Adsorption characteristics of Cu(II) and Zn(II) by nano-alumina material synthesized by the sol-gel method in batch mode

This study mainly focuses on the preparation, characterization, and sorption performance for Cu(II) and Zn(II) by using nano-alumina material (NA) synthesized through the sol-gel method. The SEM, EDS, FT-IR, and XRD analysis methods were implemented to identify the micromorphology and crystal structure of the synthesized NA absorbent and its structure after the adsorbing procedure. The effect of effective variables including various absorbent dose, contact time, initial ion concentration, and temperature on the removal of Cu(II) and Zn(II) from aqueous solution by using NA was investigated through a single factor experiment. Kinetic studies indicated that adsorption of copper and zinc ions by NA was chemical adsorption. The adsorption isotherm data were fitted by Langmuir (R²: 0.919, 0.914), Freundlich (R²: 0.983, 0.993), and Temkin (R²: 0.876, 0.863) isotherms, indicating that copper and zinc ions were easily adsorbed by NA with maximum adsorption capacities of 87.7 and 77.5 mg/g for Cu²⁺ and Zn²⁺, respectively. Thermodynamic parameters indicated that the adsorption of Cu²⁺ was spontaneous(G<0) and the adsorption of Zn²⁺ might not be spontaneous (G > 0) by NA.

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