Treatment and resource recovery method for chromium and ammonia nitrogen in electroplating wastewater

Abstract

The invention provides a treatment and resource recovery method for chromium and ammonia nitrogen in electroplating wastewater. The treatment and resource recovery method comprises the following steps: dropwise adding an inorganic alkali solution into the electroplating wastewater, and carrying out stirring, standing and filtering to obtain a mixed solution I and a chromium hydroxide precipitate;adding disodium hydrogen phosphate into the obtained mixed solution I, and carrying out stirring until the disodium hydrogen phosphate is dissolved; dropwise adding inorganic alkali liquor while stirring; adding a magnesium chloride solution, and carrying out stirring, standing and filtering to obtain a mixed solution II and a magnesium ammonium phosphate precipitate; and adding nitric acid modified activated carbon into the obtained mixed solution II, conducting oscillating and adsorbing in a water bath, and filtering and recycling the activated carbon. According to the invention, chromium and ammonia nitrogen in the electroplating wastewater are basically removed through two precipitation operations, the obtained precipitate chromium hydroxide can be used for preparing chemical reagentsor paint pigments, and the precipitate magnesium ammonium phosphate can be used as a nitrogen-phosphorus-magnesium slow-release fertilizer; and residual ammonia nitrogen is subjected to deep adsorption treatment through the modified activated carbon. The method develops an effective pollutant treatment and resource recovery treatment technology for the electroplating wastewater.

Description

technical field [0001] The invention relates to the field of wastewater treatment, in particular to a method for the treatment and recycling of chromium and ammonia nitrogen in electroplating wastewater. Background technique [0002] The electroplating industry is a traditional heavy polluting industry. The pollutants contain various heavy metal ions, organic matter and ammonia nitrogen. For several metals with high value such as nickel and copper, chemical precipitation, extraction and ion exchange have been partially realized. Or recycle it all. [0003] Chinese patent CN201720029351.4 discloses an electroplating chromium-containing wastewater treatment and recycling equipment, which uses an ion exchange method to control the chromium concentration below 0.5mg / L. However, the conventional heavy metal metal treatment technology has a poor treatment effect on the removal of ammonia nitrogen pollutants in electroplating wastewater. Reverse osmosis, electrodialysis, activated...

AI Technical Summary

Problems solved by technology

However, the conventional heavy metal metal treatment technology has a poor treatment effect on the removal of ammonia nitrogen pollutants in electroplating wastewater. Reverse osmosis, electrodialysis, activated carbon adsorption, etc. remove heavy metals and also have a good removal effect on ammonia nitrogen.

Chinese patent CN110357198 discloses an adsorption material for low-concentration ammonia-nitrogen wastewater treatment and its preparation method, CN110217949 discloses a method for treating high-ammonia-nitrogen wastewater, and CN110342686 discloses a sewage that uses chemical precipitation-adsorption to remove ammonia nitrogen in sewage Treatment system. Due to the high treatment cost of the above scheme, its application in the treatment of wastewater with high ammonia nitrogen content is greatly limited.

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