Catalyst Dosage Research Articles

Boosting the synthesis of 3-acetamido-5-acetylfuran from N-acetyl-D-glucosamine: understanding the significant role of homogeneous Cl-

Since 3-acetylamino-5-acetylfuran (3A5AF) has been regarded as a promising nitrogen-containing synthon, the conversion of renewable chitin and its monomer N-acetyl-D-glucosamine (NAG) to 3A5AF is of significance. In this paper, we compared the catalytic activity of several Cl-containing compounds and found that LiCl exhibited superior performance. The effects of solvent, catalyst dosage, reaction temperature, and reaction time on the synthesis of 3A5AF were investigated. Under the optimized conditions, about 60% yields of 3A5AF were obtained in N-methyl-2-pyrrolidone (NMP) or dimethylacetamide (DMA) medium. The spent LiCl and DMA could be recycled and reused, without obvious decrease of 3A5AF yield. Moreover, the formed 3A5AF could be purified by a facile procedure. Experiment results and density functional theory (DFT) calculations revealed that homogeneous Cl− was vital for 3A5AF formation. This study provides an example for the effective conversion of chitin biomass to value-added compounds.

Carboxyethylsilanetriol-Functionalized Al-MIL-53-Supported Palladium Catalyst for Enhancing Suzuki–Miyaura Cross-Coupling Reaction

The application of metal–organic frameworks (MOFs) has attracted increasing attention in organic synthesis. The modification of MOFs can efficiently tailor the structure and improve the property for meeting ongoing demand in various applications, such as the alteration of gas adsorption and separation, catalytic activity, stability, and sustainability or reusability. In this study, carboxyethylsilanetriol (CEST) disodium salt was used as a dual-functional ligand for modified Al-MIL-53 to fabricate CEST-functionalized Al-MIL-53 samples through a hydrothermal reaction of aluminum nitrate, terephthalic acid, and CEST disodium salt by varying the molar ratio of CEST to terephthalic acid and keeping a constant molar ratio of Al3+/-COOH of 1:1. The structure, composition, morphology, pore feature, and stability were characterized by XRD, different spectroscopies, electron microscopy, N2 physisorption, and thermogravimetric analysis. With increasing CEST content, CEST-Al-MIL-53 still preserves an Al-MIL-53-like structure, but the microstructure changed compared with pure Al-MIL-53 due to the integration of CEST. Such a CEST-Al-MIL-53 was used as the support to load Pd particles and afford a catalyst Pd/CEST-Al-MIL-53 for Suzuki–Miyaura C-C cross-coupling reaction of aryl halides and phenylboronic acid under basic conditions. The resulting Pd/CEST-Al-MIL-53 showed a high catalytic activity compared with Pd/Al-MIL-53, due to the nanofibrous structure of silicon species-integrated CEST-Al-MIL-53. The nanofiber microstructure undergoes a remarkable transformation into intricate 3D cross-networks during catalytic reaction, which enables the leachable Pd particles to orientally redeposit and inlay into these networks as the monodisperse spheres and thereby effectively preventing Pd particles from aggregation and leaching, therefore demonstrating a high catalytic performance, long-term stability, and enhanced reusability. Obviously, the integration of CEST into MOFs can effectively prevent the leaching of active Pd species and ensure the re-deposition during catalysis. Moreover, catalytic performance strongly depended on catalyst dosage, temperature, time, solvent, and the type of the substituted group on benzene ring. This work further extends the catalytic application of hybrid metal–organic frameworks.

Visible‐Light‐Driven Photocatalytic Degradation of Amoxicillin Using FeMoO2/Chitosan/CdO Nanocomposite for Sustainable Water Treatment

ABSTRACTThis work focused on the photocatalytic degradation of amoxicillin using the recently developed FeMoO4/chitosan/CdO nanocomposite (FeMoO4/CS/CdO). The most typical antibiotic, amoxicillin, raises environmental threats due to its persistence in aquatic environments. Amoxicillin, extensively utilized as an antibiotic, has environmental concerns due to its existence in aquatic environments. The nanocomposite, comprising iron molybdate (FeMoO4), chitosan (CS), and cadmium oxide (CdO) nanoparticles, was synthesized to couple the distinct properties of each constituent, enhancing its overall functionality. FCC‐NC was characterized by the presence of clearly defined peaks in the infrared (IR) spectra, ultraviolet–visible (UV–Vis) spectra, and x‐ray diffraction (XRD) patterns. We studied the photocatalytic degradation of amoxicillin (AXM) using the FeMoO4/CS/CdO nanocomposite. Under ideal conditions (40 mg catalyst dosage and 10 mg/L initial AXM concentration), we achieved a degradation efficiency of roughly 90.8%, following pseudo‐first‐order kinetics with a rate constant of 0.0222 min−1. The immobilized FeMoO2/chitosan/CdO nanocomposite was more photocatalytically active than bare FeMoO2 because it exhibited less charge carrier recombination, according to EIS and PL analysis. Hence, the FeMoO4/chitosan/CdO nanocomposite has a vast opportunity in the long‐term mechanism of eradicating pharmaceutical pollutants in water. This study shows that the obtained results may be useful in the field of environmental cleanliness and water purification technologies.

Fluted pumpkin waste potential as a green solid bioalkaline catalyst for neem seed oil biodiesel synthesis

Developing green routes for biodiesel synthesis is essential for sustaining environmental benignity. Thus, this present study investigated the development of a solid catalyst using fluted pumpkin (Telfairia occidentalis) pod husk as a bio-based raw material via high-temperature furnace heating, ranging from 300 – 1000 oC. The catalyst properties were investigated by conducting surface functional group, surface crystallinity, surface area, and pore distribution analyses. The efficacy of the synthesized catalyst was investigated using 28 randomized experiments carried out on transesterification of esterified neem oil, which established 12:1, 3.5 wt.%, and 60 min as optimal conditions for methanol/neem oil ratio, catalyst dosage, and reaction time, respectively, with a maximum neem seed oil methyl esters (NSOME) yield of 96.71% through response surface methodology. The statistical assessment of the developed model gave a correlation coefficient (R) of 0.9907 and a coefficient determination of 0.9816 (R2). The physicochemical properties of the NSOME agree with American and European standard limits, making it suitable for transportation and energy purposes. The catalyst could be deployed for three reaction cycles with high turnover frequencies. Hence, fluted pumpkin waste and neem oil are suitable as a green route for biodiesel synthesis.

In situ construction of CuBi2O4/Bi4O5Br2 Z-scheme heterojunction with enhanced photocatalytic degradation performance for polyphenolic contaminant in wastewater

Photocatalytic technique is one of the clean and promising routes for wastewater purification. In this work, a different CuBi2O4/Bi4O5Br2 Z-scheme heterojunction were successfully prepared via an in-situ mechanical agitation method. The 10% CuBi2O4/Bi4O5Br2 (10% CBO/BOB) heterojunction showed the highest photocatalytic degradation activity for catechin, and ∼99.8% catechin was degrade within 40 min visible light stimulation, which is (0.0757/min) about 6.2-folds and 8.8-folds to that of Bi4O5Br2 (0.0122/min) and CuBi2O4 (0.0086/min), The pH=7 is the optimal reaction condition for catechin degradation. Besides, The photocatalytic degradation capacity of the 10% CBO/BOB heterojunction displayed the positive and negative relationship to the dosage of catalyst and initial concentration of catechin, respectively. The enhanced photocatalytic activity of CuBi2O4/Bi4O5Br2 Z-scheme heterojunction can be ascribed to the improvement of the charge separation and light utilization rate. The results of ESR and trapping experiments revealed that the ·O2-, h+ and ·OH are the primariy reactive substances for catechin degradation. Additionally, the transfer pathway of the photogenerated charges in the CuBi2O4/Bi4O5Br2 Z-scheme heterojunction as revealed by the ESR, Mott-Schottky curve and UV-Vis diffuse reflectance absorption spectroscopy. This work provide a new idea for designing and preparing the novel Bi4O5Br2-based photocatalyst for TCM wastewater purification.

Application of Steel Waste as a Heterogenous Catalyst in Advanced Oxidation Processes—Preliminary Study

The suitability of steel shavings (SS) as a low-cost waste catalyst in catalytic ozonation and the heterogeneous Fenton process was evaluated. Three dyes were selected for the research: Indigo Carmine, Tartrazine, and Allura Red AC. Single processes (oxidation by H2O2, O3, and heterogeneous Fenton process) and hybrid processes (O3 + Fenton) were applied. The Fenton process had the highest efficiency at pH = 3 and with the highest dose of catalyst (5 mg of SS) and hydrogen peroxide (30 µL). More than 98% discoloration of the solution was observed in 10 min. Analyzing ozone-based processes, they can be ranked with the highest efficiency as follows: (O3 + H2O2 + SS) > (O3 + H2O2) > O3 > (O3 + SS). The combination of the Fenton process (5 mg of SS + 15 µL of H2O2) with ozonation accelerated the reaction rate in the case of Indigo Carmine. In the hybrid process, only 5 min were enough for complete decolorization, while more than 98% in the Fenton process was reached after 30 min. Kinetic studies revealed that the degradation of dyes in an aqueous solution through advanced oxidation processes followed first- and second-order reaction kinetics. The calculation of the energy requirement confirmed that the most economic process for removing Indigo Carmine was the O3+Fenton process (SS dose = 5 mg, H2O2 dose = 15 µL, pH = 3).

Catalytic-assisted remediation and phytotoxicity evaluations of organic pollutants in the presence of metal-doped Bi2O3-based NPs catalyst.

The chemical co-precipitation method was used to synthesize a variety of pure Bi2O3 and substituted Bi2-2xCoxCdxO3 NPs (x=0.0-0.8) and doping influences were evaluated based on the optical, photocatalytic, morphological, and structural characteristics. Powder X-ray diffraction (PXRD), scanning electron microscope (SEM), Energy dispersive X-ray (EDX), Fourier-transform infrared spectroscopy (FTIR), and UV-visible techniques were used to explore the characteristics of the synthesized Bi2O3-based NPs. XRD measurements confirmed the monoclinic structure and a P21/c space group, whereas the particle size was between 22 and 41nm. The SEM analysis gives the morphology of the synthesized NPs that were diverse and agglomerated platelets, whereas the EDX measurements provide the presence of Co and Cd in Bi2-2xCoxCdxO3 NPs. Additionally, FTIR investigations confirmed the existence of functional groups in Bi2-2xCoxCdxO3 NPs. The ultraviolet-visible absorbance region displaying a considerable red shift allowed for tuning of the band gap from 2.64 to 2.37eV. By analyzing the degradation of Reactive Black 5 (RB-5) dye in the presence of sunlight, pure Bi2O3 NPs showed 65.04% whereas the substituted Bi2-2xCoxCdxO3 NPs demonstrated enhanced photodegradation (86.40%) in 105min. For the degradation of RB-5 dye, the effects of catalyst dosage, dye concentration, and pH variations were studied as well. The phytotoxicity experiment was also performed by comparing the germination of Triticum aestivum seeds in treated and untreated RB-5 dye. In the untreated dye solution, seed germination was 50% inhibited, and in the treated dye solution, germination was observed to be 80%. Additionally, recycling investigations were used to confirm the stability of these fabricated nanoparticles, and the results showed that nanomaterials exhibited significant stability and reusability. Co and Cd-doped Bi2O3 NPs are promising solar-active photocatalysts for dye removal from wastewater applications because of their improved photocatalytic activity and narrow bandgap.

Catalytic degradation of Rhodamine B through peroxymonosulfate activation by the Co-doped hydroxyapatite.

Supported Co-based catalysts have shown attractive prospects for peroxymonosulfate (PMS) activation. In this work, Co-doped hydroxyapatite (H-Co/HAP) composites were prepared by a simple hydrothermal method. The Co content in H-Co/HAP could reach 71.2mg/g, while the Co leaching rate remained relatively low. By right of the excellent catalytic performance, the as-prepared H-Co/HAP could achieve 99.02% degradation of Rhodamine B (RhB) within 10min in the presence of 0.5mM PMS and a first-order kinetic rate constant of 0.876min-1. Even after 8 cycles, the RhB degradation efficiency remained at 81.96%. In addition, the effects of vital reaction parameters, including catalyst dosage, PMS dosage, initial pH, humic acid, and coexisting anions, on the catalytic performance in the H-Co/HAP10/PMS system were systematically investigated and discussed. The degradation mechanism of a non-radical (1O2) as the dominant active specie and a radical (•O2- and SO4•-) as the minor active specie was identified through quenching experiments and electron paramagnetic resonance testing. Moreover, possible degradation pathways of RhB were proposed in the H-Co/HAP10/PMS system. Overall, this study offers a meaningful strategy for designing high-content Co-based catalysts to degrade dye molecules in wastewater.

Development, analysis, and effectiveness of an F-C-MgO/rGOP catalyst for the degradation of atrazine using ozonation process: Synergistic effect, mechanism, and toxicity assessment.

This study considered the effects of fluoride, MgO, sucrose, and rGO on the characteristics of the fluoride-carbon-MgO/rGO predicted (F-C-MgO/rGOP) catalyst and its effectiveness in the catalytic ozonation process (COP) for atrazine elimination from aqueous solutions. Using a mixture design, the catalyst composition was optimized to 13.6% sucrose, 50% Mg (OH)2, 25% NaF, and 11.4% rGO, which demonstrated the highest catalytic activity for atrazine degradation. Analysis of the synthesized F-C-MgO/rGO revealed a mesoporous structure with a BET surface area of 145m2/g. The optimized COP parameters were a pH of 8.5, contact time of 11min, catalyst dose of 1.38g/L, and atrazine concentration of 10mg/L. Atrazine mineralization reached 62.8% after 15min of contact time. The COP exhibited a synergistic effect of 82.5%, a mineralization capacity of 17.75mg/g, and a kinetic rate constant of 0.25min⁻1 for atrazine degradation. Intermediate analysis identified alkyl oxidation, dealkylation, and dechlorination-hydroxylation as the main pathways of degradation. Biodegradability index and toxicity assessments indicated a reduction in the toxicity of treated wastewater (both synthetic and real) after COP treatment. A BOD₅/COD ratio above 0.5 in both samples indicated the wastewater was suitably biodegradable.

Photocatalytical Degradation of Methylene Blue using Laboratory Prepared Cadmium Sulphide

The cadmium sulphide (CdS) has been successfully synthesized in laboratory by chemical precipitation method. Cadmium chloride and sodium sulfide were used as precursor for the synthesis of CdS photocatalyst. The synthesized material was characterized by Fourier Transform Infrared Spectroscopy, X-ray diffraction, Scanning Electron Microscopy. The XRD peaks are obvious at 25.05, 26.9, 28.29, 43.9, 47.9, 52.07, 2θ degrees which indicates the crystalline phase of as prepared CdS material and average crystalline size was found to be 5.25 nm. Synthesized CdS nanoparticles were used to degrade the methylene blue (MB) dye under the irradiation of UV light. Different parameters like pH, concentration of MB dye, dose of CdS photocatalyst, UV irradiation time were evaluated. The preeminent pH of MB solution was found to be 9, the optimum catalyst dose was found to be 100 mg. Maximum 96% MB degradation was established when 1% of 1mL H2O2 was added along with 100 mg photocatalyst with continuous 210 minutes irradiation of UV light. The H2O2 provides sufficient •OH radicals and upsurges the efficiency of CdS photocatalyst. The results revealed that laboratory prepared CdS nanoparticles could be a good material to use as a photocatalyst for the degradation of cationic dye like MB.

Valorization of nano-scrap carbon iron filings as heterogeneous electro-Fenton catalyst for the removal of anticancer drug: insight into degradation mechanism.

This study employs mechanically synthesized nano-scrap carbon iron filings (nSCIF) as a cost-effective and sustainable catalyst in heterogeneous electro-Fenton process. The catalytic behaviour of nSCIF was studied for the oxidation of cytarabine (CBN) under the influence of various experimental parameters such as pH, catalyst dose and applied current density. The highest removal efficiency (~ 99%) was achieved in 90min of reaction at pH 3, 0.4g L-1 of nSCIF dose and applied current density of 40mAcm-2. Being a solid catalyst, nSCIF enhances the production of •OH radicals and promotes the cathodic regeneration of iron species (Fe3+ to Fe2+). The mineralization efficiency reached 78% within 3h of reaction time. The daughter products generated during the reaction were identified through mass spectrometry analysis where eight major transformation productions were identified. The degradation of CBN was mainly contributed by the oxidation of aromatic ring. These findings corroborate the potential of utilizing industrial waste in the electrocatalytic oxidation of persistent pollutant.

Sustainable Synthesis of Zirconium Dioxide (ZrO2) Nanoparticles Utilizing Asphodelus fistulosus Extract for Congo Red Degradation

This research presents a green approach to synthesizing zirconium oxide (ZrO2) nanoparticles using an Asphodelus fistulosus plant extract as a reducing and stabilizing agent. The synthesized ZrO2 nanoparticles were characterized using various advanced techniques. The XRD pattern provides different forms of ZrO2, like tetragonal and cubic forms, and the results confirmed the successful formation of crystalline ZrO2 nanoparticles with a definite morphology. The XPS data exhibit that the bioactive chemicals present in the extract, including polyphenols, flavonoids, and reducing sugars, perform the functions of reducing and capping agents. Additionally, CR dye molecules may create hydrogen bonds with these surface moieties, which are approved by FTIR. These interactions may assist in aligning dye molecules with catalytically active regions on ZrO2 surfaces and may interact with photogenerated species. The catalytic activity of the synthesized ZrO2 nanoparticles was evaluated for the degradation of Congo red dye under ultraviolet irradiation. The nanoparticles exhibited excellent photocatalytic activity, degrading a significant amount of the dye within a short period. Various parameters were investigated to optimize the photodegradation process, including irradiation time, catalyst dosage, pH, and initial dye concentration. The optimal conditions were determined to be a pH of 7, a catalyst loading of 20 mg/L, and an irradiation time of 75 min, resulting in a remarkable ≈92% degradation efficiency. This green synthesis method offers a sustainable and eco-friendly alternative to conventional chemical methods for producing ZrO2 nanoparticles, which have potential applications in environmental remediation.

Deciphering the mechanism for encapsulation of MOF (Fe-glutaric acid) onto Se/SnO2 embedded CMC for effective aqueous sequestration of pharmaceutical pollutant via adsorption.

Wastewater is commonly contaminated with many pharmaceutical pollutants, so an efficient purification method is required for their removal from wastewater. In this regard, an innovative tertiary Se/SnO2@CMC/Fe-GA nanocomposite was synthesized through encapsulation of metal organic frameworks (Fe-glutaric acid) onto Se/SnO2-embedded-sodium carboxy methyl cellulose matrix to thoroughly evaluate its effectiveness for adsorption of levofloxacin drug from wastewater. The prepared Se/SnO2@CMC/Fe-GA nanocomposite was analyzed via UV-Vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermo gravimetric analysis (TGA), energy dispersive X-ray (EDX), and X-ray diffraction (XRD) to valuate optical property, size, morphology, thermal stability, and chemical composition. The results revealed that prepared Se/SnO2@CMC/Fe-GA nanocomposite was crystalline and porous having average particle size of 6.23 nm with energy band gap of 2.60 eV. Specific heat energy of Se/SnO2@CMC/Fe-GA nanocomposite was found to be 0.028 Jg-1 °C-1. Different experimental factors for example, time, temperature, concentration of LEVO, catalyst dose, ionic strength, and pH were optimized for maximum removal of levofloxacin from wastewater. The tertiary Se/SnO2@CMC/Fe-GA nanocomposite showed 99% removal efficiency for levofloxacin at pH = 7, with contact time of 60 min at 50 °C temperature. The adsorption kinetics followed pseudo-second order. Among adsorption isotherm models, Langmuir model was found most appropriate which revealed that the process was chemisorption. Main mechanism of adsorption is pore diffusion that is confirmed from Bangham, Boyd, Crank and PVSDM kinetic models. Spontaneity and endothermic nature of the process were confirmed by the values of thermodynamic parameters. Toxicity of effluent and impact of interfering ions on adsorption were also investigated. Swelling ratio of Se/SnO2@CMC/Fe-GA nanocomposite was calculated, and nanocomposite showed better results and chemical stability even after five cycles.

Acid-catalyzed conversion of sesamolin to sesamol: Kinetics and reaction mechanism based on density functional theory.

Sesamol is a significant lignan in sesame oil, which can be converted from sesamolin under acid-catalyzed conditions. The effects of several factors on the conversion of sesamolin to sesamol under acid-catalyzed conditions were investigated. The conversion kinetics were studied and the relevant conversion mechanism was revealed by density functional theory (DFT). The results indicated that catalyst dosage and substrate concentration had significant effects on the yield of sesamol. The conversion of sesamolin conformed to the characteristics of a first-order kinetics reaction within the range of 50-70°C. The activation energy of the reaction was 35.78±1.21kJ/mol. The energy barrier to be crossed for the formation of intermediates in generating sesamol was 237.83kJ/mol; the energy barrier to be overcome for the formation of intermediates in generating sesaminol was 266.95kJ/mol. This study provides information relevant to increasing the percentage of sesamol in processed sesame oil.

Photocatalytic degradation performance of a chitosan/ZnO-Fe3O4 nanocomposite over cationic and anionic dyes under visible-light irradiation.

The sonochemical synthesis of a chitosan-ZnO/Fe3O4 nanocomposite yielded a highly porous structure and large surface area for enhancing the photocatalytic degradation of cationic (rhodamine B, RhB) and anionic (methyl orange, MO) dyes in aqueous solution. Chitosan-ZnO/Fe3O4 demonstrated a significant enhancement in photodegradation efficiency 99.49% for MO (C 0 = 5.32 mg L-1, t = 150 min) and 90.73% for RhB (C 0 = 5.03 mg L-1, t = 150 min) under visible light due to its narrow bandgap of 2.84 eV. The photocatalytic performance was investigated by varying the pH, dye concentration, reaction time, and catalyst dose. The photocatalytic reaction obeyed the Langmuir-Hinshelwood kinetic model owing to a high rate constant of 0.031 (min-1) and 0.013 (min-1) for the degradation of MO and RhB, respectively. The photocatalytic activity of the chitosan-ZnO/Fe3O4 nanocomposite lost 18.37% (MO degradation) and 11.08% (RhB degradation) of its performance after the first four cycles. The presented results highlight the degradation efficiency of the chitosan-ZnO/Fe3O4 nanocomposite under visible light irradiation with reusable and magnetically retrievable abilities.

Fabrication of MoS2@Fe3O4 Magnetic Catalysts with Photo-Fenton Reaction for Enhancing Tetracycline Degradation

Tetracycline (TCs) is widely used in the treatment of human and animal infectious disease. TCs gives rise to a growing threat to the human health and environment protection due to its overuse. Therefore, it is important to remove TCs contaminants from waste effluents. In this work, MoS2@Fe3O4 catalytic material was fabricated by the simple hydrothermal method, which was applied in the photo-Fenton system to degrade TCs. The crystal structure, surface morphology, elemental composition, chemical state, electrochemical properties, and separability of MoS2@Fe3O4 catalytic materials were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), conventional and high-resolution transmission electron microscopy (TEM/HRTEM), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), and vibrating sample magnetometry (VSM). Furthermore, MoS2@Fe3O4 could degrade 98.6% of TCs within 60 min under the optimum reaction conditions (the catalyst dosage of 3 g/L, H2O2 concentration of 5 mmol/L, the initial TCs concentration of 50 mg/L, and the initial pH of 5), which was a significant increase compared with pure Fe3O4. MoS2 can accelerate the Fe3+/Fe2+ cycle through electron transfer from Mo4+ to Fe3+, resulting in the improvement in the degradation efficiency of TCs. The quenching and electron paramagnetic resonance (EPR) results showed that OH• and photogenic hole h+ was the main active species in the photo-Fenton system. What is more, MoS2@Fe3O4 catalytic materials had remarkable stability and reusability, and can be handily regained via magnetic separation technology in a real scenario.

Process optimization and kinetics of biodiesel production from microalgal oil using potassium doped biochar heterogeneous catalyst

Biodiesel is considered to be an economical and eco-friendly substitute to fossil fuels. The present research was focused on the synthesis of potassium doped biochar catalyst from wood dust waste. The synthesized activated biochar catalyst was subjected to characterization using various techniques such as FT-IR, SEM-EDAX, XRD analysis which showed possible higher catalytic efficiency. The microalgae Chlorella vulgaris oil was used for the biodiesel production through transesterification reaction using the synthesized potassium doped biochar catalyst. The reaction parameters were optimized using statistical methods and the optimized conditions were found to be of 5.46% of catalyst dosage, 10.39:1 of methanol to algal oil ratio, 61.41 °C of temperature and 75.3 min of time with the highest biodiesel yield of 91.9%. The reaction kinetics was studied and it was found to follow the first-order kinetics with an activation energy of 12.18 KJ/mol. The catalyst reusability study exhibited higher catalytic performance until fourth cycle. Overall, the utilization of microalgae as a biofuel source and industrial waste as a catalyst contributes to sustainable biodiesel production and promotes a greener environment by reducing dependency on fossil fuels and minimizing industrial waste.

Loading of Ce and n co-doped TiO2 composites onto modified shell powder synergism of adsorption and photocatalysis phytic acid removal: performance and mechanism

Phytic acid was investigated as an organophosphorus pollutant. Titanium dioxide (TiO2) doped with Ce and N was prepared using the sol-gel method and loaded onto a modified shell power to produce modified shell powder/Ce-N-TiO2 (Msp/CeNT). The combined effects of adsorption and photocatalysis on phytic acid were explored. The actual phytic acid degradation rate with the composite photocatalyst was higher than the sum of the adsorption removal rate of phytic acid using the modified shell powder and the photocatalytic degradation removal rate of phytic acid using the Ce-N-TiO2 photocatalyst. Msp/CeNT synergistically affected adsorption and photocatalytic degradation. The effects of different factors, such as reaction temperature, catalyst dosage, initial pH, stirring speed, and light intensity, on the combined effect were investigated. The results showed that the synergistic effect increases with the increase of light intensity. Increasing the reaction temperature, catalyst dosage, initial pH, and stirring speed first increased and then decreased the synergistic effect of the composite photocatalysts. Phytic acid (69.54%) was degraded within 4 h when the temperature, pH, catalyst dosage, stirring speed, and light intensity were 25 °C, 5, 1 g/L, 300 rpm, and 500 W, respectively. We investigated and prepared a composite photocatalytic material, developing a new theoretical method for degrading organophosphorus dissolved in water and providing a basis for treating lake eutrophication as a practical application.

Visible-Light-Driven Degradation of Chloramphenicol Using CeO2 Nanoparticles Prepared by a Supercritical CO2 Route: A Proof of Concept.

Recently, the extensive use of antibiotics has unavoidably resulted in the discharge of significant quantities of these drugs into the environment, causing contamination and fostering antibiotic resistance. Among various approaches employed to tackle this problem, heterogeneous photocatalysis has emerged as a technique for antibiotic degradation. This study explores the potential of CeO2 as a photocatalyst for the degradation of chloramphenicol. Supercritical antisolvent (SAS) processing was successfully employed to synthesize photocatalyst precursor nanoparticles. After thermal annealing, the CeO2 samples were characterized through UV-Vis diffuse reflectance spectroscopy to evaluate the band gap energy values. Raman and FT-IR spectroscopy confirmed the presence of oxygen vacancies in the CeO2 lattice. During photocatalytic experiments, the CeO2 derived from the SAS-processed precursor exhibited superior photocatalytic performance compared to the catalyst synthesized from the non-micronized precursor. Various annealing temperatures were employed to tune the oxygen vacancy of CeO2. Furthermore, the impact of catalyst dosage and chloramphenicol concentration was investigated. Under optimal reaction conditions (25 mg L-1 chloramphenicol and 2.25 g L-1 catalyst dosage), a degradation efficiency of 64% was achieved. Finally, to elucidate the degradation mechanism, different scavengers (EDTA, benzoquinone, and isopropyl alcohol) were utilized, revealing that the superoxide radical is the primary species responsible for chloramphenicol degradation.

Kinetics, central composite design and artificial neural network modelling of ciprofloxacin antibiotic photodegradation using fabricated cobalt-doped zinc oxide nanoparticles

Cobalt-doped zinc oxide nanoparticles were fabricated and examined in this study as a potential photocatalyst for the antibiotic ciprofloxacin (CIPF) degradation when exposed to visible LED light. The Co-precipitation technique created Cobalt-doped zinc oxide nanoparticles that were 5, 10, and 15% Co-loaded. Different known techniques have been used to characterize the synthesized ZnO and cobalt-doped ZnO nanoparticles. Compared to ZnO and other Cobalt-doped ZnO nanoparticles, the experiments showed that 10% Cobalt-doped ZnO nanoparticles were a very effective catalyst for CIPF photodegradation. According to XRD, these NPs have a hexagonal Wurtzite structure with an average size of between 38.47 and 48.06 nm. Tauc plot displayed that the optical energy band-gap of ZnO NPs (3.21) slowly declines with Co doping (2.75 eV). The enhanced photocatalytic activity of Cobalt-doped ZnO nanoparticles, which avoids electron-hole recombination, is brought on by the implantation of Co. Within 90 min, a 30 mg/L solution of ciprofloxacin was destroyed (> 99%). The kinetics studies demonstrated that the first-order model, with R2 = 0.9703, is appropriate for illuminating the pace of reaction and quantity of CIPF elimination. The recycled Cobalt-doped zinc oxide nanoparticles enhanced photocatalytic performance toward CIPF for 3 cycles with the same efficiency. Furthermore, optimization of the 10% Cobalt-doped zinc oxide nanoparticles using a Central composite design (CCD) was also studied. The optimal parameters of pH 6.486, 134.39 rpm shaking speed, 54.071 mg catalyst dose, and 31.04 ppm CIPF initial concentration resulted in the highest CIPF degradation efficiency (93.99%). Artificial neural networks (ANN) were used to simulate the experimental data. The backpropagation technique was used to train the networks with 152 input-output patterns. After experimenting with various configurations, the best results with a correlation value (R2) of 0.9780 for data validation were obtained using a three-hidden layered network that included five, five, and eight neurons, respectively.