Advancing Phosphate Adsorption with Nanoconfinement of MgO in Magnetic Biochar

This study introduces a two-step pyrolysis method, involving KHCO3 and HNO3 activation, to nanoconfine MgO in magnetic biochar. The innovative approach overcomes MgO agglomeration, reducing pore size and enhancing negatively charged surfaces. This nanoconfined structure significantly boosts phosphate adsorption performance, providing a promising solution for sustainable wastewater treatment.

February 17, 2024

1–2 minutes

Yin, Xu, et al (2024) Nanoscale MgO confined in magnetic 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 via two-step 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 enhanced phosphate adsorption. *Separation and Purification Technology.* https://doi.org/10.1016/j.seppur.2024.126754

Nano-MgO confinement within magnetic biochar offers a promising avenue for enhancing phosphate (P) adsorption, addressing global challenges associated with elevated P concentrations in water bodies. This research introduces a novel two-step pyrolysis method, involving KHCO3 and HNO3 activation, to overcome the agglomeration hindrance associated with MgO within magnetic biochar.

The unique co-activation strategy not only reduces pore size but also increases the negatively charged surface, facilitating controlled nano-MgO formation. The study achieves a uniform dispersion of nano-MgO crystals, with sizes less than 10 nm, enhancing P adsorption performance significantly. The P adsorption capacity reaches an impressive 83.06 mg/g, nearly three times higher than biochar synthesized through a one-step pyrolysis process.

The research delves into the mechanism behind P adsorption on biochar, attributing it to chemical reactions as the driving force. The study emphasizes the urgency of effective P polishing processes for ultra-low P water or wastewater, considering the detrimental impacts of eutrophication.

Moreover, the work introduces the innovative concept of nanoconfinement, demonstrating how it prevents MgO agglomeration and improves P adsorption performance. The synergistic co-activation of KHCO3 and HNO3 in biochar synthesis, a previously unexplored approach, proves instrumental in achieving successful nanoconfinement of MgO in magnetic biochar.

In conclusion, this study not only presents a feasible path to enhance P adsorption but also introduces a novel method for nanoconfinement, opening new avenues for sustainable wastewater treatment. The results highlight the potential of this two-step pyrolysis process in addressing challenges associated with MgO agglomeration, marking a significant advancement in adsorption technology.