Nanodiamond as a state-of-the-art material for enhancing the gamma radiation resistance property of polymeric membranes
We report, for the first time, the development of gamma radiation resistant polysulfone (Psf)-nanodiamond (ND) composite membranes with varying concentration of ND, ranging up to 2 wt% of Psf. Radiation stability of the synthesized membranes was tested up to a dose of 1000 kGy. To understand the structure-property correlationship of these membranes, multiple characterization techniques were used, including field-emission scanning electron microscopy, atomic force microscopy, drop shape analysis, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, gel permeation chromatography, positron annihilation spectroscopy, and small angle X-ray scattering. All the composite membranes exhibited enhanced radiation resistance properties, with 0.5% loading of ND as the optimum. Compared to the radiation stability of Psf membranes up to a dose of 100 kGy, the optimum composite membrane are found to be stable up to a radiation dose of 500 kGy, owing to the unique surface chemistry of ND and interfacial chemistry of Psf-ND composites, as confirmed in pulse radiolysis studies. Experimental findings along with the Monte Carlo simulation studies confirmed five times enhanced life-span of the composite membranes in an environment of intermediate level radioactive waste, compared to the control Psf membrane.