表面活性剂对填料曝气塔充氧性能的影响

Effect of surfactants on oxygenation capacity in bubbling packed column

针对废水中表面活性剂对曝气充氧能力的影响,研究了4种生物填料在表面活性剂存在的三相流环境中的传氧效果.结果表明,十二烷基苯磺酸钠(SDBS)显著降低了传氧系数K_(La(20)),且在7×10~5mol/L浓度附近K_(La(20))最低.而十六烷基三甲基溴化铵(CTAB)在3.5×10^(-5) 8.1×10^(-4)mol/L浓度区间却提高了曝气塔的传质系数K_(La(20)).对比分析了生物粒状填料存在对充氧性能的影响,发现填料对传氧系数K_(La(20))均有提高,海绵填料相比清水环境对体系K_(La(20))提高了约1倍.研究认为,离子型表面活性剂分子的双电层结构以及液相表面张力对传质效果有影响,生物填料也是提高曝气过程传氧的方法之一.

To study the effect of surfactants on oxygenation capacity, oxygen mass transfer efficiency was investigated in a three-phase aeration reactor where four kinds of granular bio-media as well as surfactants were tested. It was found that the oxygenation efficiency decreased obviously by SDBS and the KLa（20） reached a minimum when the concentration was around 7×10^5mol/L. However, the mass transfer coefficient was enhanced in the presence of CTAB where its concentration was in the range of 3.5×10^5-8.1×10^4mol/L.According to the comparative investigation of effects on oxygenation efficiency among different granular bio-media, it can be regarded that the mass transfer coefficient KLa（20） was enhanced in the presence of bio-medias.The KLa（20） was approximately doubled in the presence of sponge.The results also suggest that double electrical layer mechanism of ionic surfactant molecules and surface tension variations may had influenced the mass transfer efficiency and addition of bio-media should be a method for the mass transfer improvement.