Synthesis of New Carbon-Based Adsorbent from Eriobotrya Japonica Stem for Efficient Congo Red Removal a Kinetic, Thermodynamic, and Isotherm Study

This study aims to prepare a new activated carbon from cheap and readily available plant sources, Eriobotrya japonica (AC1), and utilize it as an adsorbent. This study selected Congo Red (CR) as the target pollutant molecule. The synthesized adsorbent was characterized using available analytical techniques, including Fourier Transform InfraRed (FT-IR) spectroscopy, Brunauer-Emmett-Teller (BET) analysis, Field Emission Scanning Electron Microscope (FE-SEM), Energy Dispersive X-ray Spectroscopy (EDX), and X-ray diffraction (XRD), in addition, pHpzc (point of zero charges) was selected as well as. The adsorption study was a function of different parameters, including contact time, temperature, initial concentration, and adsorbent dose. The results of this study were compared to commercial activated carbon (AC2), the fabricated adsorbent was efficient in Congo red removal, and the optimal pH was recorded to be 5.9, with adsorption behavior conforming to the Langmuir isotherm, suggesting a monolayer adsorption pattern. The pseudo-second-order kinetics were better applied to experimental data, as indicated by a higher correlation coefficient (𝑅2 ≥ 0.998), which is closer to unity. The study of thermodynamics indicated that this adsorption process was spontaneous, endothermic, and feasible across selected temperatures. The results of this research demonstrate that AC1, as an economical biosorbent, effectively removes CR dye from wastewater.