Process for dechlorinating potable and industrial waters containing active residual chlorine

摘要

Potable or industrial water which has been treated with chlorine gas or chlorine water and contains residual chlorine in the form of hypochlorite or hypochlorous acid is dechlorinated by filtration through an aromatic polyamine formaldehyde resin having an open-lattice structure so as to remove the residual chlorine. Such resins have a pore diameter of from 20 to 50 ngstrzom units and are made by incorporating into known aromatic polyamine formaldehyde resins, by condensation, bulky molecules such, for example, as diphenyl derivatives possess: an example is a granular phenylene diamine-diphenylene-formaldehyde resin, of which the grains are 1 to 3 mms. in diameter. The filter may be periodically washed out to remove flocculent impurities and to maintain the open structure of the filter material.