生物表面活性剂对沉积物中菲的解吸附和生物降解作用的影响

Effect of Rhamnolipid Biosurfactant on the Desorption and Biodegration of Sorbed Phenanthrene in Marine Sediment

研究了阴离子型生物表面活性剂鼠李糖脂对海洋沉积物中多环芳烃的解吸附附和生物降解作用的影响,并与化学合成的表面活性剂十二烷基硫酸钠(SDS)的作用相比较.结果表明:2种表面活性剂在浓度高于有效临界胶束浓度时,均可大大增强菲的解吸附作用,鼠李糖脂比SDS更为有效.在降解体系中加入浓度适宜的表面活性剂可显著提高菲的降解率.当鼠李糖脂浓度高于500 m g/L,SDS浓度高于5 000 m g/L时,由于胶束相到水相的传质速率的限制,菲的生物降解率减小.鼠李糖脂因胶束传质限制所引起的抑制作用明显低于SDS.结果表明:在多环芳烃污染沉积物的生物修复过程中,鼠李糖脂比SDS更为有效.

The effectiveness of anionic rhamnolipid biosurfactant on the desorption and biodegradation of polycyclic aromatic hydrocarbon （PAH） in marine sediment was compared with that of synthetic surfactant sodium dodecyl sulfonate （SDS）. Both biological and chemically synthesized surfactants at high dosages （above effective critical micelle concentration） greatly enhanced desorption of sediment-sorbed phenanthrene, whereas rhamnolipids was more efficient than SDS in desorption enhancement. On the other hand, the extents of phenanthrene biodegradation were significantly enhanced by both rhamnolipids and SDS at the optimal concentrations. When the biodegradation systems modified with rhamnolipid dosages above 500 mg/L and SDS dosages above 5 000 mg/L, phenanthrene biodegradation was inhibited because of the mass transfer of phenanthrene from micelle into water. However, rhamnolipids at the high concentration showed lower inhibitory effect on phenanthrene biodegradation than SDS. These results suggest that rhamnolipid may be more effective than SDS in PAH-contaminated sediment remediation processes.