The SEM images clearly reveal the surface texture and morphology of the adsorbent (Fig. 1). The surface morphology of SCOP is different from that of OP. After treatment with sodium hydroxide and calcium chloride,SCOP has more irregular and porous structure than that of OP, and therefore more specific surface area. This surface characteristic would result in the higher adsorption capacity. The surface areas of OP and SCOP were observed to be 0.828 m2/g and 1.496 m2/g by BET method