Low-cost Biochar from Parthenium Hysterophorus for Efficient Cr⁶⁺ Removal: A Sustainable Wastewater Treatment Solution

Aims: This study explores the development of innovative, cost-effective methods for removing Cr6+ from wastewater, focusing on biochar derived from Parthenium hysterophorus shoots. The biochar was prepared using a conventional slow-pyrolysis process and evaluated for its potential to treat Cr⁶⁺ in aqueous solutions. Study Design: Batch adsorption experiments are carried out in the study. Place and Duration of Study: The study was conducted in the Department of Environmental Science, G B Pant University of Agriculture & Technology, between Feb 2024 and July 2024. Methodology: Parthenium hysterophorus shoots were collected, reagents were purchased from HiMedia, and Cr⁶⁺ solutions were prepared and adjusted using NaOH and HCl. Shoots were washed, sun-dried, ground into powder and pyrolysed at 350°C for 180 minutes. Biochar yield was calculated, pH, proximal parameters (moisture, volatile matter, ash, fixed carbon) and ultimate analysis were measured, chemical functional groups by FTIR and morphology by XRD using Bruker D8 Advance was done. Cr⁶⁺ removal was studied using biochar adsorbent under varying pH, initial Cr6+ concentration, adsorbent dose and contact time, adsorption capacity (q) and removal percentage were then calculated. Results: Characterization techniques such as Fourier Transform Infrared (FTIR) spectroscopy and X-Ray Diffraction (XRD) confirmed the presence of multiple functional groups and crystalline structures, which contribute to its adsorption efficiency. Batch adsorption experiments were conducted to investigate the influence of prepared biochar dosage, initial Cr⁶⁺ concentration, pH and contact time. The optimal removal efficiency of 72.77% was achieved under conditions of pH 10, a biochar dose of 1 g/L, an initial Cr⁶⁺ concentration of 30 mg/L and a contact time of 72 hours. Conclusion: Although challenges remain in optimizing production and functionalization, this research highlights the potential of biochar for sustainable water treatment. Addressing production costs and practical challenges will further enhance its applicability, contributing to environmental sustainability efforts.