Improvement of strontium ion adsorption by using N and NO type complexing agents deposited on SiO2

Due to the importance of removing strontium ions in nuclear wastes, in the present work, while synthesizing hydroxybenzaldehyde propyltriethoxysilane ((EtO)3Si-HL) and pyridylmethylidene propyltriethoxysilane ((EtO)3Si-L) ligands, we investigated the properties of silica nanoparticles modified with these ligands as solid adsorbents in The removal of strontium ion from the aqueous solution was investigated and parameters such as pH, time, the mass of adsorbent, temperature, and interfering ions were tested. The adsorption behavior of the adsorbents showed that by modifying the surface of the nano adsorbent, the ability of the adsorbents to adsorb strontium ion at pH=6 increased from 6.31% to 86% and 22.11% using the (EtO)3Si-HL and (EtO)3Si-L ligands, respectively. The results of isotherms and adsorption kinetics indicate that the adsorption process follows the Longmuir isotherm and the pseudo-second-order model, respectively. Also, thermodynamic parameters show that strontium removal from the aqueous solution is an endothermic process. The positive entropy values are the driving force behind the adsorption process.