Effects of Cold Sintering on the Performance of Zeolite 13X as a Consolidated Adsorbent for Cesium

Abstract

Cold sintering, a novel low-temperatureconsolidation technique,has shown promising results in various inorganic materials. However,the application of this technique to nanoporous materials for energyand environmental fields is not yet fully understood. This study investigatesthe effects of cold sintering on the relative densities, compressivestrengths, chemical durabilities, crystal structures, specific surfaceareas, and adsorption capacities of zeolites. Cold sintering at 200 & DEG;C achieved 10 to 20% greater densification than conventionalhigh temperature (700 & DEG;C) sintering; however, the original nanoporousstructure of dry cold sintered zeolite was not maintained. Introducingliquid agents during the cold sintering process resulted in reduceddegradation of the SSA and increased densification. Using NaOH asthe liquid agent increased the solubility of elements in zeolite,which promoted chemical mobility and achieved the highest relativedensity (96.7 & PLUSMN; 2.8%). However, soluble layers between the particlesled to fragmentation, making it unsuitable for aqueous applications.Using H2O as the liquid agent resulted in a relative densityof 90.4 & PLUSMN; 4.1% while maintaining the nanoporous properties andstructural integrity of zeolite under water. The cesium adsorptioncapacity (19.0 & PLUSMN; 0.1 mg & BULL;g(-1)) was similarto that of conventional zeolite ion exchangers, indicating that coldsintering with H2O was an efficient, economical, and saferalternative to conventional high-temperature consolidation method.Our findings suggest that this cold sintering can be applied to othernanoporous materials, such as metal-organic frameworks andcovalent organic frameworks, in separation, catalysis, and adsorptionapplications.