微生物异化还原针铁矿过程中4-硝基苯乙酮降解动力学特征及机理初探

以硝基类有机污染物为研究对象,探讨了在多相界面(矿物相/生物相)反应体系及纯生物相反应体系中4-硝基苯乙酮微生物还原动力学特征,同时对"针铁矿-微生物-4-硝基苯乙酮"相互作用机制进行了初步阐明.结果表明,2-磺酸钠蒽醌(AQS)对4-硝基苯乙酮微生物还原降解速率有显著的促进作用;不同反应体系中还原降解产物4-氨基苯乙酮含量(μmol·L-1)的对数值和反应时间(h)之间均呈典型的动力学一级增长模式(ExpGro1 Mode),ExpGro1模型拟合的校正R2系数(R2adj)在0.9699～0.9894之间.针铁矿介导下的多相界面反应体系中,4-硝基苯乙酮微生物还原过程可分为耦合的两个子过程,即针铁矿的微生物还原解离过程和吸附态Fe(Ⅱ)调控下的非生物还原过程.不同浓度的AQS以及反应体系中针铁矿的介入,导致4-硝基苯乙酮微生物还原反应所需"活化时间"存在一定程度的差异.研究进一步证实,针铁矿还原解离过程生成的吸附态活性Fe("Ι)在4-硝基苯乙酮微生物还原过程中起到了至关重要的作用.

The kinetic characteristics and mechanism of the biodegradation of 4-Nitroacetophenone mediated by dissimilatory goethite reduction

Exploring the kinetic characteristics of the pollutants biodegradation process is indispensable in understanding the mechanisms of the interaction of microbial-oxide-contaminants. The current study mainly focused on the influence of anthraquinone-2-sulfonicacid sodium (AQS) and the presence/absence of goethite on the 4-Nitroacetophenone biodegradation and the mechanism was also discussed. The results showed the electron shuttle, AQS, and the presence of goethite can all enhance the degree of the 4-Nitroacetophenone biodegradation. The product of the biodegradation was the 4-Aminoacetophenone, with the relationship between the natural logarithmic of 4-Aminoacetophenone concentration and reaction times fitted by the ExpGro1 Mode with a correlation coefficient, Adj.R-Square, in the range of 0.9699~0.9894. Our experiments also indicated that the whole biodegradation course mediated by goethite contained two processes, the microbial reduction of goethite and the abiotic reduction of pollutant. The various concentrations of AQS and the presence of goethite influenced the lag time of the 4-Nitroacetophenone biodegradation process. Furthermore, it implied that the reduced production, Fe(Ⅱ),adsorbed by iron oxide can play a key role in the reduction of 4-Nitroacetophenone.