ВИЗНАЧЕННЯ ЕФЕКТИВНОСТІ ВИЛУЧЕННЯ СУЛЬФАТІВ НА ЗВОРОТНООСМОТИЧНІЙ МЕМБРАНІ НИЗЬКОГО ТИСКУ

Abstract

The dependence of the efficiency of the low-pressure reverse osmosis membrane Filmtec TW30-1812-50 on the initial concentrations of sodium sulfate in the range of 10-650 mg/dm3 at permeate recovery rates of 1-90 % using a pressure of 4 atm was determined. The effect of increasing the permeate recovery rate on selectivity, membrane performance, and the in-crease in the sulfate content of concentrates was determined. It is shown that the concentration of sulfates in permeate depends on their initial concentration in solutions and increases both with an increase in the initial concentration and with an increase in the degree of permeate extraction. The latter factor is quite significant at initial sulfate concentrations of 650 mg/dm3. The membrane performance increases with decreasing salt content in water and decreases with increasing permeate removal rate, which leads to an increase in salt concentration in the pre-membrane space. The selectivity of the membrane for sulfates is 94.9-99.3 % and increases with increasing concentration of sodium sulfate solutions in solutions, despite a certain increase in salt concentrations in permeates. It is shown that as the degree of permeate selection increases, the selectivity for solutions with low initial sulfate concentrations increases. A FFP-based process modeling was performed to determine the sulfate con-centration in the permeate and concentrate at any initial sulfate concentration in a certain range. It was found that the con-centrate solutions are stable in the entire range of concentrations used with an increase in the degree of permeate recovery from 10 to 90 %. Based on the research results, a method for determining the capacity of the plant and the osmotic and oper-ating pressures based on the salt concentration and the set pressure in the system was proposed. From the data obtained, it can be concluded that the permissible level of mineralization at which the use of low-pressure reverse osmosis membranes is ad-visable.