Electrolysis is not only an effective means to deal with high-concentration organic wastewater, but also an effective and low-cost method to deal with high-concentration ammonia nitrogen. to convert ammonia to nitrogen. Through the electrode reaction, during the electrolysis process, two processes of air flotation and flocculation are realized to remove organic matter and decolorize.
Electrolysis treatment of printing and dyeing ink organic wastewater is divided into direct electrolysis and indirect electrolysis.
1. Direct electrolysis
Generally, diaphragm electrolytic cells (constant current, given cell pressure) and non-diaphragm electrolytic cells (constant potential, steady current) are used. There is no fundamental difference between these two modes, but a potentiostat is used to control the anode potential. Degrading and decolorizing the organic wastewater of printing and dyeing ink in the mode can better avoid the side reaction caused by the increase of the tank pressure, resulting in the reduction of the current efficiency and other problems.
2. Indirect electrolysis
The indirect electrolytic oxidative decolorization of organic wastewater from printing and dyeing ink is to use the strong oxidant produced by electrolysis to oxidize the dye. In the chloride-containing medium, the formation of CIO- by the anode chlorine evolution, or the electrolysis of oxidation dye molecules, is a common form of indirect electro-oxidation of organic wastewater from printing and dyeing inks.
3. Mechanism of Electrolysis Treatment of Organic Wastewater from Printing and Dyeing Ink
The added electrolyte is generally NaCl, which helps to decolorize wastewater and remove COD. The reason is that when the NaCl solution is electrolyzed, a chlorine release reaction occurs on the anode, and Cl2 is a strong oxidant. Cl2, Na+ and O2 further generate NaClO, which has stronger oxidizing properties. Both Cl2 and NaClO are strong oxidizing agents that can oxidize dye molecules, breaking long bonds and discoloring them. In addition, after adding NaCl, the electrolysis of H2O is accelerated, and the bubbles formed by H2 continuously generated at the cathode move upward with branched flocs, which accelerates the flotation and flocculation of organic matter. Electrolysis has better treatment effect on dye wastewater.
4. Titanium anode for treatment of organic wastewater from printing and dyeing ink by electrolysis
In the process of treating organic wastewater by electrolysis, the electrode not only plays the role of conveying current, but also catalyzes the oxidative degradation of organic matter. Therefore, the choice of electrode material directly affects the degradation efficiency of this organic matter. The general anode uses a titanium-based PbO2 anode or a titanium-coated titanium electrode.
The titanium anodes produced by HS metal for the treatment of organic wastewater from printing and dyeing inks by electrolysis are stable in size, and the distance between electrodes does not change during the electrolysis process. The DC power consumption can be reduced by 10-20%, and the titanium substrate can be reused, saving costs, saving energy and reducing consumption.
Some parameters of electrocatalytic titanium electrode for electrolysis treatment of industrial wastewater:
1. Product shape: commonly used mesh, plate, cylinder, can also be customized according to customer needs
2. Coating system: ruthenium series, iridium series, platinum series and their mixed oxides
3. Current density: 100—600a/sqm
4. Electrode type: oxygen evolution type, chlorine evolution type, chlorine evolution oxygen evolution type