Can organic wastewater with high concentrations be treated using composite membranes before being used in ion-exchange membrane caustic soda production?
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Dear all**, I have a humble question for you: Can the fresh water obtained after treating organic wastewater with high salt and high COD levels using composite membranes be used as brine for ion-exchange membrane caustic production? What are the requirements for the brine used in ion-exchange membrane caustic soda production?
I’m dizzy. . Is there really no answer? !
This idea is feasible. But in practice, it is basically very difficult to achieve, with the possibility of success being extremely slim. First, find out the requirements of the caustic soda industry for brine, and then think about it. If things go wrong, death from an explosion is inevitable. Reference.
You can take a look at Chen Yanxi’s electrolysis project; it covers the requirements for brine in the electrolytic chlor-alkali process. If the cost of chlor-alkali brine ends up being much higher than that of refined brine, who would use it? !
In fact, for chlor-alkali production, saltwater is required to have a TOC level below 10 ppm and a TN level below 5 ppm. As for explosions that can cause deaths, they aren’t that scary; explosions mainly occur when there is a high nitrogen content, as nitric trichloride is generated during electrolysis, and this can lead to explosions in liquid chlorine systems. However, there are now some technologies available to address the issue of nitric trichloride, such as regular discharge methods. There is also the issue of organic substances, which can lead to low chlorine purity, damage to the membrane, and an increase in cell voltage.
Reply to 3# qdzyhb: Can this type of wastewater be treated? Main components: water 65-69%, sodium chloride 18-20%, sodium hydroxide 4-5%, organic salts and other impurities 9-10%. COD: 70,400 mg/L, Ammonia nitrogen: 17,545 mg/L, pH: 14, Salinity: 182,000 mg/L.
This idea is supported by the fact that multi-effect evaporation concentration and crystallization at low temperatures require high amounts of energy, and the construction of evaporation ponds requires a large amount of land. This treatment method converts high-salt content into a usable product, which is valuable!