聚苯胺基导电复合材料促进废水厌氧生物处理中产甲烷的性能和机制研究

With a potential to be transferred to CH4 during anaerobic treatment, the organic pollutants in wastewater has thus been considered as an energy source. However, it needs a long HRT, leading a low efficiency of CH4 production. Therefore, how to improve the transformation of organics in the wastewater to CH4 is a challenge. The objective of this project is to enhance methane production in the anaerobic wastewater treatment by introducing lab-synthesized conductive materials to accelerate the direct interspecies electron transfer. According to the property of each anaerobic sludge (active sludge, granular sludge and biofilm), a series of suitable polyaniline (PANI) composites with high conductivity, stability and bioaffinity will be designed and synthesized, and will be used to improve CH4 production. The synthetic method and conditions will be optimized. The key factors affecting the methane production by adding the PANI composites will be investigated and disclosed. The capability of direct interspecies electron transfer of PANI composites will be determined. The dynamic changes on the degradation pathway of organic pollutants and the microbial communities after adding the PANI composites will be explored as well. Based on the above results, the mechanism involved in the improved CH4 production by PANI composites will be disclosed. Finally, the relationship between the conductivity and the improved CH4 production will be established by the statistical method. The research results will promote the development of resource technology on the highly efficient transformation of organics to CH4 in wastewater treatment.

废水中有机物可在厌氧条件下转化为具有较高热值的CH4，已被认为是一种能源资源。废水厌氧生物处理需较长的HRT，且产CH4速率较慢，因此如何提高有机物转化为CH4的效率成为该研究的挑战。本项目拟通过研制用于厌氧生物体系中的高导电材料来促进其产CH4性能。针对三种形态厌氧污泥(絮状污泥、颗粒污泥和生物膜)的特征，采用分子设计方法研发具有高导电性、稳定性和生物亲和性的聚苯胺(PANI)基复合材料，优化PANI基复合材料的合成方法和条件。考察PANI基复合材料应用于废水厌氧生物处理促进产CH4的关键因素；通过确定PANI基复合材料的直接种间电子传递能力，结合有机物厌氧代谢过程和微生物群落变化，解析PANI基复合材料促进厌氧产CH4的机制。采用统计学分析方法研究PANI基复合材料的导电性与促进产CH4性能之间的关系。这些研究成果对于废水高效产CH4资源化技术发展具有重要的理论意义和应用价值。

废水中有机物可在厌氧条件下转化为具有较高热值的甲烷，已被认为是一种能源资源。废水厌氧生物处理需较长的HRT，且产甲烷速率较慢，因此如何提高有机物转化为甲烷的效率成为该研究的挑战。本项目制备出了具有高导电性、高稳定性和生物亲和性的导电PANI材料，提高厌氧生物体系中具有直接种间电子传递（DIET）能力的细菌和古菌之间的电子传递效能，进而促进产甲烷性能。本研究针对颗粒状、絮状和生物膜三类形式的厌氧污泥的特征，分别制备出了杆状、颗粒状和水凝胶状的导电PANI材料，在投加量为几100mg/L时，即可以将三类污泥在处理废水过程中产甲烷性能提高了1倍以上；通过调控PANI链上的P型共轭结构，使得电子空穴在PANI材料整个链段上移动，实现了厌氧生物体系中细菌和古菌之间的直接种间电子传递。通过材料设计实现了对PANI导电性在10-6 ~ 32 S/cm范围内的调控，并率先通过调控投加PANI导电性来调控电子在导电材料分子结构内的传递速率。当投加PANI的导电性在10-6 ~ 3 S/cm范围内时，厌氧体系产甲烷速率随着导电性增加而增加；但是导电性大于3 S/cm时，产甲烷速率不再随导电性增加而增加。导电PANI的投加可使得厌氧污泥中具有DIET功能的细菌和古菌富集生长，并促进有机污染降解代谢相关酶的活性，这是其促进厌氧生物产甲烷效能的主要原因。这些研究成果对于废水高效产甲烷资源化技术发展具有重要的理论意义和应用价值。