Ring size dependent crown ether based mesoporous adsorbent for high cesium adsorption from wastewater

• Large ring DB30C10 was immobilized for the preparation of mesoporous adsorbent.
• High cesium adsorption was achieved due to the large number of coordination.
• The carrier materials played an important role for the high cesium adsorption.

The work was designed for high cesium (Cs) adsorption from wastewater based on large ring size of dibenzo-30-crown-10-ether (DB30C10) immobilized mesoporous adsorbent. The Cs ion adsorption onto the mesoporous adsorbent from aqueous solution was investigated under the different experimental conditions such as reaction times, initial Cs ion concentrations, diverse competing ions and acidities. The Cs adsorption by mesoporous adsorbent was demonstrated at higher reaction rates than that of natural clay minerals. A superior correlation coefficient from the experimental and fitting values of the isotherm demonstrated that Cs ion adsorption on the mesoporous adsorbent was well fitted using the Langmuir isotherms model and exhibited the monolayer adsorption. The mesoporous adsorbent showed the high adsorption capacity as 107.16 mg/g compared with the diverse crown ethers anchored adsorbent due to the large ring size of DB30C10 ligand. The effective surface area, adsorption capacity and encapsulation ability of mesoporous adsorbent were improved by the expanding ring size of DB30C10. The Cs adsorption by the mesoporous adsorbent was dependent on both pH and ionic strength of potassium (K) and sodium (Na). The presence of high amount K was adversely affected the Cs adsorption. On the other hand, the large amount of Na was slightly affected for Cs uptake. In addition, the adsorbent was reversible and kept remaining functionality after successful elution and regeneration using 0.25 M HCl to reuse in multiple cycles without specific deterioration in its original performances. Hence, the newly large ring size based mesoporous adsorbent is a kind of potential and efficient material for high Cs adsorption from wastewater samples in Fukushima, Japan.

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