Synergetic and advanced isotherm investigation for the enhancement influence of zeolitization and β-cyclodextrin hybridization on the retention efficiency of U(<scp>vi</scp>) ions by diatomite

Abstract

In synergetic investigations, the adsorption effectiveness of diatomite-based zeolitic structure (ZD) as well as its β-cyclodextrin (CD) hybrids (CD/ZD) towards uranium ions (U(vi)) was evaluated to examine the influence of the transformation procedures. The retention behaviors and mechanistic processes have been demonstrated through analyzing the steric and energetic factors employing the modern equilibrium approach (a monolayer model with a single energy level). After the saturation phase, the uptake characteristics of U(vi) were dramatically improved to 297.5 mg g^-1 after the CD blending procedure <i>versus</i> ZD (262.3 mg g^-1) or 127.8 mg g^-1. The steric analysis indicated a notable increase in binding site levels after the zeolitization steps (<i>N</i>_m = 85.7 mg g^-1) as well as CD implementation (<i>N</i>_m = 91.2 mg g^-1). This finding clarifies the reported improvement in the ability of CD/ZD to effectively retain the U(vi) ions. Furthermore, every single active site of the CD/ZD material has the capacity to adsorb around four ions, which are aligned according to a vertical pattern. The energetic aspects, specifically Gaussian energy (<8 kJ mol^-1) along with retention energy (<40 kJ mol^-1), validate the regulated influences of the physical mechanistic processes. The physical adsorption of U(vi) seems to depend on various intermolecular forces, such as van der Waals forces, in conjunction with zeolitic ion exchanging pathways (0.6-25 kJ mol^-1). The thermodynamic assets have been evaluated to confirm the exothermic together with spontaneous adsorption U(vi) by ZD and its blend with CD (CD/ZD).