在模拟太阳光下研究了多种腐殖质及其模型化合物的过氧化氢（H2O2）生成动力学，并对其生成机制进行了探讨.结果表明不同来源或不同形式的腐殖质在模拟太阳光照射下均能产生H2O2.不同腐殖质生成H2O2速率差异不大，范围为6.379~15.784nmol/（L·min），腐殖酸生成H2O2速率略快于富里酸.对于腐殖质模型化合物，邻苯二酚、间苯二酚、对苯二酚、苯醌、邻茴香胺、对茴香胺、水杨酸和2，6-二甲氧基-1，4-苯醌等8种模型化合物没有产生明显的H2O2，而藜芦醇、对氨基苯甲酸、3，5-二羟基苯甲酸（DHBA）、2，5-二羟基-1，4-苯醌、苯酚、苯甲酸和苯胺等7种化合物均可检测到H2O2产生.但其产生H2O2的速率差异较大，相差1~2个数量级，生成H2O2速率最快的化合物为2，5-二羟基-1，4-苯醌和DHBA，较慢的为苯酚、苯甲酸和对氨基苯甲酸.基于腐殖质生成H2O2机制，推测典型模型化合物DHBA的H2O2生成机制可能为光照条件下该化合物跃迁为单重激发态，该激发态发生分子内电子转移，生成还原性自由基中间体，该中间体和O2反应，生成了超氧负离子（O2·-），随后与水中H+反应生成了H2O2.
Abstract
The present study systematically investigated H2O2 generation kinetics and potential mechanism from irradiated humic substances (HS) and their model compounds under simulated sunlight. Our results indicated that all the selected HS with different sources or forms can produce H2O2 under irradiation, and no significant difference was observed between them, with the generation rate ranging from 6.379 to 15.784nmol/(L·min). The H2O2 generation rate from humic acid (HA) was slightly faster than that from fulvic acid (FA). In the case of humus model compounds, 7compounds including veratryl alcohol, p-aminobenzoic acid, 3,5-dihydroxybenzoic acid (DHBA), 2,5-dihydroxy-1,4-benzoquinone, phenol, benzoic acid and aniline could produce detectable H2O2, while other compounds including catechol, resorcinol, hydroquinone, quinone, o-anisidine, p-anisidine, salicylic acid and 2,6-dimethoxy-1,4-benzoquinone can't. Nevertheless, the H2O2 generation rate from the model compounds varies from each other, with one or two orders of magnitude. Among them, 2,5-dihydroxyl-1,4-benquione and DHBA exhibited the highest H2O2 yields, while phenol, benzoic and p-aminobenzoic acid showed a relative low H2O2 generation potential. Based on the generation mechanism of H2O2 from HS, a possible H2O2 formation mechanism from a typical model compound, i.e. DHBA, was proposed. DHBA was believed to excite to a singlet state, after an intramolecular electron transfer process, giving a reducing intermediate. The intermediate could further react with O2 to form O2·- and subsequently generate H2O2.
关键词
腐殖质 /
腐殖质模型化合物 /
光化学生成 /
过氧化氢 /
水体
Key words
humic substances /
humus model compounds /
hydrogen peroxide /
photoproduction /
water
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
[1] Garg S, Rose A L, Waite T D. Production of reactive oxygen species on photolysis of dilute aqueous quinone solutions[J]. Photochemistry and Photobiology, 2007,83:904-913.
[2] Moffett J W, Zika R G. Reaction kinetics of hydrogen peroxide with copper and iron in seawater[J]. Environmental Science & Technology, 1987,21:804-810.
[3] Rose A L, Waite T D. Role of superoxide in the photochemical reduction of iron in seawater[J]. Geochimica et Cosmochimica Acta, 2006,70:3869-3882.
[4] Clark C D, de Bruyn W J, Jakubowski S D, et al. Hydrogen peroxide production in marine bathing waters:implications for fecal indicator bacteria mortality[J]. Marine Pollution Bulletin, 2008,56:397-401.
[5] Clark C D, De Bruyn W J, Jones J G. Photochemical production of hydrogen peroxide in size-fractionated southern California coastal waters[J]. Chemosphere, 2009,76:141-146.
[6] Scully N M, Lean D, McQueen D, et al. Photochemical formation of hydrogen peroxide in lakes:effects of dissolved organic carbon and ultraviolet radiation[J]. Canadian Journal of Fisheries and Aquatic Sciences, 1995,52:2675-2681.
[7] Helz G R, Zepp R G, Crosby D G. Aquatic and surface photochemistry[M]. Lewis Publishers, 1994:111-127.
[8] Cooper W, Zika R, Pestasne R, et al. Photochemical formation of H2O2in natural waters exposed to sunlight[J]. Environmental Science & Technology, 1988,22:1156-1160.
[9] Garg S, Rose A, Waite T. Photochemical production of superoxide and hydrogen peroxide from natural organic matter[J]. Geochimica et Cosmochimica Acta, 2011,75:4310-4320.
[10] Kavins M, Purmalis O. Humic substances as surfactants[J]. Environmental Chemistry Letters, 2010,8:349-354.
[11] Rehm H J, Reed G. "Humification" Process or Formation of Refractory Soil Organic Matter[J]. Wiley-VCH Verlag GmbH, 2000:90-125.
[12] Park J, Dec J, Kim J, et al. Effect of humic constituents on the transformation of chlorinated phenols and anilines in the presence of oxidoreductive enzymes of birnessite[J]. Environmental Science & Technology, 1999,33:2028-2034.
[13] Montero L, Conradi S, Weiss H, et al. Determination of phenols in lake and ground water samples by stir bar sorptive extraction-thermal desorption-gas chromatography-mass spectrometry[J]. Journal of Chromatography A, 2005,1071:163-169.
[14] Davi M, Gnudi F. Phenolic compounds in surface water[J]. Water Research, 1999,33:3213-3219.
[15] Rosarioortiz F L, Canonica S. Probe compounds to assess the photochemical activity of dissolved organic matter[J]. Environmental Science & Technology, 2016,50:12532-12547.
[16] Clark C, De Bruyn W, Jones J. Photoproduction of hydrogen peroxide in aqueous solution from model compounds for chromophoric dissolved organic matter (CDOM)[J]. Marine Pollution Bulletin, 2014,79:54-60.
[17] Klassen N, Marchington D, McGowan H. H2O2Determination by the I3- method and by KMnO4titration[J]. Analytical Chemistry, 1994, 66:2921-5.
[18] Wang M J, Li J H, Shi H H, et al. Photolysis of atorvastatin in aquatic environment:Influencing factors, products, and pathways[J]. Chemosphere, 2018,212:467-475.
[19] Zhou L, Zhang Y, Wang Q, et al. Photochemical behavior of carbon nanotubes in natural waters:reactive oxygen species production and effects on·OH generation by Suwannee river fulvic acid, nitrate, and Fe (Ⅲ)[J]. Environmental Science and Pollution Research, 2016,23:19520-19528.
[20] Nosaka Y, Nosaka, A Y. Generation and detection of reactive oxygen species in photocatalysis[J]. Chemical Review, 2017,117:11302-11336.
[21] Zhang Y, Vecchio R, Blough N. Investigating the mechanism of hydrogen peroxide photoproduction by humic substances[J]. Environmental Science & Technology, 2012,46:11836-11843.
[22] Clark C, Bruyn W, Hirsch D, et al. Hydrogen peroxide measurements in recreational marine bathing waters in Southern California, USA[J]. Water Research, 2010,44:2203-2210.
[23] Plane J M C, Blough N V, Ehrhardt M G, et al. Photochemistry in the sea-surface microlayer[M]. 1997:383-424.
[24] Valentine J. Active oxygen in chemistry[M]. Springer Netherlands, 2013:280-333.
[25] Petasne R, Zika R. Fate of superoxide in coastal sea water[J]. Nature. 1987,325(6104):516-518.
[26] Ren D, Wang T, Chen F, et al. Effect of sodium hypochlorite on the structural and optical characteristics of humic acid in waters[J]. China Environmental Science, 2018,38(6):2264-2272.
[27] Ren D, Yang X X, Ma X D, et al. Structural characteristics of DOM and its effects on the photodegradation of 17β-estradiol. China Environmental Science, 2015,35(5):1375-1383.
[28] Suominen K, Kitunen V, Smolander A. Characteristics of dissolved organic matter and phenolic compounds in forest soils under silver birch (Betula pendula), Norway spruce (Picea abies) and Scots pine (Pinus sylvestris)[J]. European Journal of Soil Science, 2003,54(2):287-293.
[29] Sierra M, Fernandes A N, Szpoganicz B. Influence of amide linkages on acidity determinations of humic substances:Testing with model-mixtures[J]. Talanta, 2004,62(4):687-693.
基金
国家自然科学基金资助项目（21577059）
PDF(399 KB)
京公网安备 11010802030352号 
