Research into ion exchange softening of highly mineralized waters
Very often in the processes of water purification it is required to apply the processes of water desalting and conditioning. Their use is predetermined by the increased mineralization and high level of hardness of surface sources of water consumption. It is expedient to use methods of ion exchange for purification of these waters. We present the results of research into ion exchange softening of highly mineralized waters on weak- and strong acidic cationites.It is demonstrated that with the increase in the content of sodium ions in water, total exchanging dynamic capacity of strong acidic cationite KU-2-8 is reduced from 1744 to 1295 mg-eqv/dm3. This decrease in efficiency of the sorption of hardness ions is due to the increasing degree of desorption of calcium and magnesium ions at high concentrations of sodium ions.We defined conditions of softening highly mineralized solutions on weak acidic cationite Dowex Mac-3 in the Na+ form and it was shown that the efficiency of softening of these solutions depends little on the concentration of sodium ions. It was found that this cationite in the Na+ form is capable to absorb the hardness ions under those conditions when, in the case of strong acidic cationite KU-2-8, their desorption occurs.We defined conditions of consistent regeneration of strong- and weak acidic cationites by the solutions of acids. In this case, the solutions after regeneration of strong acidic cationite were further used for regeneration of weak acidic cationite. When carrying out such regeneration, almost total desorption of the hardness ions was achieved from both strong- and weak acidic cationite.