to flow out. With shearing speed increasing, coat is easily peeled, obvious endosperm shear plowing and oil lubrication happened in contact area. Coat damage by high roughness leads more oil output. Castor oil enters the contact area and work as lubricant, leading to the decrease of friction resistance.

Process optimization and technoeconomic assessment of biodiesel production by one-pot transesterification of Ricinus communis seed oil

In the present study, Ricinus communis seed oil with high free fatty acid content was utilized for the one-pot biodiesel production using 1-(2,3-dihydroxy)-propyl-3-methylimidazolium hydroxide, a basic ionic liquid catalyst. The 97.83% biodiesel yield was obtained at the optimized conditions of 6.26 % (w/w) of catalyst concentration, 10.51:1 M ratio of methanol to oil, 57.87 °C temperature and reaction time of 61.01 min. The transesterification of Ricinus communis seed oil to biodiesel exhibited an activation energy of 37.60 kJ/mol. The technoeconomic analysis, the profitability and the sensitivity analysis were investigated for the simulated process design. The technoeconomic analysis reported a total revenue of 20,455,431 $/yr, with gross margins, ROI, payback period, IRR, and NPV of 23.54%, 35.72%, 2.8 years, 28.20%, and 19,287,000 $, respectively. According to the sensitivity analysis, the two most important factors determining the economic viability of the simulated process are Ricinus communis seed oil cost and biodiesel selling price.

Synthesis of Mn-Doped ZnO Nanoparticles and Their Application in the Transesterification of Castor Oil

Alarming environmental changes and the threat of natural fuel resource extinction are concerning issues in human development. This has increased scientists’ efforts to phase out traditional energy resources and move on to environmentally friendly biofuels. In this study, non-edible castor oil was transesterified with methanol using a manganese-doped zinc oxide (Mn-doped ZnO) nanocatalyst. A heterogeneous nanocatalyst was prepared by means of the the sonochemical method. X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM) were used to characterize these nanocatalysts. The transesterification reaction was studied under different temperature conditions, different ratios of methyl alcohol to castor oil, and different amounts of the catalyst to identify optimum conditions in which the maximum yield of biodiesel was produced. The maximum biodiesel yield (90.3%) was observed at 55 °C with an oil-to-methanol ratio of 1:12, and with 1.2 g of nanocatalyst. The first-order kinetic model was found to be the most suitable. Several thermodynamic parameters were also determined, such as activation energy, enthalpy, and entropy. We found that this transesterification was an endergonic and entropy-driven reaction. The results showed that the Mn-doped ZnO nanocatalyst could be a suitable catalyst for the heterogeneous catalytic transesterification process, which is essential for biodiesel production.

Metal-Organic Frameworks as bio- and heterogeneous catalyst supports for biodiesel production

As biodiesel (BD)/Fatty Acid Alkyl Esters (FAAE) is derived from vegetable oils and animal fats, it is a cost-effective alternative fuel that could complement diesel. The BD is processed from different catalytic routes of esterification and transesterification through homogeneous (alkaline and acid), heterogeneous and enzymatic catalysis. However, heterogeneous catalysts and biocatalysts play an essential role towards a sustainable alternative to homogeneous catalysts applied in biodiesel production. The main drawback is the supporting material. To overcome this, currently, Metal-Organic Frameworks (MOFs) have gained significant interest as supports for catalysts due to their extremely high surface area and numerous binding sites. This review focuses on the advantages of using various MOFs structures as supports for heterogeneous catalysts and biocatalysts for the eco-friendly biodiesel production process. The characteristics of these materials and their fabrication synthesis are briefly discussed. Moreover, we address in a general way basic items ranging from biodiesel synthesis to applied catalysts, giving great importance to the enzymatic part, mainly to the catalytic mechanism in esterification/transesterification reactions. We provide a summary with recommendations based on the limiting factors.

Reactive Extraction for Fatty Acid Methyl Ester Production from Castor Seeds Using a Heterogeneous Base Catalyst: Process Parameter Optimization and Characterization

Fatty acid methyl ester (FAME) from oil seeds is conventionally produced via a two/three-process-step method: extraction of oil and subsequent esterification/transesterification to fatty FAME (biodiesel). However, in the present study, we investigated the production of castor kernel oil (CKO) FAME by reactive extraction for extraction and transesterification in a single process using a heterogeneous catalyst. The content of oil that can be extracted was checked by investigating several nonreactive extraction parameters such as solvent type (polar, nonpolar, and mixture), the solvent to kernel ratio, and extraction time. Maximum oil was extracted using methanol as a solvent with a methanol-to-seed ratio of 6.25:1 for 6 h extraction time. The viscosity of CKO obtained by nonreactive extraction was reduced from 288.83 to 19.04 mm²/s by reactive extraction using a 4.09 wt % catalyst concentration (BaO) and a 330.9:1 methanol-to-oil molar ratio for 6 h reaction time at 64 °C. Reactive extraction for transesterification of CKO was performed using BaO, CaO, and ZnO heterogeneous catalysts. BaO results in the increased yield of CKO FAME compared to other catalysts. Central composite design (CCD) using the response surface methodology (RSM) was implemented to design the experimental matrix, process parameter optimization, maximize the yield of CKO FAME, and investigate interaction effects of parameters such as reactive extraction temperature (55-65 °C), catalyst concentration (3-5 wt %), and methanol-to-oil molar ratio (175:1-350:1) on the yield of CKO FAME. A second-order model equation with a p-value < 0.05 and an R ² value near 1.0 was obtained to predict the yield using the input parameters. The maximum yield CKO FAME of 96.13 wt % with 94.4% purity of produced CKO FAME was obtained at a catalyst concentration of 4.09 wt % and a methanol-to-oil molar ratio of 330.9:1 for 6 h with a reaction temperature of 64 °C. Therefore, a comparable conversion of castor seed oil triglyceride (96.13 wt %) was obtained in a single step directly from castor seeds. Furthermore, the rheological behavior investigation of castor kernel oil and castor methyl ester revealed that the dynamic viscosity of both samples was found to be dependent on triglyceride content and temperature.

Optimization of consolidated bioprocessing by response surface methodology in the conversion of corn stover to bioethanol by thermophilic Geobacillus thermoglucosidasius

The swift depletion of fossil fuels and their associated environment and economic impact has led the world to explore the sustainable alternate fuels. Amidst the available alternatives lignocellulosic bioethanol provides the edge over the exhausting fossil fuels. In this current study, Response surface methodology, a mathematical and statistical tool was used to optimize the fermentation conditions in consolidated bioprocessing of corn stover by Geobacillus thermoglucosidasius. The impact of inoculum concentration, temperature, pH, agitation speed and time in bioethanol fermentation were screened with Plackett-Burman design and it was farther optimized with central composite design. The analysis by PBD confirmed the significant impact of fermentation time, inoculum concentration, and temperature of the fermentation process. Further, it was optimized with CCD. This showed that 15% v/v of Inoculum concentration, 50 °C of temperature and fermentation time of 72 h increased the bioethanol concentration to a maximum of 9.04 g/L with 0.45 g/g significant yield and a conversion efficiency of 88%. Thus, the CCD showed a satisfactory result in consolidated bioprocessing of bioethanol from corn stover. Thus, in the future, this approach of optimization will yield a good base for consistent production of bioethanol.

MgO Nano-Catalyzed Biodiesel Production from Waste Coconut Oil and Fish Oil Using Response Surface Methodology and Grasshopper Optimization

In India, a densely populated country, fossil fuel depletion affects the energy sector that fulfils the industrial and human needs. Concerning greenhouse gas emissions and pollutants, and sustainability, there is a great demand to search for alternate feedstocks to produce alternate fuels at a low cost. The present work focuses on waste coconut and fish oil as potential inexpensive feedstock for biodiesel production. Two-stage transesterification processes for biodiesel production from hybrid oils mixed in a 1:1 volume ratio by employing solid nano-catalyst Magnesium Oxide (MgO). Response surface methodology (RSM) was used to analyze the effects of the physics of transesterification variables, such as methanol-to-oil molar ratio (M:O), MgO catalyst concentration (MgO CC), and reaction temperature (RT), on biodiesel yield, based on experimental data gathered in accordance with the matrices of central composite design (CCD). MgO CC showed the highest contribution, followed by M:O and RT, to maximize biodiesel yield. All interaction factors showed a significant effect except the M:O with RT. Grasshopper optimization algorithm (GOA) determined optimal conditions (M:O: 10.65; MgO CC: 1.977 wt.%; RT: 80 °C) based on empirical equations, resulting in maximum biodiesel yield conversion experimentally equal to 96.8%. The physical stability of the MgO nano-catalyst and reactivity up to 5 successive cycles can yield 91.5% biodiesel yield, demonstrating its reusability for sustainable biodiesel production at low cost. The optimized biodiesel yield showed better physicochemical properties (tested according to ASTM D6751-15C) to use practically in diesel engines.

A novel process for food waste recycling: A hydrophobic liquid mulching film preparation

Appropriate and effective recycling of food waste (FW) has become increasingly significant with the promotion of garbage classification in China. In this study, a novel and green process was developed to recycle FW to prepare a biodegradable composite liquid mulching film (LMF) through crosslinking with sodium alginate (SA). The solid phase of FW was obtained as the raw material after hydrothermal pretreatment to remove pathogens and salts, and to improve the reactivity of active components at a moderate temperature. The prepared LMF had a hydrophobic surface and compact structure due to the lipid in FW and the acetalization reaction and hydrogen bonds among SA, glutaraldehyde and multi-active components of FW, resulting in enhanced water vapor barrier properties. The minimum water vapor permeability of the prepared LMF reached (8.23 ± 0.05) ✕ 10^-12 g cm/(cm²·s·Pa) with 1.82 wt % of plasticizer, 0.74 wt% of crosslinker and a mass ratio of HTP-FW to SA of 3.56:1. The prepared LMF showed good mechanical properties and could maintain its integrity after spraying it on the soil surface for 31 days. In addition, it could effectively prevent the loss of soil moisture and heat, promote the seed germination of Chinese cabbage and achieve 89.14% of weight loss after burying in the soil for 27 days. This study provides a high value-added route to convert the FW to a hydrophobic LMF with superior properties, which addresses not only the problem of food waste but also the pollution of plastic mulching film.

Spray Analysis of Biodiesels Derived from Various Biomass Resources in a Constant Volume Spray Chamber

This research aimed to analyze the spray characteristics of various biodiesels, which have rarely been investigated in terms of spray analysis in the literature compared to fossil diesel. For this purpose, four different methyl ester-type biodiesels were produced from canola, corn, cottonseed, and sunflower oils. These feedstocks were selected due to their wide availability in Turkey and being among the significant resources for biodiesel production. Measured physical properties of biodiesel samples showed that biodiesel fuels had, on average, 1.7 to 1.9 times higher viscosities, 5.3 to 6.6% larger densities, and 37 to 39.1% higher contact angle values than the reference diesel fuel. Spray characteristics of all fuels were experimentally examined in a constant volume spray chamber under chamber pressures of 0, 5, 10, and 15 bar and injection pressures of 600, 800, and 1000 bar. All tested biodiesels performed, on average, 3 to 20% longer spray penetration lengths, 5 to 30% narrower spray cone angles, and 5-18% lesser spray areas than the reference diesel fuel under chamber pressures of 5 and 10 bar. No significant differences occurred at 15 bar ambient pressure between biodiesels and diesel. In addition, analytical and empirical predictions showed that biodiesels had around 21.2-35.1% larger SMD values and approximately 7% lower air entrainment.

Prospects of Catalysis for Process Sustainability of Eco-Green Biodiesel Synthesis via Transesterification: A State-Of-The-Art Review

Environmental pollution caused by conventional petro-diesel initiates at time of crude oil extraction and continues until its consumption. The resulting emission of poisonous gases during the combustion of petroleum-based fuel has worsened the greenhouse effect and global warming. Moreover, exhaustion of finite fossil fuels due to extensive exploitation has made the search for renewable resources indispensable. In light of this, biodiesel is a best possible substitute for the regular petro-diesel as it is eco-friendly, renewable, and economically viable. For effective biodiesel synthesis, the selection of potential feedstock and choice of efficient catalyst is the most important criteria. The main objective of this bibliographical review is to highlight vital role of different catalytic systems acting on variable feedstock and diverse methods for catalysis of biodiesel synthesis reactions. This paper further explores the effects of optimized reaction parameters, modification in chemical compositions, reaction operating parameters, mechanism and methodologies for catalysts preparation, stability enhancement, recovery, and reusability with the maximum optimum activity of catalysts. In future, the development of well-planned incentive structures is necessary for systematic progression of biodiesel process. Besides this, the selection of accessible and amended approaches for synthesis and utilization of specific potential catalysts will ensure the sustainability of eco-green biodiesel.

Experimental investigation of spray characteristics of ethyl esters in a constant volume chamber

ABSTRACT

Biodiesels are mainly produced via the utilization of methanol in transesterification, which is the widespread biodiesel production process. The majority of this methanol is currently obtained from fossil resources, i.e. coal and natural gas. However, in contrast with methanol, biomass-based ethanol can also be used to produce biodiesels; this could allow the production line to become fully renewable. This study aimed to investigate the spray characteristics of various ethyl ester type biodiesels derived from sunflower and corn oils in comparison to methyl esters based on the same feedstocks and reference petroleum-based diesel. Spray penetration length (SPL) and spray cone angle (SCA) were experimentally evaluated in a constant volume chamber allowing optical access, under chamber pressures of 0, 5, 10 and 15 bar and injection pressures of 600 and 800 bar. Sauter mean diameter (SMD) values were estimated by using an analytical correlation. Consequently, ethyl esters performed longer SPL (2.8-20%) and narrower SCA (5.1-19%) than diesel under ambient pressures of 5 and 10 bar. Although the SMD values of ethyl esters were 48% higher than diesel on average, their macroscopic spray characteristics were very similar to those of diesel under 15 bar chamber pressure. Moreover, ethyl esters were found to be very similar to methyl esters in terms of spray characteristics. The differences in SPL, SCA and SMD values for both types of biodiesels were lower than 4%. When considering the uncertainty (± 0.84%) and repeatability (±5%) ratios, the difference between the spray characteristics of methyl and ethyl esters was not major.

GRAPHICAL ABSTRACT

A review of sustainable biodiesel production using biomass derived heterogeneous catalysts

The production of biodiesel through chemical production processes of transesterification reaction depends on suitable catalysts to hasten the chemical reactions. Therefore, the initial selection of catalysts is critical although it is also dependent on the quantity of free fatty acids in a given sample of oil. Earlier forms of biodiesel production processes relied on homogeneous catalysts, which have undesirable effects such as toxicity, high flammability, corrosion, by-products such as soap and glycerol, and high wastewater. Heterogeneous catalysts overcome most of these problems. Recent developments involve novel approaches using biomass and bio-waste resource derived heterogeneous catalysts. These catalysts are renewable, non-toxic, reusable, offer high catalytic activity and stability in both acidic and base conditions, and show high tolerance properties to water. This review work critically reviews biomass-based heterogeneous catalysts, especially those utilized in sustainable production of biofuel and biodiesel. This review examines the sustainability of these catalysts in literature in terms of small-scale laboratory and industrial applications in large-scale biodiesel and biofuel production. Furthermore, this work will critically review natural heterogeneous biomass waste and bio-waste catalysts in relation to upcoming nanotechnologies. Finally, this work will review the gaps identified in the literature for heterogeneous catalysts derived from biomass and other biocatalysts with a view to identifying future prospects for heterogeneous catalysts.

Current Trends and Future Prospects of Nanotechnology in Biofuel Production

Biofuel is one of the best alternatives to petroleum-derived fuels globally especially in the current scenario, where fossil fuels are continuously depleting. Fossil-based fuels cause severe threats to the environment and human health by releasing greenhouse gases on their burning. With the several limitations in currently available technologies and associated higher expenses, producing biofuels on an industrial scale is a time-consuming operation. Moreover, processes adopted for the conversion of various feedstock to the desired product are different depending upon the various techniques and materials utilized. Nanoparticles (NPs) are one of the best solutions to the current challenges on utilization of biomass in terms of their selectivity, energy efficiency, and time management, with reduced cost involvement. Many of these methods have recently been adopted, and several NPs such as metal, magnetic, and metal oxide are now being used in enhancement of biofuel production. The unique properties of NPs, such as their design, stability, greater surface area to volume ratio, catalytic activity, and reusability, make them effective biofuel additives. In addition, nanomaterials such as carbon nanotubes, carbon nanofibers, and nanosheets have been found to be cost effective as well as stable catalysts for enzyme immobilization, thus improving biofuel synthesis. The current study gives a comprehensive overview of the use of various nanomaterials in biofuel production, as well as the major challenges and future opportunities.

Research on Structural–Mechanical Properties during the Castor Episperm Breaking Process

Products from castor seeds have been widely used in various fields. In order to study the breaking behavior and rupture mechanism of castor seed episperm during coat shelling process, the force-structure property of coating castor seed was investigated by a self-developed texture analyzer with in situ optical microscopic observation. Influences of compression distance, velocity and working temperature were studied. The results showed that castor seed episperm rupture commonly happened from the tail end to the first end. Compression distance effect can change the episperm cracking degree. Under pressing distance 2–3 mm, the episperm easily cracked into two flaps, and the breaking force stabilized at 77 N. Pressing velocity has no significant effect on episperm breaking. Temperature changes the physical property. With an increase in temperature, breaking force presents a “slope” decline; under a temperature of 120 ℃, temperature effect on the breaking force decreased significantly and the breaking force fell to about 52 N. The research results can provide theoretical basis for the castor episperm peeling.

Recent advances in valorization of organic municipal waste into energy using biorefinery approach, environment and economic analysis

Researcher's all around works on a copious technique to lessen waste production and superintend the waste management for long-term socio-economic and environmental benefits. Value-added products can be produced from municipal waste by using holistic and integrated approaches. In this review, a detail about the superiority of the different methods like anaerobic digestion, biofuel production, incineration, pyrolysis and gasification were used for the conversion of municipal waste to feedstock for alternate energy and its economic- environmental impacts were consolidated. Most conversion techniques were environmentally friendly to manage municipal waste. The biological process was more economically feasible compare to the thermal process, for the reason thermal process required a large amount of capital investment and energy utilization. In the thermal process, gasification shows low emission, and pyrolysis shows low capital investment and economically feasible compare to other thermal processes. Waste to energy technology significantly reduced the emission and energy demand.

A review on non-edible oil as a potential feedstock for biodiesel: physicochemical properties and production technologies

There is increasing concern regarding alleviating world energy demand by determining an alternative to petroleum-derived fuels due to the rapid depletion of fossil fuels, rapid population growth, and urbanization. Biodiesel can be utilized as an alternative fuel to petroleum-derived diesel for the combustion engine. At present, edible crops are the primary source of biodiesel production. However, the excessive utilization of these edible crops for large-scale biodiesel production might cause food supply depletion and economic imbalance. Moreover, the utilization of edible oil as a biodiesel feedstock increases biodiesel production costs due to the high price of edible oils. A possible solution to overcome the existing limitations of biodiesel production is to utilize non-edible crops oil as a feedstock. The present study was conducted to determine the possibility and challenges of utilizing non-edible oil as a potential feedstock for biodiesel production. Several aspects related to non-edible oil as a biodiesel feedstock such as overview of biodiesel feedstocks, non-edible oil resources, non-edible oil extraction technology, its physicochemical and fatty acid properties, biodiesel production technologies, advantages and limitation of using non-edible oil as a feedstock for biodiesel production have been reviewed in various recent publications. The finding of the present study reveals that there is a huge opportunity to utilize non-edible oil as a feedstock for biodiesel production.

Heterogeneous ZnO-containing catalysts for efficient biodiesel production

Biodiesel is one of the main biofuels used to replace fossil resources, and is mainly produced from esterification and transesterification of fatty acids and oils catalyzed by acids, bases or enzymes. Among the existing catalysts, metal oxides and their derivatives play an important role because of their high catalytic activity and low cost. ZnO is a metal oxide and its related nanomaterials are easy to prepare, which gives ZnO superior reactivity and extensive applications. Suitably modified ZnO nanomaterials typically have high specific surface areas, suitable pore sizes, and enhanced catalytic performance in the production of biodiesel. The present review introduces the application progress of ZnO catalysts in biodiesel preparation. The current shortcomings and future challenges of the basic heterogeneous catalytic systems for biodiesel production are also discussed.

Effect of nanocatalysts on the transesterification reaction of first, second and third generation biodiesel sources- A mini-review

Biodiesel is a fuel that has numerous benefits over traditional petrodiesel. The transesterification process is the most popular method for biodiesel production from various sources, categorized as first, second and third generation biodiesel depending on the source. The transesterification process is subject to a variety of factors that can be taken into account to improve biodiesel yield. One of the factors is catalyst type and concentration, which plays a significant role in the transesterification of biodiesel sources. At present, chemical and biological catalysts are being investigated and each catalyst has its advantages and disadvantages. Recently, nanocatalysts have drawn researchers' attention to the efficient production of biodiesel. This article discusses recent work on the role of several nanocatalysts in the transesterification reaction of various sources in the development of biodiesel. A large number of literature from highly rated journals in scientific indexes is reviewed, including the most recent publications. Most of the authors reported that nanocatalysts show an important influence regarding activity and selectivity. This study highlights that in contrast to conventional catalysts, the highly variable surface area of nanostructure materials favours interaction between catalysts and substrates that efficiently boost the performance of products. Finally, this analysis provides useful information to researchers in developing and processing cost-effective biodiesel.

Comparison of CaO-NPs and Chicken Eggshell-Derived CaO in the Production of Biodiesel from Schinziophyton rautanenii (Mongongo) Nut Oil

The ever-increasing population growth and economic developments have heightened demand for energy. This has resulted in depletion and ever-rising prices of petroleum diesel, thus increasing environmental degradation. These complications have motivated this study for the search of an alternative eco-friendly and renewable source of energy such as biodiesel. Biodiesel has been found to be a potential alternative fuel for diesel. Biodiesel was produced by transesterification reaction of Schinziophyton rautanenii (mongongo) nut oil in the presence of a base heterogeneous catalyst: CaO derived from eggshell ash and synthesised CaO-nanoparticles (CaO-NPs). The catalysts were calcined at a temperature of 800°C for 3 h and characterized by scanning electron microscope-energy dispersive X-ray (SEM-EDX) where both catalysts showed agglomerated particles and high elemental composition of Ca and O. Powder X-ray diffraction (XRD) showed that CaO was present in both catalysts, and the average crystalline size obtained was 42 and 50 nm for CaO-NPs and eggshell ash, respectively. Fourier transmission infrared (FTIR) spectrometer showed absorption bands of CaO in both catalysts which were at 875 and 713.46 cm−1 for CaO-NPs and eggshell ash, respectively. The analysis of mongongo nut oil (MNO) and mongongo methyl esters (MMEs) was done according to the European biodiesel specification (EN 1421) and American Society for Testing and Materials (ASTM D675). Statistically, there was no significant difference between CaO-NPs and eggshell in terms of optimum yield ( $P>0.05$ ) using a sample t-test. However, in terms of catalyst loading, the eggshell was a better catalyst as it required a low catalyst load to obtain an optimum yield of 83% at 6 wt.% compared to CaO-NPs with an optimum yield of 85% at 12 wt.%. The reactions were all performed at constant reaction conditions of 9 : 1 methanol to oil ratio, 3 h reaction time, and 65°C reaction temperature.

Nanobiocatalysts for Biodiesel Synthesis through Transesterification—A Review

Converting useless feedstock into biodiesel by utilizing the process of transesterification has been regarded as an alternative approach recently used to address the fuel and energy resources shortage issues. Nanobiocatalysts (NBCs), containing the biological component of lipase enzyme immobilized on nanomaterials (NMs), have also been presented as an advanced catalyst to effectively carry out the process of transesterification with appreciable yields. This study highlights the fundamentals associated with NBCs and the transesterification reaction catalyzed by NBCs for summarizing present academic literature reported in this research domain in recent years. Classification of the NBCs with respect to the nature of NMs and immobilization methods of lipase enzyme is also provided for organizing the recently documented case studies. This review is designed to act as a guideline for the researchers aiming to explore this domain of biodiesel production via NBCs as well as for the scholars looking to expand on this field.

Sonocogreen Decoration of Clinoptilolite by CaO Nanorods as Ecofriendly Catalysts in the Transesterification of Castor Oil into Biodiesel; Response Surface Studies

A CaO/clinoptilolite green nanocomposite (CaO/Clino) was synthesized by a green modification technique using calcium nitrate and green tea extract. The CaO/Clino nanocomposite promises a total basicity of 4.82 mmol OH/g, surface area of 252.4 m²/g, and ion exchange capacity of 134.3 mequiv/100 g, which qualifies the product as an effective catalyst in the transesterification of castor oil. The transesterification performance of the CaO/Clino catalyst was addressed statistically based on the response surface methodology and central composite rotatable design, considering the essential experimental parameters. Based on the interaction effect between the studied variables, the CaO/Clino catalyst can achieve an experimental biodiesel yield of 93.8% after 2.5 h at 120 °C with 3.5 wt % catalyst loading and 15:1 ethanol/castor oil molar ratio. The optimization function of the design suggested enhancement in the performance of the CaO/Clino catalyst to achieve a yield of 95.4% if the test time interval increased to 2.65 h and the ethanol content increased to 16:1 as a molar ratio to castor oil. The produced biodiesel over CaO/ClinO has acceptable technical qualifications according to the international requirements (EN 14214 and ASTM D-6751). The synthetic green CaO/Clino nanocomposite has better recyclability as a heterogeneous catalyst and higher activity than some investigated catalysts in literature.

A Comprehensive Review on Oil Extraction and Biodiesel Production Technologies

Dependence on fossil fuels for meeting the growing energy demand is damaging the world’s environment. There is a dire need to look for alternative fuels that are less potent to greenhouse gas emissions. Biofuels offer several advantages with less harmful effects on the environment. Biodiesel is synthesized from the organic wastes produced extensively like edible, non-edible, microbial, and waste oils. This study reviews the feasibility of the state-of-the-art feedstocks for sustainable biodiesel synthesis such as availability, and capacity to cover a significant proportion of fossil fuels. Biodiesel synthesized from oil crops, vegetable oils, and animal fats are the potential renewable carbon-neutral substitute to petroleum fuels. This study concludes that waste oils with higher oil content including waste cooking oil, waste palm oil, and algal oil are the most favorable feedstocks. The comparison of biodiesel production and parametric analysis is done critically, which is necessary to come up with the most appropriate feedstock for biodiesel synthesis. Since the critical comparison of feedstocks along with oil extraction and biodiesel production technologies has never been done before, this will help to direct future researchers to use more sustainable feedstocks for biodiesel synthesis. This study concluded that the use of third-generation feedstocks (wastes) is the most appropriate way for sustainable biodiesel production. The use of innovative costless oil extraction technologies including supercritical and microwave-assisted transesterification method is recommended for oil extraction.

Process optimization, green chemistry balance and technoeconomic analysis of biodiesel production from castor oil using heterogeneous nanocatalyst

In the present work, zinc doped calcium oxide was used as a nanocatalyst for biodiesel production from castor oil. The optimal conditions of biodiesel conversion and green chemistry balance were obtained with response surface methodology. Five green chemistry parameters like carbon efficiency, atom economy, reaction mass efficiency, stoichiometric factor and environmental factor were optimized. The sustainable biodiesel yield 84.9% and green chemistry balance 0.902 was achieved at methanol to oil molar ratio 10.5:1, temperature 57 °C, time 70 min, and catalyst concentration 2.15%. The synthesized biodiesel was characterized by GCMS and FTIR, and physic-chemical properties were determined. Based on experimental study annually 20.3 million kg capacity plant was simulated using SuperPro designer. The sensitivity analysis of oil purchase cost and biodiesel selling price on ROI, payback period, IRR and NPV were investigated. The optimization and technoeconomic analysis provided a sustainable platform for commercial based biodiesel production.

Optimization and techno-economic analysis of biodiesel production from Calophyllum inophyllum oil using heterogeneous nanocatalyst

The present research work is aimed at reducing the consumption of reactants by process optimization and economic analysis of large-scale commercial plant using techno-economic analysis. The statistical optimization of biodiesel production from Calophyllum inophyllum oil using Zn doped CaO nanocatalyst was used to optimize the conversion efficiency and green chemistry value. The environmental studies on transesterification reaction were done using green chemistry parameters like carbon efficiency, atom economy, reaction mass efficiency, stoichiometric factor and environmental factor. The biodiesel conversion 91.95% was achieved when maintaining the methanol to oil ratio 9.66:1, concentration of catalyst 5% (w/v), time 81.31 min and temperature 56.71 °C with green chemistry value of 0.873. Techno-economic analysis of biodiesel production from Calophyllum inophyllum oil was executed used optimized lab-scale data. The techno-economic analysis of 21 million kg/year biodiesel production plant was investigated. The annual biodiesel revenue of 15,224,000 $/yr and the payback period was about 1.15 years.

Optimization Using Response Surface Methodology (RSM) for Biodiesel Synthesis Catalyzed by Radiation-Induced Kenaf Catalyst in Packed-Bed Reactor

In this study, continuous transesterification of refined palm oil by using radiation-induced kenaf denoted as anion exchange kenaf catalyst in a packed-bed reactor was developed. The application of full factorial design and response surface methodology (RSM) based on the central composite design (CCD) was used to design the process and analyzed the effect of reactor operating variables such as packed bed height, the molar ratio of oil to ethanol and volumetric flow rate on the production of fatty acid ethyl ester (FAEE). The statistical analysis results showed that all three operating parameters affect the reaction efficiency significantly. The optimum conditions were determined to be 9.81 cm packed bed height, a molar ratio at 1:50, and a volumetric flow rate of 0.38 mL min−1. Three tests were carried out to verify the optimum combination of process parameters. The predicted and actual values of molar conversion fatty acid ethyl ester (FAEE) molar conversion were 97.29% and 96.87%, respectively. The reusability of kenaf fiber-based catalysts is discussed with a specially highlighted on fiber dissolution, leaching, and fouling. Nevertheless, the impurities absorption properties of anion exchange kenaf catalyst towards biodiesel production could eventually simplify the biodiesel purification steps and cost. In sum, anion exchange kenaf catalyst shows the potential commercial applications to transesterification of FAEE in a packed-bed reactor.

The Challenges of a Biodiesel Implementation Program in Malaysia

The palm biodiesel industry is facing many challenges implementing biodiesel program in Malaysia. This paper addresses the importance of the B10 blend (10% biodiesel, 90% petroleum diesel), global challenges of palm oil import and export, and protective measures for continuous positive growth of the palm oil sector. Palm oil is the backbone of Malaysia’s economy, covering more than 5% of its gross domestic product (GDP). The key steps taken by the Malaysian government for the successful implementation of the B10 program are discussed in this review study. Till now, B5 and B7 biodiesel programs have been successfully implemented in Malaysia. The B10 biodiesel program is attractive because of the developed local palm oil sector. The B10 biodiesel program will increase the use of renewable energy sources, and is expected to increase the productivity of palm oil and biodiesel implementation in the country. Despite successful B5 and B7 programs, Malaysia is facing challenges for the implementation of biodiesel due to fluctuation in crude palm oil prices, low domestic usage of palm oil, and vehicle warranty. The improvement of palm oil and promotion of B10 through targeted agencies in the central region of Malaysia will help to implement the biodiesel program successfully.

Pineapple (Ananás comosus) leaves ash as a solid base catalyst for biodiesel synthesis

Homogeneous catalysts used for biodiesel synthesis have several limitations, including non-recoverability/reusability, saponification, emulsification, equipment corrosion, and environmental pollution. To overcome these limitations, we synthesized a novel catalyst via calcination of pineapple leaves waste. This catalyst was characterized by X-ray powder diffraction, X-ray fluorescence, Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and soluble alkalinity measurements. The catalyst's activity with regards to soybean oil transesterification was analyzed, and multiple process parameters (temperature, catalyst amount, reaction time, and methanol:oil molar ratio) were examined. A high catalytic activity, probably related to the 85 wt% content of alkali/alkali metals (K, Ca and Mg), was observed after a 30 min reaction time, 60 °C, 4 wt% of catalyst, oil to methanol molar ratio of 1:40, reaching an oil to biodiesel conversion above 98%. We conclude that the novel catalyst presented here is efficient, cost-effective, and sustainable, while simultaneously abundant waste is reduced.

Phoenix dactylifera L. Seed Pretreatment for Oil Extraction and Optimization Studies for Biodiesel Production Using Ce-Zr/Al-MCM-41 Catalyst

This work compared the effect of soaking and roasting Phoenix dactylifera L. seeds pretreatment methods on oil yield. The conversion of the Phoenix dactylifera L. seed oil to fatty acid methyl ester (FAME) was conducted via transesterification reaction using Ce-Zr/Al-MCM-41 monometallic and bimetallic catalysts. The reaction conditions were optimized using response surface methodology based on the central composite design (RSM-CCD). The result shows a quadratic model fitting with an R2 value of ~0.98% from the analysis of variance. In addition, the optimum FAME yield of 93.83% was obtained at a reaction temperature of 60.5 °C, a reaction time of 3.8 h, a catalyst concentration of 4 wt.%, and a methanol to oil molar ratio of 6.2:1 mol/mol. The effect of the regenerated catalyst was significantly maintained for five cycles. The fuel properties of the produced FAME lie within the values reported in studies, ASTM D6751, and EN14214 standards.

Production of Biodiesel from Castor Oil: A Review

An attractive alternative to the use of fossil fuels is biodiesel, which can be obtained from a variety of feedstock through different transesterification systems such as ultrasound, microwave, biological, chemical, among others. The efficient and cost-effective biodiesel production depends on several parameters such as free fatty acid content in the feedstock, transesterification reaction efficiency, alcohol:oil ratio, catalysts type, and several parameters during the production process. However, biodiesel production from vegetable oils is under development, causing the final price of biodiesel to be higher than diesel derived from petroleum. An alternative to decrease the production costs will be the use of economical feedstocks and simple production processes. Castor oil is an excellent raw material in terms of price and quality, but especially this non-edible vegetable oil does not have any issues or compromise food security. Recently, the use of castor oil has attracted attention for producing and optimizing biodiesel production, due to high content of ricinoleic fatty acid and the possibility to esterify with only methanol, which assures low production costs. Additionally, biodiesel from castor oil has different advantages over conventional diesel. Some of them are biodegradable, non-toxic, renewable, they can be used alone, low greenhouse gas emission, among others. This review discusses and analyzes different transesterification processes, technologies, as well as different technical aspects during biodiesel production using castor oil as a feedstock.