生物法净化磷化氢废气的作用机理及过程调控

Phosphine is a kind of highly toxic gas, and it is widely produced from many processes such as refuse landfill, wastewater treatment, or industrial production. Recently, the biopurification of low concentration PH3, with the advantages of simple process, convenient operation and low cost, has already been paid much attentions, and the effectiveness of the new technology has been verified by some previous researches. However, many key issues are still not clear, for example, what is the key factors during the PH3 biopurification, how to regulate the technical process to improve the PH3 removal, what is the mechanism for PH3 bioconversion. In this project, those microbes are screened from the culture mixture in our previous research to identify their characteristics for PH3 biodegradation, then the physical and chemical properties, even the metabolism of carbon and phosphor, may be investigated. After the effects of environmental factors on purification process is analyzed, the contents of O2-▪ in the microorganisms and the mixed solution are investigated at the same time, and oxidase activity and the metabolism of carbon and phosphor are also studied, then the bio-oxidation mechanism of gaseous phosphine can be elucidated at the molecular level according to above results obtained from series experiments. Aimed to resolve the existing problems such as high mass transfer resistance and low PH3 purification efficiency, carbon-baseed materials or metal cations are respectively added to the biopurification system, and the PH3 removal can be improved through strengthening biopurification process. The research can provide significant support for the application of new technology of PH3 biopurification, and it is also of great scientific significance for the biological oxidation mechanism of low-concentration phosphine.

磷化氢是一种有恶臭气味的剧毒气体，广泛产生于垃圾填埋、废水处理、工业生产等过程。生物法净化低浓度磷化氢废气具有操作简便、运行经济等优点，其技术有效性已经得到证实，但影响生化体系的关键因素是什么、工艺过程如何调控、磷化氢生物氧化机制是什么？这类深层次基础理论问题尚未明晰。本项目采用微生物、分子生物学手段，从前期驯化的活性污泥体系中分离、纯化典型菌株，并对其理化特性进行测试，辨识具有磷化氢降解性能的典型菌株；在考察环境因子影响净化效果的同时，首次同时分析微生物体内以及消化液中O2-▪含量及其变化规律，并结合氧化酶活性以及碳源代谢，阐明磷化氢失去电子的生化代谢模式；采用投加炭基多孔材料或金属阳离子的方式调控工艺过程，有效解决PH3生物净化过程传质阻力大、净化效率不高的难题。研究成果能从分子层面阐明磷化氢生物氧化的作用机理，对磷化氢生物净化新技术的推广与应用也具有重要的科学指导意义。

磷化氢广泛产生于垃圾填埋、废水处理、工业生产等过程，其严重污染环境、危害人体健康，也影响工业气体的后续利用。本项目采用生物法净化低浓度磷化氢尾气，研究内容如下：①分离、纯化了具有磷化氢耐性或降解性能的微生物，并测试其理化特性，对比分析不同净化体系的微生物种群多样性；②利用活性污泥与生物滴滤塔两类体系净化磷化氢，优化了工艺技术参数，阐明了磷化氢生物净化的作用过程及特性；③揭示了磷化氢生物净化过程的抑制因子及作用途径；④采用投加金属阳离子、添加富里酸类外源物质这类方式调控工艺过程，结合氧化酶活性、有机质代谢、磷形态及含量变化等指标，阐明磷化氢生物转化的影响因素及作用机制。. 取得如下重要研究结论：（1）得到5株典型菌株，分别与Bacteroides、Methanogenium、Chryseobacterium、Stenotrophomonas、Pediococcus高度相似，但这些微生物在长期运行的磷化氢生物净化体系中同样具有较高的丰度；相比单一菌株体系，驯化后的微生物复合体系磷化氢去除效果更高。（2）生物滴滤塔内具有较高的微生物种群多样性，磷化氢去除效率较活性污泥体系提升近10%。（3）生物净化体系能以磷化氢为唯一磷源，适当添加正磷酸盐有利于生物净化进程；采用活性污泥体系同步净化PH3与H2S尾气时，H2S去除率近100%，PH3去除率可达70%以上。（4）生化代谢进程受到抑制时，生物体内活性氧ROS累积更为明显，MDA含量相对较高，磷化氢去除效率下降。（5）维持吸收液中Cu2+离子1.5mmol/L或者Fe2+离子1.0mmol/L有利于增强PH3生物净化效果。（6）添加椰壳炭至生物反应器时，磷化氢吸收速率达到0.0552mg/(m2·s)，去除率提升至67.3%。（7）富里酸和茶多酚均能增强PH3生物氧化进程，建议通过添加富里酸的方式降低生物体内ROS含量从而提升PH3净化效率。（8）气态PH3容易被微生物所吸附，随后氧化生成其他磷化合物，部分含磷物质被微生物同化吸收；增强氧化酶活性是生物体系提升PH3去除效率的内在因素。本项目研究成果为低浓度磷化氢尾气或者恶臭气体的生物净化提供理论参考与技术支撑。