| 摘要 |
569,112. Purifying water. RESINOUS PRODUCTS & CHEMICAL CO. May 25, 1943, No. 8332. Convention date, July 16, 1942. [Class 46] In the process of removing dissolved salts from water by passage first through a cationexchange material in the hydrogen form to substitute hydrogen for the cations, so giving free acids corresponding to the anions of the dissolved salts, and then through an anionexchange resin in the basic form to absorb such acids and wherein regeneration of the cation - exchange material and the anionexchange resin is effected by acid and an alkaline solution respectively, the rinsing of the regenerated anion-exchange resin is effected by acidic effluent previously drawn off from the anion-exchange resin while in the spent condition. For removal of acid from dilute solutions, an anion-exchange material alone is used and regenerated as above. Rinsing of the cation-exchange material is effected by raw water. The anion-exchange resin may be a gelled and heat-hardened phenol-formaldehydepolyalkylene polyamine condensate in basic form. Modified natural materials such as casein or leather which have free basic amino groups may be used as anion-exchange material. Regeneration may be effected by sodium, potassium, or ammonium hydroxides, sodium carbonate. The cation-exchange material may be a sulphonated organic solid, e.g. lignin, coal, cellulose, or a resin such as a sulphited quebracho-formaldehyde condensate, or a sulphonated phenol-formaldehyde condensate ; regeneration may be effected by hydrochloric, sulphuric or acetic acid. Specifications 556,622 and 557,414 are referred to. |
