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1.
Thermal degradation of sulfur mustard (2,2′-dichlorodiethyl sulfide, HD) in the presence of metal oxide adsorbents was investigated by thermal desorption in conjunction with gas chromatography–mass spectrometry (GC-MS). Zr(OH)4, Al2O3, Al2CoO4, MgO, CeO2, and V2O5 were used as metal oxide adsorbents. Neat HD was spiked onto the metal oxides packed in glass tubes, which were kept at room temperature and then heated at moderately elevated temperatures of 100°C by a thermal desorption system. The products of thermal degradation were directly transferred and analyzed by GC-MS. 1,4-Dithiane and 1,4-oxathiane were characterized as the major products of the thermal degradation of HD in the presence of Zr(OH)4, Al2O3, Al2CoO4, and CeO2 adsorbents. No effective degradation was observed with MgO and V2O5. Of particular note is Zr(OH)4, which extremely enhanced the thermal degradation of HD.  相似文献   

2.
A novel chrysanthemum-shaped monocline ZnWO4 photocatalyst was synthesized by microwave-assisted hydrothermal method with Na2WO4·2H2O and Zn(NO3)2·6H2O as raw materials at different reaction temperatures. The prepared ZnWO4 photocatalysts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Field emission scanning electron microscopy (FE-SEM), Transmission electron microscopy, Photoluminescence spectrum (PL) and UV–Vis absorption spectrum (UV–Vis). The photocatalytic property of the prepared chrysanthemum-shaped monocline ZnWO4 photocatalyst was evaluated by the degradation of Rhodamine B (RhB) in aqueous solution. The effects of reaction temperature on the photocatalytic degradation efficiency of RhB were investigated. The results indicated that the chrysanthemum-shaped monocline ZnWO4 photocatalyst is prepared by foliated powders with the sizes of about 30 nm and 500 nm respectively at 160 and 220 °C. The PL relative intensity of prepared ZnWO4 photocatalyst is apparently intensifying with increasing temperature. The photocatalytic property decreases with the increasing recombination probability of the excited electrons and holes. The chrysanthemum-shaped monocline ZnWO4 photocatalyst prepared at 160 °C possesses the best photocatalytic property, and the degradation efficiency of RhB at 180 min UV-light irradiation is achieved 75 %. The ZnWO4 has good reusability property on degradation of RhB and the degradation rate is still higher than 65 % after three cycles.  相似文献   

3.
Herein, cobalt (Co)-based metal–organic zeolitic imidazole frameworks (ZIF-67) coupled with g-C3N4 nanosheets synthesized via a simple microwave irradiation method. SEM, TEM and HR-TEM results showed that ZIF-67 were uniformly dispersed on g-C3N4 surfaces and had a rhombic dodecahedron shape. The photocatalytic properties of g-C3N4/ZIF-67 nanocomposite were evaluated by photocatalytic dye degradation of crystal violet (CV), 4-chlorophenol (4-CP) and photocatalytic hydrogen (H2) production. In presence of visible light illumination, the photocatalytic dye results showed that 95% CV degradation and 53% 4-CP degradation within 80 min. The H2 production of the g-C3N4/ZIF-67 composite was 2084 μmol g−1, which is 3.84 folds greater than that of bare g-C3N4 (541 μmol g−1).  相似文献   

4.
Using a grinding method, nanocomposites of graphitic carbon nitride (g-C3N4) and magnesium aluminate (MgAl2O4) spinel were successfully synthesized for the photocatalytic degradation of methylene blue (MB) and methyl orange (MO). Variously formulated g-C3N4/MgAl2O4 nanocomposites were characterized by thermal gravimetric analysis (TGA), X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy equipped with energy dispersive spectroscopy (SEM/EDS), transmission electron microscopy (TEM) and surface area and micropore analysis (BET surface area). The g-C3N4 powder exhibited a nanosheet structure whereas the MgAl2O4 spinel comprised agglomerated nanoparticles. The optical properties of the g-C3N4/MgAl2O4 nanocomposites were investigated by diffuse reflectance spectroscopy (DRS). As the g-C3N4 loading content increased from 0 to 30%, the optical band gap energy of the nanocomposite decreased from 3.84 to 2.86 eV, the specific surface area decreased from 153.78 to 114.45 m2/g, and the porosity decreased from 0.447 to 0.347 cm3/g. A 20%g-C3N4/MgAl2O4 nanocomposite proved to be the most effective photocatalyst and degraded MB faster and more completely than MO. The degradation rates of both MO (0.0107 min?1) and MB (0.0386 min?1) in a mixed MO-MB system were greater than the degradation rates in their single systems. The key factor that improved the photocatalytic degradation of MO was the synergistic effect whereas the synergistic effect and photosensitization were the key factors that enhanced the photocatalytic degradation of MB. The g-C3N4/MgAl2O4 nanocomposite is suitable for the photocatalytic degradation of mixed dyes because its point of zero charge is neutral and it is stable and recyclable.  相似文献   

5.
The unique heterojunction photocatalyst of graphite carbon nitride(g-C3N4) modified ultrafine TiO2(gC3N4/Ti O2) was successfully fabricated by electrochemical etching and co-annealing method. However,the effects of various environmental factors on the degradation of TC by g-C3N4/Ti O2and the internal reaction mechanism are still unclear. In this study, the effects of initial p H, anions, and cations on the ph...  相似文献   

6.
A series of metal oxide catalysts for catalytic oxidative degradation of 2-chlorophenol (2-CP) and 4-chlorophenol (4-CP) were prepared, and the supported CuO catalysts were studied particularly. The supported CuO catalysts were characterized by XRD and NH3-TPD techniques, in which CuO/γ-Al2O3 exhibited high degradation activity. The addition of Na2O or K2O into CuO/γ-Al2O3 improved the oxidative degradation of CPs remarkably, in which Na2O was more efficient than K2O. Over CuO/γ-Al2O3-Na2O, CPs were completely converted and the liberation of the inorganic chloride from 2-CP or 4-CP reached 97% or 100% respectively at 30 ?C for 2 h. The supported CuO catalysts with good dispersion of CuO particles and less acid sites were favorable for the efficient oxidative degradation of CPs. In addition, the initial pH of the reaction solution was found to be an important factor which influenced the catalytic oxidative degradation of CPs and the initial pH of 11.2 and 9.8 was preferred for the oxidative degradation of 2-CP and 4-CP respectively over CuO/γ-Al2O3 catalyst.  相似文献   

7.
Hierarchically porous CaFe2O4/carbon ber hybrids with enhanced microwave induced cat-alytic activity for the degradation of methyl violet (MV) from water were synthesized from kapok by a novel two-step process coupling pore-fabricating and nanoparticles assembling. The as-prepared samples exhibited characteristic hollow ber morphology, CaFe2O4 nanopar-ticles dispersed uniformly on the surface of hollow carbon fibers (HCF). The effects of various factors such as CaFe2O4 loading, microwave power, catalyst doses, initial concen-tration of MV solution and pH value on the microwave induced degradation of MV over CaFe2O4/HCF were evaluated. It was found that the microwave induced degradation of MV over CaFe2O4/HCF had high reaction rate and short process time. The kinetic study indicated that the degradation of MV over CaFe2O4/HCF followed pseudo-first-order kinet-ics model. The high catalytic activity of CaFe2O4/HCF was facilitated by the synergistic relationship between microwave induced catalytic reaction and adsorption characteristics.  相似文献   

8.
《中国化学快报》2022,33(8):3713-3720
Eggshell-loaded CoFe2O4 catalyst was synthesized via a convenient hydrothermal method during our work, then the surface morphology and elemental composition of the composites were systematically investigated. Performance of CoFe2O4/eggshell-activated peroxymonosulfate (PMS) system was evaluated by selecting florfenicol (FF) as the model pollutant, and effects of operating parameters and water matrices on the FF removal efficiency in this system were investigated. In addition, main radicals involved in FF degradation were identified by EPR tests and radical quenching experiments, and possible mechanism was proposed. The reduction of toxicity during FF degradation was confirmed, and in combination with HP-LC tests, it was found that dehalogenation and defluorination were effectively carried out during FF degradation. In addition, the prepared CoFe2O4 polyvinylidene fluoride (PVDF) membrane effectively improved the stability of the material and reduced the precipitation of metals.  相似文献   

9.
In the present study, formation of hydrogen peroxide (H2O2) and degradation of 4-chlorophenol (4-CP) induced by DC diaphragm glow discharge (DGD) in a sodium sulfate solution were investigated. The discharge was generated in a small hole on a quarts plate interposed between two submersed graphite electrodes. Experimental results showed that 750 V was the optimum voltage for H2O2 formation and 4-CP degradation. Both the H2O2 formation and the 4-CP degradation proceeded faster in cathodic compartment than in anodic compartment. Lowering the solution pH was favorable for 4-CP degradation but showed no appreciable effect on H2O2 formation. Addition of hydroxyl radical scavenger (methanol) to the solution decreased the H2O2 formation and the 4-CP degradation. Iron species especially ferric ions enhanced the 4-CP degradation markedly. Based on the analyzes of Current–Voltage characteristics and chemical effects, it was deduced that the mechanism of DGD was similar to that of contact glow discharge electrolysis.  相似文献   

10.
Nickel aluminate (NiAl2O4) and doped nickel aluminate (Ni1-xMxAl2O4; M = Mg, Zn, Cu; x = 0.1) were prepared by sol-gel method using citric acid. The synthesized compounds were analyzed by various techniques such as powder XRD, FTIR, SEM-EDAX and UV-DRS. The lattice parameter was found to increase with the copper, zinc and magnesium doping in nickel aluminate. The band gap was decreased from 3.0 eV (NiAl2O4) to 2.9 (zinc doped), 2.7 eV (magnesium doped) and increased to 3.1 eV in the case of copper doping. The catalytic study was carried out for a cationic (methylene blue) and an anionic dye (methyl orange). The percentage degradation of methyl orange using Zn0.1Ni0.9Al2O4 and Mg0.1Ni0.9Al2O4 was found to be 92% (180 min) and 96% (90 min). 93% (120 min) and 97% (120 min) degradation of methylene blue was observed using zinc doped and magnesium doped nickel aluminate respectively. These results are comparatively higher than its parent analogue (94% (180 min) degradation against methyl orange and 91% (120 min) against methylene blue). Whereas the percentage degradation was found to be less in the case of Cu0.1Ni0.9Al2O4 (83% (180 min) against methyl orange and 90% (120 min) against methylene blue).  相似文献   

11.
In the present research, Fe3O4 and WS2 nanoparticles immobilized on or in KIT-6 (KIT: Korea Institute of Science and Technology) pores (KIT-6/WS2-Fe3O4) were synthesized and studied as a photocatalyst for degradation of representative chlorpyrifos as an organophosphorus pesticide. In addition, the KIT-6/WS2-Fe3O4 photocatalyst was characterized by different methods such as TEM, FESEM-EDS-Mapping, XRD, and N2 adsorption/desorption surface area, in order to understand their morphology, structural, and physical properties. The photocatalytic performance of this photocatalyst was investigated for degradation of chlorpyrifos by visible light irritation. The effects of variables such as chlorpyrifos concentration, KIT-6/WS2-Fe3O4 nanocatalyst amount, pH, and irradiation time on chlorpyrifos degradation efficiency was studied by central composite design with response surface methodology. The optimum conditions for CP degradation were obtained by 50 mg KIT-6/WS2-Fe3O4 nanocatalyst, and 7.2 ppm chlorpyrifos solution with pH = 6, at 52 min. The pseudo-first-order model with rate constants equal to 0.069 min−1 as best choice efficiency described the chlorpyrifos degradation process according to Langmuir-Hinshelwood kinetic.  相似文献   

12.
Super paramagnetic ZnFe2O4 nanoparticles were prepared by a surfactant assisted (ethylamine) hydrothermal method along with heat treatment. The nanoparticles were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, high resolution scanning electron microscopy, Transmission electron microscopy, vibrating sample magnetometer and diffuse reflectance spectra technique. From the analyses, influence of calcination temperature on the structural, vibrational, morphological, magnetic and optical properties of ZnFe2O4 nanoparticles were investigated. The ZnFe2O4 nanoparticles with an average particle size of 17 nm showed high photocatalytic activity in the degradation of methylene blue (90 %). This work demonstrates that ZnFe2O4 can be used as a potential monocomponent in visible-light photocatalysis for the degradation of organic pollutants. Furthermore, the products were super paramagnetic and could be conveniently separated within 15 min and recycled by using simple magnet, which is very beneficial for the degradation of organic pollutants.  相似文献   

13.
Atomic Layer Deposition (ALD) precise controlling ultra-thin platinum (Pt) modified Graphite carbon nitride (g-C3N4) photocatalysts, which had been doped with gold nanoparticles (Au NPs) by photodeposition, were successfully synthesized. The experimental results showed that precise regulation of platinum decorated C3N4-Au(C3N4-Au/nPt (n is the number of Pt ALD cycles, 1 Å per cycle)) exhibited excellent photocatalytic degradation ability for Rhodamine B (RhB). Under simulated sunlight irradiation, the degradation rate of 10 mg/L RhB(100 mL) by 1.5 mg C3N4-Au/10Pt catalysts was 95.8% within 60 min that is much better than other photocatalysts for the degradation of RhB. The efficient degradation mechanism of RhB by C3N4-Au/10Pt photocatalysts was studied and the experiments demonstrated the ·O2 as main active species played an important role in the photocatalytic process. Local surface plasmon resonance (LSPR) of Au NPs and Schottky barrier between Pt clusters and g-C3N4 may be the reasons for enhanced C3N4-Au/10Pt photocatalytic performances. Furthermore, the successive catalytic cycles revealed the excellent stability of C3N4-Au/10Pt photocatalyst.  相似文献   

14.
用化学沉淀法制备中空管状g-C3N4/Ag3PO4复合催化剂。通过X射线衍射(XRD)、扫描电子显微镜(SEM)、紫外可见漫反射光谱(UV-Vis DRS)和荧光光谱对其结构、形貌和光学性能进行了表征。结果表明:Ag3PO4纳米颗粒均匀地分散在中空管状g-C3N4表面,两者紧密结合形成异质结。研究复合催化剂在可见光照射下降解盐酸四环素(TC)的光催化活性。结果显示:复合催化剂在80 min内对TC的降解率为98%,其降解反应速率常数是纯相Ag3PO4的3倍。经过5次循环实验后复合催化剂对于TC的降解率仍保持87%,具有优良的循环稳定性。捕获实验表明空穴(h+)和超氧负离子(·O-2)是光催化反应过程中的主要活性物种。根据能带理论,提出了复合催化剂异质结的Z型光催化机理。  相似文献   

15.
In this work we synthesize a novel and highly efficient photocatalyst for degradation of methyl orange and rhodamine B. In addition, a new method for synthesis of Fe_3O_4@SiO_2@TiO_2@Ho magnetic core-shell nanoparticles with spherical morphology is proposed. The crystal structures, morphology and chemical properties of the as-synthesized nanoparticles were characterized using Fourier transform infrared spectroscopy(FT-IR), scanning electron microscopy(SEM), transmission electron microscopy(TEM), energy dispersive X-ray(EDS), X-ray diffraction(XRD), UV–vis diffuse reflectance spectroscopy(DRS) and vibrating sample magnetometer(VSM) techniques. The photocatalytic activity of Fe_3O_4@SiO_2@TiO_2@Ho was investigated by degradation of methyl orange(MO) as cationic dye and rhodamine B(Rh B) as anionic dye in aqueous solution under UV/vis irradiation. The results indicate that about 92.1% of Rh B and78.4% of MO were degraded after 120 and 150 min, respectively. These degradation results show that Fe_3O_4@SiO_2@TiO_2@Ho nanoparticles are better photocatalyst than Fe3O4@Si O2@TiO 2@Ho for degradation of MO and Rh B. As well as, the catalyst shows high recovery and stability even after several separation cycles.  相似文献   

16.
《中国化学快报》2020,31(7):1961-1965
Herein, we prepared novel three-dimensional (3D) gear-shaped Co3O4@C (Co3O4 modified by amorphous carbon) and sheet-like SnO2/CC (SnO2 grow on the carbon cloth) as anode and cathode to achieve efficient removal of 4-nitrophenol (4-NP) in the presence of peroxymonosulfate (PMS) and simultaneous electrocatalytic reduction of CO2, respectively. In this process, 4-NP was mineralized into CO2 by the Co3O4@C, and the generated CO2 was reduced into HCOOH by the sheet-like SnO2/CC cathode. Compared with the pure Co0.5 (Co3O4 was prepared using 0.5 g urea) with PMS (30 mg, 0.5 g/L), the degradation efficiency of 4-NP (60 mL, 10 mg/L) increased from 74.5%–85.1% in 60 min using the Co0.5 modified by amorphous carbon (Co0.5@C). Furthermore, when the voltage of 1.0 V was added in the anodic system of Co0.5@C with PMS (30 mg, 0.5 g/L), the degradation efficiency of 4-NP increased from 85.1%–99.1% when Pt was used as cathode. In the experiments of 4-NP degradation coupled with simultaneous electrocatalytic CO2 reduction, the degradation efficiency of 4-NP was 99.0% in the anodic system of Co0.5@C with addition of PMS (30 mg, 0.5 g/L), while the Faraday efficiency (FE) of HCOOH was 24.1 % at voltage of −1.3 V using the SnO2/CC as cathode. The results showed that the anode of Co3O4 modified by amorphous carbon can markedly improve the degradation efficiency of 4-NP, while the cathode of SnO2/CC can greatly improve the FE and selectivity of CO2 reduction to HCOOH and the stability of cathode. Finally, the promotion mechanism was proposed to explain the degradation of organic pollutants and reduction of CO2 into HCOOH in the process of electrocatalysis coupled with advanced oxidation processes (AOPs) and simultaneous CO2 reduction.  相似文献   

17.
TiO2/g-C3N4 nanofibers with diameter of 100–200 nm were prepared by electrospinning method after calcination at high temperature, using polyvinylpyrrolidone (PVP), Melamine (C3H6N6), Ti(OC4H9)4 as raw materials. The composite nanofibers were characterized by XRD, FT-IR, SEM, UV–vis and PL respectively. The effects of different g-C3N4 contents on structure and photocatalytic degradation of the composite nanofibers were investigated. The results indicated that with increasing g-C3N4 content, the diameter of the composite fibers increased and the morphology changed from uniform structure to a nonuniform one, containing beads. The composite nanofibers displayed the best photocatalytic degradation on RhB, when the g-C3N4 content was 0.8 wt%. The degree of degradation was up to 99% at the optimal conditions of 40 min. The degradation activity of the composite nanofibers on RhB, MB and MO was found to be higher than that of the TiO2 nanofibers.  相似文献   

18.
A one-step green-chemistry method was applied to prepare sulfur/reduced graphene oxide (S/RGO). The synthesized S/RGO was modified by 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP) and Fe3O4 nanoparticles to form TCPP–Fe3O4@S/RGO. The prepared composites were investigated by X-ray diffraction (XRD) analysis, Fourier-transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray (EDX) mapping, and transmission electron microscopy (TEM) and scanning electron microscopy (SEM) imaging. Diffuse reflectance spectroscopy (DRS) was used to determine the photocatalytic ability of S/RGO and TCPP–Fe3O4@S/RGO. In addition, photocatalytic degradation of a hazardous dye (methylene blue) by the TCPP–Fe3O4@S/RGO composite under visible-light irradiation is reported. The results demonstrate synthesis of TCPP–Fe3O4@S/RGO by an environmentally friendly method with excellent degradation effect.  相似文献   

19.
《中国化学快报》2021,32(9):2787-2791
A novel carbon-rich g-C3N4 nanosheets with large surface area was prepared by facile thermal polymerization method using urea and 1,3,5-cyclohexanetriol. Plenty of carbon-rich functional groups were introduced into the surface layers of g-C3N4, which constructed the built-in electric field (BIEF) and resulted in improved charge separation; therefore, the carbon-rich g-C3N4 displayed superior photocatalytic activity for amoxicillin degradation under solar light. The contaminant degradation mechanism was proposed based on radical quenching experiments, intermediates analysis and density functional theory (DFT) calculation. Moreover, the reusing experiments showed the high stability of the material, and the amoxicillin degradation under various water matrix parameters indicated its high applicability on pollutants treatment, all of which demonstrated its high engineering application potentials.  相似文献   

20.
《中国化学快报》2023,34(8):108090
Electrochemical oxidation of aqueous tris(1,3-dichloro-2-propyl) phosphate (TDCPP) by using Ti/SnO2-Sb/La-PbO2 as anode was investigated for the first time, and the degradation mechanisms and toxicity changes of the degradation intermediates were further determined. Results suggested that electrochemical degradation of TDCPP followed pseudo-first-order kinetics, and the reaction rate constant (k) was 0.0332 min−1 at the applied current density of 10 mA/cm2 and Na2SO4 concentration of 10 mmol/L. There was better TDCPP degradation performance at higher current density. Free hydroxy radical (OH) was proved to play dominant role in TDCPP oxidation via quenching experiment, with a relative contribution rate of 60.1%. A total of five intermediates (M1, C6H11Cl4O4P; M2, C3H7Cl2O4P; M3, C9H16Cl5O5P; M4, C9H14Cl5O6P; M5, C6H10Cl3O6P) were identified, and the intermediates were further degraded prolonging with the reaction time. Flow cytometer results suggested that the toxicity of TDCPP and degradation intermediates significantly reduced, and the detoxification efficiency was achieved at 78.1% at 180 min. ECOSAR predictive model was used to assess the relative toxicity of TDCPP and the degradation intermediates. The EC50 to green algae was 3.59 mg/L for TDCPP, and the values raised to 84, 574, 54.6, 391, and 8920 mg/L for M1, M2, M3, M4, and M5, respectively, indicating that the degradation intermediates are less toxic or not toxic. Electrochemical advanced oxidation process is a valid technology to degrade TDCPP and pose a good detoxification effect.  相似文献   

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