A certain chemical site is seriously polluted by chromium. How to use chemical washing technology to
Chemical washing remediation technology is a technology that uses chemical solvents to dissolve or migrate pollutants in the soil, and then separate and treat them. It is a simple, fast and efficient contaminated soil remediation technology, suitable for the removal of a variety of heavy metal pollu
Chemical washing remediation technology is a technology that uses chemical solvents to dissolve or migrate pollutants in the soil, and then separate and treat them. It is a simple, fast and efficient contaminated soil remediation technology, suitable for the removal of a variety of heavy metal pollutants, especially for the treatment of hexavalent chromium. Chemical washing repair technology can be divided into two methods: in-situ washing and ex-situ washing.
In-situ elution refers to applying eluent to the soil through injection wells or other methods in the contaminated site, allowing it to penetrate into the contaminated zone and combine with the pollutants, and convert the pollutants into Migrant compounds. The solution containing the contaminants is then collected through extraction wells or other means and processed. This method does not require excavation and transportation of soil, reduces secondary pollution and costs, and is suitable for the removal of various pollutants in the vadose zone and saturated zone. However, this method also has some limitations, such as it may cause groundwater pollution, the removal effect and duration cannot be predicted, and it is affected by soil geological conditions.
Ex-situ washing refers to excavating contaminated soil and washing it in an external container or equipment. This method can increase the contact area and time between soil and eluent through screening, stirring, etc., and improve elution efficiency. At the same time, different eluting agents and process parameters can be selected according to different soil characteristics and pollutant types to achieve directional removal. However, this method also has some disadvantages, such as the need for a large amount of excavation and transportation of soil, which increases secondary pollution and costs, and is not suitable for large or deep contaminated sites.
Currently, commonly used chemical eluents include acidic solvents, alkaline solvents, complexing agents, reducing agents, oxidants, etc. Different eluents have different action mechanisms and effects on different forms and types of heavy metals. For example, acidic solvents can desorb heavy metal ions from the surface of soil particles or dissolve from mineral structures by lowering the pH value, and form soluble salts with acid ions; alkaline solvents can precipitate heavy metal ions into water-insoluble hydrogen oxides by increasing the pH value. substances; complexing agents can form stable complexes with heavy metal ions and improve their solubility; reducing agents can reduce high-valence heavy metal ions to low-valence states, reducing their toxicity and mobility; oxidants can reduce low-valence heavy metal ions Heavy metal ions are oxidized to high valence states, increasing their solubility and reactivity.
When chemical washing technology remediates chromium-contaminated soil, it mainly uses reducing agents to reduce highly toxic hexavalent chromium into low-toxic trivalent chromium, and separates it from the soil through complexing agents or acidic solvents. The key to soil washing remediation technology lies in the selection of soil remediation agents. Once the selection is wrong, it is likely to cause secondary pollution. Therefore, the soil washing equipment developed by Desen Environment adopts a skid-mounted integrated design, which is fast to install and easy to transfer, which greatly shortens the repair time. It is also equipped with a 5G smart module that can be remotely connected to PC and mobile phones for operation. Always pay attention to the repair dynamics and connect with the government platform to achieve the purpose of trial supervision. The equipment has reached a repair capacity of 100t/h during operation, and is running well, which greatly exceeds our expectations and has been highly appreciated by customers.
