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Kinetic Study Of Iron Oxides Dissimilatory Reduction And Its Impacts On Degration Of4-nitroacetophenone

Posted on:2015-06-09Degree:MasterType:Thesis
Country:ChinaCandidate:X Y HeFull Text:PDF
GTID:2271330452467757Subject:Municipal engineering
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Iron is widespread in the earth, and most of them exists in soil and sediment withthe form of oxidation, the redox reaction of alienation of iron and iron reducing bacteriacan degrade the organic and inorganic pollutants, so the study of iron circulation’smechanism and influent factors is vital. In the environment of the anoxia or anaerobic,iron oxide can be reduct to active Fe(ΙΙ) by microorganism, this reaction go with theprocess of pollutants’degradation. It has been confirmed that dissolved organic matter(DOM) which in environment (soil, sediment, etc.) actively participated in the processof alienation iron reduction in a lot of researches. Due to active chemical reactivity ofDOM, it undoubtedly become the major focus of affection and restriction of alienationiron reduction, and the key of the iron reduction mechanism, so it is necessary expoundregulatory mechanism of the reduction of DOM to iron oxidation. This experimentsadded2-sodium sulfonate anthracene hydroquinone (AQS) as dissolved organic matter,AQS contain quinoid structure that is sensitive functional groups. Building a interactionsystem included the typical metal reducing mechanism (Shewanella decolorationis, S12)and goethite and lepidocrocite, this system indicated the influence factors of the goethitealienation reduction with the AQS’s effection, which can provide scientific theoreticalsupport for the mechanism of goethite alienation reduction process with DOM’sregulation. Based on the interaction of Shewanella decolorationis,S12and goethite, theregulatory mechanism of alienation iron by the effection AQS of anthraquinonesorganic matter is discussed. The results showed that the AQS electron transport’s carrierincresed concentration of the reduction dissociation total iron (Fetot) and concentrationof soluble iron (Fedis) rapidly grow. After adding different concentrations of AQS, average rate of goethite reduction significantly rise which is between2.4~4.0, the ratioand concentration of AQS are significantly linear relationship, the correlationcoefficient is0.9947. Fedis/Fetotratio decreased with the increasing of concentration ofAQS, Fedis/Fetotratio decreases from0.935to0.705with the increasing ofconcentration of AQS from0.05mM to0.3mM. Concentration of Feadsincreased withthe increasing of concentration of AQS, when the system don’t contain AQS, Feadscontent is low (<0.05mM) without AQS. With AQS adding in the reaction, it actuallycomposed of two independent processes, one is microbial respiration which drive thecirculation process of AQS AH2QS, another is that goethite reducted by the AH2QS.Thelepidocrocite made into magnetite in the system which has AQS, another system haveon change.High valence of iron oxide obviously effect the degradation of organic pollutants,this experiment also explained the biological/abiological degradation characteristics of4-Nitroacetophenone under the condition of anaerobic and anoxia. But considering thenatural environment exists complex and quantity sensitive functional groups, so addingAQDS as electron transfer which have sensitive functional groups. The results showed:AQDS can contribute to the goethite of reduction and dissociation, within limits,reduction and dissociation rate is higher with the increasing of concentration of AQDS,so joining AQDS can accelerate the degradation rate of4–nitrobenzene; the reductionand dissociation rate of goethite is lower with the increasing of concentration of goethite,this is mainly because high concentration of goethite enhance gathering effect, colloidalparticles significantly increased and surface area is significantly reduced, hindering themicrobial contact the surface of goethite.
Keywords/Search Tags:iron dissimilatory reduction, 4-Nitroacetophenone, DOM, anthraquinonessulfonate, microbial degradation
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