Project description:A Cu(II)-quinoline complex immobilized on a silica support was prepared to enhance the degradation of dyes. Mesoporous silica functionalized with this Cu(II) complex was turned into a photo-Fenton-like catalyst. Various techniques were used to characterize the resulting material, and the catalytic activity was determined by the degradation of methylene blue (MB) under UV light irradiation. The Cu(II) ion was successfully coordinated to the quinoline ligand on a silica support. The dye degradation investigation has shown that 95% of the dye was degraded in 2.5 h. The active radical species involved in the reaction were OH• and O2 •-, suggesting that a peroxo complex intermediate might be formed during degradation processes.
Project description:A novel three-dimensional (3D) ?-Fe2O3/MoS2 hierarchical nanoheterostructure is effectively synthesized via a facile hydrothermal method. The zero-dimensional (0D) Fe2O3 nanoparticles guide the growth of two-dimensional (2D) MoS2 nanosheets and formed 3D flower-like structures, while MoS2 facilitates the good dispersion of porous Fe2O3 with abundant oxygen vacancies. This charming 3D-structure with perfect match of non-equal dimension exhibits high recyclable photo-Fenton catalytic activity for Methyl orange pollutant and nice specific capacity in reusing as supercapacitor after catalysis. The synergistic effect between Fe2O3 and MoS2, the intermediate nanointerfaces, the 3D porous structures, and the abundant oxygen vacancies both contribute to highly active catalysis, nice electrochemical performance and stable cycling. This strategy is simple, cheap, and feasible for maximizing the value of the materials, as well as eliminating the secondary pollution.
Project description:A series of carbon nanotubes doped with Fe and/or Cu, Fe100?xCux/CNT (x = 0, 25, 50, 75 and 100) has been prepared by an easy method of wetness impregnation of commercial multiwalled carbon nanotubes previously oxidized with nitric acid. The wide characterization of the solids by different techniques demonstrates that the incorporation of Fe and Cu to the CNTs has been successfully produced. Fe100-xCux/CNT samples were tested as catalysts in the removal of paracetamol from aqueous solution by a combined process of adsorption and Fenton-like oxidation. Under mild conditions, 25 °C and natural pH of solution, i.e., nearly neutral, values of oxidation of paracetamol between 90.2% and 98.3% were achieved after 5 h of reaction in most of cases. Furthermore, with the samples containing higher amounts of copper, i.e., Cu100/CNT and Fe25Cu75/CNT, only 2 h were necessary to produce depletion values of 73.2% and 87.8%, respectively. The influence of pH and dosage of H2O2 on the performance has also been studied. A synergic effect between both Cu+/Cu2+ and Fe2+/Fe3+ in Fenton-like reaction was observed. These results demonstrate that Fe100-xCux/CNT are powerful Fenton-like catalyst for degradation of paracetamol from aqueous solution and they could be extended to the removal of other organic pollutants.
Project description:In this work, the combination of high surface area diatomite with Fe and Cu bimetallic MOF material catalysts (Fe0.25Cu0.75(BDC)@DE) were synthesized by traditional solvothermal method, and exhibited efficient degradation performance to tetracycline hydrochloride (TC). The degradation results showed: Within 120 min, about 93% of TC was degraded under the optimal conditions. From the physical-chemical characterization, it can be seen that Fe and Cu play crucial roles in the reduction of Fe3+ because of their synergistic effect. The synergistic effect can not only increase the generation of hydroxyl radicals (•OH), but also improve the degradation efficiency of TC. The Lewis acid property of Cu achieved the pH range of reaction system has been expanded, and it made the material degrade well under both neutral and acidic conditions. Loading into diatomite can reduce agglomeration and metal ion leaching, thus the novel catalysts exhibited low metal ion leaching. This catalyst has good structural stability, and less loss of performance after five reaction cycles, and the degradation efficiency of the material still reached 81.8%. High performance liquid chromatography-mass spectrometry was used to analyze the degradation intermediates of TC, it provided a deep insight of the mechanism and degradation pathway of TC by bimetallic MOFs. This allows us to gain a deeper understanding of the catalytic mechanism and degradation pathway of TC degradation by bimetallic MOFS catalysts. This work has not only achieved important progress in developing high-performance catalysts for TC degradation, but has also provided useful information for the development of MOF-based catalysts for rapid environmental remediation.
Project description:Today, the presence of recalcitrant pollutants in wastewater, such as pharmaceuticals or other organic compounds, is one of the main obstacles to the widespread implementation of water reuse. In this context, the development of innovative processes for their removal becomes necessary to guarantee effluent quality. This work presents the potentiality of magnetic nanoparticles immobilized on SBA-15 mesoporous silica as Fenton and photo-Fenton catalysts under visible light irradiation. The influence of the characteristics of the compounds and nanoparticles on the removal yield was investigated. Once the key aspects of the reaction mechanism were analyzed, to evaluate the feasibility of this process, an azo dye (Orange II) and an antibiotic (sulfamethoxazole) were selected as main target compounds. The concentration of Orange II decreased below the detection limit after two hours of reaction, with mineralization values of 60%. In addition, repeated sequential experiments revealed the recoverability and stability of the nanoparticles in a small-scale reactor. The benchmarking of the obtained results showed a significant improvement of the process using visible light in terms of kinetic performance, comparing the results to the Fenton process conducted at dark. Reusability, yield and easy separation of the catalyst are its main advantages for the industrial application of this process.
Project description:This work aims to unravel the potential of copper(II) phosphate as a new promising heterogenous catalyst for the degradation of ciprofloxacin (CIP) in the presence of H2O2 and/or visible light (λ > 400 nm). For this purpose, copper(II) phosphate was prepared by a facile precipitation method and fully characterized. Of our particular interest was the elucidation of the kinetics of CIP degradation on the surface of this heterogeneous catalyst, identification of the main reactive oxygen species responsible for the oxidative degradation of CIP, and the evaluation of the degradation pathways of this model antibiotic pollutant. It was found that the degradation of the antibiotic proceeded according to the pseudo-first-order kinetics. Copper(II) phosphate exhibited ca. 7 times higher CIP degradation rate in a Fenton-like process than commercial CuO (0.00155 vs. 0.00023 min-1, respectively). Furthermore, the activity of this metal phosphate could be significantly improved upon exposure of the reaction medium to visible light (reaction rate = 0.00445 min-1). In a photo-assisted Fenton-like process, copper(II) phosphate exhibited the highest activity in CIP degradation from among all reference samples used in this study, including CuO, Fe2O3, CeO2 and other metal phosphates. The main active species responsible for the degradation of CIP were hydroxyl radicals.
Project description:Methanol synthesized from carbonate hydrogenation is of great importance for CO2 utilization indirectly. Herein, a series of Cu/Zn/Al heterogeneous catalysts were prepared by co-precipitation with a synchronous aging step, and were applied for hydrogenation of diethyl carbonate (DEC) to produce methanol. Furthermore, the catalysts were characterized by physicochemical methods, such as N2 adsorption, ICP-OES, N2O titration, SEM, TEM, XRD, H2-TPR and XPS in detail. Higher copper concentration led to a higher ratio of bulk CuOx species in the calcined samples, which resulted in different copper species distribution after the reduction process. Structure activity relationship analysis indicated that the balance of surface Cu0 and Cu+ species influenced the formation rate of methanol. A higher proportion of Cu+ to (Cu+ + Cu0) was conductive to methanol formation, while excessive Cu0 site density played a negative influence on the methanol synthesized from DEC. Cu/Zn/Al with a 45.2% weight fraction of copper showed better performance with a total methanol formation rate of 131.0 mg gcat. -1 h-1. The reaction temperature and reaction time could obviously affect the reaction performance and the results suggested that 200 °C and 6 h were suitable. Furthermore, the long-term stability and activity of the catalyst was also studied on a fixed bed, and the yield of total methanol reached to 88.5% and the selectivity of total methanol gradually decreased to 74.0% within 200 h, which could be attributed to the detrimental influence derived from the increase of Cu0. The reaction pathways involved in the hydrogenation of DEC process were proposed. The substance scope was also extended to other carbonates and the catalyst exhibited superior catalytic performance toward linear carbonates. This work provided insights into carbonate hydrogenation over an effective Cu/Zn/Al catalyst, which could be utilized into upgrading CO2 indirectly to produce commodity methanol under relatively mild reaction conditions.
Project description:The study on the removal of refractory veterinary antibiotic florfenicol (FF) in water is still very limited. In this study, an efficient Fenton-like catalyst was developed by synthesizing a series of Cu-based multi-metal layered double hydroxides (CuNiFeLa-LDHs) to degrade FF in aqueous solution. In the experiments, the screened CuNiFeLa-2-LDH with the molar ratio of La3+/(Fe3+ + La3+) = 0.1 exhibited high catalytic activity, achieving almost complete degradation of 5 mg L-1 FF under 5 mmol L-1 H2O2 conditions. The mechanisms revealed that the enhanced catalytic performance was ascribed to the existence of Ni which accelerated the electron transfer rate and La which served as a Lewis acidic site to provide more reactive sites in this Cu-dominated Fenton-like reaction, further generating •OH, •O2 -, and O2 1 as active species to attack pollutants directly. Interestingly, the catalyst showed a wide pH adaptability and little release of copper ions to the solution. The regenerated CuNiFeLa-2-LDH is demonstrated to be a stable and reliable material for florfenicol degradation.
Project description:Copper-alumanyl complexes, [LCu-Al(SiNDipp )], where L=carbene=NHCiPr (N,N'-diisopropyl-4,5-dimethyl-2-ylidene) and Me2 CAAC (1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethyl-pyrrolidin-2-ylidene) and featuring unsupported Al-Cu bonds, have been prepared. Divergent reactivity observed with carbodiimides and CO2 implies an ambiphilicity in the Cu-Al interaction that is dependent on the identity of the carbene co-ligand.
Project description:Non-noble metal nanoparticles are becoming more and more important in catalysis recently. Cu/CuO nanoclusters on highly ordered TiO2 nanotube arrays are successfully developed by a surfactant-free photoreduction method. This non-noble metal Cu/CuO-TiO2 catalyst exhibits excellent catalytic activity and stability for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) with the presence of sodium borohydride (NaBH4). The rate constant of this low-cost Cu/CuO based catalyst is even higher than that of the noble metal nanoparticles decorated on the same TiO2 substrate. The conversion efficiency remains almost unchanged after 7 cycles of recycling. The recycle process of this Cu/CuO-TiO2 catalyst supported by Ti foil is very simple and convenient compared with that of the common powder catalysts. This catalyst also exhibited great catalytic activity to other organic dyes, such as methylene blue (MB), rhodamine B (RhB) and methyl orange (MO). This highly efficient, low-cost and easily reusable Cu/CuO-TiO2 catalyst is expected to be of great potential in catalysis in the future.