In the journal Chemosphere, Filip Budimir et al. explore the effectiveness of oak-based biocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More in removing hexavalent chromium, a toxic pollutant, from aqueous solutions. This study highlights biochar’s potential as a sustainable and efficient solution for environmental remediation, specifically in combating chromium contamination. Biochar, derived from biomassBiomass is a complex biological organic or non-organic solid product derived from living or recently living organism and available naturally. Various types of wastes such as animal manure, waste paper, sludge and many industrial wastes are also treated as biomass because like natural biomass these More pyrolysisPyrolysis is a thermochemical process that converts waste biomass into bio-char, bio-oil, and pyro-gas. It offers significant advantages in waste valorization, turning low-value materials into economically valuable resources. Its versatility allows for tailored products based on operational conditions, presenting itself as a cost-effective and efficient More, has unique physicochemical properties, including high surface area, porous structure, and functional groups, making it an exceptional adsorbent for metals.

The research involved exposing oak-based biochar to a hexavalent chromium solution and monitoring the removal process. The biochar demonstrated remarkable efficiency, removing 99% of the chromium from the solution. Further analysis using sophisticated techniques such as Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and X-ray absorption near edge structure (XANES) spectroscopy revealed the mechanisms behind chromium removal. The process involves both reduction of hexavalent chromium to its less toxic trivalent form and sorption onto the biochar surface.

Isotope analysis provided additional insights, showing chromium isotope fractionation during the removal process, a phenomenon that can be used to trace biochar-chromium reactions. This study not only confirms biochar’s effectiveness in chromium removal but also enhances our understanding of the underlying chemical processes. The findings underscore biochar’s potential as a valuable tool in environmental remediation, offering a sustainable approach to mitigating toxic metal pollution in water.

SOURCE: Budimir, F., Ptacek, C. J., Amos, R. T., & Blowes, D. W. (2024). Chromium isotope fractionation during the removal of hexavalent chromium by oak-based biochar. Chemosphere, 369, 143880.