本文以合成商业腐殖酸Aldrich humic acids （ AHA）与国药化学试剂腐殖酸（ TJHA）为研究对象，与铁氰化钾反应测定不同浓度AHA与TJHA还原前后氧化还原能力．研究发现，原态和还原态的HA均能向铁氰化钾传递电子，还原后两种HA的氧化还原能力均大于其原态的氧化还原能力．原态和还原态TJHA的单位碳电子转移数（原态1．49 meq·g C－1；还原态20．95 meq·g C－1）均大于 AHA（原态0．52 meq·g C－1；还原态1．75 meq·g C－1）．同时随着HA浓度的增加，两种HA的原态与还原态单位碳电子转移数均逐渐降低（ AHA：0．91—0．52 meq·g C－1；TJHA：13．57—1．49 meq·g C－1），而 AHA 单位体积电子转移数目逐渐增大（0．002—0．072 meq·L－1），TJHA单位体积电子转移能力无明显变化．这是由于在HA与铁氰化钾电子转移体系中，氧化还原能力的高低与腐殖酸中氧化还原官能团数量和分布有关，与HA粒径大小，分子质量也有关系．进一步通过E465，E4／E6值表明两种HA E465值与浓度呈明显正线性关系，E4／E6值与浓度呈对数增加趋势．三维荧光分析发现，HA还原后，激发／发射（ Ex／Em）峰出现蓝移，相对荧光强度降低，说明HA还原的过程中有π—π?的断裂．进一步对HA 荧光测定发现TJHA中具有更多数量的氧化还原官能团而AHA中氧化还原官能团种类相对丰富．
This study choose the intentional commercial Aldrich humic acids ( AHA ) and humic acids ( HA ) produced by Sinopharm Chemical Reagent Co, Ltd ( TJHA ) . Reducing capacities ( RC ) of AHA and TJHA reacting with ferricyanide in native and reduced state have been determined. RC of TJHA ( Native:1.49 meq·g C-1;Reduced:20.95 meq·g C-1 ) were higher than that of AHA ( Native:0.52 meq·g C-1;Reduced:1.75 meq·g C-1 ) . With HA concentrations from 0.005 mg·mL-1 to 0. 5 mg·mL-1 , the per gram carbon RC of AHA and TJHA decreased ( AHA:0.91—0.52 meq·g C-1;TJHA:13.57—1.49 meq·g C-1). However, the per liter volume electron transfer numbers of AHA increased ( 0. 002—0. 072 meq·L-1 ) and the liter volume of electron transfer numbers for TJHA has no significantly change. These results indicated that the RC dependent on either distributions of functional group or molecules size. Furthermore, we obtained a highly significant inverse relationship between HA concentrations and E465 , and a logarithmic function relationship between HA concentrations and E4/E6. The fluorescence spectroscopy analysis of HA observed that Excitation/Emission ( Ex/Em ) peak shifted to short wavelength and relative fluorescence intensities decreased for reduced HA samples, which indicated that π—π? bonds ruptured during reduction. The fluorescence spectroscopy analysis of TJHA and AHA indicated that TJHA had amount of redox functional group, and AHA had abundant classes of redox functional group.
参考文献
| [1] | Lovley D R;Coates J D;Blunt-Harris E L et al.Humic substances as electron acceptors for microbial respiration[J].NATURE,1996,382(6590):445-448. |
| [2] | Benz M;Schink B;Brune A .Humic acid reduction by Propionibacterium freudenreichii and other fermenting bacteria[J].Applied and Environmental Microbiology,1998(11):4507-4512. |
| [3] | Peretyazhko T;Sposito G .Reducing capacity of terrestrial humic acids.[J].Geoderma: An International Journal of Soil Science,2006(1/2):140-146. |
| [4] | Jiang J;Bauer I;Paul A.Arsenic redox changes by mcrobially and chemically formed semiquinone radicals and hydroquinones in a humic substance model quinone[J].Environmental Science and Technology,2009:43,3639-3645. |
| [5] | Francisco J. Cervantes;Frank A. M. de Bok;Tuan Duong-Dac;Alfons J. M. Stams;Gatze Lettinga;Jim A. Field .Reduction of humic substances by halorespiring, sulphate-reducing and methanogenic microorganisms[J].Environmental microbiology,2002(1):51-57. |
| [6] | Coates J D;Chakraborty R;O′Connor S M et al.The geochemical effects of microbial humic substances reduction[J].Acta Hydrochimica et Hydrobiologica,2000,28(7):420-427. |
| [7] | Jiang J;Kappler A .Kinetics of microbial and chemical reduction of humic substances: Implications for electron shuttling[J].Environmental Science & Technology: ES&T,2008(10):3563-3569. |
| [8] | 邓红梅,陈永亨,常向阳.腐殖酸对铊污染土壤中铊形态和分布的影响[J].生态环境学报,2009(03):891-894. |
| [9] | Andreas Kappler;Stefan B. Haderlein .Natural organic matter as reductant for chlorinated aliphatic pollutants[J].Environmental Science & Technology: ES&T,2003(12):2714-2719. |
| [10] | Kappler A.;Benz M.;Schink B.;Brune A. .Electron shuttling via humic acids in microbial iron(III) reduction in a freshwater sediment[J].FEMS Microbiology Ecology,2004(1):85-92. |
| [11] | Stevenson F J.Humus chemistry:Genesis,composition,reactions,2nd ed[M].New York:John Wiley and Sons,Inc,1994:443-456. |
| [12] | D. T. Scott;D. M. McKnight;E. L. Blunt-Harris;S. E. Kolesar;D. R. Lovley .Quinone moieties act as electron acceptors in the reduction of humic substances by humics-reducing microorganisms[J].Environmental Science & Technology: ES&T,1998(19):2984-2989. |
| [13] | Van der Zee FP;Cervantes FJ .Impact and application of electron shuttles on the redox (bio)transformation of contaminants: A review[J].Biotechnology Advances: An International Review Journal,2009(3):256-277. |
| [14] | 窦森;陈恩凤;须湘成.土壤有机培肥后胡敏酸结构特征变化规律的探讨---Ⅰ.胡敏酸的化学性质和热性质[J].土壤学报,1992(02):199-207. |
| [15] | Senesi N .Molecular and quantitative aspects of the chemistry of fulvic acid and its interactions with metal ions and organic chemicals.Part II.The fluorescence spectroscopy approach[J][J].Anal Chin Acta,1990,232:77-106. |
| [16] | Pullin M J;Cabaniss S E .Rank analysis of the pH-dependent synchronization fluorescence spectra of six standard humic substances[J].Environmental Science and Technology,1995,29(6):1460-1467. |
| [17] | Diane M. McKnight;Elizabeth W. Boyer;Peter T. Doran .Spectrofluorometric characterization of dissolved organic matter for indication of precursor organic material and aromaticity[J].Limnology and Oceanography,2001(1):38-48. |
| [18] | 傅平青,刘丛强,尹祚莹,吴丰昌.腐殖酸三维荧光光谱特性研究[J].地球化学,2004(03):301-308. |
| [19] | Chen L;Senesi N;Sehnizer M.Information provided on humic substance by E4/E6 ratios[J].Soil Sci Soc Amer Proe,1977:41,352-358. |
| [20] | 文启孝.土壤有机质的组成、形成和分解[J].土壤,1984(4):121-129. |
| [21] | Senesi N;D′Orazio V.Fluorescence Spectroscopy. in encyclopedia of soils in the environment[M].Elsevier:Oxford,2005:35-52. |
| [22] | ROSE M.CORY;DIANE M.MCKNIGHT .Fluorescence Spectroscopy Reveals Ubiquitous Presence of Oxidized and Reduced Quinones in Dissolved Organic Matter[J].Environmental Science & Technology: ES&T,2005(21):8142-8149. |
| [23] | 姜杰,李黎,孙国新.基于三维荧光光谱特征研究土壤腐殖质氧化还原特性[J].环境化学,2012(12):2002-2007. |
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