Preparation of Na‐P1‐Type Zeolite and its Composite Material with Nanosized Magnetite

Abstract

The Na‐P1‐type zeolite having a high cation‐exchange capacity (CEC) was obtained using the waste coal fly ash from thermal power stations and a 2M NaOH solution at 100°C. The Na‐P1‐type zeolite was formed with the reaction time of 6 h at 100°C, and its CEC value increased with an increase in the reaction time. The addition of a suitable amount of NaAlO2 to the fly ash was also effective for improving the CEC value. A new composite material consisting of the Na‐P1‐type zeolite and magnetite was synthesized from the fly ash and iron chlorides because the magnetic collection was possible using this composite material after radioactive Cs+ ion adsorption. The existence of nanosized magnetites in the polycrystalline zeolite (several micrometers) was confirmed by TEM observations. The CEC and magnetic property of these composite materials were characterized.

Adsorption characteristics of Cs⁺ onto artificial zeolites synthesized from coal fly ash and diatomite

“…An artificial Na-P1 was synthesized from a coal fly ash (JIS II type) discharged from a thermal power plant (Shikoku Electric Power Co., Takamatsu, Japan), by heating 10 g of the coal fly ash with 80 mL of 2.0 M NaOH at 100°C 19) using a reflux method. An artificial mordenite was synthesized by heating 5 g of diatomite (Wako Pure Chemical Ind., Ltd.) with 22.5 mL of 1.0 M NaOH in a stainless steel autoclave at 170°C for 24 h.…”

“…A Na-P1 type artificial zeolite synthesized from coal fly ash had a high ability for Cs + adsorption, and the high Cs + adsorptivity was ascribed to its 0.38 nm pore opening size which is close to the diameter of Cs + . 19) In addition, a natural mordenite also had high selectivity for Cs + adsorption. 6) An artificial Na-P1 from coal fly ash and an artificial mordenite from diatomite were hybridized with magnetite for the purpose of the decontamination of Cs + from waters and soils.…”

Synthesis of mordenite and its composite material using chemical reagents for Cs decontamination

“…In our previous paper, we evaluated the conditions for the Na-P1 type zeolite preparation and synthesized the composite material (magnetic zeolite) of the Na-P1 type zeolite and nanosized magnetite by alkali processing from a mixed solution of the fly-ash and iron chlorides for the magnetic collection of the zeolite after the Cs + ion adsorption. 10) For our study, the order of the adsorption capacity of Cs + in Na + or NH 4 + coexisting solution was mordenite > clinoptilolite > Na-P1 ) zeolite A > zeolite X. 11) To improve the efficiency of the decontamination, we evaluated other kinds of zeolites having a higher Cs + ion adsorption ability and focused on mordenite (Na 8 Al 8 Si 40 O 96 ·24H 2 O).…”

Preparation of mordenite and its composite material with nano-sized magnetite from diatomites for radioactive Cs decontamination

“…In our previous study, we synthesized a composite material of Na-P1-type zeolite (synthesized from fly-ash) and magnetite for the magnetic collection. 9) Decontamination of the soil containing radioactive Cs was possible using this composite material.…”

“…14), 15) Furthermore, preparation of a composite material of artificial mordenite and magnetite also seems possible by using our method. 9) In this study, we investigated the synthesis conditions of the mordenite from various diatomites as raw materials and the composite material of the mordenite and the magnetite.…”