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1.
Photocatalytic degradation of chrysene in polluted seawater was successfully achieved under illumination of natural sunlight using carbon modified titanium oxide (C-TiO2) nanoparticles. The morphological and structural characteristics of the as-synthesized nanoparticles were investigated by X-ray diffraction (XRD), UV–Vis spectra, scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FT-IR), and X-ray photoelectron spectroscopy (XPS). The characterization results confirmed the successful incorporation of carbon into C-TiO2 nanoparticles. As a result of C-modification, a significant enhancement of the photocatalytic degradation efficiency was observed for C-TiO2, compared with pure TiO2. In order to optimize the operating parameters, the impacts of catalyst loading and pH on the photocatalytic degradation of chrysene were investigated. The best degradation rate was obtained at pH 3 and C-TiO2 loading of 1.0 g L−1. The photodegradation of chrysene in seawater by using C-TiO2 was found to follow a pseudo first-order kinetics in terms of the Langmuir-Hinshelwood model.  相似文献   

2.
In this research article, ZnO–Al2O3–CeO2–Ce2O3 mixed metal oxides phases were prepared by calcination of Zn–Al/Ce–CO3 layered double hydroxides (LDH) precursors, and evaluated for the photocatalytic degradation of methyl orange (MO) as a model textile dye from aqueous solution under UV irradiation. First, Zn–Al–CO3 and a series of Zn–Al/Ce–CO3 with different Ce content (5, 10, 15, 20%) were synthesized through co-precipitation method at Zn/(Al+Ce) molar ratio (r) of 3, then subjected to calcination at 500 °C for 6 h. Samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy coupled with energy dispersive X-ray analysis and pH point of zero charge. The experimental results of the photodegradation reveal that the photocatalyst developed from Zn–Al–Ce10%-CO3 LDH exhibits the highest photocatalytic activity, with a degradation efficiency of 99.8% after 300 min of irradiation. This performance was mainly ascribed to the presence of difference state of Ce, leading a highest separation efficiency of electrons and holes. The recycling tests suggests a much high photostability and reusability of the photocatalyst.  相似文献   

3.
The present work shows the photocatalytic degradation of nitrobenzene (NB) using Fe3O4 magnetic nanoparticles (MNP) as a photocatalyst in the presence of UV light. The MNP were synthesized by an ultrasonic-assisted reverse co-precipitation (US-RP) method using FeSO4, FeCl3 and NH4OH as precursors. The prepared nanoparticles were characterized by UV–vis spectroscopy, attenuated total reflectance Fourier transformed infrared spectroscopy (ATR FT-IR), Raman spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Dynamic light scattering (DLS), Zeta potential, Vibrating sample magnetometer (VSM) and Magnetic thermogravimetric analysis (MTGA). The successive decrement in the absorbance at 265 nm shows the effective decrease in NB concentration measured by UV–vis spectroscopy. The reaction intermediates detected by gas chromatography/mass spectrum (GC/MS) were 2-nitrophenol (2-NPh), 3-nitrophenol (3-NPh) and 4-nitrophenol (4-NPh). The prepared MNP showed an optimal NB degradation at an initial pH of 2 and 100 ppm of the photocatalyst.  相似文献   

4.
In the present work, element modification semiconductor photocatalyst Fe-Bi2SiO5 was successfully synthesized by combining the hydrothermal method and impregnation technique. The obtained photocatalysts were systematically characterized through XRD, SEM, XPS, BET and UV–Vis diffuse reflectance spectroscopy. The synthesized heterojunction Fe/Bi2SiO5 photocatalyst exhibited excellent photocatalytic activity for 17β-Estradiol(E2). While using 20 W mercury lamp as UV light source, the degradation efficiency of E2 by 5% Fe/Bi2SiO5 (the molar ratio of Fe/Bi was 5:100) at 60 min irradiation was 99.5%. The rate constant of E2 degradation on 5% Fe/Bi2SiO5 were about 3.42 times of the P25 and 2.63 times of the pure Bi2SiO5. The impact of catalyst loading and pH as well as the photocatalytic mechanism was investigated. The possible photocatalytic mechanism has been discussed on the basis of the theoretical calculation and the experimental results. The results of this study indicated that Fe/Bi2SiO5 was a stable and efficient photocatalyst, with promising practical applications.  相似文献   

5.
Novel C,N-doped TiO2 nanoparticles were prepared by a solid phase reaction. The catalyst was characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX). The results showed that crystallite size of synthesized C,N-doped TiO2 particles were in nanoscale. UV light photocatalytic studies were carried out using sodium naphthalenesulfonate formaldehyde condensate (SNF) as a model pollutant. The effects of initial concentration of surfactant, catalyst amount, pH, addition of oxidant on the reaction rate were ascertained and optimum conditions for maximum degradation was determined. The results indicated that for a solution of 20 mg/L of SNF, almost 98.7% of the substance were removed at pH ~ 4.0 and 0.44 g/L photocatalyst load, with addition of 1 mM K2S2O8 and irradiation time of 90 min. The kinetics of the process was studied, and the photodegradation rate of SNF was found to obey pseudo-first-order kinetics equation represented by the Langmuir–Hinshelwood model.  相似文献   

6.
Water pollution due to industrial effluents from industries which utilize dyes in the manufacturing of their products has serious implications on aquatic lives and the general environment. Thus, there is need for the removal of dyes from wastewater before being discharged into the environment. In this study, a nanocomposite consisting of silver, silver oxide (Ag2O), zinc oxide (ZnO) and graphene oxide (GO) was synthesized, characterized and photocatalytically applied in the degradation (and possibly mineralization) of organic pollutants in water treatment process. The Ag–Ag2O–ZnO nanostructure was synthesized by a co-precipitation method and calcined at 400 °C. It was functionalized using 3-aminopropyl triethoxysilane and further anchored on carboxylated graphene oxide via the formation of an amide bond to give the Ag–Ag2O–ZnO/GO nanocomposite. The prepared nanocomposite was characterized by UV–Vis diffuse reflectance spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electronic microscopy (SEM), energy dispersive X-ray spectrometry (EDX), Fourier transformed infrared spectroscopy (FTIR), and Raman spectroscopy. The applicability of Ag–Ag2O–ZnO/GO nanocomposite as a photocatalyst was investigated in the photocatalytic degradation of acid blue 74 dye under visible light irradiation in synthetic wastewater containing the dye. The results indicated that Ag–Ag2O–ZnO/GO nanocomposite has a higher photocatalytic activity (90% removal) compared to Ag–Ag2O–ZnO (85% removal) and ZnO (75% removal) respectively and thus lends itself to application in water treatment, where the removal of organics is very important.  相似文献   

7.
C, N codoped TiO2 catalyst has been synthesized by thermal decomposition of a novel water-soluble titanium complex. The structure, morphology, and optical properties of the synthesized TiO2 catalyst were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and UV–vis diffuse reflectance spectroscopy. The photocatalytic activity of the Pt deposited TiO2 catalysts synthesized at different temperatures was evaluated by means of hydrogen evolution reaction under both UV–vis and visible light irradiation. The investigation results reveal that the photocatalytic H2 evolution rate strongly depended on the crystalline grain size as well as specific surface area of the synthesized catalyst. Our studies successfully demonstrate a simple method for the synthesis of visible-light responsive Pt deposited TiO2 catalyst for solar hydrogen production.  相似文献   

8.
A magnetized nano‐photocatalyst based on TiO2/magnetic graphene was developed for efficient photodegradation of crystal violet (CV). Scanning electron microscopy, X‐ray diffraction, energy‐dispersive X‐ray spectroscopy and elemental mapping were used to characterize the prepared magnetic nano‐photocatalyst. The photocatalytic activity of the synthesized magnetic nano‐photocatalyst was evaluated using the decomposition of CV as a model organic pollutant under UV light irradiation. The obtained results showed that TiO2/magnetic graphene exhibited much higher photocatalytic performance than bare TiO2. Incorporation of graphene enhanced the activity of the prepared magnetic nano‐photocatalyst. TiO2/magnetic graphene can be easily separated from an aqueous solution by applying an external magnetic field. Effects of pH, magnetized nano‐photocatalyst dosage, UV light irradiation time, H2O2 amount and initial concentration of dye on the photodegradation efficiency were evaluated and optimized. Efficient photodegradation (>98%) of the selected dye under optimized conditions using the synthesized nano‐photocatalyst under UV light irradiation was achieved in 25 min. The prepared magnetic nano‐photocatalyst can be used in a wide pH range (4–10) for degradation of CV. The effects of scavengers, namely methanol (OH? scavenger), p‐benzoquinone (O2?? scavenger) and disodium ethylenediaminetetraacetate (hole scavenger), on CV photodegradation were investigated.  相似文献   

9.
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   

10.
Nanosized platinum particles loaded on the TiO2 nanoparticles were prepared to assess its photocatalytic activity in simple one-pot synthesis of quinaldines from anilines in ethanol using UV light. The catalyst was characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy, X-ray photoelectron spectra (XPS), Brunauer?CEmmer?CTeller surface area, atomic force microscope and diffuse reflectance spectra. XRD patterns revealed that the crystal structure of Pt?CTiO2 resembled anatase phase of TiO2. The UV?CVis spectra indicated an increase in absorption of visible light when compared to TiO2. XPS analysis reveals that platinum particles are present mainly in metallic form. Furthermore, TEM analysis showed non-spherical-shaped Pt?CTiO2 nanoparticles of the diameter 10?C30?nm. Upon irradiation in the presence of Pt?CTiO2, aniline and oxidation products derived from ethanol undergo condensation?Ccyclization to afford quinaldines. Higher efficiency of Pt?CTiO2 than Au?CTiO2 in the conversion of aniline to quinaldines is due to the higher work function of Pt.  相似文献   

11.
Visible light active Ag doped SnO2 nanoparticles modified with curcumin (Cur–Ag–SnO2) have been prepared by a combined precipitation and chemical impregnation route. The optical properties, phase structures and morphologies of the as-prepared nanoparticles were characterized using UV–visible diffuse reflectance spectra (UV–vis-DRS), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The surface area was measured by Brunauer. Emmett. Teller (B.E.T) analysis. Compared to bare SnO2, the surface modified photocatalysts (Ag–SnO2 and Cur–Ag–SnO2) showed a red shift in the visible region. The photocatalytic activity was monitored via the degradation of rose bengal (RB) dye and the results revealed that Cur–Ag–SnO2 shows better photocatalytic activity than that of Ag–SnO2 and SnO2. The superior photocatalytic activity of Cur–Ag–SnO2 could be attributed to the effective electron-hole separation by surface modification. The effect of photocatalyst concentration, initial dye concentration and electron scavenger on the photocatalytic activity was examined in detail. Furthermore, the antifungal activity of the photocatalysts and the reusability of Cur–Ag–SnO2 were tested.  相似文献   

12.
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   

13.
以三聚氰胺为前驱体,通过热氧化刻蚀法制备多孔超薄g-C3N4纳米片(CNHS),将其与氯铂酸钾溶液混合后采用原位光化学还原法成功制备了CNHS负载Pt光催化剂(Pt-CNHS)。使用粉末X射线衍射、场发射扫描电子显微镜、X射线光电子能谱、透射电子显微镜、紫外可见漫反射光谱和N2吸附-脱附测试等技术对所制备样品的结构、形貌、光吸收特性、光电化学性能和比表面积等进行系统分析。并以气相甲苯为目标降解物,研究其光催化性能。结果表明,相对于体相g-C3N4(CNB)和CNHS,Pt的引入可以有效增强催化剂对可见光的吸收能力、响应范围及载流子分离效率。与纯g-C3N4和CNHS相比,Pt-CNHS在紫外和可见光照射下均表现出更高的光催化降解气相甲苯的活性。此外,也对Pt-CNHS光催化剂在可见光照射下降解气相甲苯的反应历程做了初步研究。  相似文献   

14.
The thin films of TiO2 doped by Sn or Nb were prepared by sol–gel method under process control. The effects of Sn and Nb doping on the structural, optical and photo-catalytic properties of applied thin films have been studied by X-ray diffraction (XRD) high resolution transmission electron microscopy and UV–Vis absorption spectroscopy. Surface chemical state of thin films was examined by atomic X-ray photoelectron spectroscopy. XRD results suggest that adding impurities has a great effect on the crystallinity and particle size of TiO2. Titania rutile phase formation in thin film was promoted by Sn4+ addition but was inhibited by Nb5+ doping. The activity of the photocatalyst was evaluated by photocatalytic degradation kinetics of aqueous methylene blue under UV and Visible radiation. The results show that the photocatalytic activity of the Sn-doped TiO2 thin film have a larger degradation efficiency than Nb-doped TiO2 under visible light, but under UV light photocatalytic activity of the Nb-doped TiO2 thin film is better.  相似文献   

15.
Nanocrystalline TiO2 was synthesized using the microwave plasma technique and characterized using X-ray diffraction, transmission electron microscopy, scanning electron microscopy, laser particle size analyzer, UV–vis spectroscopy and BET surface area analyzer. The synthesized TiO2 powder crystallized in anatase phase and the crystallite sizes were in nanometers. The photocatalytic activity of the compound was determined and compared against the activity of the commercial Degussa P-25 TiO2 catalyst. The degradation rates of the dyes were found to be higher over the synthesized TiO2 as compared to that over commercial Degussa P-25 TiO2.  相似文献   

16.
Water decontamination still remains a major challenge to some developing countries not having centralized wastewater systems. Therefore, this study presents the optimization of photocatalytic degradation of Basic Blue 41 dye in an aqueous medium by an activated carbon (AC)-TiO2 photocatalyst under UV irradiation. The mesoporous AC-TiO2 synthesized by a sonication method was characterized by X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) spectroscopy for crystal phase identification and molecular bond structures, respectively. The efficiency of the AC-TiO2 was evaluated as a function of three input variables viz. catalyst load (2–4 g), reaction time (15–45 min) and pH (6–9) by using Box-Behnken design (BBD) adapted from response surface methodology. Using color and turbidity removal as responses, a 17 run experiment matrix was generated by the BBD to investigate the interaction effects of the three aforementioned input factors. From the results, a reduced quadratic model was generated, which showed good predictability of results agreeable to the experimental data. The analysis of variance (ANOVA), signposted the selected models for color and turbidity, was highly significant (p < 0.05) with coefficients of determination (R2) values of 0.972 and 0.988, respectively. The catalyst load was found as the most significant factor with a high antagonistic impact on the process, whereas the interactive effect of reaction time and pH affected the process positively. At optimal conditions of catalyst load (2.6 g), reaction time (45 min), and pH (6); the desirability of 96% was obtained by a numerical optimization approach representing turbidity removal of 93% and color of 96%.  相似文献   

17.
Effective removal of organic pollutants from wastewater becomes notable research because of its ecological and environmental importance. In the present study Andrographis echioides leaf extract was used for the synthesis of calcium hydroxide nanoparticles (Ca(OH)2-NPs) from calcium oxide as the calcium source. The secondary metabolites present in the plant source act as a capping agent for the formation Ca(OH)2-NPs. Further NPs were applied for photocatalytic degradation. The intention of the approach is to be low-cost preparation and easy degradation (degradation of dye without any effect) to the environment. The synthesized Ca(OH)2-NPs was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, ultra violet diffuse reflectance spectroscopy, energy dispersive X-ray spectroscopy, zeta potential and high-resolution transmission electron microscopy. The photocatalytic degradation of methylene blue (dye pollutant) studied under three different light sources such as UV, visible and sun light using Ca(OH)2-NPs. Degradation efficiency of Methylene blue dye examined under UV–Vis spectroscopy. Degradation percentage of Ca(OH)2-NPs under UV, visible and sunlight are (98.96, 97.52 and 96.38%) respectively. The overall study suggests that Ca(OH)2-NPs exhibit excellent photocatalytic property against UV, visible and sunlight.  相似文献   

18.
Bare TiO2 and Cu-doped TiO2 nanoparticles with different nominal doping amounts of Cu ranging from of 0.5 to 5.0 mol% were synthesized using the modified sol–gel method. The samples were physically characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, Brunauer–Emmett–Teller-specific surface area, UV–Vis diffuse reflectance spectroscopy, zeta potential, X-ray photoelectron spectroscopy, inductively coupled plasma, and photoluminescence techniques. The Cu-doped TiO2 exhibited good photocatalytic activity in mineralization of oxalic acid and formic acid under visible light irradiation. Photomineralization of oxalic and formic acids under visible light irradiation revealed greatly enhanced photoactivity exhibited by the 2.0 mol% Cu-doped TiO2 photocatalyst compared to bare TiO2 . The enhanced photocatalytic performance arises from copper ion doping in the TiO2 structure, leading to an extended photoresponsive range, enhanced photogenerated charge separation, and transportation efficiency.  相似文献   

19.
Degradation of ethylenediaminetetraacetic acid (EDTA) present in the liquid waste was demonstrated by photocatalytic oxidation route by using nanoparticles of anatase titania. Nano sized titania photocatalyst was synthesized using sol–gel method coupled with ultrasonication mode and characterized using X-ray diffraction, transmission electron microscope, BET, Fourier transform infrared spectroscopy and TG–DTA. A cylindrical photoreactor was employed for the degradation studies. Five milligram of the nano anatase TiO2 + 0.5 ml of 30% H2O2 were employed as catalysts for the degradation studies of 1,000 mg/L EDTA. EDTA degradation was followed by a complexometric titration method. Complete degradation of 1,000 mg/L EDTA could be achieved in 90 min and the photocatalytic efficiency of the synthesized titania photocatalyst was higher than that of P-25 TiO2 for EDTA degradation. The influence of pH on the degradation of EDTA follow the order acidic > neutral > alkaline. More than ten fold increases in the decontamination factors were obtained for the chemical precipitation step for the liquid waste containing degraded EDTA compared to liquid waste without EDTA degradation.  相似文献   

20.
We have synthesized a nitrogen‐doped activated carbon (NAC) derived from oak using KOH and N2 thermal treatment at 400 °C as well as CuS nanoparticles. The NAC was decorated with the synthesized CuS to apply as a photocatalyst for degradation of norfloxacin (NOR). Before its application for photodegradation, the adsorbent/photocatalyst structural properties were investigated using X‐ray diffraction, X‐ray photoelectron spectroscopy, Raman spectroscopy and scanning electron microscopy. The photocatalytic degradation of NOR was successfully done under visible light using NAC–CuS. The results revealed that the investigated fluoroquinolone degraded very efficiently and pseudo‐first‐order kinetics was adopted for the photodegradation process. In addition, isothermal studies showed that the adsorption process in darkness followed the Langmuir model. The degradation characteristics of the NAC–CuS photocatalyst were studied for 120 min and 15 h under visible light for degradation of NOR, exhibiting a good efficiency for NOR removal. During 120 min of degradation, some intermediate degradation products that can be considered as secondary pollutants were produced. Then, to degrade these pollutants the radiation time was increased up to 15 h. The results displayed a perfect degradation of NOR and its secondary pollutants. The effective variables including pH, degradation time and photocatalyst dosage were optimized and studied in a multivariate method using Design Expert 7. Determination of photodegradation products was carried out using liquid chromatography–mass spectrometry. The results are of significance for estimating the environmental fate of NOR in aqueous media.  相似文献   

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