碘掺杂Bi_4O_5Br_2可见光催化降解2,4-二羟基苯甲酸甲酯
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摘要
2,4-二羟基苯甲酸甲酯(MDB)是对羟基苯甲酸甲酯在高级氧化过程中形成的较稳定的中间产物,具有比甲酯更强的毒性,其在环境中的存在对水资源及生态系统具有较高的潜在风险.文中首次提出在可见光照射下利用微波法合成的碘掺杂Bi_4O_5Br_2(I-Bi_4O_5Br_2)催化降解MDB,并取得了较好的进展.与纯Bi_4O_5Br_2相比,I-Bi_4O_5Br_2催化剂表现出优异的可见光降解MDB活性,其降解速率是纯Bi_4O_5Br_2的5倍(0.038 min-1). I-Bi_4O_5Br_2光催化活性增强的主要原因是其更佳的光生电子空穴对的分离效率和更宽的光吸收范围.机理研究表明:光生空穴和超氧自由基为MDB可见光催化降解过程中的主要活性氧化物种.
Methyl 2,4-dihydroxybenzoate( MDB) is a relatively stable hydroxylated product of methylparaben( MeP) during advanced oxidation process( AOPs),which has more toxicity than pure MeP. Its presence in the environment means potential risks to the ecosystem. Photocatalytic degradation of MDB under visible light irradiation using the I-doped Bi_4O_5Br_2 photocatalyst is newly proposed and has produced good results. Compared with pure Bi_4O_5Br_2,the I-doped Bi_4O_5Br_2 photocatalyst exhibited enhanced photocatalytic activity( 0.038 min-1) in the degradation of MDB under visible light,the degradation rate being approximately 5 times as high as that of pure Bi_4O_5Br_2. The better efficiency for separating the photogenerated electron-hole pairs and the wider range of visible light absorption are considered the key causes for the enhanced photocatalytic activity of I-doped Bi_4O_5Br_2. Photogenerated holes and superoxide radicals were identified as the main reactive species by the scavenger experiments.
Methyl 2,4-dihydroxybenzoate( MDB) is a relatively stable hydroxylated product of methylparaben( MeP) during advanced oxidation process( AOPs),which has more toxicity than pure MeP. Its presence in the environment means potential risks to the ecosystem. Photocatalytic degradation of MDB under visible light irradiation using the I-doped Bi_4O_5Br_2 photocatalyst is newly proposed and has produced good results. Compared with pure Bi_4O_5Br_2,the I-doped Bi_4O_5Br_2 photocatalyst exhibited enhanced photocatalytic activity( 0.038 min-1) in the degradation of MDB under visible light,the degradation rate being approximately 5 times as high as that of pure Bi_4O_5Br_2. The better efficiency for separating the photogenerated electron-hole pairs and the wider range of visible light absorption are considered the key causes for the enhanced photocatalytic activity of I-doped Bi_4O_5Br_2. Photogenerated holes and superoxide radicals were identified as the main reactive species by the scavenger experiments.
引文
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[3] FENG X N,CHEN Y,FANG Y,et al. Photodegradation of parabens by Fe(III)-citrate complexes at circumneutral p H:Matrix effect and reaction mechanism[J]. Science of the Total Environment,2014,472:130-136.
[4] DARBRE P D,ALJARRAH A,MILLER W R,et al. Concentrations of parabens in human breast tumours[J].Journal of Applied Toxicology,2004,24(1):5-13.
[5] ROUTLEDGE E J,PARKER J,ODUM J,et al. Some alkyl hydroxy benzoate preservatives(parabens)are estrogenic[J]. Toxicology and Applied Pharmacology,1998,153(1):12-19.
[6] BEDZKA D,GROMADZI'NSKA J,WASOWICZ W. Parabens:From environmental studies to human health[J]. Environment International,2014,67:27-42.
[7] FANG H,GAO Y,LI G,et al. Advanced oxidation kinetics and mechanism of preservative propylparaben degradation in aqueous suspension of Ti O2and risk assessment of its degradation products[J]. Environmental Science&Technology,2013,47(6):2704-2712.
[8] VELEGRAKI T,HAPESHI E,FATTA-KASSIONS D,et al. Solar-induced heterogeneous photocatalytic degradation of methyl-paraben[J]. Applied Catalysis B:Environmental,2015,178:2-11.
[9] GAOY,JI Y,LI G,et al. Theoretical investigation on the kinetics and mechanisms of hydroxyl radical-induced transformation of parabens and its consequences for toxicity:Influence of alkyl-chain length[J]. Water Research,2016,91:77-85.
[10] XIAO X,LU M,NAN J,et al. Rapid microwave synthesis of I-doped Bi4O5Br2with significantly enhanced visiblelight photocatalysis for degradation of multiple parabens[J]. Applied Catalysis B:Environmental,2017,218:398-408.
[11]简蓝,万霞,铁绍龙. Cu2O/Ag复合催化剂的合成及红外光激发下的光催化性能研究[J].华南师范大学学报(自然科学版),2015,47(5):44-49.JIAN L,WAN X,TIE S L. Synthesis of Cu2O/Ag composite catalysts and their photocatalytic property under infrared light irradiation[J]. Journal of South China Normal University(Natural Science Edition),2015,47(5):44-49.
[12] YANG Y,WANGH,LI X,et al. Electrospun mesoporous W6+-doped Ti O2thin films for efficient visible-light photocatalysis[J]. Materials Letters,2009,63(2):331-333.
[13] XU J,MENG W,ZHANGY,et al. Photocatalytic degradation of tetrabromobisphenol A by mesoporous Bi OBr:Efficacy,products and pathway[J]. Applied Catalysis B:Environmental,2011,107:355-362.
[14]易云强,方战强.纳米零价铁-双氧水协同提升甲硝唑矿化率的研究[J].华南师范大学学报(自然科学版),2018,50(1):28-32.YI Y Q,FANG Z Q. Enhancedmineralization of metronidazole by synergism of hydrogen peroxide and nanoscale zero-valent iron[J]. Journal of South China Normal University(Natural Science Edilion,2018,50(1):28-32.
[15] GONDAL M A,CHANG X F,YAMANI Z H. UV-light induced photocatalytic decolorization of Rhodamine 6G molecules over Bi OCl from aqueous solution[J]. Chemical Engineering Journal,2010,165(1):250-257.
[16] KONSTANTINOU I K,ALBANIS T A. Ti O2-assisted photocatalytic degradation of Azo dyes in aqueous solution:kinetic and mechanistic investigations[J]. Applied Catalysis B:Environmental,2004,49:1-14.
[17] LI H,SHANG J,AI Z,et al. Efficient visible light nitrogen fixation with Bi OBr nanosheets of oxygen vacancies on the exposed{001}facets[J]. Journal of the American Chemical Society,2015,137(19):6393-6399.
[18] QIN F,LI G,WANG R,et al. Template-free fabrication of Bi2O3and(Bi O)2CO3nanotubes and their application in water treatment[J]. Chemistry-A European Journal,2012,18(51):16491-16497.
[19] YE L,JIN X,LIU C,et al. Thickness-ultrathin and bismuth-rich strategies for Bi OBr to enhance photoreduction of CO2into solar fuels[J]. Applied Catalysis B:Environmental,2016,187:281-290.
[20] XIAO X,XING C,HE G,et al. Solvothermal synthesis of novel hierarchical Bi4O5I2nanoflakes with highly visible light photocatalytic performance for the degradation of 4-tert-butylphenol[J]. Applied Catalysis B:Environmental,2014,148:154-163.
[21] LI Y,WANG J,YAO H,et al. Efficient decomposition of organic compounds and reaction mechanism with Bi OI photocatalyst under visible light irradiation[J]. Journal of Molecular Catalysis A:Chemical,2011,334:116-122.