Nut shell activated carbon is a black granular adsorbent made from natural nut shells such as walnut shells and apricot shells through carbonization and activation processes. It is natural, eco-friendly, high in mechanical strength and not easy to pulverize. Featuring a well-developed pore structure and large specific surface area, it exhibits excellent adsorption performance and can effectively adsorb formaldehyde, residual chlorine, pigments and other pollutants, being widely used in environmental protection, water treatment and other fields.