Silkworms' feces-based activated carbons as cheap adsorbents for removal of cadmium and methylene blue from aqueous solutions

摘要

Activated carbon samples, ACs, were obtained from silkworms' feces via chemical activation method. Many activating agents including the new ones KCl, CrCl3 and TiCl4 were compared. Acidic and basic oxidic groups in addition to aromatic tertiary and secondary amines have been detected on the surface of produced ACs. Furthermore, micro-porous solids furnishing high internal specific surface area, ranging between 1000 and 2000 m~2/g, and total pore volume up to 0.85cm~3/g were obtained. TiCl4 resulted in the solid possessing the highest area and pore volume. The obtained solids showed high efficiency in removing methylene blue and cadmium from their aqueous solutions. Adsorption capacity of sample AC/TiCl4 is 461 mg/g of MB at pH = 10, and 62.6 mg/g of Cd~(2+) at pH = 8. The nature of the formed microporous texture and the prevailing surface oxidic groups are the main controlling parameters for the observed high efficiency toward both adsorbates.