Passivation method for heavy metal contaminated farmland soil

Abstract

The invention relates to a passivation method for passivating heavy metal contaminated farmland soil, which comprises the following steps: 1) adding a passivating agent mainly playing a chemical reaction role into the heavy metal contaminated soil, uniformly stirring, and standing for maintenance; 2) adding a passivating agent mainly playing an adsorption role into the mixture obtained in the step1), uniformly stirring, and standing for maintenance; and 3) adding water into the mixture obtained in the step 2), adjusting the weight moisture content to 20-40%, and standing for maintenance. According to the invention, ferric oxide, calcium carbonate, hydroxyl calcium phosphate, plant ash and bentonite are combined and used step by step, the advantages of chemical complexation, precipitationand physical adsorption of heavy metal pollutants of different passivation materials are brought into full play, the advantages of all the components are combined together, the economical, efficient,green and environment-friendly heavy metal passivation agent and the remediation method thereof are established, and effective remediation of heavy metal contaminated farmlands is effectively achieved.

Description

technical field [0001] The invention belongs to the field of soil remediation in the technical field of environmental engineering, and in particular relates to a passivation method for farmland soil polluted by heavy metals. Background technique [0002] Soil heavy metal pollution has become one of the main environmental pollution problems in my country. With the continuous and rapid development of industries involving heavy metals such as mining, metal smelting, chemical industry, and battery manufacturing, the discharge of heavy metal pollutants has also increased year by year. In addition, the problems of excessive discharge of pollutants by some illegal enterprises have made my country's heavy metal pollution a high incidence. situation. The area of ​​cultivated land polluted by heavy metals in different degrees in my country is close to 10 million hm 2 , Every year due to heavy metal pollution, grain production is reduced by more than 10 million tons, and grains pollut...

AI Technical Summary

Problems solved by technology

[0006] Chinese invention patents CN201711464010, CN201610596960, CN201710178365, CN201810365538, CN201610079842 and many other existing technologies disclose the method of soil passivation and the passivating agent used in the method, which is mainly by mixing different types of passivating agents with soil to It reacts with heavy metals to passivate them, but the principle of removing heavy metals is different for each type of passivating agent, it is difficult to distinguish the actual effect and interaction of each passivating agent, and it is difficult to further improve the removal effect of heavy metals

Moreover, in the prior art, many actions such as adsorption and chemical actions are carried out simultaneously, which may have restrictive effects between different actions.

Chinese invention patent CN201710902422 discloses a technical solution to remove heavy metals in the soil by first adding an adsorbent and then adding a chemical reaction reagent. However, the heavy metals may be partially excessive in the soil if the heavy metals are adsorbed first, which may have an adverse effect on further improving soil passivation.

Images