Enhanced Biochar Effectively Removes Chromium from Contaminated Water

Greg Howard
19th May, 2024

Enhanced Biochar Effectively Removes Chromium from Contaminated Water
Image Source: © Natural Science News. This image is an artistic rendition.

Key Findings

  • Researchers at Arizona State University developed a biochar from pineapple skins to remove toxic chromium from water
  • The biochar was chemically modified to enhance its ability to adsorb chromium, showing high efficiency for both Cr(VI) and Cr(III)
  • The modified biochar maintained its adsorption capacity even in the presence of high concentrations of interfering ions, making it suitable for real-world water purification
Chromium pollution of groundwater is a significant global issue, primarily driven by human activities such as industrial processes and improper waste disposal. Chromium exists in two main forms: Cr(VI), which is highly toxic and carcinogenic, and Cr(III), which is less toxic but can still pose health risks. Traditional methods for removing these contaminants from water can be energy-intensive and inefficient. Recent advancements in adsorption technologies offer a more sustainable and effective solution. In this context, a new study conducted by Arizona State University[1] explores the use of biochar derived from pineapple skins, chemically modified through a green amination method, to remove both Cr(VI) and Cr(III) from water. Biochar, a type of charcoal produced from organic waste through pyrolysis, has been gaining attention for its potential in environmental remediation. This study builds on previous research that demonstrated the effectiveness of carbon-based nanomaterials in removing heavy metals from water[2]. The researchers at Arizona State University took an innovative approach by using agricultural waste—pineapple skins—to create a biochar sorbent. This not only addresses waste management issues but also provides a cost-effective material for water purification. The biochar was chemically modified using a green amination method, which introduced new C-N and N-H bonds while depleting N-O and C-H bonds. This modification significantly enhanced the biochar's ability to adsorb chromium. FTIR analysis confirmed the presence of these new functional groups, which are crucial for the adsorption process. The modified biochar was tested for its ability to adsorb Cr(VI) and Cr(III) at room temperature, showing binding capacities of 46.5 mg/g for Cr(VI) and 27.1 mg/g for Cr(III). The study also delved into the performance of the biochar in complex aqueous matrices, which often contain various interfering ions. Remarkably, the modified biochar maintained its adsorption capacity for Cr(VI) even in the presence of interfering ions at concentrations up to 3,000 times higher. For Cr(III), the adsorption efficiency reached 100% at interfering ion concentrations up to 330 times higher, although it diminished at higher concentrations. This selective removal capability makes the modified biochar highly suitable for real-world applications where water sources are often contaminated with multiple pollutants. The findings of this study are consistent with earlier research that highlighted the potential of carbon-based materials for heavy metal removal. For instance, graphene oxide/alginate hydrogel membranes have been shown to effectively remove Cr(III) and Pb(II) from water[3]. Similarly, biochars like hydrochar and pyrochar have demonstrated different mechanisms for Cr(VI) removal, with hydrochar showing a higher reduction percentage under simulated sunlight[4]. The current study extends this knowledge by demonstrating that biochar derived from agricultural waste can be chemically modified to achieve high efficiency and selectivity in removing both Cr(VI) and Cr(III). In summary, the study from Arizona State University presents a promising solution for chromium pollution in groundwater. By upcycling agricultural waste into a chemically modified biochar, the researchers have developed a sustainable and effective adsorbent for removing toxic chromium species from water. This approach not only addresses environmental pollution but also offers a practical application for agricultural waste, contributing to a more sustainable future.

EnvironmentSustainabilityBiotech

References

Main Study

1) Amino-modified upcycled biochar achieves selective chromium removal in complex aqueous matrices.

Published 17th May, 2024

https://doi.org/10.1016/j.jenvman.2024.121160

Related Studies

2) Carbon Nanomaterials for the Treatment of Heavy Metal-Contaminated Water and Environmental Remediation.

https://doi.org/10.1186/s11671-019-3167-8

3) Adsorption of Cr(III) and Pb(II) by graphene oxide/alginate hydrogel membrane: Characterization, adsorption kinetics, isotherm and thermodynamics studies.

https://doi.org/10.1016/j.ijbiomac.2019.09.249

4) Structural dependent Cr(VI) adsorption and reduction of biochar: hydrochar versus pyrochar.

https://doi.org/10.1016/j.scitotenv.2021.147084


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