Abstract:
In the passivation experiment and pot experiment, the passivation effect of calcium oxide modified palygorskite (1∶1, 2∶1, 3∶1, 4∶1 and 5∶1, mass ratio) on Cd pollution in paddy soil was analyzed by using soil physical and chemical properties, Cd form distribution, available Cd and corn seedling growth. The results showed that calcium oxide modified palygorskite significantly improved soil pH, cation exchange capacity and electrical conductivity. Compared with the control, the contents of Cd in DTPA extracted, TCLP extracted and acid soluble fractions decreased by 3.44%-23.3%, 4.12%-30.7% and 2.30%-21.8%, respectively. The stem length, root length, fresh weight and dry weight of corn increased by 2.04%-17.7%, 4.66%-25.1%, 7.62%-39.4% and 0.70%-26.1%, respectively; The contents of Cd in the aboveground and underground parts of corn decreased by 5.17%-27.3% and 4.62%-22.7%, respectively. It can be seen that the passivation effect of calcium oxide modified palygorskite on Cd was better than that of unmodified palygorskite, and the addition of palygorskite and calcium oxide at ratio og 3∶1 showed the most significant effect.