Transition metal oxide (NiO, CuO, ZnO)-doped calcium oxide catalysts derived from eggshells for the transesterification of refined waste cooking oil

Discovery of lanthanide metal oxide catalyst for transesterification reaction by fluorescence-based high-throughput screening method and application to biodiesel production

The development of heterogeneous metal oxide catalysts for transesterification reactions is crucial owing to their seamless reusability and environmental friendliness. In recent years, numerous studies have been conducted on rare-earth oxides, such as lanthanide metal oxides. Various metal oxides were screened for transesterification using a new fluorescence-based high-throughput screening (HTS) method with a pyrene excimer probe, bis(4-(1-pyrenyl)butyl) maleate (BPBM). Praseodymium(iv) oxide (PrO2) yielded the highest catalytic activity among the prepared metal oxides. Various substrates were successfully transesterified, and biodiesel was produced in a high yield (90%) from soybean oil through transesterification using the catalyst. The selected catalyst required minimal amounts for the transesterification of various organic substrates (0.7 mol%) and soybean oil (0.8 wt%).

Biodiesel Production by Methanolysis of Rapeseed Oil-Influence of SiO2/Al2O3 Ratio in BEA Zeolite Structure on Physicochemical and Catalytic Properties of Zeolite Systems with Alkaline Earth Oxides (MgO, CaO, SrO)

Alkaline earth metal oxide (MgO, CaO, SrO) catalysts supported on BEA zeolite were prepared by a wet impregnation method and tested in the transesterification reaction of rapeseed oil with methanol towards the formation of biodiesel (FAMEs-fatty acid methyl esters). To assess the influence of the SiO2/Al2O3 ratio on the catalytic activity in the tested reaction, a BEA zeolite carrier material with different Si/Al ratios was used. The prepared catalysts were tested in the transesterification reaction at temperatures of 180 °C and 220 °C using a molar ratio of methanol/oil reagents of 9:1. The transesterification process was carried out for 2 h with the catalyst mass of 0.5 g. The oil conversion value and efficiency towards FAME formation were determined using the HPLC technique. The physicochemical properties of the catalysts were determined using the following research techniques: CO2-TPD, XRD, BET, FTIR, and SEM-EDS. The results of the catalytic activity showed that higher activity in the tested process was confirmed for the catalysts supported on the BEA zeolite characterized by the highest silica/alumina ratio for the reaction carried out at a temperature of 220 °C. The most active zeolite catalyst was the 10% CaO/BEA system (Si/Al = 300), which showed the highest triglyceride (TG) conversion of 90.5% and the second highest FAME yield of 94.6% in the transesterification reaction carried out at 220 °C. The high activity of this system is associated with its alkalinity, high value of the specific surface area, the size of the active phase crystallites, and its characteristic sorption properties in relation to methanol.

Advances in the fabrication, modification, and performance of biochar, red mud, calcium oxide, and bentonite catalysts in waste-to-fuel conversion

Various catalysts are being used in fuel production from biomass and polymeric waste for the obtention of an alternative energy source with both environmental friendliness and economic viability. Biochar, red mud bentonite, and calcium oxide have been shown to play a pertinent role as catalysts in waste-to-fuel conversion processes, such as transesterification and pyrolysis. In this line of thought, this paper has provided a compendium of the fabrication and modification technologies of bentonite, red mud calcium oxide, and biochar, together with their various performances in their application in the waste-to-fuel processes. Additionally, an overview of the structural and chemical attributes of these components is discussed regarding their efficiency. Ultimately, research trends and future points of focus are evaluated, and it is observed that techno-economic optimization of catalyst synthetic routes and investigation of new catalytic formulations, such as biochar and red mud-based nanocatalysts, are potential prospects. This report also offers future research directions that are anticipated to contribute to the development of sustainable green fuel generation systems.

Ni modified distillation waste derived heterogeneous catalyst utilized for the production of glycerol carbonate from a biodiesel by-product glycerol: Optimization and green metric studies

Biodiesel prices could be made competitive with petrol-diesel prices by valorizing its by-product glycerol. Glycerol carbonate can be derived from glycerol and is one of the widely needed chemical having high price and its extensive application in different industrial purposes. Glycerol carbonate can be synthesized via many routes; among them catalytic route gives promising activity and selectivity towards glycerol carbonate. For the first time, Ni modified distillation waste (CaO) derived heterogeneous catalyst Ni/CaO (NDW) was synthesized and utilized for the conversion of glycerol (Gl) to glycerol carbonate (GC). The catalyst's physicochemical properties were studied by performing TGA-DSC, XRD, FT-IR, SEM- EDAX, HRTEM, and basicity through Hammet indicator. Through NDW, solvent-free synthesis of glycerol carbonate was achieved using glycerol and dimethyl carbonate (DMC) as reactants upon conventional heating (90 °C). The validation of the synthesized product was performed through proton and carbon NMR analysis. In addition to this, HR-MS was performed to check the composition of the product formed. A plausible mechanism for the transesterification of glycerol (Gl) to glycerol carbonate (GC) was also designed. Higher conversion (99.2%) and selectivity (95%) towards glycerol carbonate (GC) were achieved at mild reaction conditions, viz., 1:3 M ratio of glycerol to DMC, reaction temperature 90 °C, reaction duration of 90 min with catalyst dose of 300 mg. The green metric parameters were also calculated to show that the overall process is sustainable and the environment benign.

Catalytic pyrolysis of high-density polyethylene over nickel-waste chicken eggshell/HZSM-5

The main objective of the current work is to investigate the effect of nickel-waste chicken eggshell modified Hydrogen exchanged Zeolite Socony Mobil-5 (Ni-WCE/HZSM-5) on pyrolysis of high-density polyethylene (HDPE). Ni-WCE/HZSM-5 was synthesized via the impregnation incipient wetness (IWI) method with Ni and WCE mass loading of 4 and 12 wt% respectively. HZSM-5, CaO, WCE, WCE/HZSM-5, and Ni/HZSM-5 were prepared for comparison purposes with Ni-WCE/HZSM-5. All the synthesized catalysts were characterized for phase analysis, metal loading, surface morphology, and textural properties. The impregnation of nickel and WCE had significantly affected the original framework of HZSM-5, where the crystallinity percentage and average crystal size of HZSM-5 dropped to 44.97% and increased to 47.90 nm respectively. The surface morphology of HZSM-5 has drastically changed from a cubic-like shape into a spider web-like surface after the impregnation of WCE. The BET surface area of HZSM-5 has been lowered due to the impregnation of nickel and WCE, but the total pore volume has increased greatly from 0.2291 cm³/g to 0.2621 cm³/g. The catalyst performance was investigated in the pyrolysis of HDPE via a fixed bed reactor and the pyrolysis oil was further analysed to evaluate the distribution of C₆ to C₉> hydrocarbons. Among the tested catalytic samples, the highest pyrolysis oil yield was achieved by WCE (80%) followed by CaO (78%), WCE/HZSM-5 (63%), HZSM-5 (61%), Ni/HZSM-5 (44%) and Ni-WCE/HZSM-5 (50%). For hydrocarbon distribution in pyrolysis oil, the Ni/HZSM-5 produced the highest of total C₆ and C₇ hydrocarbons at 12% and 27% respectively followed by WCE/HZSM-5 (4% and 20%), non-catalytic (5% and 13%), Ni-WCE/HZSM-5 (0% and 15%), WCE (0% and 10%), HZSM-5 (0% and 6%) and CaO (0% and 0%).

Synthesis and properties of wax based on waste cooking oil

In this work, a cost-effective wax was synthesized from waste cooking oil (WCO), and its properties including melting point, color, hardness, combustion performance and micro-morphology were tested and analyzed. The obtained results showed that the epoxy waste cooking oil had lighter color, higher melting point and hardness than that of original WCO, which could be used as wax. Moreover, introducing stearic acid further improved the performances of WCO-based wax. The WCO-based wax made of epoxy waste cooking oil and stearic acid (containing ≥50 wt% stearic acid) displayed a relatively high melting point (≥46 °C), light color (Lovibond color code Y ≤ 16.1, R ≤ 2.3), good hardness (needle penetration index ≤2.95 mm) and long combustion time (≥227 min), and could achieve the required national standard and be used as a substitute for the commercially available soybean wax. Together with many additional benefits such as low synthesis cost, mild reaction conditions, convenient synthesis route, and no secondary pollution, producing wax based on WCO could provide a new path for WCO recycling in economically trailing regions.

Facile Synthesis of Silane-Modified Mixed Metal Oxide as Catalyst in Transesterification Processes

The fast depletion of fossil fuels has attracted researchers worldwide to explore alternative biofuels, such as biodiesel. In general, the production of biodiesel is carried out via transesterification processes of vegetable oil with the presence of a suitable catalyst. A mixed metal oxide has shown to be a very attractive heterogeneous catalyst with a high performance. Most of the mixed metal oxide is made by using the general wetness impregnation method. A simple route to synthesize silane-modified mixed metal oxide (CaO-CuO/C6) catalysts has been successfully developed. A fluorocarbon surfactant and triblock copolymers (EO)106(PO)70(EO)106 were used to prevent the crystal agglomeration of carbonate salts (CaCO3-CuCO3) as the precursor to form CaO-CuO with a definite size and morphology. The materials show high potency as a catalyst in the transesterification process to produce biodiesel. The calcined co-precipitation product has a high crystallinity form, as confirmed by the XRD analysis. The synthesized catalyst was characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX). The mechanism of surface modification and the effects of the catalytic activity were also discussed. The biodiesel purity of the final product was analyzed by gas chromatography. The optimum biodiesel yield was 90.17% using the modified mixed metal oxide CaO-CuO/C6.