[雙語(yǔ)翻譯]--外文翻譯--ctab輔助合成單斜相bivo4及其在可見(jiàn)光下對(duì)有機(jī)染色劑的高效降解（英文）

1、Journal of Hazardous Materials 173 (2010) 194–199Contents lists available at ScienceDirectJournal of Hazardous Materialsjournal homepage: www.elsevier.com/locate/jhazmatCTAB-assisted synthesis of monoclinic BiVO4 photoca

2、talyst and its highly efficient degradation of organic dye under visible-light irradiationWenzong Yin, Wenzhong Wang ?, Lin Zhou, Songmei Sun, Ling ZhangState Key Laboratory of High Performance Ceramics and Superfine Mic

3、rostructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road,Shanghai 200050, PR Chinaa r t i c l e i n f oArticle history:Received 11 March 2009Received in revised form 11 August 2009Accept

4、ed 16 August 2009Available online 22 August 2009Keywords:Monoclinic BiVO4 PhotocatalystCTABDe-ethylationConjugated chromophore structurea b s t r a c tA highly efficient monoclinic BiVO4 photocatalyst (C-BVO) was synthes

5、ized by an aqueous method withthe assistance of cetyltrimethylammonium bromide (CTAB). The structure, morphology and photophys-ical properties of the C-BVO were characterized by XRD, FE-SEM and diffuse reflectance spectr

6、oscopy,respectively. The photocatalytic efficiencies were evaluated by the degradation of rhodamine B (RhB)under visible-light irradiation, revealing that the degradation rate over the C-BVO was much higher thanthat over

7、 the reference BiVO4 prepared by aqueous method and over the one prepared by solid-statereaction. The efficiency of de-ethylation and that of the cleavage of conjugated chromophore structurewere investigated, respectivel

8、y. The chemical oxygen demand (COD) values of the RhB were measuredafter the photocatalytic degradation over the C-BVO and demonstrated a 53% decrease in COD. The effectsof CTAB on the synthesis of C-BVO were investigate

9、d, which revealed that CTAB not only changed thereaction process via the formation of BiOBr as an intermediate, but also facilitated the transition fromBiOBr to BiVO4. Comparison experiments were carried out and showed t

10、hat the existence of impuritylevel makes significant contribution to the high photocatalytic efficiency of the C-BVO.© 2009 Elsevier B.V. All rights reserved.1. IntroductionOrganic dyes in textile and other industri

11、al effluents havebecome one type of the major environmental contaminants. Asmany dyes are highly water-soluble, traditional treatment methodsincluding flocculation, activated carbon adsorption, and biologi-cal treatment

12、do not work efficiently [1]. Recently, photocatalysismethod has played an important role in the degradation of organicdyes in wastewater [2,3]. Compared with other treatment, pho-tocatalytic degradation has several advan

13、tages, such as the use ofenvironmentally friendly oxidant O2, complete mineralization, nowaste disposal problem, and a necessity of only mild tempera-ture and pressure conditions [3,4]. Moreover, the photocatalyticdegrad

14、ation is able to work out even at a much low concentra-tion of organic dyes. Therefore, photocatalytic degradation is apromising solution to organic dyes. Early studies on photocata-lysts mainly focused on the Ultraviole

15、t-driven TiO2 photocatalyst[5–7]. However, UV light takes up only ca. 4% of the solar energywhile visible-light ca. 43%. Hereby, visible-light-driven photocata-lysts have been the new focus [8–10].Since BiVO4 was found t

16、o be an active photocatalyst for O2 evolution from aqueous AgNO3 solution under visible-light irra-? Corresponding author. Tel.: +86 21 5241 5295; fax: +86 21 5241 3122.E-mail address: wzwang@mail.sic.ac.cn (W. Wang).dia

17、tion [11], more and more attention has been attracted to thesynthesis of visible-light-driven BiVO4 photocatalyst. Among thethree crystalline phases of BiVO4, tetragonal zircon (z-t), tetrago-nal scheelite (s-t) and mono

18、clinic scheelite (s-m) structures [12],it is found that the monoclinic scheelite BiVO4 (m-BiVO4) exhibitsmuch higher photocatalytic activity than the other two tetrago-nal phases [13,14]. Therefore, many methods have bee

19、n employedfor the synthesis of m-BiVO4, such as solid-state reaction [15,16],hydrothermal or solvothermal method [17–21], aqueous method[22–24], ultrasound- or microwave-assisted route [25,26], metal-organic decompositio

20、n [27,28], flame spray pyrolysis [29], andsolution combustion method [30]. Compared with other meth-ods, aqueous method provides a milder environment for thesynthesis of monoclinic BiVO4 and the reaction parameters aswel

21、l as the properties of the products could be easily tuned.To the best of our knowledge, however, the synthesis of BiVO4 by aqueous method with the assistance of CTAB has not beenreported.In the present study, highly effi

22、cient m-BiVO4 photocatalyst wassynthesized by a CTAB-assisted aqueous method and rhodamine B(RhB) was used as a model dye to evaluate its photocatalytic effi-ciency under visible-light irradiation. Furthermore, the effic

23、ienciesboth in de-ethylation and cleavage of chromophore structure wereinvestigated, respectively. The 53% decrease of the COD values forthe RhB solutions after the irradiation confirmed the photocatalyticdegradation of

24、RhB. The effects of CTAB addition on the products0304-3894/$ – see front matter © 2009 Elsevier B.V. All rights reserved.doi:10.1016/j.jhazmat.2009.08.068196 W. Yin et al. / Journal of Hazardous Materials 173 (2010)

25、 194–199Fig. 2. SEM images of the C-BVO. (a) panoramic view; (b) magnified view.Fig. 3. DRS spectra of the C-BVO (a) and C-BVO-cal (b).Fig. 4. Decrease of RhB (C/C0) (100 mL, 10?5 M) as a function of irradiation timeover

26、 0.1 g of (a) C-BVO, (b) AM-BVO and (c) SSR-BVO, and (d) direct photolysis ofRhB (100 mL, 10?5 M) under visible-light (? > 420 nm).BVO and 281 times higher than that for the SSR-BVO, indicating ahigh photocatalytic ef

27、ficiency of the C-BVO.As reported by Zhao et al. [33], two procedures are involvedin the degradation of RhB: the de-ethylation and the cleavage ofconjugated chromophore structure. The former one could be char-acterized b

28、y the shift of the maximum absorption band (?max) ofRhB while the latter one by the change in the absorption maxi-mum (Amax/A0 max) of RhB. Usually these two procedures take placesimultaneously in the presence of photoca

29、talyst under irradiation.As a result, it is a cooperative effect that results in the decrease ofabsorbance at the wavelength of 553 nm with the irradiation timeprolonged.To investigate the efficiencies of the de-ethylati

30、on and the cleav-age of conjugated chromophore structure, here we analyzed thechanges in the maximum absorption bands and the absorptionmaxima of the RhB solutions irradiated for different time. Theresults are shown in F

31、ig. 5. The C-BVO exhibits high photocat-alytic efficiencies in both the de-ethylation and the cleavage ofconjugated chromophore structure of RhB. During the first 20 minthe de-ethylation proceeds in a stepwise manner wit

32、h the colorof the suspension changing from initial red to light green-yellow,as reported in the Ref. [32]. De-ethylation of the fully N, N, N?,N?-tetraethylated rhodamine molecule (RhB) results in significanthypsochromic

33、 shifts. The maximum absorption band of RhB isFig. 5. Changes of the maximum absorption band (?max, dot line) and the absorptionmaximum (Amax/A0 max, solid line) of RhB as a function of irradiation time during thephotoca