Determining the amount of metal removal: For batch kinetic studies, 20 g of the mussel shells/clay beads were introduced into a 180 m L solution of the Cd(II) solution of initial concentration of 5 ppm. The samples were shaken in a thermostatic shaker at a speed of 150 rpm at 30°C. After a predetermined time, each solution was filtered through Whatman filter paper. The metal concentration in supernatant was determined by using an atomic absorption spectrometer(AAS, Perkin Elmer, A Analyst 800, USA).