Background: Heavy metal pollution is a very serious issue that affects the survival of all living organisms and can have several adverse effects on the human body. Nickel, which is a toxic metal, is also present everywhere in the environment and can enter the human body. Hydrochar is considered an economical and efficient adsorbent for the removal of nickel from aqueous solutions.
Aim: The use of Conocarpus tree leaves for the preparation of hydrochar via the hydrothermal method and the identification of hydrochar using various spectroscopic methods. Investigation of the effects of different factors such as temperature, time, initial nickel concentration, adsorbent amount, and pH on adsorption capacity, as well as the study of isotherm patterns, kinetic models, and thermodynamic calculations of adsorption.
Methodology: biomass derived from Conocarpus tree leaves was prepared using an autoclave. Then, hydrochar was identified using spectroscopic methods such as X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and Fourier transform infrared (FTIR) spectroscopy. Nickel adsorption was measured in the presence of the adsorbent by varying one parameter at a time (such as temperature, contact time, initial nickel concentration, and pH) while keeping the others constant, and the variation curve for each parameter was obtained. Subsequently, Adsorption changes were fitted to various isotherm models based on the initial nickel concentration. Similarly, adsorption variations over time were fitted to different kinetic models. Finally, by plotting equilibrium constants at different temperatures, the Gibbs free energy, enthalpy, and entropy of adsorption were calculated. This comprehensive study provides valuable insights into optimizing adsorption conditions and understanding the thermodynamic and kinetic behavior of the process.
Findings: In this study, Conocarpus tree leaves were used as an adsorbent. Analyses including XRD, SEM, FTIR, and VSM were
