Enhanced remediation of U(vi) ions from water resources using advanced forms of morphologically modified glauconite (nano-sheets and nano-rods): experimental and theoretical investigations

Abstract

Two forms of morphologically transformed glauconite (GL) involved exfoliated nanosheets (EXG) and nanorods (GRs), which were synthesized by facile exfoliating and scrolling modification under sonication. The two advanced forms (EXG and GRs) were applied as enhanced adsorbents for U(VI) ions and compared with using raw glauconite. The developed GRs structure displays higher saturation retention properties (319.5 mg g⁻¹) in comparison with both EXG (264.8 mg g⁻¹) and GL (237.9 mg g⁻¹). This enhancement is assigned to the noticeable increment in the surface area (32.6 m² g⁻¹ (GL), 86.4 m² g⁻¹ (EXG), and 123.7 m² g⁻¹ (GRs)) in addition to the surface reactivity and exposure of effective siloxane groups. This was supported by the steric investigation based on the isotherm basics of the monolayer model of one energy site. The steric functions declared a strong increase in the density of the existing effective uptake receptors throughout the modification stages (GRs (112.1 mg g⁻¹) > EXG (87.7 mg g⁻¹) > 72.5 mg g⁻¹ (GL)). Also, each active site can be filled with 4 U(VI) ions, donating the parallel orientation of these ions and the operation of multi-ionic mechanisms. The energetic functions, either the uptake energy (<13 kJ mol⁻¹) or Gaussian energy (<5 kJ mol⁻¹), validate the retention of U(VI) by physical reactions. These reactions displayed spontaneous properties and exothermic behaviors based on the investigated thermodynamic functions, including entropy, enthalpy, and internal energy. The structures also showed significant recyclability, indicating potential application on a realistic and commercial scale.