Study On Treatment Of Oilfield Waste Water Using Ionic Liquids

Oil well injection stimulation is a very important method to improve oil recovery.Nowadays, most of oilfields in China have entered the middle or later periods of oilproduction, the water content（or water cut）have reached85%. So the waste water isenormous in the oil production. How to treat the waste water effectively has become veryimportant issues for environmental protector and oil production engineers.Ionic liquids have get good applications in all industrial areas for their unique properties,they also be used in waste water treatment processes.The hydrophobic ionic liquid,l-butyl-3-methylimidazolium hexafluorophos-phate（[BMIM]PF₆）was synthesized, and theeffect factors on product yields were studied. The structure of [BMIM]PF6are determined byUV, IR and NMR.Application [BMIM]PF₆, the treatment experiments for oilfield wastewaterwere carried out, and the results shown that the optimum treatment conditionsare:（l）extraction ratio=10:2;（2）pH<7;（3）treatment time=15min. Under such conditions, theoil removal ratio is95.6%, and COD_Cr removal ratio is93.6%. The regeneration experimentsfor ionic liquids were also carried out, and the results have proven that ionic liquids can beregeneration by simple ways.Using the regeneration ionic liquids, the oil removal is95.4%.The results indicate that the regenerated ionic liquids has the same effect as the fresh ionicliquids.By diesel oil as model compounds, the mechanism of ionic liquids on oilfieldwastewater are also investigated in this report.