Heavy metal ion chelating agent for treating electroplating wastewater and preparation method and application of heavy metal ion chelating agent

Abstract

The invention discloses a heavy metal ion chelating agent for treating electroplating wastewater and a preparation method and application of the heavy metal ion chelating agent. The preparation method includes the steps of firstly, dropwise adding a magnesium sulfate solution into a sodium silicate solution, magnetically stirring for 2-4 hours, and performing hydrothermal reaction to obtain magnesium silicate gel liquid; secondly, dissolving 4-amino benzo-18-crown ether-6 into an organic solvent; thirdly, adding the solution obtained in the second step into the magnesium silicate gel liquid obtained in the first step, magnetically stirring for 2-4 hours, evenly mixing, performing hydrothermal reaction, filtering after the reaction, performing suction filtration on a filtered product, washing, and drying to obtain the heavy metal ion chelating agent. The preparation method has the advantages that the heavy metal ion chelating agent prepared by the method is used for treating the electroplating wastewater and especially the electroplating wastewater whose heavy metal ions mainly exist in the form of compounding agent complexing, and high removing rate and high-stability removing of the heavy metal ions can be achieved.

Description

technical field [0001] The invention relates to the technical field of industrial wastewater treatment, in particular to a heavy metal ion chelating agent for electroplating wastewater treatment, a preparation method and application thereof. Background technique [0002] Electroplating is the process of plating a thin layer of other metals or alloys on some metal surfaces by using the principle of electrolysis. The commonly used types of plating include nickel plating, copper plating, chrome plating, and zinc plating. A large amount of wastewater will be generated during the electroplating production process, among which the two main sources of electroplating wastewater-plated piece cleaning water and waste electroplating solution will inevitably carry a large amount of heavy metal ions. The heavy metal ions contained in electroplating wastewater are chromium, nickel, copper, zinc, cadmium, etc., which are highly toxic and cause serious harm to humans, animals, and crops. W...

AI Technical Summary

Problems solved by technology

However, with the improvement of electroplating quality standards, in the electroplating process, in order to enhance the dispersion ability of the plating solution to achieve a good coating effect, some complexing agents are often added to the plating solution, such as nitrilotriacetic acid, ethylenediamine, tartaric acid, etc. Salt, citrate, triethanolamine, EDTA, etc. These complexing agents can combine with metal ions to form strong and stable complexes. Especially when the content of metal ions in wastewater is high, heavy metal ions and ligands are stable. Hydroxide precipitation cannot be completely formed, resulting in substandard metal ions in the effluent

In the 1990s, domestic research on the trapping of heavy metal ions by dithiocarbamate and its derivatives (DTC) in electroplating wastewater has not begun. So far, the heavy metal ion traps developed can work with Hg in wastewater 2+ 、Cd 2+ 、Cu 2+ , Pb 2+ , Mn 2+ 、Ni 2+ , Zn 2+ 、Cr 3+ Various heavy metal ions react quickly to form water-insoluble chelate salts, and then add a small amount of organic or (and) inorganic flocculants to form flocculent precipitates, thereby achieving the purpose of trapping and removing heavy metals; the coexistence of certain heavy metals in wastewater Salt and complex salt can also play a certain role, but when the metal ion is complexed by a strong complexing agent, due to the strong stability of the complexing ion, the existing heavy metal scavenger has no effect on heavy metal ions and strong complexing agents such as EDTA, NTA, The effect of HEDTA ion complexation treatment is not obvious

Therefore, when the content of such strong heavy metal complex salts in the wastewater is high, the existing heavy metal collectors obviously cannot fully meet the environmental protection requirements.