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Removing Waste Textile Dyes in Wastewaters
The textile industry is third only to the precious metal mining and metal plating industries for cyanide consumption. Textile dyes are complex organic-inorganic compounds often cyanide-based, and they cannot be discharged into streams and lakes because of discoloration and human-animal-plant danger. They must be ionized (turning organics to ions) and thereafter removed from the discharge water. Dyes are perdurable chemicals that are difficult to remove from water. Typical processing requires high oxidation (chlorination, hydrogen peroxide, Caro's Acid, etc.) to destroy the dyes followed by an ion exchange or similar process to remove the oxidation byproducts (chlorides, sulfates, carbonates, etc.) This procedure has proven to be so expensive that many textile plants, particularly those subjected to competitive stresses, simply do not remove them but rather simply discharge them into ambient waters or shut down and move to another country that does not impose strong environmental laws. In many developing countries in which environmental controls can be an expensive luxury, textile dyes are simply discharged into ambient waters.
Organic mineralization processes have demonstrated the ability to mineralize dyes in water. Such a process is of course a very valuable precursor for Reticle—mineralizing the offending dyes into a series of constituent ions. However, mineralized dyes are environmentally problematic—they contain not only mineralized organics but also mineralized metals and other radicals. All the chemicals that formerly comprised the dyes are turned into ions. Mineralizing a complex organic-inorganic dye stream does not solve the problem; those ions must be removed before the water can be discharged or recycled. However, such mineralization allows Reticle CDI cells to remove the dyes and the ion that comprise them and therefore cleans all dyes formerly dissolved in water. A series process consisting of organic mineralization to mineralize dyes followed by a Reticle Carbon CDI to remove the fragments of such decomposition promises a low cost, inexpensive treatment plant because with this configuration there is no need for costly equipment capable of withstanding highly oxidative condition. The joint mineralization-Reticle Carbon CDI removal process promises to be effective and continuous. Industries that rely on dyes for their workproduct such as the textile industry, the newspaper industry, the magazine industry, the publishing industry, etc. all use troublesome dyestuffs and therefore could be expected to embrace the organics mineralization-Reticle Carbon series configuration to meet increasingly stringent cleanup standards.
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