• Energy Research

Abstract In the present research, various spherical mesoporous ZnO-based nanocrystalline(ZnAl2O4, CuO-ZnO, TiO2-ZnO) were synthesized via post-calcination treatment at 600 °C for 4 h over N2 flow gas, which initially went through a simple PEG-assisted microwave hydrothermal route by adapting the varieties of PEG (i.e. PEG 2000, PEG 4000, PEG 6000, PEG 10000, and PEG 20000) using incomplete carbonized glucose (ICG) as a template. The as-synthesized mesoporous ZnO-basednanocrystallineswere further characterized by mean of XRD, N2 adsorption and desorption, NH3-TPD, FESEM, and EDX. The experimental outcomes revealed that the extent of PEG 6000 in mixture played the vital role in the growth of spherical mesoporous ZnO-based nanocrystallines compared to other PEG molecular weights. The N2 adsorption and desorption data confirmed the mesopore structure of the samples, possessing the specific surface areas in the range of 450.35–592.55 m2g−1. By verifying the optimum PEG-assisted microwave hydrothermal conditions, one-pot polymerization of poly(sodium4-styrenesulfonate) was employed to activate surface areas and mesopore walls by -SO3H functional groups using for ester productionthrough transesterification of used cooking oil, resulted in methyl ester content of 97.4% and excellent reusability for ten sequential reactions withoutanyfurtherregeneration. Moreover, biodiesel quality evaluation analysis showed that the prepared methyl ester satisfied both EN (14214) and ASTM (D6751) specifications.

Abstract Biodiesel produced from non-edible feedstocks is increasingly attractive alternative to both fossil diesels and renewable fuels derived from food crops. Date pits are one such lipid containing feedstock, and are widely available in Oman as a waste stream. This study analyses the effects of soxhlet process parameters (temperature, solvent to seed ratio and time) on the extraction of oils from waste Date pits and the subsequent production of biodiesel from it. The highest yield of oil extracted from the Date pits was 16.5 wt% obtained at a temperature of 70 °C, solvent to seed ratio of 4:1 and extraction duration of 7 h. Gas Chromatography analysis showed that Date pits oil consisted of 54.85% unsaturated fatty acids (UFA). Transesterification of the oil extracted was undertaken at 65 °C, a methanol to oil ratio of 6:1 and a reaction time of 1 h for biodiesel production. Biodiesel produced from the Date pits oil was found to have a cetane number of 58.23, density 870 of kg m−3, cloud point of 4 °C, pour point of −1 °C, CFPP of −0.5 °C and kinematic viscosity of 3.97 mm2 s−1 (40 °C). In general, Date pit oil appears to be a potential alternative feedstock for biodiesel production.

Abstract Response surface methodology (RSM), with central composite rotatable design (CCRD), was used to explore optimum conditions for the transesterification of Moringa oleifera oil. Effects of four variables, reaction temperature (25–65 °C), reaction time (20–90 min), methanol/oil molar ratio (3:1–12:1) and catalyst concentration (0.25–1.25 wt.% KOH) were appraised. The quadratic term of methanol/oil molar ratio, catalyst concentration and reaction time while the interaction terms of methanol/oil molar ratio with reaction temperature and catalyst concentration, reaction time with catalyst concentration exhibited significant effects on the yield of Moringa oil methyl esters (MOMEs)/biodiesel, p

Abstract Many industrial applications involve the transesterification of natural oils and fats. In the present work, methyl esters were transesterified from white mahlab oil (WMO) using methanol via base and lipase-catalyzed reactions. The oil content of the mahlab seeds was found to be 31%. The composition of the fatty acid methyl esters (FAMEs) produced from the WMO was analyzed by GC/MS, revealed α-eleostearic acid (40.7%), oleic acid (29.8%) and linoleic acid (26.6%). The effects of the reaction conditions ( i.e. , time, temperature, the amount of catalyst, methanol/oil molar ratio, water content and the amount of solvent) on FAME’s yield were appraised. The important fuel properties of the FAME’s were measured and compared with ASTM 6751 and EN 14214 biodiesel standards.

Abstract Biodiesel is considered as a sulfur free, non-toxic and biodegradable source of energy and its burning provide less pollution than petroleum based fuels. In case of using fried waste oils, animal’s fats and waste cultivated oil which contain high free fatty acid (FFA), esterification is taking place. Through esterification reaction, catalyst is an integral part which accelerates the FFA conversion to the methyl ester (ME) in shorter reaction time. Although, most of the current catalysts have some defect such as poor recyclability, less surface area and poor porosity. Mesoporous materials have been recently attracted remarkable interests because of its desirable properties, such as large and harmonized surface area, tuneable mesoporous channels with flexible pore size, excellent thermal stability, and post-functionalization surface characteristics. The combination of remarkable physico-chemical and textural properties as well as high activity has proposed them as advanced materials. In this review, it has been attempted to present the details of fundamental properties of mesoporous catalysts, various synthetic methods and formation mechanisms, and surface functionalization methodologies. The effects of various factors (such as surface area, porosity, acidity, post-calcination temperature, and reaction parameters) on esterification of different feedstocks are discussed in detail. Furthermore, the kinetic study of esterification reaction in the presence of mesoporous catalysts is also elaborated. At the end, remarkable challenges and outlooks are recommended for further improvement and commercialization of mesoporous catalysts.

Abstract Yucca aloifolia Linn ( Y. aloifolia ) is a drought-resistant arid land plant that grows in most soil types. In this work, Y. aloifolia seed oil (YAO) was evaluated for the first time as a potential biodiesel feedstock, which contains 16.23% oil (w/w) whereas the acidity of the oil was 11%. Two step processes i.e. acid-catalyzed esterification to reduce the acid value of YAO and then standard base-catalyzed transesterification procedure were used to synthesis the Y. aloifolia methyl esters (Yame) at optimization conditions. YAO has a high content of linoleic acid (70.77 %) followed by oleic acid (12%), and palmitic acid (8.59%). The fuel properties of biodiesel derived from YAO including density, iodine value, kinematic viscosity, cetane number, flash point, pour point, cloud point, and gross heating value were evaluated and compared with the limits of ASTM D6751 standards. The comparison showed that the biodiesel obtained from Y. aloifolia oil could be used as an alternative fuel for diesel engines.

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.

Biodiesel derived from simultaneous esterification and transesterification of waste cooking oil has been attracting consideration as a replacement green fuel for diesel fuels, as it is economically feasible and circumvents the issue of energy versus food, which is estimated to take place with current biodiesel production techniques. In this optimization study, iron-manganese doped zirconia-supported molybdenum oxide catalyst has been prepared and used in the synthesis of waste cooking oil based biodiesel by a simultaneous esterification and transesterification method. The catalyst is prepared via an impregnation method and consequently characterized by XRD, TEM, TGA (thermogravimetric analysis), TPD-NH3, and Brunauer–Emmer–Teller (BET) techniques. The simultaneous process for biodiesel production has been assessed and improved statistically via response surface methodology in combination with the central composite design. It has been established that the process for synthesis of waste cooking oil based biodiesel achieved about 96.8% biodiesel yield at a best condition of 200 °C, waste cooking oil/ methanol molar ratio of 1:30 and 5.0 wt. % as loading of the catalyst. The highest ester yield of 96.8% has been obtained due to the improved physicochemical properties of zirconia-supported molybdenum oxide catalyst which accesses diffusion of the reactants to the active sites.