Studies On The Synthesis Of High Capability Potassium Adsorbent

The synthesis of the potassium adsorbent and it's adsorbability was studied in this paper. It mainly included three aspects: the synthesis of the potassium adsorbent with aluminosilicate by hydrothermal method; the study on the adsorbability of the potassium adsorbent and the research on the thermodynamics of the adsorbent.The conclusion was drawn by the synthesis of molecular sieve: after mixed soluble glass and aluminium sulfate with proper proportion under room temperature, it was stirred stormily to react. And then we mixed with potassium hydroxide solution after filtrating. At last, the molecular sieves of potassium type was synthesized after the mixture reacted in the oven or autoclave for 24 hours. The molecular sieve was remodeled more than twice with ammonium chloride solution that the concentration was 3mol/L and then remodeled twice with the saturated sodium chloride solution. Finally the molecular sieve was changed into the sodium type. It was named W zeolite.In this paper, the potassium adsorbent which was prepared in the autoclave was mainly studied. It included: the absorption of potassium ion in potassium chloride solution and seawater, the absorption of ammonium ion in ammonium chloride solution, and the recycling of molecular sieve in the experiment. It was showed that: among those adsorbents synthesized in autoclave, the adsorbability of adsorbent is the best when the zeolite has a silica to alumina ratio about 4.6. The adsorption capacity of potassium ion is 59.18mg per gram zeolite in seawater, and is 235.38mg per gram zeolite in potassium chloride solution. The adsorption capacity of ammonium ion is 102.46mg per gram zeolite in ammonium chloride solution. The adsorbability of molecular sieve would not change after it was eluted with ammonium chloride solution and then was regenerated with saturated sodium chloride solution.That the free energy value of the standard Gibbs was less than zero was found by determining the adsorptive isotherm. So the heat was set out when ion-exchange reaction happened. The reaction was easy to process under lower temperature and the capacity of K+ exchange was enhanced with the reduction of temperature. W-zeolite can adsorb K+ selectively because of its structure characteristic. There is plenty of potassium resource to exploit and use in seawater. So it had far-reaching meaning to study on the synthesis W zeolite and use it to exploit the abundant potassium resource in our ocean.