Non-Thermal Plasma Desorption of Copper (II) Ions from a Cu(II)-Clay Composite and Recuperation of the Adsorbent Part B

The regeneration of the adsorbents and recovery of heavy metals are of crucial importance in assessing their potential for commercial application. In this study, Non-thermal plasma (NTP) Glidarc was applied as desorbing agent for Cu(II) desorption from Cu(II)-clay composite. The kinetics was also studied and the comparison with other desorbing agents was performed. Results showed that, NTP Glidarc efficiently removed adsorbed Cu(II). Cu(II) desorption process by NTP occurred following three major steps: a fast initial desorption step followed by a slow desorption step and finally the equilibrium. The increase of the stirring rate and the Cu(II)-clay composite dosage also increases the efficiency of desorption. The equilibrium was reached after 180 min and 99.79% of Cu(II) was recovered. A comparison with other desorbing agents followed the order: plasma > HCl > CaCl2 > NaCl. Six adsorption-desorption cycles did not significantly affect the adsorption capacity of the clay. Desorption with NTP and HCl fitted well the first order, Elovich, parabolic diffusion and modified Freundlich kinetic models. The time of half reaction was 45 min for NTP and 61 min for HCl. NTP can thus be considered as an efficient heavy metal desorption strategy from adsorbents.