Enhancement of γ-radiation stability of polysulfone membrane matrix by reinforcement of hybrid nanomaterials of nanodiamond and ceria

Abstract

For the first time, a hybrid nanoparticle system of nanodiamond (ND) and cerium oxide (ceria) is used as a reinforcement material in order to enhance the γ-radiation stability of polysulfone (Psf) host membrane matrix. Control Psf and Psf–(ND + Ce) hybrid membranes are synthesized and characterized, with the loading of each nanomaterial varying from 0.25 to 0.5 wt%. The membranes are exposed to γ-radiation at different doses (up to 1000 kGy) and the effect of radiation on the Psf matrix is evaluated. Gel permeation chromatography studies confirm that the average molecular weight of the hybrid membranes is restored to a reasonable extent, in contrast to the control Psf membrane, which is reduced by 45% at a radiation dose of 1000 kGy. The optimum loading of ND and ceria in the membrane matrix is found to be 0.5% each, which offers a remarkable ∼10-fold enhancement of radiation stability compared to the control Psf membrane, making it a novel membrane material for potential applications in radioactive environments. The enhanced stability of the optimum hybrid membrane is due to the ability of ND and ceria in scavenging the secondary e_aq⁻ and OH˙ radicals, respectively, generated due to the radiolysis of water, as confirmed by the free radical scavenging studies.