改性竹炭固定化威尼斯不动杆菌吸附协同降解柴油废水的机理及动力学分析

利用改性竹炭作为载体来固定化威尼斯不动杆菌(Acinetobacter venetianus),用于去除柴油.结果显示,培养96 h后,固定化菌对柴油的去除率为86.35%,要高于游离菌(80.50%).为了探究固定化菌去除柴油的机理,采用动力学拟合实验数据,发现固定化菌去除(吸附-降解)柴油中总石油烃(TPHs)的过程符合伪二级动力学,表明TPHs是先吸附在改性竹炭上,然后被目标菌降解.为了进一步证实,利用扫描电镜(SEM)观察到Acinetobacter venetianus很好地固定在载体材料上.傅里叶红外光谱(FTIR)结果表明,经固定化菌处理后,柴油水溶液的谱图在3437.2、2924.4、1407.8 cm-1处出现新的吸收峰,可能为烷烃降解的酯类及羧酸类物质.GC-MS分析表明,相比游离菌,固定化菌对柴油的去除更为彻底.因此,改性竹炭不仅可以作为良好的固定化载体,同时因其对TPHs良好的吸附性能从而提高了去除效率,为油类污染中TPHs的生物材料修复提供了一个新的视角.

The Adsorption-synergic biodegradation mechanism and kinetics of diesel oil in wastewater by immobilized Acinetobacter venetianus onto the modified bamboo charcoal

The biodegradation of diesel oil in wastewater by Acinetobacter venetianus immobilized on modified bamboo charcoal (MBC) was investigated. The results showed that biodegradation efficiency was improved using cells immobilized on MBC compared to that of free cells, increasing from 80.50% (free cells) to 86.35% (immobilized cells) in 96 hours. To understand the biodegradation mechanism of diesel oil by Acinetobacter venetianus immobilized on MBC, the kinetics studies showed that biodegradation of total petroleum hydrocarbons (TPHs) in diesel oil fitted well to the pseudo-second model (R² >0. 999), indicating that the TPHs were adsorbed onto bamboo charcoal and then degraded by immobilized cells. To further confirm it, scanning electron microscopy (SEM) showed that Acinetobacter venetianus were immobilized well on MBC. Fourier transform infrared analysis (FTIR) demonstrated the new bands at 3437.2 cm^-1, 2924.4 cm^-1,1407.8 cm^-1 were formed, confirming degradation products such as esters and carboxylic compounds existed in the degraded solution. Gas Chromatography-Mass Spectrometer (GC-MS) analysis indicated that the degradation of diesel oil was enhanced by immobilized cells compared to free cells. In summary, MBC not only served as a carrier for bacteria growth, but also as absorbent for diesel oil, leading to the enhancement of the degradation efficiency, which provides a new insight into the remediation of diesel oil in oil-contaminated site by biomaterials.