WASTE-WATER TREATMENT USING REVERSE-OSMOSIS - REAL OSMOTIC-PRESSURE AND CHEMICAL FUNCTIONALITY AS INFLUENCING PARAMETERS ON THE RETENTION OF CARBOXYLIC-ACIDS IN MULTICOMPONENT SYSTEMS

The influence of chemical functionality in carboxylic acids and osmoti c pressure of multi-component solutions on the retention in the revers e osmosis process are discussed. Therefore formic-, acetic-, propionic -, glycolic-, acrylic-and methoxyacetic acid (target substances) were combined with one or two other carboxylic acids (active substances), c hosen out of a pool of 16. All investigations were carried out with an aromatic polyamide membrane and the operating conditions were kept co nstant. Although the combination of all effects is extremely complex, the experiments showed that the influence on the retention of a substa nce equate as an outcome of molecular mass, acidity, functionality and spatial requirement. The influence of functionality in the active sub stances could be further divided into an additional carboxylic group, double bond and aromaticity. The calculation of the osmotic pressure d emonstrated that there was no observable difference between the real a nd ideal one when the solution contained the same number of components . Therefore it can be concluded that in this study the osmotic pressur e has no influence on the retention of the target substance.