... Stable property, not soluble in acid and alkali. 3. Good adsorbability, hydrophily,anti oil Walnut shell , water treatment materials, filter ... resistance, good pressure resistance, resistance to pressure of 23.4kgf, stable chemical property, do not dissolve in acid and alkali ... removal, easily backwashing etc in water treatment. walnut shell has been widely used in oil field wastewater treatment, ...