Investigation the effect of Injection Pressure of the Hypochlorite sodium on Mechanical and Permeability Properties of the Polysulfone Hollow Fibrous Membranes

Recently, the high pressure injection technique has been introduced for hypochlorite treatment of hollow fibrous membranes. In this process, the hypochlorite solution is injected into the channels of fibers at a high pressure. Literatures show that this technique is more efficient than conventional methods of hypochlorite treatment. In this study, the effects of injection pressure (in the range of 10-30 psig) on the mechanical, pore sizes and hydraulic permeability of the polysulfone (PSf) hollow fibrous membranes have been investigated. The pore sizes and pore structures were analyzed by atomic force microscope (AFM) and scanning electron microscope (SEM) images. Results showed that the pore sizes and hydraulic permeability of the hollow fibers are increased with increase in injection pressure of sodium hypochlorite. On the contrary, the mechanical properties of the membranes dropped after an increase in injection pressure from 10 to 30 psig. This decrement could have been occurred due to removal of the polyvinyl pyrrolidone (PVP) from the polymer matrix of the PSf hollow fibers. These results can be useful for control and adjustment of the process parameters of hypochlorite treatment of the hollow fibrous membranes.