Evaluation of loblolly pine wood biochar properties derived from the slow-pyrolysis process for the synergetic benefit of carbon sequestration and soil conditioning

Abstract

Loblolly pine biochar was produced through slow pyrolysis using a rotary kiln at three temperatures (450 °C, 550 °C, and 650 °C), and its potential for carbon sequestration and soil conditioning were evaluated using carbon structure analysis and labile/stable carbon analysis. Among the three biochar samples, the biochar produced at 450 °C exhibited the highest yield (23 %), a hydrophilic static contact angle (82.75 °), water holding capacity (560.60 %), acid buffering capacity (969.70 mmol H⁺/kg), a soil-compatible pH (6.29), low electrical conductivity (0.17 dS/m), and a high nutrient content with heavy metal levels well below the US Environmental Protection Agency thresholds. Also, the PAHs levels is below the regulatory limits for environmental application. The low static contact angle of the 450 °C biochar indicates the presence of hydrophilic surface functional groups, which enhance wetting properties and water-holding capacity. Notably, all biochar samples demonstrated potential synergetic benefits for carbon sequestration and soil health improvement without raising concerns about heavy metal contamination.