Valorization of orange peel waste: activated carbon production and its role in enhancing particleboard performance

Abstract

The valorization of agricultural waste has gained increasing attention in recent years, with orange peel waste emerging as a promising precursor for activated carbon (AC) production. This study investigates the production of AC from orange peel waste using zinc chloride (ZnCl₂) as a chemical activator and evaluates its impact on the physical, mechanical, and environmental properties of three-layer particleboards. AC was incorporated into the urea–formaldehyde (UF) adhesive at 0.5–1.5% by weight and applied to both surface and core chips, ensuring its distribution across all three layers of the particleboard. The AC exhibited a specific surface area of 572.14 m²/g and a total pore volume of 0.280 cm³/g, demonstrating its high porosity and adsorption capabilities. Mechanical test results of particleboard indicate that the inclusion of 1.5% AC increased MOR by 26% (from 10.02 N/mm² to 12.65 N/mm²) and MOE by 52% (from 1083.83 N/mm² to 1645.33 N/mm²), while IB rose from 0.41 N/mm² to 0.53 N/mm². Additionally, formaldehyde emissions of particleboard decreased significantly from 11.25 mg/100 g (control) to 8.01 mg/100 g at production (0th month) and further to 3.20 mg/100 g after 12 months. Based on TS EN 312 (2012) classification, the AC-modified panels at 1.0–1.5% met the requirements of P2 boards for general-purpose use in dry conditions, while also complying with the E1 formaldehyde emission standard. The orange peel waste-derived AC can serve as an effective additive in composite materials, simultaneously improving mechanical performance and meeting international environmental and safety standards.