Biodiesel production from high acid value waste frying oil catalyzed by superacid heteropolyacid

Fortified edible oils in Bangladesh: A study on vitamin A fortification and physicochemical properties

Food fortification has always been an effective and proven practice for eradicating various nutrient deficiencies in Bangladesh. This study investigated different quality parameters of three types (soybean, sunflower, and palm) of extensively consumed fortified edible oils in Bangladesh. Vitamin A analysis has shown that the vitamin A fortification level of most of the oil brands (73 %) did not comply with the Bangladesh Standard and Testing Institution (BSTI) standards (1.5-3.0 mg/100 g). Vitamin A contents of soybean, sunflower, and palm oil brands ranged from 0.13 to 2.06, 0.92-1.34, and 0.99-1.31 mg/100 g, respectively. Inter-brand values of vitamin A were also significantly different (p < 0.05). The majority of the samples were found to be within the acceptable ranges of Codex and BSTI, taking into account the significant chemical quality parameters for soybean, sunflower, and palm oil, such as acid value (0.31-0.93, 0.31-0.56, 0.39-0.81 mg KOH/g), free fatty acid (0.15-0.46, 0.15-0.28, 0.2-0.41 %), saponification (188.64-196.35, 186.53-188, 197.05-199.86 mg KOH/g), and peroxide values (0.06-2.9, 0.65-1.58, 1.35-1.75 meq O2/kg) respectively. All the brands' physical quality parameters (density, specific gravity, pH, viscosity, smoke point, color, and RI) complied with Codex standards. Various physical and chemical quality parameters were analyzed for significant correlations at 0.01 and 0.05 levels of significance. Remarkably, significant correlations were found between vitamin A and peroxide value (p < 0.01), iodine value and viscosity (p < 0.01), saponification value and viscosity (p < 0.01), pH and viscosity (p < 0.01), and saponification value and pH (p < 0.05). In conclusion, although the vitamin A status of most of the fortified edible oil brands was poor, the key quality indicators (except iodine value) of most of the oils were within the Codex and BSTI standard limits and were acceptable for human consumption.

Reactivity of metal-oxo clusters towards biomolecules: from discrete polyoxometalates to metal-organic frameworks

Metal-oxo clusters hold great potential in several fields such as catalysis, materials science, energy storage, medicine, and biotechnology. These nanoclusters of transition metals with oxygen-based ligands have also shown promising reactivity towards several classes of biomolecules, including proteins, nucleic acids, nucleotides, sugars, and lipids. This reactivity can be leveraged to address some of the most pressing challenges we face today, from fighting various diseases, such as cancer and viral infections, to the development of sustainable and environmentally friendly energy sources. For instance, metal-oxo clusters and related materials have been shown to be effective catalysts for biomass conversion into renewable fuels and platform chemicals. Furthermore, their reactivity towards biomolecules has also attracted interest in the development of inorganic drugs and bioanalytical tools. Additionally, the structural versatility of metal-oxo clusters allows for the efficiency and selectivity of the biomolecular reactions they promote to be readily tuned, thereby providing a pathway towards reaction optimization. The properties of the catalyst can also be improved through incorporation into solid supports or by linking metal-oxo clusters together to form Metal-Organic Frameworks (MOFs), which have been demonstrated to be powerful heterogeneous catalysts. Therefore, this review aims to provide a comprehensive and critical analysis of the state of the art on biomolecular transformations promoted by metal-oxo clusters and their applications, with a particular focus on structure-activity relationships.

Recent advances and challenges in the utilization of nanomaterials in transesterification for biodiesel production

Due to diminishing fossil fuel supplies and rising energy needs, there has been an ever-increasing demand for renewable energy sources. The available renewable energy resources, such as solar, wind, hydropower, and biofuels, provide a new way of supplying the world's energy needs. Biofuels stand out among them because they are sustainable and have the potential to bring the idea of a global bioeconomy to life. As a result of their production of biofuels like biomethane, biohydrogen, and biodiesel, atmospheric CO₂ is being fixed, eventually lowering the world's carbon footprint. Current developments in the production of bioenergy have concentrated on producing biodiesel among other biofuels. Biodiesel is being produced from a variety of feedstocks using a number of processes, including transesterification, micro-emulsion, direct mixing, and pyrolysis. The most popular method among these is transesterification, which makes use of a variety of catalysts. As a result of the development of nanotechnology, nanocatalysts with desirable properties, such as increased catalytic activity, increased surface area, and superior thermal stability, have been made and modified. In this review, various nanocatalyst types and manufacturing processes are examined in relation to transesterification. It explores how crucial nanocatalysts are in boosting biodiesel production, highlights potential barriers, and makes recommendations for their widespread use in the future.

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.

Comprehensive Comparison of Hetero-Homogeneous Catalysts for Fatty Acid Methyl Ester Production from Non-Edible Jatropha curcas Oil

The synthesis of biodiesel from Jatropha curcas by transesterification is kinetically controlled. It depends on the molar ratio, reaction time, and temperature, as well as the catalyst nature and quantity. The aim of this study was to explore the transesterification of low-cost, inedible J. curcas seed oil utilizing both homogenous (potassium hydroxide; KOH) and heterogenous (calcium oxide; CaO) catalysis. In this effort, two steps were used. First, free fatty acids in J. curcas oil were reduced from 12.4 to less than 1 wt.% with sulfuric acid-catalyzed pretreatment. Transesterification subsequently converted the oil to biodiesel. The yield of fatty acid methyl esters was optimized by varying the reaction time, catalyst load, and methanol-to-oil molar ratio. A maximum yield of 96% was obtained from CaO nanoparticles at a reaction time of 5.5 h with 4 wt.% of the catalyst and an 18:1 methanol-to-oil molar ratio. The optimum conditions for KOH were a molar ratio of methanol to oil of 9:1, 5 wt.% of the catalyst, and a reaction time of 3.5 h, and this returned a yield of 92%. The fuel properties of the optimized biodiesel were within the limits specified in ASTM D6751, the American biodiesel standard. In addition, the 5% blends in petroleum diesel were within the ranges prescribed in ASTM D975, the American diesel fuel standard.

A Novel Heterogeneous Superoxide Support-Coated Catalyst for Production of Biodiesel from Roasted and Unroasted Sinapis arvensis Seed Oil

Disadvantages of biodiesel include consumption of edible oils for fuel production, generation of wastewater and inability to recycle catalysts during homogenously catalyzed transesterification. The aim of the current study was to utilize low-cost, inedible oil extracted from Sinapis arvensis seeds to produce biodiesel using a novel nano-composite superoxide heterogeneous catalyst. Sodium superoxide (NaO2) was synthesized by reaction of sodium nitrate with hydrogen peroxide via spray pyrolysis, followed by coating onto a composite support material prepared from silicon dioxide, potassium ferricyanide and granite. The roasted (110 °C, 20 min) and unroasted S. arvensis seeds were subjected to high vacuum fractional distillation to afford fractions (F1, F2 and F3) that correlated to molecular weight. For example, F1 was enriched in palmitic acid (76–79%), F2 was enriched in oleic acid (69%) and F3 was enriched in erucic acid (61%). These fractions, as well as pure unroasted and roasted S. arvensis seed oils, were then transesterified using NaO2/SiO2/PFC/Granite to give biodiesel a maximum yield of 98.4% and 99.2%, respectively. In contrast, yields using immobilized lipase catalyst were considerably lower (78–85%). Fuel properties such as acid value, cetane number, density, iodine value, pour point, and saponification value were within the ranges specified in the American biodiesel standard, ASTM D6751, where applicable. These results indicated that the nano-composite catalyst was excellent for production of biodiesel from unroasted and roasted S. arvensis seed oil and its fractions.

Advances in Nanocatalysts Mediated Biodiesel Production: A Critical Appraisal

The excessive consumption of petroleum resources leads to global warming, fast depletion of petroleum reserves, as well as price instability of gasoline. Thus, there is a strong need for alternative renewable fuels to replace petroleum-derived fuels. The striking features of an alternative fuel include the low carbon footprints, renewability and affordability at manageable prices. Biodiesel, made from waste oils, animal fats, vegetal oils, is a totally renewable and non-toxic liquid fuel which has gained significant attraction in the world. Due to technological advancements in catalytic chemistry, biodiesel can be produced from a variety of feedstock employing a variety of catalysts and recovery technologies. Recently, several ground-breaking advancements have been made in nano-catalyst technology which showed the symmetrical correlation with cost competitive biodiesel production. Nanocatalysts have unique properties such as their selective reactivity, high activation energy and controlled rate of reaction, easy recovery and recyclability. Here, we present an overview of various feedstock used for biodiesel production, their composition and characteristics. The major focus of this review is to appraise the characterization of nanocatalysts, their effect on biodiesel production and methodologies of biodiesel production.

Lanthanum Exchanged Keggin Structured Heteropoly Compounds for Biodiesel Production

La-exchanged 12-tungstophosphoric acid (LaxTPA) and 12-molybdophosphoric acid (LaxMPA) salts (x = 0.25, 0.50, 0.75 and 1.00) were prepared via an ion exchange method. The physico-chemical characteristics of the materials were analyzed by using elemental analysis, X-ray diffraction (XRD), Fourier transformed infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), N2-physical adsorption, X-ray photoelectron spectroscopy (XPS), and acidity-basicity measurements. The results indicated that La was introduced into the secondary structure of heteropolyacid (HPA) and have not influenced the primary structure, which effectively improved the surface area and pore size. Acidity-basicity studies indicated that incorporation of La resulted in a decrease in the number of acid sites and an increase in the number of basic sites. The catalytic activity of samples was studied in transesterification of glyceryl tributyrate with methanol and LaxTPA samples which exhibited high activity compared to LaxMPA samples due to having more active basic sites and a larger surface area. Calcined LaxTPA samples showed excellent stability, outstanding recyclability, and high activity for one pot transesterification and esterification processes. This outcome was attributed to the presence of balanced acidic and basic sites.

Synergism of clay with zinc oxide as nanocatalyst for production of biodiesel from marine Ulva lactuca

In the present work, Ulva lactuca, a marine macroalgae was used for the production of biodiesel. The ultrasound assisted extraction of oil from autoclaved algal biomass was found effective with maximum yield. The maximum oil was extracted at optimal conditions of 5% moisture content of algal biomass, 0.15 mm size of biomass, 6:1 solvent: solid ratio, at 55 °C in 140 min. The n-hexane with co-solvent methyl tertbutyl ether has shown higher oil when compared to other co-solvents. The extracted oil was transesterified into biodiesel using silica doped with zinc oxide as novel heterogeneous nanocatalyst. The maximum biodiesel yield of 97.43% was obtained at optimized conditions of 800 °C calcination temperature, 8% catalyst concentration, 9:1 methanol to oil ratio, 55 °C reaction temperature and 50 min reaction time. The kinetics of the transesterification reaction was also studied. The Ulva lactuca was found as a potential source for biodiesel production.

Incorporation of Ce3+ ions into dodecatungstophosphoric acid for the production of biodiesel from waste cooking oil

A series of cerium-exchanged dodecatungstophosphates Ce_xH_3-3xPW₁₂O₄₀ (Ce_xH_3-3xPW, x = 0.4, 0.6, 0.7, 0.8, 0.9, and 1.0) were designed and characterized by Fourier transform infrared spectroscopy (FT-IR), pyridine adsorption IR spectra, X-ray diffraction (XRD), and temperature programmed desorption of ammonia (NH₃-TPD). The activity of these catalysts was evaluated for the generation of biodiesel from waste cooking oil (WCO) with 27 wt% of free fatty acids (FFAs) and 1 wt% of water. Compared to theri parent H₃PW₁₂O₄₀, Ce_xH_3-3xPW showed higher activity for esterification of FFAs and transesterification of triglyceride to mono-alkyl esters of fatty acids (FAMEs) in one-pot. The acidic properties of Ce_xH_3-3xPW depended on the amount of Ce³⁺ ions in the secondary structure of Keggin heteropolyacids, while conversion of triglycerides and FFAs depended on their increasing acid contents. Among Ce_xH_3-3xPW, Ce_0.7H_0.9PW showed significant activity due to its high Brønsted acidity and Lewis acidity with 98% conversion of WCO and almost 100% selectivity to FAME at the molar ratio of methanol to WCO = 21:1 and 65 °C for 12 h. The reaction adhered to first-order kinetics with the activation energy (Ea) of 71 kJ/mol and the frequency factor (A) of 1.8 × 10⁸ min^-1, while the reaction rates were not influenced by the internal mass transport. The catalyst behaved as a heterogeneous catalyst, which can achieve the regeneration and be used more than five runs but without obvious decrease in activity. The characteristics of the WCO methyl ester were found to be close to the engine requirement.

Kinetics of Transesterification of Safflower Oil to Obtain Biodiesel Using Heterogeneous Catalysis

The kinetics of the transesterification of safflower oil and methanol catalyzed by K2O/NaX was studied and modeled. The influence of the oil-methanol initial molar ratio and amount of catalyst were investigated to achieve a maximum triglycerides conversion (99 %) and a final methyl esters content of 94 % ±1. A kinetic model based on an Eley–Rideal mechanism was found to best fit the experimental data when assuming methanol adsorption as determining step. Other models derived from Langmuir – Hinshelwood – Hougen –Watson (LHHW) mechanisms were rejected based on statistical analysis, mechanistic considerations and physicochemical interpretation of the estimated parameters.

Process development for scum to biodiesel conversion

A novel process was developed for converting scum, a waste material from wastewater treatment facilities, to biodiesel. Scum is an oily waste that was skimmed from the surface of primary and secondary settling tanks in wastewater treatment plants. Currently scum is treated either by anaerobic digestion or landfilling which raised several environmental issues. The newly developed process used a six-step method to convert scum to biodiesel, a higher value product. A combination of acid washing and acid catalyzed esterification was developed to remove soap and impurities while converting free fatty acids to methyl esters. A glycerol washing was used to facilitate the separation of biodiesel and glycerin after base catalyzed transesterification. As a result, 70% of dried and filtered scum was converted to biodiesel which is equivalent to about 134,000 gallon biodiesel per year for the Saint Paul waste water treatment plant in Minnesota.

Synthesis and characterization of a CaFe2O4 catalyst for oleic acid esterification

Esterification of free fatty acid (oleic acid) with ethanol over a calcium ferrite catalyst was investigated in the present study.

Synthesis of Biodiesel from Castor Oil Catalyzed by Cesium Phosphotungstate with the Assistance of Microwave

Two cesium phosphotungstate-derived solid acid catalysts (Cs2.5H0.5PW12 and Cs0.5H2.5PW12) were prepared. The resulting catalysts were characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), N2 adsorption and desorption isotherm and temperature programmed desorption of ammonia(NH3-TPD). The Cs2.5H0.5PW12 and Cs0.5H2.5PW12 were respectively used to catalyze the tranesterification of castor oil and methanol for the synthesis of biodiesel with the assistance of microwave. Results shown microwave radiation can greatly enhance the transesterification process when compared with conventional heating method. Cs2.5H0.5PW12 showed better catalyst performance than Cs0.5H2.5PW12. A maximum yield of 90% was obtained from the using of 30:1 molar ratio of methanol to castor oil and 15 wt % mass ratio of catalyst to castor oil at 343 K under microwave radiation after 4h.

Preparation of solid acid catalyst from glucose-starch mixture for biodiesel production

The aim of this work is to study the catalyst prepared by glucose-starch mixture. Assessment experiments showed that solid acid behaved the highest esterification activity when glucose and corn powder were mixed at ratio of 1:1, carbonized at 400°C for 75 min and sulfonated with concentrated H(2)SO(4) (98%) at 150°C for 5 h. The catalyst was characterized by acid activity measurement, XPS, TEM and FT-IR. The results indicated that solid acid composed of CS(0.073)O(0.541) has both Lewis acid sites and Bronsted acid sites caused by SO(3)H and COOH. The conversions of oleic acid esterification and triolein transesterification are 96% and 60%, respectively. Catalyst for biodiesel production from waste cottonseed oil containing high free fatty acid (FFA 55.2 wt.%) afforded the methyl ester yield of about 90% after 12h. The catalyst deactivated gradually after recycles usage, but it could be regenerated by H(2)SO(4) treatment.

Hydrocracking of used cooking oil for biofuels production

Hydrocracking of used cooking oil is studied as a potential process for biofuels production. In this work several parameters are considered for evaluating the effectiveness of this technology, including hydrocracking temperature, liquid hourly space velocity (LHSV) and days on stream (DOS). Conversion and total biofuels production is favored by increasing temperature and decreasing LHSV. However moderate reaction temperatures and LHSVs are more attractive for diesel production, whereas higher temperatures and smaller LHSVs are more suitable for gasoline production. Furthermore heteroatom (S, N and O) removal increases as hydrocracking temperature increases, with de-oxygenation being particularly favorable. Saturation, however, is not favored with temperature indicating the necessity of a pre-treatment step prior to hydrocracking to enable saturation of the double bonds and heteroatom removal. Finally the impact of extended operation (catalyst life) on product yields and qualities indicates that all reactions are affected yet at different rates.

Zn(1.2)H(0.6)PW(12)O(40) Nanotubes with double acid sites as heterogeneous catalysts for the production of biodiesel from waste cooking oil

Out of the frying pan: A ZnPW nanotube catalyst containing Brønsted and Lewis double acid sites promotes the conversion of waste cooking oil into biodiesel. The catalytic activity of the ZnPW nanotubes is stable to the presence of free fatty acids or water in the feedstock. The high catalytic activity of the ZnPW nanotubes is attributed to the synergistic effect of Lewis acid sites and Brønsted acid sites.Zinc dodecatungstophosphate (Zn(1.2)H(0.6)PW(12)O(40); ZnPW) nanotubes, which feature Lewis acid and Brønsted acid sites, were prepared using cellulose fibers as templates. The structure, acid properties, and catalytic activity of the nanotubes as heterogeneous catalysts for biodiesel production were then studied in detail. The ZnPW nanocatalyst exhibited higher catalytic activities for the simultaneous esterification and transesterification of palmitic acid than the parent acid catalyst 12-tungstophosphoric acid (H(3)PW(12)O(40)). Moreover, the doubly acidic nanotubes led to markedly enhanced yields of methyl esters in the conversion of waste cooking oil (containing 26.89 wt % free fatty acids and 1 % moisture) to biodiesel. The catalyst could be recycled and reused with negligible loss in activity over five cycles. The ZnPW nanocatalyst is acid- and water-tolerant and is an environmentally benign heterogeneous catalyst for the production of biodiesel from low-quality feedstocks.

Catalytic applications in the production of biodiesel from vegetable oils

The predicted shortage of fossil fuels and related environmental concerns have recently attracted significant attention to scientific and technological issues concerning the conversion of biomass into fuels. First-generation biodiesel, obtained from vegetable oils and animal fats by transesterification, relies on commercial technology and rich scientific background, though continuous progress in this field offers opportunities for improvement. This review focuses on new catalytic systems for the transesterification of oils to the corresponding ethyl/methyl esters of fatty acids. It also addresses some innovative/emerging technologies for the production of biodiesel, such as the catalytic hydrocracking of vegetable oils to hydrocarbons. The special role of the catalyst as a key to efficient technology is outlined, together with the other important factors that affect the yield and quality of the product, including feedstock-related properties and various system conditions.