Science Research  Academic Press

Exploration of the passivation effect of different types of passivators on cadmium contaminated soil

Xiaoping  Ning 
Deheng  Deng 
Shujuan  Lv 
Jinbin  Lai 
Shengshan  Liu 
Xinyu  Liu 
Wenzhong  Liang 
Keywords:

Abstract

The problem of excessive cadmium in farmland soil in China is severe, and it is of great significance to explore suitable passivators for specific polluted soils. Three typical and representative commercially available passivators were selected as the test agents, and simulated the natural production process of irrigation and drainage in farmland soil. Through soil cultivation experiments, the remediation effects of different types of passivators and water management on Cd contaminated farmland soil in a certain area of Sichuan were explored. The results showed that the passivator agent 1# based on organic matter reduced the soil pH value, the passivator agent 2# based on alkaline substance and the passivator agent 3# based on clay mineral could increase the soil pH value in different degrees, and the passivator agent 2# was better than the passivator agent 3#. Under flooding condition, soil pH value can be increased. The three passivator agents can increase the content of soil organic matter in different degrees, and the maximum increase rate was 35.2% under 8%. The three passivator agents can reduce the available Cd in different degrees, and the maximum reduction of passivator agents 1#, 2# and 3# was 61.8%, 67.1% and 46.4% respectively. The correlation analysis showed that the flooding state was conducive to the decrease of available Cd. Under the action of passivator agent 1# , the correlation between available Cd and pH was weak, and there was a strong negative correlation between Cd and organic matter (R=0.9922). Under the action of passivator agent 2#, available Cd had a strong negative correlation with pH (R=0.8702) and a weak negative correlation with organic matter (R=0.4041). Under the action of passivator agent 3#, available Cd was strongly negatively correlated with soil pH value and organic matter.