Study On Reduction Of Nitrate From Groundwater With Ion Exchange Resin As The Reactive Media In Permeable Reactive Barrier

Lately forty years, Nitrate pollution in groundwater is increasingly severity, and now is one of the most important environmental problems all over the world, so the restoration of it has become an urgent affair. In this thesis, the status, sources and detrimental effects of nitrate pollution were summarized. Meanwhile, present remediation methods, such as physicochemical method, biologic method, chemical method and permeable reactive barrier technology were analyzed and compared. The permeable reactive barrier is a comparatively promising technology for in-situ groundwater remediation.This paper do the experiment on the removal of nitrate from groundwater with ion exchange resin as the reactive media in PRB. Removal of nitrate by five delegated anion ion exchange resins were parallel studied; reviewed on the circumstance of electrodialysis, the influence of parameters on the removal of nitrate; studied on the effect of parameters on electro-regeneration of resins; in the end, ion exchange,electrodialysis and ion exchange—electroregeneration were made a parallel experiment.The results represent that, 717 and D407 have a better adsorption capability for the nitrate, these two resins'adsorption isotherm are according to Langmuir equation, temperature has a bigger influence on 717 than D407, chlorate and sulfate has a bigger influence on 717 than D407 also. For electrodialysis experiment, voltage and polar room electrolyte concentration have best value in order to assure the higher removal effect and lower energy, in this paper, voltage grads of about 1v/cm and polar room electrolyte concentration triple than middle room were suggested. Results on static electro-regeneration experiment represents that, the electro-regeneration quantity of only 717 is about 3.96mg/mL, more than blending anion and cation resins at a ratio of 2:1; results on dynamic electro-regeneration experiment represents that, bigger voltage and smaller flowrate have a better electro-regeneration effect, the unit electro-regeneration is about 91.38mg nitrate for the the voltage at 25V, runoff at 5ml/min, electro-regeneration time at 430min. Results on ion exchange,electrodialysis and ion exchange—electroregeneration experiment represents that, in the course of ion exchange—electroregeneration, the ion exchange resin is in alteration course of adsorption and regeneration; the transfer rate of ion in resin's passage is faster than in water; when voltage is 25v, the nitrate concentration of treated water can arrive at half of untreated water.Integrated on the study, ion exchange is suit for the permeable reactive barrier medium request, and by using electro-regeneration instead of chemistrySo we think in the course of ion exchange—electroregeneration,using the ion exchange,electricity transfer and electro-regeneration,the passage of the resin, the nitrate can be moved to condense room faster and more economy. This paper thought reduction of nitrate from groudwater with ion exchange as permeable reactiv barrier medium is possible. Thereby, thread the progressing studying, we believe the method will be very promising in application.