Sodium bentonite (NaBent) was modified by poly(acrylic acid) (PAAc) to prepare the carriers for immobilization of Bacillus subtilis. Different mixtures of NaBent/AAc were regularly dispersed in distilled water and irradiated under gamma rays at an absorbed dose of 6.5 kGy with dose rate of 0.85 kGy/hr in air for polymerization of acrylic acid and formation of poly(acrylic acid)/sodium bentonite (PAAc–NaBent). The reaction yield was determined with the initial concentration of acrylic acid (AAc). The functional group properties of the resulting PAAc–NaBent were analyzed by Fourier Transform Infrared spectra (FTIR). Bacillus subtilis cells were immobilized on both NaBent and PAAc–NaBent as carriers by adsorption method for treating the sludge contaminated by fish feces and residual feed from the Pangasius farming ponds. The results showed that immobilization capacity of Bacillus subtilis on the PAAc–NaBent was better than that on non-modified NaBent. Analysis of BOD for the farming pond water containing Bacillus subtilis and the bacteria immobilized carriers with time revealed the lower BOD values obtained with the samples containing PAAc–NaBent, suggested that degradation of organic pollutants by Bacillus subtilis immobilized on the PAAc–NaBent was faster than that by free bacteria.

Gamma-irradiation effects on graphene oxide (GO) in a monoglyceride/ethanol (MG/EtOH) solution was investigated.  GO was dispersed in MG/EtOH solution (GOM) with the GO: MG ratio of 1:10 (w/w). The prepared GOM was irradiated by g-ray under nitrogen atmosphere in a range of absorbed dose from 0 to 50 kGy. The characteristics and morphology of reduced GOM were analyzed by Ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM). The results confirmed that the structure of reduced graphene oxide in monoglyceride solution was changed and exfoliated completely after g-ray irradiation at absorbed dose 50 kGy compared with non-irradiation sample.

Vietnamese graphite powder was irradiated by electron beam radiation (EB) at a range of dose from 0 to 120 kGy, then the graphite samples were expanded with a mixture of H2O2:H2SO4 (1,4:20, v/v) incorporating microwave treatment at 700 W for 30 seconds. The characteristic properties of graphite before and after expansion were evaluated by methods of FTIR, Raman, SEM and XRD. Besides the self-assembled of the graphite’s structure after irradiation, the electron beam radiation also facilitated intercalation processing to make expanded graphite, with coefficient of expansion (Kv) 35% higher than that of pristine graphite.

Reduction of graphene oxide (GO) for preparing the reduced graphene oxide (rGO) by γ–ray irradiation was investigated. GO was dispersed in the ethanol solution with the GO concentration of 1 mg/ml, then irradiated with γ–ray in presence of oxygen at dose range of 0 – 100 kGy for preparation of rGO product. The characteristic properties of GO and rGO were determined by UV-Vis spectroscopy, X–ray diffraction (XRD), Transmission Electron Microscopy (TEM), contact angle measurement and test of water desalination. The result showed that water desalination efficiency of rGO was about 46 – 48%.

Hydrogel of carboxymethyl starch (CMS)/polyvinyl pyrrolidone (PVP)/kappa – carrageenan (KC)/montmorillonite (MMT) was prepared by electron beam (EB) crosslinking irradiation on an EB linear accelerator UERL-10-15S2 (10 MeV, 15 kW, Russia). The crosslinking capacity of the resulting hydrogels was determined based on gel content and degree of swelling. The mechanical properties, adhesion force on the PE surface and water vapor transmission rate (WVTR) were measured. The preliminary results suggested that the mixture hydrogels (CMS/PVP/KC/MMT) can be used for personal care applications such as facial mask, moisturizing membrane for skin and so on