1、 Advantages of heavy metal chelating agents
The DTC heavy metal chelating agent SDD produced by Forcheng has greater advantages in performance due to the system design at the molecular structure level. The molecular polarity increases, and the force with heavy metal ions increases, so it has stronger heavy metal chelating ability, more scientific charge distribution, and can self assemble into a more complex bridge structure, so the flocculation effect is significantly improved. Taking copper as an example, heavy metal chelating agents can reduce the concentration of copper ions in copper containing wastewater to below 0.1ppm, but the dosage is only 1/2-1/5 of that of similar products in the market (free copper), which has a more obvious advantage in the dosage of complex copper.
However, the heavy metal chelating agent itself is non-toxic, and will not produce toxic and harmful substances such as hydrogen sulfide in the use process, and the use amount will not increase the COD of wastewater. The Chelation of heavy metal chelating agent and heavy metal will not decompose under high temperature (not higher than 250 ℃) and strong acid and alkali conditions, so the heavy metal soil stabilized by heavy metal chelating agent will not produce secondary pollution.
2、 Usage of heavy metal chelating agents
Firstly, calculate the amount of heavy metal chelating agent based on the content of heavy metals and the type of chelating agent. Calculate based on the list of heavy metal ion usage. For copper, the amount of heavy metal chelating agent used is about 3-6 times that of copper (weight ratio); For nickel, the amount of heavy metal chelating agent used is about 7.5 times that of nickel, and the actual amount depends on the specific situation.
2. Dissolve the heavy metal chelating agent into a 2% solution using tap water.
3. Adjust the pH value of the wastewater, and the pH suitable for the heavy metal chelating agent is 2-14, with a better pH of 8-9. The specific initial pH is determined based on the water quality situation.
4. Under rapid stirring (>150 rpm), add a metered solution of heavy metal catcher and chelator, and the reaction time is 2-5 minutes. If there is a strong complexing agent (such as EDTA) in the wastewater, the reaction time should be appropriately extended to 10-15 minutes.
5. Filter a small amount of wastewater after the reaction,
A. Qualitative detection of the removal of heavy metals from the filtrate. Detection method: Add a heavy metal chelating agent solution to the filtrate. If discoloration or precipitation occurs, it indicates that the heavy metal ions have not been completely removed. Continue to add heavy metal chelating agent solution to the wastewater; If there is no discoloration or precipitation, it indicates that the heavy metals have been removed.
B. Qualitatively determine whether the heavy metal chelating agent is excessive. Method: Add the original wastewater to the filtrate, causing discoloration or precipitation, indicating an excessive amount of heavy metal chelating agent; If there is no discoloration or precipitation, it proves that the amount of heavy metal chelating agent is just right. Proceed to the next step.
6. Add a 2% PAC solution with a dosage of 0.7 to 1.2 times that of heavy metal chelating agents. If the dosage of PAC is less than 100ppm, it is generally necessary to increase the dosage of PAC to make it more than 100ppm. This will result in larger alum particles and faster settling speed in subsequent processes. Under rapid stirring, the reaction time is 3-8 minutes.
7. Add 0.05% PAM (anionic) solution at a dosage of 5ppm of wastewater, stir slowly (<10 rpm), and flocculate for 3-5 minutes. Precipitate for 30-60 minutes, and take the upper clear liquid to measure the content of heavy metal ions.
As a high capacity heavy metal treatment agent supplier in China, Hunan Forcheng Environmental Protection has focused on the R&D and production of DTC heavy metal chelating agent "Fumei Sodium" for more than 10 years. Our products are widely used in environmental protection projects, sewage treatment stations, Incineration power plants, electroplating plants, manganese mines and other industries throughout the country, and have achieved remarkable results in sewage treatment, fly ash treatment, soil remediation and other projects, We have established good cooperative relationships with multiple domestic listed companies.
