Analysis of heavy metals adsorption and desorption processes from polluted soils [articol]

Abstract

Heavy metals adsorption in soils is a process which takes place in few hours, but their desorption is a difficult process. Adsorption efficiency depends on metallic cation, its concentration and humus content of soil. Maximum yields were determined for soil samples with higher content of organic matter, except that of Cr6+ : Cu2+ = 92 – 99.2 %, Zn2+ = 89.4 – 98.5 %, Cr3+ = 88 – 98 %, Ni2+ = 70.5 – 77.2 %; Cr6+ = 25.4 – 47.6 %. Mobilization yields of metallic ions depends on solid:liquid ratio and pH. Maximum yields were determined for the ratio 0.1 g/100 ml calcium chloride solution (0.1 M), 31.5 – 72.8 %, at pH = 4 and 19.3 – 51 %, at pH =6.