Amount Of Catalyst Research Articles

A porous phenolic resin sorbent for enhanced CO2 capture: Synthesis, optimization, and techno-economic analysis

Amidst rising global concerns about climate change, the capture and sequestration of carbon dioxide (CO2) from industrial emissions is becoming increasingly critical. In the present study, a phenolic resin-based porous polymer for CO2 capture is developed, offering a solution to the dual challenges of efficacy and cost in current carbon capture technologies. Optimization of synthesis parameters, including temperature, reaction time, and catalyst amount was performed using response surface methodology (RSM) to maximize surface area and economic benefits. The optimized polymer demonstrated a substantial CO2 adsorption capacity of 3.06 mmol/g at 273 K and 1 bar, with a specific surface area of 860 m2/g. An early-stage techno-economic analysis of sorbent synthesis was conducted, relating cost to sorbent quality and surface area. It was found that producing the polymer at low temperatures is more cost-effective, while synthesis at higher temperatures offers operational advantages. This research addresses a gap in existing literature by focusing on the sorbent material and its economic viability, paving the way toward the commercialization of such adsorption technology.

Optimization of Biodiesel Production from Jatropha Oil and its Impact on Engine Performance and Emissions Using Response Surface Methodology

This study aims to improve biodiesel production by assessing the effects of biodiesel-diesel fuel blends on engine performance and emissions using response surface methodology (RSM). The biodiesel was produced by the transesterification process. Here we see how the molar ratio (A), catalyst quantity (B), reaction temperature (C), and reaction time (D) affect the biodiesel conversion rate. During optimization, a Box-Behnken design (BBD) based on RSM was employed. Ideal conditions for achieving a biodiesel yield of 98.2069% were a B of 0.811601 wt%, a C of 75.8837°C, a D of 98.2069 min, and A of 10935:1. Adjusting parameters like engine speed and biodiesel fuel mix ratio enhanced engine behavior and condensed exhaust emissions. The trials were structured utilizing the central composite design (CCD) technique grounded on RSM. The optimum operating criteria for the engine were evaluated to be a biodiesel ratio of 12.5845% and speed of engine is 2011.24 rpm. Under these conditions, the power output was 50.0817kW, torque was 254.757 Nm, smoke opacity was 6.48966%, CO emissions were 270.009 ppm, and NOx emissions were 819.573 ppm.

Photocatalytic degradation of Alizarin Red contaminant using Ag2CrO4@NiFe-LDH composite under visible light irradiation.

In this study, Ag2CrO4@NiFe-LDH nanoparticles were synthesized by hydrothermal method for photocatalytic degradation of Alizarin Red (AR) dye. Three composites with different molar percentages were prepared, among which 50%Ag2CrO4@50%NiFe-LDH composite was the best sample with a removal rate of 97.1% in AR degradation. Also, the properties, structure, and characteristics of pure Ag2CrO4 and NiFe-LDH and their composites were determined by XRD, FESEM, FTIR, EDX mapping, and UV-visible analyses. It was found that Ag2CrO4@NiFe-LDH composites with the formation of heterogeneous structure of Z-scheme, in addition to increasing the active sites and increasing the specific surface, decrease the recombination rate of pure Ag2CrO4 and NiFe-LDH. Also, the Box-Behnken design technique, which is one of the most common designs used in response surface methodology, was used to optimize the operating conditions and investigate the effect of 4 independent parameters: catalyst amount, solution concentration, pH, and light intensity. The importance of independent parameters and their interactions were determined by ANOVA. By means of numerical optimization, the optimal values of the selected parameters equal to 1.34 g/L of catalyst, concentration of 16.45 mg/L, pH = 10.74, and light intensity of 15.53 W were obtained as optimal conditions with a desirability coefficient of 1.00 and an absorption value of 89.34%. The closeness of adjusted R2 (0.9838) and predicted R2 (0.9507) values show that this model can be successfully used for prediction.

Design a WO3/Zn heterojunction for boosting the photodegradation of Favipiravir in aqueous solutions

ABSTRACT This study was aimed at designing a new type of heterojunction catalyst for the degradation of Favipiravir using visible light. Several WO3–ZnO nanocomposites with different Zn contents varying from 1 to 20 wt% were successfully developed via a simple one-step microwave irradiation procedure. Various analytical methods, including XRD, TEM, FESEM, EDAX, FTIR, and BET, BJH characterised the WO3-Zn catalysts. XRD pattern revealed that the small size of Zn ions is caused by the easy penetration of Zn ions into the WO3 crystalline with a monoclinic phase, which will lead to an increase in the surface area and a decrease in the size of the particles. According to FESEM and TEM images, nanocomposite particles had a non-uniform, irregular shape and a smaller particle size (20 to 40 nm). EDAX analysis related to WO3-Zn synthesised showed the O, W and Zn elements are 10%, 67%, and 23%, respectively. Response surface methodology using R software was used as a tool to optimise the amount of catalyst and Favipiravir concentration, time and pH. Effective parameters in the process, including the amount of catalyst in the range (0.5 to 2.5 g L−1), Favipiravir concentration in the range (1–10 mg L−1), time in the range (10–90 min) and pH in the range (4 to 9) were entered into the software and analysed. Under the optimised conditions of the parameters (pH, 4.96; amount of catalyst, 2 g L−1; amount of Favipiravir concentration, 10 mg L−1; and time, 60 min), the maximum removal efficiency (99.99%) was obtained. Also, 85.8% of the mineralisation of Favipiravir was found under the determined optimum conditions. Quenching experiments were conducted to investigate the reaction mechanism, the results showed that superoxide and hydroxyl oxidising radicals play an essential role in Favipiravir degradation..

Synthesis of carrageenan/DFNS composite and its application in the esterification of levulinic acid with alcohols

The surface acidity of dendritic fibrous nano-silica (DFNS) was modified by a k-carrageenan biopolymer having sulfonic acid functional groups. The composite was used as a solid acid catalyst in the Fischer esterification reaction to convert levulinic acid (LA) to alkyl levulinates. The samples were characterized by analytical and instrumental techniques such as FT-IR spectroscopy, X-ray diffraction (XRD), N2 adsorption–desorption analysis, FESEM, and TEM. By using different alcohols including a short chain (ethanol), a medium chain (n-butanol), and a long chain (n-hexanol), the impact of various parameters on the esterification reaction was investigated. Under the optimum reaction conditions including 6 h as the reaction time, 10 mg catalyst amount, 12:1 ethanol: LA ratio, and 150 °C as the reaction temperature a 61 % ethyl levulinate was obtained. The selected catalyst was recycled and regenerated for use in successive runs without worthy loss in its activity.

Study on Grouting Performance Optimization of Polymer Composite Materials Applied to Water Plugging and Reinforcement in Mines.

With the increasing drilling depth of mines, the cross-complexity of fissures in the rock body, and the frequent occurrence of sudden water surges, polymer slurry, with its advantages of good permeability and strong water plugging, is increasingly used in mine grouting projects. Additional research is needed in order to further improve the grouting performance of polymer slurry, ensure the safety of mining operations, and reduce the grouting cost. In this paper, a polymer composite grouting material was prepared with diphenyl methyl diisocyanate, polyether polyol, and fly ash, as the main raw materials, with coupling agent and catalyst as auxiliary reagents. The performance of the composite grouting material in terms of mechanical properties, thermal stability, hydrophobicity, and bonding was explored. This study's findings indicated that incorporating fly ash led to notable enhancements in the thermal stability and water resistance of the polymer slurry. Furthermore, the introduction of fly ash notably raised the starting degradation temperature of the polymer, boosted the water contact angle of the composite material, and reduced the density and reaction temperature of the composite material. In addition, the catalyst and coupling agent as auxiliary reagents affected the polymers in terms of mechanical properties; in this paper, dibutyltin dilaurate was used as the catalyst, and organosilanes were used as the coupling agent. The catalyst successfully sped up the polymer's gel time, however, an excessive quantity of catalyst compromised the polymer's mechanical characteristics. The addition of organosilanes has a positive effect on the dynamic mechanical properties of the composites, fracture toughness, compression, bending, and bond strength. The research can offer a theoretical direction for creating polymer mixtures in mine grouting projects.

Fungus mediated synthesis of biogenic palladium catalyst for degradation of azo dye.

Dyes are the coloured substances that are applied on different substrates such as textiles, leather and paper products, etc. Azo dyes release from the industries are toxic and recalcitrant wastewater pollutants, therefore it is necessary to degrade these pollutants from water. In this study, the palladium (0) nanoparticles (PdNPs) were generated through the biological process and exhibited for the catalytic degradation of azo dye. The palladium nanoparticles (PdNPs) were synthesized by using the cell-free approach i.e. extract of fungal strain Rhizopus sp. (SG-01), which significantly degrade the azo dye (methyl orange). The amount of catalyst was optimized by varying the concentration of PdNPs (1mg/mL to 4mg/mL) for 10 mL of 50 ppm methyl orange (MO) dye separately. The time dependent study demonstrates the biogenic PdNPs could effectively degrade the methyl orange dye up to 98.7% with minimum concentration (3mg/mL) of PdNPs within 24h of reaction. The long-term stability and effective catalytic potential up to five repeated cycles of biogenic PdNPs have good significance for acceleration the degradation of azo dyes. Thus, the use of biogenic palladium nanoparticles for dye degradation as outlined in the present study can provide an alternative and economical method for the synthesis of PdNPs as well as degradation of azo dyes present in wastewater and is helpful to efficiently remediate textile effluent.

Biodiesel synthesis from waste coconut scum oil utilizing SnFe2O4/cigarette butt-derived biochar as a magnetic nanocatalyst: Optimization, kinetic and thermodynamic study

This study aims to develop a novel and efficient magnetic nanocatalyst for producing biodiesel from waste coconut scum oil (WCSO). In this regard, a retrievable and robust nanocatalyst, SnFe2O4/biochar derived from cigarette butts, was synthesized and applied in the transesterification of WCSO under ultrasonication. The aforementioned nanocatalyst was synthesized by sol-gel technique. Various analyses were conducted to characterize the prepared nanocatalyst. These analyses confirmed the successful decoration of biochar on SnFe2O4. The Surface area and pore diameter were 128.47 m2/g and 15.62 nm, respectively. Central composite design (CCD) was applied to optimize the parameters influencing biodiesel synthesis. Moreover, the highest biodiesel yield employing SnFe2O4/cigarette butt-derived biochar nanocatalysts was attained at 98.67 % under optimal conditions, which include a methanol/WCSO ratio of 11.81:1 mol/mol, ultrasonic time of 34.25 min, temperature of 64.05 °C, and a catalyst amount of 2.73 wt%. Besides, SnFe2O4/cigarette butt-derived biochar demonstrated a notable biodiesel yield (90.48 %) even after seven reuse steps, highlighting its exceptional reusability. The thermodynamic and kinetic analyses of transesterification indicate that the synthesis of biodiesel is an endothermic reaction. The SnFe2O4/cigarette butt-derived biochar nanocatalyst stands out as a highly promising candidate for future research due to biodiesel performance, quick reaction time, and remarkable catalyst reusability.

Data-driven interpretation, comparison and optimization of hydrogen production from supercritical water gasification of biomass and polymer waste: Applying ensemble and differential evolution in machine learning algorithms

Supercritical water gasification (SCWG) has been utilized for producing hydrogen from organic wastes, which is associated with sustainable development. Nevertheless, identifying the optimal SCWG conditions and appropriate catalysts for diverse waste materials to yield hydrogen-rich syngas is consistently a laborious and costly endeavor. The current research presents a comprehensive framework that combines machine learning models (Decision Tree, Ensembled Learning Tree, Support Vector Machine, and Gradient Boost Regression) with Differential Evolution Optimization (DEO) to predict and optimize hydrogen production from Supercritical Water Gasification (SCWG) using 24 different biomass characteristics and process parameters.The findings indicate that ELA-DEO emerges as the preferred method for forecasting hydrogen yield (R2test = 0.95, RMSETest = 0.091), demonstrating its effectiveness in handling intricate variable-target relationships. Conversely, Support Vector Machine (SVM) displayed weaker performance with an R2Test of 0.73 and RMSETest of 0.116. In the SHAP feature importance analysis, temperature, catalyst amount, catalyst type, hydrogen and oxygen were highlighted as important parameters affecting the process. In addition, by fine-tuning the machine learning hyperparameters, the DEO optimization method was used to maximize the production of H2. The optimized ELA-DEO model was used to identify the ideal features and conditions applicable to our experimental setup. Based on these findings, a recommended biomass table was finally formulated, which was validated by the ELA-DEO model. According to our laboratory results, Dunaliella salina produced 12 mmol of hydrogen with a 35% selectivity. Black liquor with 3% (wt) wood has the capacity to produce 17.21 mmol of hydrogen. Also, when crude glycerol was reacted with RuCl3, 18.7 mmol of hydrogen were generated. However, Dunaliella salina produced a 64% mole fraction of total gas output, which matched the maximum value predicted by our ELA-DEO models.

Synthesis and Characterization of Palladium Catalyzed (Carbon-carbon Bond Formation) compounds

In atmospheric condition, cesium carbonate was dissolved in water in a small bottle. Aryl halides, phenyl boronic acid, tetra butyl ammonium bromide, Bis (tri phenyl phosphine) palladium II chloride catalyst and toluene were taken in another small bottle. The contents of both the small bottles were added in a pressure tube. Heating of reaction mixture was done at 80-900C and then stirred until the reaction completion, which was confirmed by TLC. After this, the reaction mixture was extracted with ethyl acetate and the organic layer was washed with brine solution and then filtered by buckner funnel prepared with celite bed. Sodium sulphate was added to the filtrate, filtered again using cotton bed and silica (60-120 mesh size) was added to the filtrate and evaporated by using rotavapour. Through column chromatography, the crude product obtained was purified using Ethyl acetate/Hexane as mobile phase.Bis (tri phenyl phosphine) palladium II chloride catalyzes the reaction of aryl halides and phenyl boronic acid at 80-900C giving moderate to high yields even when the catalyst quantity used was low.

The efficient and reusable imidazolium-organoboron catalysts for green CO2 insertion reactions in solvent-free under atmospheric and high-pressure conditions

Organoboron compounds that are available in industrial and scientific research were investigated as organocatalysts for the coupling reaction of CO2 into cyclic carbonates as fine chemicals in solvent-free and under sustainable green atmospheric and high-pressure conditions (1 atm and 1.6 MPa, 100 °C, 2 h). This work synthesized a series of imidazolium-organoboron catalysts (IBC1-IBC8) using the eco-friendly and metal-free methodology and characterized by various analysis techniques. These techniques were NMR (1H, 13C, and 11B), UV–Vis, FT-IR, Mass spectrometry, C/H/N analysis, and melting point measurement together with thermal gravimetric analysis (TGA-DTA), respectively. After that, the Lewis acidity of the synthesized imidazolium-organoboron catalysts, which is important for catalytic CO2 conversion studies, was investigated by the traditional Gutmann-Beckett test, and the Lewis acidity order of the target compounds was found at range 54.96–50.36 ppm. In the presence of 0.1 mol% imidazolium-organoboron catalyst (IBC8) and 0.2 mol% DMAP as co-catalyst, 4-chloromethyl-1,3-dioxalan-2-one was obtained as cyclic carbonate from epichlorohydrin in 44.9 % yield and 97.6 % selectivity (1 atm and 100 °C) and in an excellent 97 % yield with 98.9 % selectivity (1.6 MPa and 100 °C) in 2 h without any solvents. After the imidazolium-organoboron catalyst (IBC8) showed efficient catalytic conversion and high selectivity, the effect of different parameters, including the effect of substrate, Lewis acid-base, reaction time, reaction temperature, CO2 pressure, and catalyst amount, was studied for this catalyst. According to the obtained catalytic conversion results, it was also determined that the optimum Cat./ECH ratio for CO2 cycloaddition reactions is 1/1000.

Pd-Ru pair on Pt surface for promoting hydrogen oxidation and evolution in alkaline media

Hydrogen oxidation reaction in alkaline media is critical for alkaline fuel cells and electrochemical ammonia compressors. The slow hydrogen oxidation reaction in alkaline electrolytes requires large amounts of scarce and expensive platinum catalysts. While transition metal decoration can enhance Pt catalysts’ activity, it often reduces the electrochemical active surface area, limiting the improvement in Pt mass activity. Here, we enhance Pt catalysts’ activity without losing surface-active sites by using a Pd-Ru pair. Utilizing a mildly catalytic thermal pyrolysis approach, Pd-Ru pairs are decorated on Pt, confirmed by extended X-ray absorption fine structure and high-angle annular dark-field scanning transmission electron microscopy. Density functional theory and ab-initio molecular dynamics simulations indicate preferred Pd and Ru dopant adsorption. The Pd-Ru decorated Pt catalyst exhibits a mass-based exchange current density of 1557 ± 85 A g−1metal for hydrogen oxidation reaction, demonstrating superior performance in an ammonia compressor.

Green synthesis of Mn3O4@CoO nanocomposites using Rosmarinus officinalis L. extract for enhanced photocatalytic hydrogen production and CO2 conversion

In response to the urgent need for sustainable environmental remediation technologies and clean energy production, this study introduces an eco-friendly synthesized Mn3O4@CoO nanocomposite (MCNC) leveraging the natural reducing capabilities of Rosmarinus officinalis leaves (L.) extract. Focused on the hydrogen evolution reaction (HER) and CO2 methanation, our findings reveal significant enhancements in photocatalytic activity and CO2 methanation efficiency. The MCNC exhibited a promising hydrogen production rate of up to 823 μmol g−1 h−1 and a CO2 conversion efficiency exceeding 84 % under optimal conditions. The investigation highlights the synergistic interfacial effect between Mn3O4 and CoO, contributing to notable performance improvements. Additionally, the study explores the role of catalyst quantity in optimizing reaction efficiencies, presenting a scalable and environmentally benign approach to address global energy and environmental challenges. The apparent quantum efficiency (AQE%) was calculated to be 1.92, 2.39, 2.73, 3.21, 3.44, and 3.56 % for mass values of 15, 25, 35, 45, 55, and 65 mg, respectively. Furthermore, the CO2 methanation also shows a rise with the increase in catalyst quantity. A mass of 0.35 mg achieved a remarkable CO2 conversion efficiency of 71.9 %, while its 0.5 mg counterpart showcased an even more striking CO2 conversion efficiency of 84.4 %. The green synthesis method, characterized by its low energy requirement and the absence of toxic chemicals, aligns with the sustainable practices sought in environmental chemistry and nanotechnology. This work not only opens new avenues for developing efficient photocatalysts but also contributes to the broader application of green synthesized nanomaterials in environmental remediation and clean energy generation.

High-temperature planar asymmetric ceramic membranes: Effect of the Pt amount and dispersion on the H2 separation performance

This work investigates for the first time the effect of Pt catalyst amount and dispersion on hydrogen permeation performances of BaCe0.65Zr0.20Y0.15O3−δ–Gd0.2Ce0.8O2−δ (BCZY–GDC) composite planar Cer-Cer membranes with asymmetrical architecture, aiming to maximize the ratio between the permeated hydrogen and the metal content. To boost the hydrogen separation reactions, Pt must be deposited on both the dense and porous sides of the membrane. Moreover, the complex architecture of the porous layer can be used to disperse Pt particles providing a good interaction with the membrane. To fulfil this aim BCZY-GDC membranes composed of a 20 μm thick active dense layer and a 600 μm thick, porous support were produced by tape casting and impregnated with different amounts of platinum. Hydrogen permeation properties were thoroughly investigated examining the composition of the feed and the sweep gasses, temperature, stream humidification, catalyst amount and nature of the dispersion media. The effect of Pt-catalysed hydrogen permeation and water splitting reaction at the permeate side was investigated and discussed. It was found that using an optimal amount of Pt solution to activate the porous side of the membranes is paramount to increase hydrogen permeation in the whole operating temperature range while keeping low the amount of noble metal catalyst. Moreover, the selection of a proper solvent with good interaction with the membrane allows the obtainment of smaller Pt nanoparticles resulting in higher permeation. The best performances in terms of hydrogen permeation (0.74 and 1.29 mL min−1 cm−2 at 750 °C using a feed stream with respectively 50 % and 80 % of H2 in He) were obtained using an acetone-based solution for depositing 1.5 mg cm−2 of Pt at the porous side. This work suggests that the metal deposition plays a non-trivial role in the hydrogen separation process and should be fully evaluated to increase the final performance while cutting down the cost of the Pt catalyst and therefore, of the final device.

Functionalized Phosphorus‐Doped Porous Organic Polymers (FPPOPs)‐Promoted Pd‐Catalyzed Arylation of Hydrosilanes

The development of novel catalyst systems, especially as highly efficient heterogeneous catalysts for Si‐C bond ‐forming arylation reaction of hydrosilanes is highly desirable. Herein, we developed a simple and eco‐friendly methodology for construction of functionalized phosphorus‐doped porous organic polymers (FPPOPs) and its heterogeneous palladium catalyst through anchoring on FPPOPs bearing a phosphine ligand, in which the fabrication of FPPOPs was completed through the vinyl‐substituted triphenylphosphine (ViPPh3) and vinyl‐substituted polyhedral oligomeric silsequioxane (ViPOSS) as well as functional olefins via radical co‐polymerization. All these FPPOPs could act as a phosphine ligand for Pd‐catalyzed arylation of hydrosilanes have been characterized by SEM, FTIR, and X‐RAD. Moreover, the POSS‐based functionalized phosphorus‐doped porous organic polymers (POSS‐PPOPs) proved to be a high efficiency catalyst system for Si‐C bond ‐forming arylation of hydrosilanes with aryl iodides and with good yields as well as excellent chemoselectivity with low amount of catalyst under mild conditions. The mechanistic studies supported the effect of functional group on the catalytic activity of Pd/FPPOPs catalyst, which revealed that the weak coordination as well as non‐covalent interaction between porous organic polymers and substrate played important role in the enhancement of chemoselectivity.

Harnessing palladium-decorated g-C3N4 nanosheets for selective catalytic benzyl alcohol synthesis

The selective reduction of benzaldehyde to benzyl alcohol (a pivotal model reaction for the low-temperature stabilization of bio-oil) was meticulously investigated. This study delved into the catalytic prowess of Pd-modified g-C3N4 nanosheets (PdxCN) within a liquid-phase environment, utilizing H2 as the reducing agent under benign conditions. A series of photocatalysts were synthesized by impregnating graphitic carbon nitride nanosheets (NS-CN) with varying weight percent loadings of Pd nanoparticles. In the context of this selective hydrogenation, the catalytic activity of Pd2CN catalysts outshone that of pure NS-CN and other reference catalysts, exhibiting remarkable efficacy with benzyl alcohol yields nearing perfection at approximately 99%. Moreover, these catalysts demonstrated enduring catalytic reusability and reproducibility. The optimization of experimental parameters, encompassing weight percent loading of co-catalyst, catalyst quantity, temperature, and reaction duration, was systematically undertaken to achieve optimal benzyl alcohol yield.

Control of burning rate pressure sensitivity for solid propellants by changing the interfacial contact of Al/HMX/AP with precisely located graphene-based energetic catalysts

The control of burning rate pressure sensitivity is essential for stable and reliable combustion of solid propellants. It has been proved that the combustion behavior of propellants can be effectively tuned by interfacial control of Al/oxidizers. In this work, core-shell Al-based composites, using oxidizers such as ammonium perchlorate (AP) and cyclotetramethylene tetranitramine (HMX) as the shell layer, have been prepared with a well-controlled location of graphene-based carbohydrazide complexes (GO-CHZ-M, M = Co2+ or Ni2+) as the catalysts. The catalysts can be located inside HMX or embedded on the surface of AP particles. The decomposition of AP and HMX could be greatly promoted with a trace amount of catalyst. Under the synergistic effects of Al/oxidizer interfacial control and GO-CHZ-M, the ignition delay time is shortened by >48 % with increased in flame radiation. More importantly, the burning rate (r) and pressure exponent (n) of the solid propellants are effectively regulated in a wide range. In particular, the use of Al@HMX/Co results in a lowered n of 0.29 within 1∼20 MPa compared to 0.79 for the blank reference sample. The agglomeration of Al particles during combustion was also inhibited due to the micro-explosion effect of Al@HMX composites. Novelty and Significance statementThe innovative approaches of integrating Al/HMX/AP composites and precise catalysis of graphene-based energetic catalysts in solid propellants have successfully achieved, regarding the modulation of the burning rates and pressure sensitivity. Moreover, the effect of catalyst location on the ignition delay and burning rates has also been studied thoroughly and clarified. This paper provides new insight into the regulation of combustion performance of solid propellants, with improved reaction efficiency and maintained energy density.

Synthesis of the acidic/magnetic catalyst x-MoO3/Ni0.5Zn0.5Fe2O4 by combustion reaction and evaluation of its catalytic potential/reuse in biodiesel production

The objective of this work was to synthesize a new catalyst x-MoO3/Ni0.5Zn0.5Fe2O4 using the combustion reaction method and to evaluate its catalytic potential and reuse in biodiesel production from waste oil, optimizing the process through experimental design. The catalysts were characterized in terms of structure by X-ray diffraction and phase quantification by Rietveld refinement, surface area by the Brunauer-Emmett-Teller technique, experimental density by helium pycnometry, acidity tests by ammonia desorption at programmed temperature, chemical analysis by X-ray fluorescence, morphology by scanning and transmission electron microscopy, and catalytic properties. The products of the simultaneous transesterification and esterification reactions were characterized by gas chromatography and acidity index. The results indicate the formation of catalysts with surface area ranging from 1.5 to 1.7 m2/g and density ranging from 4.5 to 5.1 g/cm3, composed of major crystalline phases of MoO3 in the orthorhombic configuration and cubic Ni0.5Zn0.5Fe2O4 ferrite, with total acidity ranging from 70 to 182 μmol/g of NH3. Morphological characterization revealed that the catalyst comprises irregular plates of various sizes and shapes with a wide range of cluster sizes. In the simultaneous transesterification and esterification reactions of residual oil, the catalysts were active under all conditions tested, with emphasis on the catalyst containing 50 % Mo ions and 50 % Ni0.5Zn0.5Fe2O4 presenting the best catalytic performance with a conversion of 95 % in ethyl esters and a reduction of 71 % in acidity, with a service life of 6 cycles, an average conversion of 90 % and good thermal and structural stability after use. The experimental design was significant and predictive, with a confidence level of 95 %. Statistical analysis identified that all input variables (temperature, time, and amount of catalyst) were significant for the adopted design. The new catalyst composed of molybdenum, iron, nickel, and zinc has a positive impact on biodiesel synthesis from frying oil and ethanol.

Mono-and bi-metal catalytic hydrothermal liquefaction of food waste: Screening the process parameter on product yield and characterizations

Biofuels and chemicals derived from wet food waste (FW) can serve as a strategy to significantly reduce emissions and mitigate environmental pollution while preventing the loss of valuable resources. Hydrothermal liquefaction (HTL) is one of the most promising thermochemical techniques for converting wet waste into crude oil-like products (biocrude). In this study, catalytic HTL of FW was carried out using cobalt (Co), magnesium (Mg), and cobalt-magnesium (Co–Mg) supported on ZSM-5 to produce high-quality biocrude. The impact of key operating parameters, such as reaction solvent, temperature, reaction holding time, and catalyst amount, was investigated. In comparison to non-catalytic liquefaction, catalytic liquefaction significantly improved the biocrude yield. The maximum biocrude yield (60.89 wt%) was achieved with bimetallic Co–Mg/ZSM-5 catalysts at 280 °C with 10 wt% of catalyst at a reaction time of 15 min. Various analytical methods, including GC-MS, FT-IR, CHNS, TGA, and NMR, were employed to identify the composition and quality of the biocrudes. Catalytic liquefaction with Co–Mg/ZSM-5 in an ethanol solvent resulted in a higher percentage of ester compounds (74.15%, area percentage). The biocrude obtained through the catalytic process had lower oxygen and nitrogen content, which led to a higher heating value (HHV). Biocrude quantification revealed the presence of 12.16 wt% of linoleic ester compounds. The concentration of total nitrogen (TN) in the catalytic aqueous phase was as high as 2.44 g/L, significantly greater than the 0.32 g/L found in the non-catalytic aqueous phase. Furthermore, the optimum Co–Mg/ZSM-5 catalyst demonstrated excellent reusability and stability in FW liquefaction.

Photocatalytic degradation of methylene blue under visible light using carbon-doped titanium dioxide as photocatalyst

A visible light-active photocatalyst, carbon-doped titanium dioxide (C-doped TiO2) with an anatase phase, was synthesized using a simple and cost-effective method, with glucose serving as the carbon source for doping. The surface morphology, crystal structure and elemental composition of the catalyst was analyzed by SEM, XRD and EDX respectively. Raman spectroscopic and XRD analysis showed the consistency of the anatase phase throughout the preparation process. FT-IR, TGA, and EDX depicted the purity of the prepared catalyst. SEM images revealed that the average particle size of the catalyst is approximately 178 nm, which is smaller than that of pure TiO2. Finally, as a proof-of-concept photocatalytic activity of the catalyst was investigated on a typical organic dye, methylene blue, under two different light sources (UV light and visible light) by varying the catalyst amount, the concentration of dye, and pH of the degrading medium. Results showed that the prepared C-doped TiO2 shows a promising result under the visible light irradiation which seems limited in case of pure TiO2. The optimum photocatalytic degradation conditions are pH 3, catalyst dosage 0.15 g, and dye concentration 3 × 10−5 M. At optimum conditions visible light shows 53 % degradation and UV light degrades almost all the dye molecules. The enhanced photocatalytic activity of C-doped TiO2 in visible light is due to carbon doping, which reduces the bandgap energy and enables the absorption of visible light photons. This convenient technique can be a great solution for the removal of dyeing wastes economically using low-cost visible light or sunlight and large scale production for industrial application.