Ultrasound Boosts Biochar for Nutrient Removal and Eco-Friendly Reuse

Eutrophication, a major environmental concern, demands efficient phosphorus and ammonium removal. A new study explores promising “greener” solutions using magnesium-based biochar composites (MBCs). The researchers employed ultrasonic cavitation to create more adsorption sites on MBCs, significantly improving their capacity to capture nutrients and their suitability for green recycling.

January 27, 2024

1–2 minutes

Tan, Zhao, et al (2024) Synergistic removal of ammonium and phosphate using ultrasonic Mg-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 composite: Mechanism, behavior and green recycling. *Journal of Environmental Chemical Engineering, Vol. 12.* https://doi.org/10.1016/j.jece.2024.111995

Eutrophication, caused by excess nutrients like ammonium and phosphate, threatens aquatic ecosystems. To combat this, efficient removal and sustainable reuse of these nutrients are crucial. This study explores magnesium-based biochar composites (MBCs) enhanced with ultrasound to tackle this challenge.

Ultrasonic waves, known for their ability to break bonds, were used to modify MBCs, creating ultrasonic magnesium-based biochar composites (UMBCs) with increased adsorption capacity and reusability. By optimizing the power and duration of the ultrasound treatment, the researchers developed UMBC-5, which exhibited remarkable improvements in nutrient removal compared to untreated MBCs. Phosphate removal rate jumped from 93.0% to 96.6%, while ammonium removal skyrocketed from 23.9% to 50.6%.

Further analysis revealed that ultrasound enhanced the surface properties of UMBC-5, introducing more hydrophilic functional groups. These groups act like magnets, attracting and binding ammonium ions through electrostatic interactions. Additionally, the main forms of nutrients captured by UMBC-5 were identified as phosphate and struvite, a valuable slow-release fertilizer.

Not only did UMBC-5 excel in nutrient removal, but it also showcased its potential for eco-friendly reuse. The combination of abundant hydrophilic groups and nutrient-rich content led to a significant increase in plant 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 and soil moisture when applied as fertilizer. This demonstrates the complete cycle of nutrient capture, conversion, and utilization, aligning with the principles of green chemical engineering.

This study paves the way for utilizing ultrasound-treated biochar composites as efficient tools for combating eutrophication and promoting sustainable nutrient management in agriculture. By maximizing nutrient removal and facilitating eco-friendly reuse, UMBCs offer a promising solution for cleaner waterways and healthier ecosystems.