Device and method for removing hexavalent chromium from electroplating wastewater for electrocoagulation-electric flotation

Abstract

The invention provides a device and method for removing hexavalent chromium from electroplating wastewater for electrocoagulation-electric flotation, wherein the device includes an electrocoagulation unit and a neutralization reaction unit arranged in sequence and communicated with each other, and a pump for pump is arranged beside the neutralization reaction unit An air compressor for feeding compressed air, a communication pipe for preventing liquid backflow is provided between the electrocoagulation unit and the neutralization reaction unit; a flow guide pipe for guiding compressed air is arranged in the neutralization reaction unit After the neutralization reaction unit, a first electric floating unit and a second electric floating unit are sequentially arranged, and the first electric floating unit is provided with a first interlocking electrode and a first three-phase separator; The second electric floating unit is provided with a second interlocking electrode and a second three-phase separator. The device and method provided by the invention have high electrical conductivity and low power consumption, can effectively reduce operating costs, do not need to add polymer flocculants, and can effectively improve the removal efficiency of hexavalent chromium and total chromium.

Description

technical field [0001] The invention relates to the technical field of electroplating wastewater treatment, in particular to a device and method for removing hexavalent chromium from electroplating wastewater for electroflocculation-electric flotation. Background technique [0002] Electroplating is an industrial process that uses chemical or electrochemical methods to decorate, protect or obtain certain new properties on metal or non-metal surfaces. It has strong industrial versatility and wide application. The functional requirements of different components are different, and the operation methods and processes are also inconsistent, resulting in a variety of heavy metal ions in the water quality components of electroplating wastewater, among which hexavalent chromium ions are seriously harmful to the human body. Traditional electroplating wastewater treatment methods include adsorption, chemical precipitation, biodegradation, ion exchange, and electrochemical methods. Th...

AI Technical Summary

Problems solved by technology

This invention adopts electroflocculation equipment and method to deal with the heavy metal ions in the electroplating wastewater, but the cathode will produce H in the electroflocculation reactor 2 , which prevents the floc from fully settling on the way out of the electrolyzer

At the same time, in order to meet the removal standard, because the particle size of the floc is very small, the filtration step, ultrafiltration step and reverse osmosis step must be carried out after electrocoagulation, which increases the tediousness and production cost of electroflocculation treatment of electroplating wastewater

Chinese patent 201510995773.2 discloses a treatment system and method for electroplating chromium-containing wastewater, and specifically discloses that the system includes a regulating tank, an acidification tank, an electroflocculation reduction device, a neutralization tank, a flocculation tank, a buffer tank, and a separation tank. The electro-flocculation reduction device is also used to reduce the hexavalent chromium ions in the electroplating wastewater under acidic conditions, and the neutralization step is separated from the flocculation step and the electro-flocculation step, but the membrane separation method is still used for the treatment of flocs , and the hexavalent chromium ions not completely reduced in the electro-flocculation step cannot be completely removed, which has caused the disadvantages of inconvenient equipment and methods protected by this invention, high processing costs and low removal efficiency

Images