48. Equilibrium and Kinetic Studies of Adsorption of Cd (II), Zn(II), and Cu(II) from Aqueous Solution into Cereal By-Products

The present study concerns the test of natural adsorbent obtained from a local cereal by-product as adsorbent for the removal of heavy metals such as Cu, Zn, and Cd ions from aqueous solutions. The solid support was used after calcinations at a temperature of 600 °C in exclusion of the air. The study was an opportunity to investigate the adsorption kinetics where equilibrium was reached after 30 min for the three metallic pollutants. The kinetic was of pseudo-second-order and controlled by intra-particle diffusion phenomenon. The isotherm of adsorption was also examined and showed a type C from Langmuir classification. The effect of important parameters such as the initial concentration and the contact time was also considered. The results showed a high retention capacity of the cereal by-product adsorbent, where yield values exceeding 90 % was reached for an initial concentration of 10 mg/L, at 20 °C, a mean size diameter of 0.1 mm, a mixing velocity of 600 rpm, a solid–liquid ratio of 10 g/L, a pH between 3 and 6, and a contact time of 2 h.