Removal of Some Heavy Metals from Tannery Wastewater Using Activated Carbon from Neocarya Macrophylla Seeds

Abstract

This study presents an analysis of activated carbon derived from Neocarya Macrophylla seeds for the removal of Cr3+ and Fe3+ ions from tannery wastewater. The activated carbon was prepared using both acid and base. The base-activated carbon exhibited a higher yield compared to the acid-activated carbon. Modification led to an increase in ash content, suggesting chemical interactions' influence on ash content. X-ray diffraction (XRD) analysis revealed miller indices of (002) and (101) for reflection peaks at 28o and 51.26o, respectively. Acid modification resulted in sharp and intense peaks, indicating enhanced crystalline size and pore development. High-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) confirmed a disordered and porous microstructure, with SAED exhibiting distinct crystalline patterns in base and acid-activated carbon. Fourier-transform infrared (FTIR) spectra indicated various functional groups like OH groups, carbonyl groups, C=C stretching vibrations, C-H stretching vibrations, and Si-O-Si symmetric stretching vibrations in the activated carbon. The study investigated the effects of adsorbent dosage, contact time, and temperature on the adsorption process using batch process techniques. Kinetic and isotherm data were analyzed using the pseudo-first-order and pseudo-second-order models, as well as the Langmuir and Freundlich isotherm models. The findings revealed that the pseudo-second-order and Freundlich models provided the best fit for the data. The results demonstrate that activated carbon is a highly efficient adsorbent for removing heavy metal ions from tannery wastewater.