Study On The Treatment Of Aniline Wastewater By Emulsion Liquid Membrane In IS-RPB

Aniline is one of the most important chemical raw materials and products, which iswidely used in dyeing, pesticide, pharmaceutical and military industries. A great amount ofaniline wastewater was produced during its manufacture and using. Aniline wastewater hascaused serious harm to biological and natural environment, with the characters of serioushazard, difficult biodegradability. Aniline wastewater treatment methods are generallydivided into three categories which are physical method, advanced oxidation method andbiological method. Because of the characteristics and limits of the traditional treatmentmethods, new and efficient method should be developed to treat aniline wastewater.Emulsion liquid membrane technique, which is a new aniline wastewater treatmenttechnology, with the characteristics of high mass transfer rate, high separation efficiency, lowcost, energy conservation and wide scope of application, has become an effective means ofseparation, enrichment and recovery of the solute. In view of the shortcomings of emulsionliquid membrane process, such as, batch process, small handling capacity, long running timeand bad emulsion stability, using impinging stream-rotating packed bed (IS-RPB) asemulsifying equipment is proposed, and the treatment of aniline wastewater by emulsionliquid membrane in IS-RPB is researched.Firstly, high speed distributor is used to prepare emulsion. The factors on stability ofemulsion and aniline removal rate are investigated, including surfactant dosage, theconcentration of hydrochloric acid, the ratios of both water to oil and water to emulsion,initial pH of external phase and so on. According to the experiment results, the formula ofemulsion membrane to treat aniline wastewater is preliminary determined. Secondly, watertreatment by Emulsion liquid membrane in IS-RPB is studied. The influence of the IS-RPB operation conditions on stability of emulsion and aniline removal rate is investigated. Theoptimum operation conditions are obtained, which is, Span-80content4%, kerosene content96%, hydrochloric acid concentration1mol/L, Roi=1:1, Rew=1:20, initial pH=9, high gravityfactor42, impinging initial speed10m/s. Under these conditions, the removal rate can reach99.5%, the residual concentration of aniline decreases to5mg/L. The effluent complies to thethird grade of national emission standard. Finally, by comparing the emulsion capabilityprepared by IS-RPB with emulsion capability prepared by common methods, the producingtime is greatly reduced, the production of emulsion is of high stability and aniline removalrate is highly increased in IS-RPB emulsifying equipment. Above all, IS-RPB provides a newthought for the further development of liquid membrane technology.