Ion-exchange capadty

The wettability or the water content of a membrane depends on the equivalent weight (EW) or the ion-exchange capadty (lEC), pretreatment, solution composition, operating temperature, etc. The equivalent weight is defined as the weight of the polymer which is neutralized by one equivalent of alkali and is the redprocal of lEC as... 

Anion exchange resins are generally lower in their exchange capadty and durability than cation exchange resins and are seldom used for industrial separation. In general, ion exchange as a tool for separation is only used when other steps fail, because of its tedious operation, small capadty and high costs. 

The natural choioe of a sqMuation technique for both inorganic cations and anions is icm-exdiangB duomatography. The standard detection technique for these analytes is conductivity detection. This requires a low background conductance of the mol phase. Special techniques have been developed under the name of i< i diromatograpby that combine spedal low-capadty ion exchangers with special mobile phases. For many analytical proble cookbook methods have been worked out by the su q>Iiers of ion-chromatography equipment Therdore there is usually little need to develop new methods. 

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