Long Term Stability Assessment of Heavy Metal Passivation in Farmland Soil Based on Accelerated Carbonation
Soil heavy metal pollution has seriously affected the safe utilization of farmland and human health in China,and the control of heavy metal pollution in farmland has also become a major environmental problem that needs to be solved.The commonly used inorganic remediation agents in soil remediation engineering,such as hydrated lime,sodium sulfide,and potassium hydrogen phosphate,are used to passivate copper zinc lead cadmium contaminated soil.Through accelerated carbonation tests,the effect of carbon dioxide on the long-term stability of commonly used inorganic agents in passivating heavy metals such as copper,zinc,lead,and cadmium is investigated.The results indicate that,without considering carbonation,the addition of the three inorganic remediation agents mentioned above can significantly reduce the content of heavy metals in the leachate of contaminated farmland soil and lower the risk of heavy metal pollution.After accelerated carbonation,the contents of copper and cadmium in the leachate treated with hydrated lime significantly increased,while the contents of lead and zinc unchanged.In the leachate treated with sodium sulfide,the contents of copper,zinc,lead,and cadmium all showed a certain degree of increase.In the leachate treated with potassium hydrogen phosphate,the contents of copper and lead remain unchanged,and the content of zinc slightly decreased and the content of cadmium slightly increased.When implementing soil heavy metal pollution remediation projects using passivation technology,in addition to selecting appropriate amounts of remediation agents based on the type of heavy metal,accelerated carbonation tests should also be combined in order to clarify the stability changes of pollution factors under carbonation,and ensure the remediation effect.
passivationheavy metal leachingfarmland soilcarbonationsoil remediation
NETL
NSTL
万方数据
