Reaserch On The Ability Of Heavy Metals Removal Using Synthetic Zeolite From Fly Ash In Water

This study used high calcium fly ash and low calcium fly ash to get zeolite synthesis respectively by alkali melting hydrothermal method, and also studied the characterization of zeolites and adsorption capacity of in heavy metal Zn2+, Cu2+, Cd2+. Pb2+in the ion mixing solution. At the same time, the effects of time, pH, adding amount of zeolite synthesis, initial solution concentration and temperature on 4 kinds of mixed heavy metal ion adsorption had be inspected.First of all, the removal performance of zeolite synthesis of high calcium and low calcium fly ash on heavy metal ions had be studied. The test results showed that, the main composition of high calcium fly ash zeolite synthesis is an unnamed zeolite (Na6[AlSiO4]6+4H2O),and the low calcium fly ash zeolite synthesis is faujasite. Compared with the fly ash, the surface of both zeolites become rough, the specific surface area and cation exchange capacity increased. The fly ash zeolite synthesis had a high adsorption rate of mixed heavy metal ions, and the adsorption process accord with two order reaction kinetics. In the pH 2.0-12.0 range, zeolite had higher removal efficiency of heavy metal ions, pH showed little influence. The removal rate increased with the increase of zeolite dosage, and decreased with the increase of initial solution concentration.To the high calcium fly ash zeolite synthesis, the adsorption of Zn+, Cu2+, Cd2+, Pb2+are 129.26mg/g,195.15mg/g,108.46mg/g、196.24mg/g;to the low calcium fly ash zeolite synthesis, the adsorption of Zn2+, Cu2+, Cd2+, Pb2+are 104.41mg/g,180.94mg/g,84.15mg/g,195.00mg/g respectively, the removal of order is Pb2+>Cu2+>Cd2+>Zn2+.Adsorption isotherm data is accord with Langmuir model and Freundlich model, so it could be sured that Zn2+, Cu2+, Cd2+, Pb2+belongs to a favorable adsorption in the zeolite synthesized from fly ash, adsorption process is spontaneous.Release experiments showed that regenerated zeolite adsorption capacity of the heavy metals decreased, but still can be recycle.As the result of various tests, adsorption capacity of zeolite on Cu2+and Pb2+is stronger than Zn2+and Cd2+,and two kinds of synthetic zeolite both can be used as efficiency adsorbent for heavy metal removal. High calcium fly ash zeolite synthesis was proved to have a higher ability to remove heavy metal ions than low calcium fly ash synthesized zeolite.