Research On Fouling Performance Of Ion Exchange Membranes Of Electrodialysis By HPAM And Oil In Polymer Flooding Wastewater

To meet the request of reclaiming the oil-field wastewater, the treated polymer flooding wastewater can be used to confect polymer flooding solution. This method could protect the environment and save water resources, and have multiple significances in economic returns and social as well as environmental benefits. Currently the key problem in reusing polymer flooding wastewater to confect polymer solution is desalting the salt in it. Right now, Daqing oil-field uses partly hydrolysis of anionic polyacrylamide (HPAM) as a flooding polymer. Determined from the early researches of our laboratory, a hybrid UF-ED process could be used to reclaim polymer flooding wastewater from Daqing oil-field as confecting polymer water effectively. However, ultrafiltration could not desalt the salt, and the polymer flooding wastewater treated by ultrafiltration still had some oil and HPAM which would decline the quality of polymer flooding solution and reduce the flooding effect seriously. In this paper, effects of HPAM and oil in polymer flooding wastewater which was treated by ultrafiltration on the desalintion process of electrodialysis (ED) and the static adsorption as well as fouling performance of ion exchange membranes by HPAM and oil were investigated.Under a certain desalination condition, effects of saltwater which had the same total salinity with oil only or HPAM only or with HPAM and oil at the same time on desalination process by ED were studied. The results showed that no mater in the saltwater with oil only or the compound saltwater with HPAM and oil at the same time, the oil in the saltwater had little impact to the desalination process. But the HPAM in the saltwater had serious influence on the desalination process, which prolonged the time of desalting the saltwater to 1mS/cm by 20%. Otherwise, regulating the parameters such as concentration of HPAM, temperature, pH of saltwater are to clearly understand the greatest impact factor which could do some favour in studying the fouling performance of HPAM on ion exchange membranes.In the static adsorption experiment of HPAM, adsorption balance time under different initial concentrations of HPAM was studied first. The influences of HPAM concentration, temperature, pH and ion concentration of solution on adsorption characteristics of membranes were taken into account, the results indicated that adsorption was higher at higher concentrations and temperatures; pH had the same effect on adsorption under different initial concentrations of HPAM , the adsorption capacity was greatest when pH was 6.0; ion concentration had dramatic influence in adsorption. Fitting the experimental data utilizing different thermodynamic and kinetic models showed that Freundlich isotherm model fitted experimental membrane adsorption well under different temperatures; adsorption thermodynamics parameters indicated that adsorption of HPAM onto ion exchange membranes was a entropy increase and spontaneous endothermic process, and it was a physical adsorption. Pseudo-second-order kinetics could describe the adsorption of HPAM on ion exchange membranes better.In the static adsorption experiment of oil, adsorption balance time under different initial concentrations of oil was investigated at first. The influences of oil concentration, temperature, pH, ion and HPAM concentration of solution on adsorption characteristics of ion exchange membranes were taken into account. The results indicated that adsorption was higher at higher initial oil concentrations and temperatures as well as ion concentrations; pH had great effect on adsorption, and the adsorption capacity was greatest when pH was 7.0; the fouling of membranes were serious when HPAM and oil coexisted in the water.