Value of biochars from Miscanthus x giganteus cultivated on contaminated soils to decrease the availability of metals...

Area of Science:

• Environmental Science
• Soil Science
• Materials Science

Background:

• Agricultural soils are often contaminated with heavy metals and polycyclic aromatic hydrocarbons (PAHs).
• Biochar, a charcoal-like material produced from biomass pyrolysis, shows potential for soil remediation.
• Miscanthus x giganteus grown on contaminated soil offers a sustainable source for biochar production.

Purpose of the Study:

• To evaluate the metal and PAH sorption efficiency of eight biochars derived from Miscanthus x giganteus.
• To investigate the influence of pyrolysis conditions on biochar properties and sorption performance.
• To compare Miscanthus biochars with a commercial wood-based biochar.

Main Methods:

• Biochar production using varying pyrolysis temperatures (400/600°C), heating rates (5/10°C min⁻¹), and durations (45/90 min).
• Physicochemical characterization of biochars (pH, cation exchange capacity, specific surface area).
• Sorption and desorption experiments using aqueous solutions contaminated with single or mixed metals (Cd, Pb, Zn) and PAHs.

Main Results:

• Biochars produced at 600°C exhibited higher sorption efficiency for Cd, Pb, and Zn compared to those produced at 400°C.
• Pyrolysis conditions significantly impacted biochar physicochemical properties.
• The sorption process was predominantly irreversible, indicating strong metal binding.

Conclusions:

• Miscanthus x giganteus biochars, particularly those produced at higher temperatures, are effective sorbents for heavy metals.
• The irreversible nature of sorption highlights the long-term potential of these biochars for metal remediation.
• Biochar derived from contaminated biomass offers a viable strategy for environmental cleanup.