Study On Adsorption Performance Of Ammonia Nitrogen And Zeolite Synthesized From Fly Ash

In this paper, the fly ash zeolite has a good adsorption performance of ammonianitrogen, which is synthesized by using fly ash as raw materials and sodium hydroxide asactivator respectively in the alkali fusion-hydrothermal method and the alkali fusion-microwave method. In the synthesis process, the influence of various factors on the fly ashzeolite adsorption properties of ammonia nitrogen is studied by using the fly ash zeoliteadsorptive capacity of ammonia nitrogen as a scale standard. The phase, appearance feature,specific surface area, pore structure and microstructure of the fly ash zeolite can be analyzedby XRD, SEM, BET, BJH and TEM detecting method.The experimental result indicates that the optimum conditions of the fly ash zeolitewhich is synthesized by the method of alkali fusion-hydrothermal is that the calciningtemperature is650℃, the calcining time is60minutes, the alkali ash ratio is1.2, the agingtime is12hours, the hydrothermal time is6hours and the liquid solid ratio is10; theoptimum conditions of the fly ash zeolite which is synthesized by the method of alkalifusion-microwave is that the calcining temperature is650℃, the calcining time is60minutes,the alkali ash ratio is1.2, the aging time is16hours, the microwave time is20minutes andthe liquid solid ratio is14; the fly ash zeolite, which is synthesized in the optimum conditionusing alkali fusion-hydrothermal method, is P type zeolite, the specific surface area thereof is148.81m~2/g, the average aperture is3.821nm and the pore volume is0.245cc/g; the fly ashzeolite, which is synthesized in the optimum condition using alkali fusion-microwavemethod, is X and P type zeolite, the specific surface area thereof is108.49m~2/g, the averageaperture is3.779nm and the pore volume is0.221cc/g. Because the average aperture of thefly ash zeolite obtained by the above two methods is bigger than the ion diameter of NH4+which is2.86nm, the fly ash zeolite is appropriate for the adsorption processing of ammonianitrogen in the wastewater.In this paper, we have studied the adsorption performance of the fly ash zeolite asadsorbent to ammonia nitrogen in the wastewater. By means of the study on the relationshipsamong the removal rate and solution concentration, dosing quantity, adsorption time and pHvalue, the optimum adsorption conditions of fly ash zeolite to ammonia nitrogen issummarized as follows: the removal rate of ammonia nitrogen is69.3%when the solutionconcentration is60~100mg/L, the dosing quantity is20mg/ml, the adsorption time is20minutes and the pH value is6~8; meanwhile, we found that the isothermal adsorption disciplinarian conforms to the Freundlich model, and the cation exchange is primary and theadsorption is subsidiary in the adsorption process of the fly ash zeolite to ammonia nitrogen.In dynamic test conditions, the adsorption effect to ammonia nitrogen is optimum, that is, theremoval rate is39.83%, when the filling quantity of fly ash zeolite is25g/L, the flowingvelocity of water is28.31m/h and the watering time is20minutes.In this paper, the method of alkali fusion-microwave is used to synthesize the fly ashzeolite which is applied to ammonia nitrogen wastewater treatment for the first time. Thismethod has some significance for the fly ash zeolite synthesis method in the future.