Population growth, industrialization, global warming cause rapid pollution and depletion of surface and underground water resources. Considering these and similar factors, it is predicted that water wars will occur in the world in the 2050s. The increasing need for clean water increases the importance of water treatment technologies rapidly. Recently, membrane technology is the one of the most important advanced treatment technology used in the treatment of drinking water and waste water. Because of their high chemical resistance, good thermal stability and mechanical properties Polyvinyldene fluoride (PVDF) membranes are generally preferred for water applications. Hydrophilic additives are generally applied to PVDF membranes in order to increase the membrane flux performance. These additives dissolve in the coagulation bath and leave the membrane structure, which are providing a more porous membrane structure. However, since not all additives can be separated from the membrane structure during production, it is known that the mechanical performance of the membrane decreases over time during use because of leaching of the additives during water treatment. Using additives to the membranes that will not dissolve in water but will increase the pore formation will prevent the mechanical performance decrease in the membrane that will occur over time during use. In this sense, in this study, pore formation was aimed with the addition of sodium bicarbonate in the PVDF membrane structure. Sodium bicarbonate causes carbon dioxide output in an acidic aqueous environment. It is thought that membranes that can maintain their mechanical performance for a longer period of time, unlike hydrophilic additives, can be produced when suitable conditions are set for carbon dioxide output during membrane production. In this study, pure and 1% sodium bicarbonate added PVDF membranes were produced by phase separation method in baths with different acidity values (pH 3 and pH 7). Pure water flux and BSA rejection performances of the produced membranes were determined. Cross-sectional images of the membranes were examined with a microscope. In addition, the effects of the additive on the membrane structure and thermal behavior were revealed by FTIR and DSC analyzes, respectively, and the mechanical performances of the membranes were characterized by the tensile test.
Anahtar Kelimeler: Membrane, Phase Seperation, Pore Forming, Water Treatment