CLEANING WATER FROM COPPER AND IRON IONS, USING THE DYNAMIC NYLON-POLYSTYRENE MEMBRANE
This paper deals with the studies of cleaning the model machine-building enterprise sewage water from heavy-metal ions, using dynamic membranes made of nylon with the polystyrene (PS) surface layer. PS mass content in the dynamic membrane was 4 %. Contents of copper and iron ions in the model solution make 138 mg/dm<sup>3</sup>and 96 mg/dm<sup>3</sup>, respectively. PS forms a porous layer on the nylon substrate surface, which leads to reducing the pore sizes of membranes and to the 14-time decrease in the specific performance of the modified membranes. Thus, at separating the copper sulfate solution, the performance decreased by 5 %, while in separating the FeCl<sub>3</sub> solution, the membrane permeability decreased by 40 %, as compared to distilled water. Efficiency of cleaning the water from the Fe<sup>3+ </sup>ions with the initial nylon membrane makes 48.9 %, while upon the PS modification, the cleaning efficiency increased up to 95.7 %. At the same time, the efficiency of cleaning the model liquid from the Cu(II) ions by the initial nylon membrane makes 0.72 %, while the cleaning efficiency increased up to 55.8 % upon modifying the PS membrane surface. Particle sizes in the iron chloride solution are distributed within the range of 8.5-2,690 nm. Upon the membrane-induced separation, the particle sizes of the FeCl<sub>3</sub> solution dispersed phase are decreased. By their efficiency, the modified nylon-PS membranes meet or exceed ion-exchange and nano-filtering membranes.