Design And Synthesis Of New Chelates Used In Heavy Metal Contaminated Soil Remediation And Its Mechanism Of Enhanced Phytoremediation

Soil heavy metal pollution is becoming an environmental problem that can not be ignored all over the world.Phytoremediation is one of the most promising methods for remediation of heavy metals in soil,which has the characteristics of no two pollution and convenient implementation.Chelating agents combined with phytoremediation can solve the problem of inefficient extraction of heavy metals from plants,thus greatly enhancing the application value of phytoremediation.However,most chelating agents are difficult to degrade or chelate.As a chelating heavy metal and degradable polymer material,Poly(aspartic acid)(PASP)has inherent advantages in this field.In this paper,Poly(aspartic acid)and its three derivatives were prepared by water phase method in the laboratory.On the basis of environment-friendly,Poly(aspartic acid)was grafted with different functional group side chains.Meanwhile,the adsorption behavior of several chelating agents on heavy metals was simulated by computer molecular dynamics,which played a guiding role in the experiment.Water solution experiments show that several Poly(aspartic acid)chelating agents have good chelating properties to 4 kinds of heavy metal ions,and the removal rate of heavy metal ions is up to 95%.These chelating agents have different sensitivity to pH and temperature conditions.The chelating stability constants of Poly(aspartic acid)for heavy metals were higher than 105 by UV spectrophotometry.They are excellent chelating agents.Soil column leaching experiments showed that Poly(aspartic acid)and its modifier could release more than 50%of heavy metals in soil columns.Pot experiments proved that the new chelating agent in this paper can increase the total amount of heavy metals by 2.2 to 7 times by activating heavy metals and promoting plant growth.