| With the development of industeal and the improvement of people’s livingstandards, Chinese water resources situation become worse and worse. Nitrate riched inwater has become a major problem in our country. However, the method of removingnitrate has become one of the main problems in Water treatment engineering，which isasked low cost, efficiently.This paper summarized the present situation，harms to human and the main causeof the nitrate pollution. What’s more, compared the current technology which canremove nitrate (biological method, chemical method, adsorption and ion exchangemethod),we find that ion exchange method is considered as the best technology thatremoving nitrate.This article had studied that Purolite A520E and HZ-222resin remove nitrate asion exchange material. The experiment investigated the nitrate adsorption behavior,while measured experimental conditions having the influence on the adsorption capacity.In addition, the experiments matched the adsorption dynamics model, the dynamicboundary control model and thermodynamic model, in order to master two kinds ofresin’s adsorption principle. The ultimate goal is developing new high efficiency,low-cost macroreticular ion exchange resin.The test results are as follows:(1) The dynamics results of resins adsorbing nitrate show that the adsorptionequilibrium time is sixty min, the Purolite A520E resin adsorption capacity is14.947mg/g, HZ-222resin adsorption capacity is21.647mg/g. The resins adsorption kineticsof water nitrate can be well accord with pseudo secondary adsorption dynamics model.The resins adsorption rate is controlled by particle diffusion. Therefore, the resins’ adsorption capacity of nitrate can be improved by decreasing patical and increasingaperture.(2) The resins for nitrate of isothermal adsorption conform to the Langmuiradsorption isothermal model. Moreover, the resins adsorption can be spontaneous andadsorption process is endothermic reaction. So the resins’ adsorption capacity of nitratecan be improved by improving the reaction temperature.(3) In the condition of20℃、180rpm、pH=6、adsorption initial concentration for100mg/L nitrate, the test shows that the best initial dose:0.3g/50mL. The PuroliteA520E resin and HZ-222resin removal were90.88%,94.05%.(4) In other anion coexist system, only SO2-4had larger inhibition on resinsadsorption, but the rest of the anion (Cl-, HCO-3) were not significant influence. Thosemean that resins all can selectively adsorb nitrate. Compared with Purolite A520E resin,the influence of those anionic on HZ-222resin was remarkable.(5) The stripping test can be concluded that mass concentration was9%NaClsolution is the best regeneration solution of Purolite A520E and HZ-222resin. Afterregenerating10times, A520E resin adsorption was reduced by2%, the removal rate ofHZ-222is reduced by5%;(6) The dynamic test results show that the initial nitrate solution (100mL/min)could increase through time; while initial nitrate concentration of150mg/L could addthe exchange capacity of adsorption column. Moreover, high diameter ratio of17.14made the adsorption column through time increased.(7) A520E resin and HZ-222resin of maximum dynamic adsorption capacitywere18.34mg/g and20.33mg/g; A520E resin dynamic adsorption capacity was largerthan the static adsorption capacity, the dynamic adsorption capacity of HZ-222resinwas smaller than its static adsorption capacity. |
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