Hydrophobization of pet track-etched membranes for direct contact membrane distillation of liquid radioactive wastes

Abstract

This article provides the results of liquid low-level radioactive wastes treatment by direct contact membrane distillation using polyethylene terephthalate hydrophobic track-etched membranes. The hydrophobization of track-etched membranes was carried out by UV-induced graft polymerization of triethoxyvinylsilane with styrene and coating with fluorine-containing silanes. Hydrophobic membranes were investigated by scanning electron microscope, Fourier-transform infrared spectroscopy, contact anglemeasurements, and liquid entry pressure analysis. Prepared membranes were tested in treatment of liquid low-level radioactive wastes by membrane distillation. The influence of pore sizes on water flux and rejection degree was studied. Rejection degree was evaluated by conductometry and atomic emission method. Decontamination factors evaluated by gamma-ray spectroscopy for 60Co, 137Cs, and 241Am are 85.4, 1900 and 5.4 for membranes modified with polystyrene and triethoxyvinylsilanewith pore diameters of 142 nm; 85.0, 1462 and 4 for membranes modified with perfluorododecyltrichlorosilanewith pore diameters of 150 nm respectively.