A recent study published in ChemEngineering by Diego Barzallo and colleagues investigates the effectiveness of 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 derived from rice husks in removing methylene blue (MB) and malachite green (MG) dyes from aqueous solutions. The research evaluates unactivated biochar, chemically activated biochar, and γ-Fe2O3 nanoparticle-functionalized biochar to determine the most effective adsorption mechanism.

Biochar is gaining attention for its potential in environmental remediation. This study explores three biochar variants: (1) unactivated biochar, (2) biochar chemically activated with phosphoric acid (H3PO4), and (3) biochar impregnated with γ-Fe2O3 nanoparticles. Advanced characterization techniques were used to assess their structural properties and adsorption capacity.

The results showed that biochar functionalized with γ-Fe2O3 nanoparticles had the highest adsorption efficiency, achieving 97% removal for MB and 95% for MG. Further analysis revealed that biochar activation plays a crucial role in adsorption efficiency. Chemically activated biochar showed improved adsorption compared to unactivated biochar due to a greater number of oxygen-containing functional groups. A key advantage of γ-Fe2O3 functionalized biochar is its reusability. Even after four adsorption-desorption cycles, the material retained high removal efficiency, making it a cost-effective and sustainable option for wastewater treatment. This aligns with circular economy principles by transforming agricultural waste into valuable adsorbent materials.

While this study highlights the potential of magnetic biochar, future research should focus on large-scale applications and optimizing the functionalization process for different types of wastewater contaminants. As industries seek eco-friendly water treatment solutions, biochar emerges as a promising, low-cost, and efficient alternative for pollutant removal.

Source: Barzallo, D., Carrasquero, E., Andrade, M., Heredia Jara, D.A., & Palmay, P. (2025). Preparation and characterization of unactivated, activated, and γ-Fe2O3 nanoparticle-functionalized biochar from rice husk via 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 for dyes removal in aqueous samples: Comparison, performance, and mechanism. ChemEngineering, 9(2), 30.