Duan Huiqi, Yan Rong, Koe Lawrence Choon Chiaw
Environmental Engineering Research Center, School of Civil and Environmental Engineering, Nanyang Technological University, Blk N1, 50 Nanyang Avenue, Singapore 639798, Singapore.
Appl Microbiol Biotechnol. 2005 Dec;69(3):350-7. doi: 10.1007/s00253-005-0057-z. Epub 2005 Nov 15.
The use of supporting media for the immobilization of microorganisms is widely known to provide a surface for microbial growth and a shelter that protects the microorganisms from inhibitory compounds. In our previous studies, activated carbon (AC) alone used as a support medium for H(2)S biological removal was proved prompt and efficient in a bench-scale biofilter and biotrickling filter. In this study, the mechanisms of H(2)S elimination using microbial immobilized activated carbon, i.e., biological activated carbon (BAC), are investigated. A series of BAC as supporting medium were taken from the inlet to outlet of a bench-scale horizontal biotrickling filter to examine the different effects of physical/chemical adsorption and microbial degradation on the overall removal of H(2)S. The surface properties of BAC together with virgin and exhausted carbon (after H(2)S breakthrough test, non-microbial immobilization) were characterized using the sorption of nitrogen (Braunner-Emmett-Teller test), scanning electron microscopy (SEM), surface pH, thermal, carbon-hydrogen-nitrogen-sulfur (CHNS) elemental and Fourier transform infrared (FTIR) analyses. Tests of porosity and surface area provide detailed information about the pore structure of BAC along the bed facilitating the understanding of potential pore blockages due to biofilm coating. A correlation between the available surface area and pore volume with the extent of microbial immobilization and H(2)S uptake is evidenced. SEM photographs show the direct carbon structure and biofilm coated on carbon surface. FTIR spectra, differential thermogravimetric curves and CHNS results indicate less diversity of H(2)S oxidation products on BAC than those previously observed on exhausted carbon from H(2)S adsorption only. The predominant oxidation product on BAC is sulfuric acid, and biofilm is believed to enhance the oxidation of H(2)S on carbon surface. The combination of biodegradation and physical adsorption of using BAC in removal of H(2)S could lead to a long-term (i.e., years) good performance of biotrickling filters and biofilters based on BAC compared to carbon adsorption only.
使用载体介质固定化微生物，众所周知可提供微生物生长的表面以及保护微生物免受抑制性化合物影响的庇护所。在我们之前的研究中，单独使用活性炭（AC）作为去除H₂S的生物载体介质，在实验室规模的生物滤池和生物滴滤池中被证明迅速且高效。在本研究中，对使用微生物固定化活性炭即生物活性炭（BAC）去除H₂S的机制进行了研究。从实验室规模的水平生物滴滤池的入口到出口采集了一系列作为载体介质的BAC，以研究物理/化学吸附和微生物降解对H₂S整体去除的不同影响。使用氮气吸附（Brunauer-Emmett-Teller测试）、扫描电子显微镜（SEM）、表面pH、热分析、碳-氢-氮-硫（CHNS）元素分析和傅里叶变换红外（FTIR）分析对BAC以及原始碳和耗尽碳（H₂S穿透试验后，未进行微生物固定化）的表面性质进行了表征。孔隙率和表面积测试提供了沿滤床BAC孔隙结构的详细信息，有助于理解由于生物膜覆盖导致的潜在孔隙堵塞。证明了可用表面积和孔体积与微生物固定化程度和H₂S吸收之间的相关性。SEM照片显示了碳的直接结构和覆盖在碳表面的生物膜。FTIR光谱、差示热重曲线和CHNS结果表明，BAC上H₂S氧化产物的多样性低于之前仅从H₂S吸附耗尽碳上观察到的情况。BAC上的主要氧化产物是硫酸，并且认为生物膜增强了碳表面H₂S的氧化。与仅使用碳吸附相比，在去除H₂S中使用BAC的生物降解和物理吸附相结合可使基于BAC的生物滴滤池和生物滤池长期（即数年）保持良好性能。
