Preparation of Activated Carbon from Cashew Nut Shells for Water Purification

The application of the agricultural waste of cashew nut shells (CNSs) from the Ivory Coast is proposed for the production of activated carbon (AC) used in water treatment by the physical activation. Washed and crushed CNSs are carbonized at 800°C. The crushed CNS carbonizate is activated by the physical method in a temperature range from 400 to 700°C. The specific surface (SBET) and porous structure of the AC samples are investigated by low-temperature nitrogen desorption and X-ray structural (X-ray phase) analysis. The results show that an increase in the activation temperature at a fixed time leads to an increase in the material specific surface, the development of a microporous structure, and an increase in the summary volume of mesopores and micropores of AC. The X-ray phase analysis data shows that the degree of graphitization, interplanar spacing, and crystallite sizes vary insignificantly. The possibility of using CNSs to fabricate AC no worse in sorption properties than its analogs currently in use to purify water is proven.