生物炭基固定化菌剂对石油类污染物的高效降解

以生物炭为载体，采用吸附法制备固定化菌剂，通过分析不同材料生物炭的结构差异，探讨了不同生物炭的结构在固定化中的影响机制。SEM和EDS分析表明，降解菌主要固定在生物炭表面。生物炭内含有C、N和P成分，能为降解菌提供营养物质。生物炭的多孔结构能促进石油污染物的降解。结果表明，经玉米芯和秸秆生物炭固定化后F-3、R-7及其混合菌的除油率显著提高，分别为41.7%和29.5%、52.5%和42.8%、63.8%和53.2%。玉米芯生物炭固定化菌剂的除油率比秸秆生物炭固定化菌剂高10.6%。玉米芯生物炭表面比秸秆生物炭粗糙，其固定的微生物量为4.2×1010 cfu·g-1，固定效率达71.2%；秸秆生物炭固定的微生物量为2.5×1010 cfu·g-1，固定效率为57.6%。固定化菌剂的最佳制备条件为：选择500℃下热解3 h的玉米芯生物炭为载体，微生物接种量为10%，载体投加量为10 g·L-1，置于35℃、130 r·min-1摇床中固定18 h。

Efficient degradation of petroleum pollutant by immobilized bacteria based on biochar material

In this study, we selected biochar as the carrier medium to prepare immobilized bacteria by adsorption. The effect of different biochar structures on immobilization was analyzed. The SEM and EDS analyses showed that most microorganisms were immobilized on the surface of the biochar. The carbon, nitrogen, and phosphorus content of biochar can provide nutrients to the degrading bacteria. The porous structure of biochar can promote the degradation of petroleum pollutants. The results indicated that the oil-removal rates of F-3 strain, R-7 strain, and their mixed strain were significantly increased by 41.7% and 29.5%, 52.5% and 42.8%, 63.8% and 53.2% after being immobilized by corncob-biochar and straw-biochar, respectively. Oil-removal rate of the corncob-biochar-immobilized bacteria was 10.6% higher than that of the straw-biochar-immobilized bacteria. The surface of the corncob-biochar was rougher than that of the straw-biochar. The number of immobilized microorganisms in corncob-biochar was 4.2×1010 cfu·g-1 and the immobilization rate was 71.2%. The number of immobilized microorganisms in straw-biochar was 2.5×1010 cfu·g-1 and the immobilization rate was 57.6%. The optimal preparation conditions of immobilized bacteria were as follows:the corncob-biochar was pyrolyzed at 500℃ for 3 h as the carrier, the microbial inoculation level was 10%, the biochar dosage was 10 g·L-1, and the immobilization temperature, rotation speed, and time were 35℃, 130 r·min-1 and 18 h, respectively.