International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

Corn stalk was used as a biosorbent for the adsorption of copper ions from synthetic solutions. To examine the mechanism of the adsorption process and identify the potential rate-determining step, the following kinetic models were used in this study: the pseudo-first order kinetic model, the pseudo-second order kinetic model, the Elovich kinetic model, and the interparticle diffusion model. Kinetic studies show that copper ions adsorption followed the pseudo-second order kinetic model. The maximum adsorption capacity was 5.5 mg g⁻¹. The results indicate that corn stalk can be successfully used as a biosorbent for the adsorption of copper ions from synthetic solutions.

In this paper, the results of the DTA-TGA, SEM-EDS, and FTIR analysis of the corn silk are presented. The DTA-TGA analysis shows that the decomposition of corn silk has several stages which are manifested with corresponding peaks on obtained DTA-TGA curves. SEM-EDS analysis was performed before and after the adsorption of copper ions. It has shown that untreated corn silk has a non-uniform structure, consisting of channels and cavities of irregular orientation, which facilitates the penetration of the water phase into the adsorbent structure, and incorporation of copper ions in the internal active sites. After the adsorption of Cu2+ ions, the structure becomes more compact, and uniform, as a result of the incorporation of copper ions into the molecular structure of the corn silk. FTIR analysis shows that ion exchange is not the dominant mechanism of binding copper ions to the active sites in the molecular structure of the corn silk, but also chemisorption and physical adsorption is present.