CATION EXCHANGE PROPERTIES OF ZEOLITES OBTAINED FROM COAL FLY ASH BY ALKALI HYDROTHERMAL TREATMENT

摘要

Syntheses of zeolitic materials were carried out from coal fly ash by alkali hydrothermal treatment as part of the reuse and recycle technologies of coal ash. For the obtained zeolites, the cation exchange capacity and acid resistance, which are very important in the practical use of cation exchanger in aqueous solution, are investigated during this stufy. The cation exchange amounts of the NaP, CaP and K-CHA zeolites are measured for various cations such as K~+, Na~+, NH_4~+, Ca~(2+), Mg~(2+), Pb~(2+), Cd~(2+) and so on. The change in crystallization degree are researched as a function of pH. The simultaneous removal ability of NHV_4~+ and PO_4~(3-) in solution is examined for an example of the water purification with CaP zeolite. From these results, the characteristic and its mechanism of cation exchange are clarified for the various zeolitic materials obtained from coal fly ash.