Retrieval of zirconium ions from laboratory solutions upon insitu-gel-precipitated aluminium based composite sorbents

Abstract

Synthesis of innovative substances that serve as potential adsorbents used to reduce pollution impacts or even capture valuable elements is still a target. The strategic point of this work is the preparation of aluminum silicate vanadate nano particles (AlSiV-NPs) and aluminum silicate vanadate tungstate nano particles (AlSiVW-NPs) via the insitu technique. The prepared adsorbents were characterized using FTIR, TGA, TEM, XRD, and SEM-EDX analyses. Studies were conducted on the effects of pH variation, feeding solution concentrations, equilibrium times, and adsorbent weight on the Zr4+ adsorption process on the synthesized adsorbents. With the experimental maximum adsorption capacities of 89 and 95 mg/g for AlSiV-NPs and AlSiVW-NPs, respectively, the equilibrium adsorption results for Zr4+ were in good agreement with the Langmuir isotherm and the qe values were more fitting. The pseudo-second-model kinetically matches both adsorbents suggesting that chemisorption was the approach of adsorption. Thermodynamic results for composites AlSiV-NPs and AlSiVW-NPs show similar values for enthalpy change (−31.5 and −21.08 kJ/mol), entropy change (−47.8 and −7.8 J/mol.. K), and negative free energy change. In summary, Zr4+ adsorption over AlSiV-NPs and AlSiVW-NPs is exothermic, spontaneous, and has a lower degree of disorder. These findings proved the promising future of these composites to recover Zr4+ from aqueous media.