Development and Characterization of a Bio-Based Wood Preservative from Terminalia mantaly, Albizia lebbeck and Lemon Peel Oil Blend

Abstract

Abstract: The increasing environmental concerns associated with heavy-metal-based wood preservatives have necessitated the development of sustainable and eco-friendly alternatives. This study investigated the formulation and characterization of a bio-based preservative derived from the exudates of Terminalia mantaly (TM), Albizia lebbeck (AL), and Lemon Peel Oil (LPO). Exudates obtained from mature trees were purified and blended with LPO extracted through hydrodistillation. The resulting bio-composite was characterized using physicochemical analysis, Gas Chromatography–Mass Spectrometry (GC-MS), Fourier Transform Infrared (FTIR) spectroscopy, and Scanning Electron Microscopy (SEM).The formulated blend exhibited a pH of 4.63, intermediate between TM (4.86), AL (5.35), and LPO (3.72), indicating a stable moderately acidic system. Incorporation of LPO reduced viscosity from 280.50 cP in AL exudate to 193.30 cP in the blend, while moisture content decreased from 12.80% and 10.25% in AL and TM, respectively, to 8.77% in the formulated composite. Total ash content decreased to 2.92%, and specific gravity was reduced from approximately 1.45 in the raw exudates to 1.19 in the blend. GC-MS analysis revealed the presence of important bioactive constituents, including limonene (20.8%), tannins (12.1%), methyl esters (9.1%), uronic acids (7.9%), saponins (4.1%), β-pinene (3.9%), and γ-terpinene (2.9%). FTIR analysis showed a shift in the hydroxyl absorption band from 3379 cm⁻¹ in the exudates to 3334 cm⁻¹ in the blend, indicating intermolecular interactions between the gum matrix and oil constituents, while a carbonyl absorption peak was retained at 1730 cm⁻¹. SEM analysis demonstrated significant microstructural modification, with pore size decreasing from 45 µm in the raw exudates to 12 µm in the blend and the polydispersity index reducing from 0.84 to 0.23, indicating improved dispersion uniformity. The combined physicochemical, phytochemical, spectroscopic, and morphological results demonstrate that the TM–AL–LPO formulation forms a stable and chemically compatible bio-composite. The developed material possesses characteristics desirable for sustainable wood preservation and represents a promising environmentally friendly alternative to conventional synthetic wood preservatives.