Abstract:

Constrained by various conditions, the unified purification program for removing soil cadmium (Cd) can not achieve the best effect. A novel soil Cd pollution removal and purification technology based on magnetic solid chelator (MSC-IDA) was proposed. We collected three Cd-polluted soil samples (0.925, 0.642 and 0.61 mg/kg), set MSC-IDA concentrations (0.01, 0.05, 0.1 and 0.20 mol/L), purification time (0-120 min) and different soil particle size conditions (50, 100 and 200 mesh), and designed 4 programs to study the removal and purification efficiency of MSC-IDA on soil Cd. The results showed that under program 1, by adding MSC-IDA, the Cd content in the three Cd polluted soil samples decreased significantly, and the Cd removal rate of the first soil sample was the highest of 5.22%. The results of program 2 showed that when the addition amount of MSC-IDA was less than 0.1 mol/L, the removal rate of Cd in soil increased with the increase of MSC-IDA concentration, but when the concentration exceeded 0.1 mol/L, the increase gradually tended to be flat. The Cd removal rate of the first soil sample (Cd: 0.925 mg/kg) was higher than that of the second soil sample (Cd: 0.642 mg/kg) and the third soil sample (Cd: 0.61 mg/kg). The results of program 3 indicated that the shaking time was positively proportional to the removal rate of Cd, but after 90min, the enhancement of Cd removal rate tended to be flat and declining. Program 4 found that the larger the soil particle size, the better the purification effect of MSC-IDA was. To the three Cd-polluted soil samples, MSC-IDA had the best purification effect on the second one (Cd: 0.642mg/kg).

Key words: MSC-IDA, soil pollution, cadmium, removal efficiency, purification