东海沉积物中铁(Ⅲ)氧化物还原活性的动力学表征
Kinetic characterization of reductive reactivity of iron(Ⅲ) oxides in sediments of the East China Sea
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摘要: 运用还原性溶解动力学实验和活性连续体(reactive continuum)模型表征了东海表层和柱状沉积物中铁(Ⅲ)氧化物的还原活性及反应进程中的动力学行为,通过动力学数据拟合得到了活性铁氧化物理论含量m0、表观速率常数k'和活性非均匀度γ。结果表明,表层沉积物中铁氧化物的m0在26.14~60.51 μmol/g之间,变化较小;表征高活性铁氧化物还原动力学行为的标准化初始还原速率(J/m0=k')变化也较小,最大相差仅7.25倍;但不同站位沉积物中铁氧化物活性的非均匀度变化较大,当铁氧化物溶解达到90%时,其速率与初始速率相差2~4个数量级。表层沉积物中铁氧化物的m0,k'和γ 3个动力学参数之间不存在相关性;柱状沉积物中m0,k'和γ 3个动力学参数都随深度的增加呈总体减小的趋势,且三者之间存在良好的线性关系,这是沉积物早期成岩作用中铁成岩循环的结果。与传统的化学提取相比,活性连续体模型得到3个动力学参数(m0,k'和γ)能从多个角度表征铁氧化物还原活性和动力学行为的细微差别。Abstract: Kinetic experiments and the reactive continuum model were combined to characterize the reductive reactivity of iron(Ⅲ) oxides in surface and core sediments of the East China Sea.Three kinetic parameters,i.e.,theoretical amounts of total reactive iron(Ⅲ) oxides (m0),apparent rate constants (k'),and heterogeneity of reactivity (γ),were obtained by fitting kinetic data to the reactive continuum model.The results show that m0 values in the surface sediments are within a narrow range (26.14~60.51 μmol/g). Normalized initial rates (J/m0=k'),which characterize the kinetic behavior of highly reactive iron(Ⅲ) oxides,are also within a narrow range,with the highest initial rate being only 7.25 times the lowest.But heterogeneity of reductive reactivity of iron(Ⅲ) oxides in the surface sediments displays a wide range of variation.The kinetic rates after 90% dissolution of iron(Ⅲ) oxides are 2~4 orders of magnitude lower than the initial rates.The values of m0,k',and γ for core C0702 decrease generally with depth,and display good linear relationships between each other,which could be attributed to diagenetic cycling of iron in the sediments.However,no correlations among m0,k' and γ were observed in the surface sediments.In comparison with traditional chemical extraction methods,the reactive continuum model allows a more nuanced picture of the reactivity and kinetic manner of iron(Ⅲ) oxides in reductive dissolution.
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Key words:
- iron(Ⅲ)-oxides /
- reductive reactivity /
- marine sediments /
- kinetics /
- East China Sea
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CANFIELD D E,KRISTENSEN E,THAMDRUP B.Aquatic Geomicrobiology[M].Amsterdam:Elsevier,2005. THAMDRUP B.Bacterial manganese and iron reduction in aquatic sediments[J].Advance in Microbial Ecology,2000,16:41-84. LOVLEY D R,PHILLIPS E J P.Rapid assay for microbially reducible ferric iron in aquatic sediments[J].Applied Environmental Microbiology,1987,53:1536-1540. CANFIELD D E,RAISWELL R,BOTTRELL S.The reactivity of sedimentary iron minerals toward sulfide[J].American Journal of Science,1992,292:659-683. ROZAN T F,TAILLEFERT M,TROUWBORST R E,et al.Iron-sulfur-phosphorus cycling in the sediments of a shallow coastal bay:implications for sediment nutrient release and benthic macroalgal blooms[J].Limnology and Oceanography,2002,47:1346-1354. ZACHARA J M,FREDRICKSON J K,SMITH S C,et al.Solubilization of Fe(Ⅲ) oxide-bound trace metals by a dissimilatory Fe(Ⅲ) reducing bacterium[J].Geochimica et Cosmochimica Acta,2001,65:75-93. BURDIGE D J.Geochemistry of Marine Sediments[M].Princeton:Princeton University Press,2006. CHAO T T,ZHOU L.Extraction techniques for selective dissolution of amorphous iron oxides from soils and sediments[J].Soil Science Society of America Journal,1983,47:225-232. PHILLIPS E J P,LOVLEY D R.Determination of Fe(Ⅲ) and Fe(Ⅱ) in oxalate extracts of sediment[J].Soil Science Society of America Journal,1987,51:938-941. KOSTKA J,LUTHER G W.Partitioning and speciation of iron in saltmarsh sediments[J].Geochimica et Cosmochimica Acta,1994,58:1701-1710. POULTON S W,CANFIELD D E.Development of a sequential extraction procedure for iron:implications for iron partitioning in continentally derived particulates[J].Chemical Geology,2005,214:209-221. POSTMA D.The reactivity of iron oxides in sediments:a kinetic approach[J].Geochimica et Cosmochimica Acta,1993,57:5027-5034. ZHAO YIYANG.Geochemistry of some elements in sediments of the East China Sea[J].Chinese Journal of Oceanography and Limnology,1983,1:210-222. 段伟民,陈丽蓉.黄、东海早期成岩过程中黄铁矿的形成史[J].中国科学:B辑,1993,23(5):545-552. 尹希杰,周怀阳,杨群慧,等.珠江口淇澳岛海岸带沉积物中硫酸盐还原和不同形态硫的分布[J].海洋学报,2010,32(3):31-39. 宋金明,李鹏程.渤海南部沉积物中的活性铁及氧化还原环境[J].海洋科学,1997,2(4):32-36. 李学刚,吕晓霞,孙云明,等.渤海沉积物中的"活性铁"与氧化还原环境的关系[J].海洋环境科学,2003,22(1):20-24. CHRISTOFFERSEN J,CHRISTOFFERSEN M R.The kinetics of dissolution of calcium sulphate dihydrate in water[J].Journal of Crystal Growth,1976,35:79-88. BOUDREAU B P,RUDDICK B R.On reactive continuum representation of organic matter diagenesis[J].American Journal of Science,1991,291:507-538. CHRISTOFFERSEN J.Kinetics of dissolution of calcium hydroxyapatite[J].Journal of Crystal Growth,1980,49:29-44. LARSEN O,POSTMA D.Kinetics of reactive bulk dissolution of lepidocrocite,ferrihydrite,and goethite [J].Geochimica et Cosmochimica Acta,2001,65:1367-1379. LARSEN O,POSTMA D,JAKOBSEN R.The reactivity of iron oxides towards reductive dissolution with ascorbic acid in a shallow sandy aquifer (R?m?,Denmark) [J].Geochimica et Cosmochimica Acta,2006,70:4827-4835. HYACINTHE C,BONEVILLE S,Van CAPPELLEN P.Reactive iron(Ⅲ) in sediments:chemical versus microbial extractions[J]. Geochimica et Cosmochimica Acta,2006,70:4166-4180. Van DER ZEE C.VAN RAAPHORST W,2004.Manganese oxide reactivity in North Sea sediments[J].Journal of Sea Research,2004,52:73-85. POSTMA D,JESSEN S,HUE N T M,et al.Mobilization of arsenic and iron from Red River floodplain sediments,Vietnam[J]. Geochimica et Cosmochimica Acta,2010,74:3367-3381. HYACINTHE C,VAN CAPPELLEN P.An authigenic iron phosphate phase in estuarine sediments:composition,formation and chemical reactivity[J].Marine Chemistry,2004,91:227-251. DENG Y.Effect of pH on the reductive dissolution rates of iron(III) hydroxide by ascorbate[J].Langmuir,1997,13:1835-1839. REYES I,TORRENT J.Citrate-ascorbate as a highly selective extractant for poorly crystalline iron oxides[J].Soil Science Society of America Journal,1997,61:1647-1654. PEDERSEN H D,POSTMA D,JAKOBSEN R,et al.Fast transformation of iron oxyhydroxides by the catalytic action of Fe(Ⅱ)[J]. Geochimica et Cosmochimica Acta,2005,69:3967-3977. PEDERSEN H D,POSTMA D,JAKOBSEN R,et al.Release of arsenic associated with the reduction and transformation of iron oxides [J].Geochimica et Cosmochimica Acta,2006,70:4116-4129. 吕仁燕,朱茂旭,李 铁,等.东海陆架泥质沉积物中固相Fe形态及其对有机质、Fe、S成岩路径的制约意义[J].地球化学,2011,40(4):363-371. RICKARD D,MORSE J W.Acid volatile sulfide (AVS)[J].Marine Chemistry,2005,97:141-197. FAN D-J,NEUSER R D,SUN X-G,et al.Authigenic iron oxide formation in the estuarine mixing zone of the Yangtze River[J].Geo-Marine Letter,2008,28:7-14. LEHTORANTA J,EKHOLM P,HEIKKI P.Coastal eutrophication thresholds:a matter of sediment microbial processes[J].AMBIO,2009,38:303-308. 鲍根德.铁、锰早早期成岩过程中分离及其生物地球化学机制[J].中国科学:B辑,1989,19(1):93-102. 鲍根德,张桂芬.长江口及邻区陆架区沉积物和孔隙水中铁和锰及其与细菌的关系探讨[J].热带海洋,1991,10(1):32-39. JAKOBSEN R,POSTMA D.Redox zoning,rates of sulfate reduction and interactions with Fe-reduction and methanogenesis in a shallow sandy aquifer,Rm,Denmark[J].Geochimica et Cosmochimica Acta,1999,63:137-151.
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