Effects of physicochemical properties of poly-ε-caprolactone on nitrate removal efficiency during solid-phase denitrification
Effects of physicochemical properties of poly-ε-caprolactone on nitrate removal efficiency during solid-phase denitrification
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DOI：
10.1016/j.cej.2015.07.085
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发表时间：
2016
影响因子：
15.1
通讯作者：
Qian Zhang;F. Ji;Xiaoyi Xu
中科院分区：
文献类型：
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作者：
Qian Zhang;F. Ji;Xiaoyi Xu
通过用重均分子量（MW）为60，000（PCL-1）、80，000（PCL-2）和140，000（PCL-3、PCL-4）g mol−1的聚-ε-己内酯（PCL）驯化活性污泥，构建了用于脱氮的间歇式和连续流固相反硝化反应器。在间歇试验中，PCL的生物降解性和反硝化速率随着分子量的降低而增加。但在间歇和连续试验中，PCL-4在高剪切力作用下的硝酸盐去除率均高于其他PCL载体，说明PCL-4的粗糙表面和孔结构有利于反硝化细菌的附着，在固相反硝化过程中比MW 4在生物反硝化中发挥更重要的作用。环境扫描电子显微镜（ESEM）观察表明生物膜在PCL-4上的牢固附着和所有PCL载体的微生物利用，傅立叶变换红外光谱仪（FTIR）分析表明PCL载体在表面的生物利用没有显著改变PCL载体的化学结构，无论其分子量如何。微生物群落分析表明，粘细菌（DeltaProteobacteria）、Thauera、Rubrivivax和丛毛单胞菌（Betaproteobacteria）是PCL-4驯化固定床反应器中的优势菌属，在PCL降解和反硝化过程中起主要作用。
Laboratory-scale batch and continuous flow solid-phase denitrification reactors for nitrogen removal were constructed by acclimating activated sludge with poly-ε-caprolactone (PCL) with weight-average molecular weights (MW) of 60,000 (PCL-1), 80,000 (PCL-2), and 140,000 (PCL-3, PCL-4) g mol−1. The biodegradability and denitrification rate of PCL in batch tests increased with decreasing molecular weight. However, PCL-4 showed higher nitrate removal efficiency than the other PCL carriers under high shear forces in batch and continuous tests, suggesting that the rough surface and pore structure of PCL-4, which was beneficial to the attachment of denitrifying bacteria, may play a more important role thanMWin biological denitrification during the solid-phase denitrification process. Environmental scanning electron microscope (ESEM) observations demonstrated the firm attachment of biofilm on PCL-4 and microbial utilization of all the PCL carriers, and the Fourier Transform Infrared Spectrometer (FTIR) analysis indicated that biological utilization of PCL carriers on the surface did not significantly change the chemical structure of PCL carriers, regardless of theMW. Microbial community analysis showed thatMyxobacterium(Deltaproteobacteria) andThauera,Rubrivivax, andComamonas(Betaproteobacteria) were the dominant microbial genus and played a primary role in PCL degradation and denitrification in the PCL-4-acclimation packed-bed reactor.