Influence of biochar produced from negative pressure-induced carbonization on transformation of potentially toxic metal(loid)s concerning plant physiological characteristics in industrially contaminated soil

Soil contamination and its subsequent impact on the food chain is a pressing challenge in the present day. The application of biochar has demonstrated a significant and positive effect on soil health, thereby enhancing plant growth and development. However, the application of biochar (BC) produced from negative pressure-induced carbonization to mitigate metal(loid) contamination is a new strategy that has been studied in current research. Results depicted that the application of biochar derived from the negative pressure carbonization (vacuum-assisted biochar (VBC) has a significant (p <= 0.05) positive impact on plant growth and physiological characteristics by influencing immobilization and speciation of metal(loid) in the soil system. Moreover, the interactive effect of VBC on physiological characteristics (photosynthesis, gas exchange, and chlorophyll contents) and antioxidant activities of maize (Zea mays L.) was significantly (p <= 0.05) positive by confining the translocation and movement of metal(loid)s to the aerial part of the maize plant. X-ray diffraction (XRD) provided information on the structural and chemical changes induced by the VBC-500 degrees C explaining metal(loid) adsorption onto mineral surfaces and complexation that can affect their mobility, availability, and toxicity in the contaminated soil. Fourier transform infrared spectroscopy (FTIR) further provided a more detailed understanding of the metal(loid)s and biochar complexation mechanisms influenced by VBC-based functional groups -OH, C-Hn, -COOH, C--O, C-O-C, C--C, C-O, C-H, OH, and C-C in the binding process. These results suggest that the application of biochar prepared at 500 degrees C under negative pressure-induced carbonization conditions to the soil is the most efficient way to reduce the uptake and transfer of metal(loid)s by influencing their mobility and availability in the soil-plant system.

Automated summary

This study shows that biochar prepared under negative pressure-induced carbonization can have a positive impact on metal(loid) contamination in the soil system, enhancing plant growth and development. The use of vacuum-assisted biochar (VBC) can affect the immobilization and speciation of metal(loid) in the soil, leading to improved physiological characteristics and antioxidant activities in maize plants. X-ray diffraction and Fourier transform infrared spectroscopy provide insights into the structural and chemical changes induced by VBC, explaining its effects on metal(loid) adsorption and complexation. The application of biochar prepared at 500 degrees Celsius is the most efficient way to reduce the uptake and transfer of metal(loid)s in the soil-plant system.