针铁矿的非生物还原解离特征及Slogistic模型拟合

以针铁矿为研究对象,分析了电子供体和针铁矿浓度以及氧化还原中介体AQS对针铁矿非生物还原解离作用的影响.结果表明,在没有氧化还原中介体的参与下,针铁矿的非生物还原作用十分微弱;AQS加入体系后,针铁矿的非生物还原程度在经历一定的反应时间后显著加剧,且还原过程中生成的解离态Fe(ΙΙ)含量随时间的变化趋势符合典型的Slogistic曲线特征.Slogistic拟合结果表明:一定电子供体浓度下,不同浓度针铁矿的非生物还原Slogistic模型拟合的校正R2在0.9887~0.9953之间.当针铁矿浓度维持为一恒定值时,电子供体浓度不足的情况下,针铁矿的非生物还原的Slogistic 曲线特征较弱;当电子供体浓度充足的条件下,Slogistic模型拟合的校正R2系数可高达0.9967.电子供体和针铁矿浓度以及氧化还原中介体AQS的参与对Slogistic模型拟合参数均有一定的影响.

The characteristics and slogistic model fit of the abiotic goethite reduction.

The current study mainly discussed the influence of AQS, the concentration of the electron donor and goethite on the abiotic reduction of goethite. The electron shuttle, AQS, can enhance the degree and extend of goethite abiotic reduction. Without AQS addition, the phenomenon of goethite abiotic reduction was slim; while with the addition of AQS, the abiotic reduction dramatically increased after a certain lag time, the time course of produced Fe(ΙΙ) concentration showed a typical characteristic of Slogistic model. In the reaction system containing different goethite contents and fixed lactate content, the Slogistic model fit calculations showed the significant correlation between the reaction time and produced Fe(ΙΙ) concentration with a correlation coefficient, Adj. R2, in the range of 0.9887 to 0.9953. When reaction system was lacked of electron donor, the characteristic of Slogistic model was not obvious, while the electron donor concentrations were adequate, the Adj. R2 could be high enough to 0.9967. The concentration of electron donor/acceptor and presence/absence of electron shuttle could have a certain influence on the Slogistic model fitted parameters.