微乳液处理含油污泥的机理及应用研究

One the one hand oily sludge is a kind of pollution, but on the other hand it is also a valuable resource. Solvent extraction and thermal elution are currently the main methods used for disposal and resource reuse of oily sludge. However these methods are considered expensive and are likely to cause secondary pollution. But few studies have been undertaken on using biosurfactant microemulsion in this field. The project is aimed at using biosurfactant produced by the strain Bacillus amyloliquefaciens to develop microemulsion system and elute petroleum from the contaminated soil. Firstly, the strain will be mutated to obtain an excellent mutant that could produce more biosurfactant. Subsequently, orthogonal and response surface methodology will be used to optimize the medium and fermentation process to improve the efficiency of biosurfactant fermentation. The HPLC-ESI-MS will also be used to identify the structure of the biosurfactant. Then biosurfactants microemulsion system are developed using salinity (or concentration of alcohol) scanning method. Microcosmic structure and phase behavior of the microemulsion will be investigated by freeze-fracture transmission electron microscope (FFTE). Finally, the biosurfactants microemulsion was used to treat oily sludge with high concentration of oil and the recovery efficiencies of oil from oily sludge were determined. The purpose of this project is to reveal biosurfactants microemulsion formation and elution principles that can provide technical support for harmless disposal and resource utilization of oily sludge with high concentration of oil.

含油污泥既是污染源，也是一种宝贵的资源。目前针对含油污泥资源化利用的方法主要有溶剂萃取法和热洗脱法，但这两种方法均存在成本较高、可能造成二次污染等缺点。然而环境友好的生物表面活性微乳液在该领域的应用却鲜有研究。本项目拟在前期筛选得到的高产生物表面活性剂菌Bacillus amyloliquefaciens BZ-6、Pseudomonas aeruginosa SB等基础上，通过诱变进一步提高其产生物表面活性剂的能力。利用正交和响应面分析法优化培养基和发酵工艺，提高其发酵生产效率，并利用HPLC-ESI-MS鉴定其结构。然后以此为基础研制生物表面活性剂微乳液，系统考察醇度和盐度对微乳液相行为的影响，并探讨其微观结构与作用机理。最后利用研发的生物表面活性剂微乳液开展高含油污泥洗脱实验。该项研究不仅有利于探明生物表面活性剂微乳液形成与作用机理，也为含油污泥的无害化处理与资源化利用提供技术支持。

目前针对含油污泥资源化利用的方法主要有溶剂萃取法和热洗脱法，但这两种方法均存在成本较高、可能造成二次污染等缺点。本研究利用血平板法从石油污染的土壤中分离得到57株产生物表面活性剂的菌株，选取其中16株发酵液表面张力＜30 mN m-1的菌株进一步研究，发现解淀粉芽孢杆菌（Bacillus amyloliquefaciens） BZ-6和假单胞菌（Pseudomonas aeruginosa SB-5）对石油污染土壤表现出较强的洗脱能力。对其产生的表面活性物质进行了鉴定发现菌株SB-5所产生物表面活性为糖脂类物质，BZ-6菌株所产的表面活性剂为脂肽类物质芬荠素。随后利用其开展了微乳液的研制及其对石油污染土壤/含油污泥的淋洗研究，结果发现微乳液对不同地区石油污染土壤洗脱效果较好，洗脱效率均在99%以上，且油水土分层明显，便于原油和洗脱液的回收再利用。但对油田生产过程中产生的池底泥等含油污泥的处理效果较差，可能原因是由于含油污泥中含有大量高分子聚合物，影响了淋洗效果。针对这一现象，本研究开发了无水碳酸钠和过氧化氢相结合的氧化试剂，结果发现含油污泥经过氧化剂氧化预处理后，淋洗剂对石油的洗脱效率大幅提高到92.9%，经过洗脱后的油泥总石油烃含量降至达到相关国家标准的要求。