Preparation of Ceramsite Based on Clay and Its Static Adsorption Study for Cd~(2+)

The porous ceramsite based on clay is prepared by pore-forming method as adsorption material.The adsorption capacity of ceramsite on Cd~(2+),the adsorption kinetics and mechanism are investigated.The results show that the ceramsite based on clay has an excellent Cd~(2+) adsorption capacity.When the s/w is relativehy high,the adsorption quantity is relatively small.The adsorption efficiency and rate of ceramsite on Cd~(2+) decrease with the increase of s/w.The adsorption process divides into the outside surface adsorption and the balanced adsorption stages,the first stage carries on quickly,achieving in 30min.The adsorption kinetics models show that,Quasi-two adsorption rate equation fits well with the Cd~(2+) adsorption of ceramsite.Intrapartical transport model proves that the adsorption process is controlled by two or more procedures.The -OH and C-O groups of the ceramsite participates in the Cd~(2+) adsorption and kainotype CdO is formed,showing that the Cd~(2+) adsorption of ceramsite is chemical adsorption.