Potential of Wood Processing Residues as Eco-Friendly Adsorbents for Wastewater Treatment

In the context of global warming mitigation through energy conservation and pollution control, integrating green waste into treatment processes has become more popular. This study evaluated the potential of raw wood processing residues generated from furniture manufacturing as renewable sorbents for water treatment. Comparative studies assessed the Mn(II) removal efficiency of raw walnut (WW) and cherry (CW) wood shavings and the derived biochars (BChWW, BChCW) produced by hydropyrolysis. SEM, BET, FTIR, and TGA analyses characterized their surface and structural properties. CW demonstrated a higher adsorption capacity compared to WW. Physical activation enhanced the surface properties and Mn(II) adsorption affinity of the materials. Maximum adsorption capacities ranged from 2.1 to 2.2 mg/g for CW and WW, and 2.4 to 2.5 mg/g for BChCW and BChWW. The Freundlich model best fits to the data obtained using CW (R² = 0.997) and BChCW (R² = 0.984), while the RALF isotherm almost perfectly describes the mechanism of the Mn(II) adsorption onto WW (R² = 0.999) and BChWW (R² = 1.000). The pseudo second-order kinetic model shows strong agreement with experimental data, which suggests chemisorption on a heterogeneous surface. The results underscore the potential of wood industry byproducts as efficient and low-cost adsorbents for water treatment, supporting the circular economy and sustainable environmental management.