Evaluation and characterization of waste walnut shells as a porous material

The demand for porous materials in consumer products and for societal welfare improvements has led to 20th-century global regulations aimed at reducing pollution. The increased need for energy resources and storage materials further boosts demand. A key factor affecting activated carbon costs, a porous material, is raw material source; walnut shells are highly suitable. In 2023, Türkiye produced ~360,000 tons of walnuts, resulting in ~180,000 tons of shell waste, often discarded or incinerated. Converting these shells into products is essential. Activated carbon is made by carbonizing biomass in an oxygen-free environment. This study used walnut shells as a carbon source to synthesize a porous solid, achieving a surface area of 1328 m²/g at 400 °C with a 4:1 impregnation ratio.