ABSTRACT Downed timber is valuable for manufacturing biochar in environmental remediation applications due to the low cost of raw materials and low-temperature manufacturing process. Loblolly pine (Pinus taeda L.) trees at different maturities (15-, 30-, and 39-year-old) with 0, 6, and 12 months of local environmental exposure in the southeastern region of the US were collected for biochar manufacturing. The biochar samples were characterized for their physicochemical properties, including morphologies, elemental compositions, surface functional groups, carbon structure, pH, electrical conductivity, and specific surface area. The Pb2+ adsorption isotherms were measured. The results indicated that the biochar physicochemical properties, affected by the tree maturities and the environmental exposure periods, significantly impacted the Pb2+ adsorption capacity. The Pb2+ adsorption capacity of biochar increased with the environmental exposure of wood for 6 months, followed by a decrease for biochar made from wood with an environmental exposure of 12 months. A recommendation can be made that downed timber collected up to a 6-month environmental exposure period can manufacture biochar with superior performance regarding adsorbing Pb2+ in water systems. The research outcome offered insights for the biochar manufacturing community to prepare forest feedstock for biochar production with better performance in Pb2+ adsorption.
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