Removal of Heavy Metal Ions (Fe2+, Mn2+, Cu2+ and Zn2+) on to Activated Carbon Prepared from Kashmiri Walnut Shell (Juglans regia)

Abstract

Heavy metal pollution poses significant threats to the environment and human health, even at trace concentrations. In this study, activated carbon derived from Kashmiri walnut shell (Juglans regia) was investigated for its potential to adsorb heavy metal ions (Fe2+, Mn2+, Cu2+, and Zn2+). Standard solutions containing heavy metal ions at concentrations ranging from 10 to 50 ppm were prepared for adsorption experiments, i.e., at temperature 25 ◦C, and adsorbent dosage 1 g using a column mechanism. The activated carbon was first treated with 0.1M HCl and 0.5M ammonia solutions, and then washed with demineralised water. Subsequently, the metal ion solutions were passed through the column individually, and the filtrates were analyzed for heavy metal ion presence. The experimental results demonstrated that walnut shell-derived activated carbon exhibited promising adsorption capacity spanning from 0.36 mg/g for Zn2+, 0.5 mg/g for both Mn2+ and Cu2+ and 0.54 mg/g for Fe2+ thus showing the adsorption trend as Fe2+ > Mn2+ = Cu2+ > Zn2+. This study highlights the potential of using walnut shell-derived activated carbon as an effective and cost-efficient method for mitigating heavy metal pollution in contaminated water sources.