Assessment of chromium removal efficiency from chromium-contaminated water using ball-milled <i>Eichhornia crassipes </i>biochar

Hexavalent chromium {Cr (VI)} contamination in water sources poses a significant threat to human health and the environment due to its toxicity and carcinogenicity. In recent years, biochar-based adsorbents have gained attention for their potential to effectively remove heavy metals from water. The present study focuses on the synthesis and application of ball-milled nano-Eichhornia (water hyacinth) biochar (BMNEBC) as an innovative adsorbent for the removal of Cr (VI) from aqueous solutions. In this research, Eichhornia plant leaves were utilized as the precursor for biochar production through a pyrolysis process. The produced biochar was subjected to physical modification (ball milling) to obtain nano-sized particles, thereby increasing the surface area and porosity of the material. Batch adsorption experiments were conducted to evaluate the Cr(VI) removal efficiency of BMBNBC under various operating conditions, including initial Cr(VI) concentration (10 to 70 mg), adsorbent dosage (25 to 125mg), contact time (0 to 180 minutes), and pH (3 to 12). The study revealed that the optimal conditions were identified as pH 6, an adsorbent dosage of 75 mg, and a contact time of 4 hours, resulting in an impressive Cr (VI) removal capacity of 256.3 mg/g (91%). These findings provide valuable insights for developing effective strategies to remove chromium from contaminated water samples.