Authors: Shivendra Singh, Manoj Yadav
Abstract: Tannery effluents are a major source of chromium contamination, particularly hexavalent chromium [Cr(VI)], which is highly toxic, carcinogenic, and persistent in aquatic systems. Conventional treatment methods for chromium removal are often costly and environmentally unsustainable. This study investigates the potential of low-cost, eco-friendly agro-waste materials—sawdust, clay, and used tea leaves—as adsorbents for the removal of both total chromium and hexavalent chromium from tannery effluent. Batch adsorption experiments were carried out to evaluate the effect of parameters such as pH, contact time, adsorbent dosage, and initial chromium concentration. The results demonstrate that all three materials exhibit significant adsorption capacities, with efficiency varying across the different adsorbents. Sawdust and used tea leaves showed higher affinity towards Cr(VI), while clay exhibited better overall performance in reducing total chromium levels. The adsorption process was found to follow pseudo-second-order kinetics and fit well with the Langmuir isotherm model, suggesting monolayer adsorption on homogeneous surfaces. This study highlights the feasibility of employing locally available agro-waste adsorbents as sustainable alternatives to conventional methods for the treatment of tannery wastewater, thereby contributing to cost-effective and environmentally friendly wastewater management
DOI: http://doi.org/10.5281/zenodo.17098961
