Adsorption and desorption processes for copper removal from water using different eluents and calcined clay as adsorbent

In this work, the copper removal in fixed-bed of Bofe calcined clay was realized, in which the adsorption and desorption of copper ions, the time of equilibrium and kinetic curves were investigated. Different types of eluents were utilized for calcined clays bed regeneration. Desorption tests were performed using a NaCl solution at 1% and seawater both at pH 3. The results indicated that the regeneration of the bed with NaCl/HCl or saline water at pH 3 is very efficient and the elution was verified as 50%. Also, it was observed an increase in removal after exposure of the bed to the eluent. The highest adsorption capacities of copper were ≈0.3 mmol/g, on the Bofe calcined clay. The equilibrium time increased from 120 min to 400 min considering the first to the last cycle. During the regeneration process, the mass-transfer zone decreased almost linearly from 9.8 to 3.4 cm with the use of NaCl and from 9.9 to 6.7 cm with seawater. In addition, those eluents provide the ideal breakthrough behavior. The recovery efficiency of the water showed that the desorption of copper ions with NaCl or seawater is feasible and has great potential.