Adsorption of Cu(II) and Zn(II) onto ZrO2–SiO2 composite: Characteristics, mechanism and application in wastewater treatment

The presented paper describes a perspective methodology of hazardous post-production wastewater treatment focused on recovering selected metal ions species, mainly copper, zinc, and arsenic. The idea included the design of multifunctional adsorbents composed of zirconia and silica, their physicochemical evaluations, and verification tests in the adsorption process performed using model wastewaters. The proposed synthesis protocol allowed to obtain the materials with unique structural and physicochemical properties, including well-developed surface area (ABET = 398 m2∙g−1), as well as specific surface nature. It was confirmed by the results of energy dispersive X-ray, X-ray fluorescence and Fourier transform infrared spectroscopy analyses. Furthermore, by analysing the batch experiments, optimal process parameters for recovering the analyzed metal ions were established as follows: T = 313 K, pH = 5, S:L ratio = 6.67 mg:cm3, and t = 120 min. It was found that the performed removal of selected metal ion species followed pseudo-second-order kinetic and Langmuir isotherm models, and the estimated sorption capacity of the designed material was 23.5 mg∙g−1 and 12.4 mg∙g−1 for Cu(II) and Zn(II) ions, respectively. The results indicate that it is possible to separate arsenic compounds from copper and zinc ions with efficiencies of 98.9 % and 99.5 % respectively.