Abstract: Based on good cation exchange property of vermiculite，the adsorption of vermiculite for simulated radionuclide Sr was studied by the static adsorption method. The adsorption behaviors and the effect of the experimental conditions were investigated. The results show that the saturated adsorption capacity of vermiculite sample for the simulated radionuclide Sr was 8.246×10-2 mmol/g. The suitable pH value ranged from 4 to 11, the balanceable adsorption time was 3d, and the suitable temperature was 30°C. The main adsorption type was cation exchange. The adsorption mechanism can be described by Langmuir and Freundlich models. It acts better in accord with Langmuir model, and the correlation coefficient is 0.99974. This experimental study has important significance on low concentration of Sr radioactive waste liquid treatment.
Abstract: Study on adsorption thermodynamics and kinetics of Lipoic acid by NG-16, NDA-100 and ND-90 resin was carried out through static experiments. The results showed that the adsorption of Lipoic acid on NG-16 resin is Langmuir monolayer, and the adsorption rate appears to be the first order kinetics. The adsorption date of Lipoic acid on NDA-100 and ND-90 resin also were described well by the Langmuir isotherm, which was caused by the capillary condensation and the volume filling of micropores besides monolayer adsorption. When the concentration of Lipoic acid is higher than 400mg/L, the capillary condensation and the volume filling of micropores act the main part. The adsorption of Lipoic acid on NDA-100 and ND-90 resin pass through two phases: macropores, mespores area and micropores area. And the adsorptions in micropores area are described well by the Dubinin-Radushkevich isotherm. The adsorption rates of the two phases are the first order kinetics.
Abstract: Hydrophlogopite, a regular interstratified mineral with 1:1 ratio of vermiculite and phlogopite crystal layers, was modified with sodium and organically intercalated with HDTMAB, and then the samples were examined with XRD. Based on the theoretical geometric dimensions of organic cations, the structure and arrangement model of HDTMA+ cation in the interlayer space of vermiculite crystal layers were studied, the reaction mechanism of organic intercalation was also discussed. The results show that HDTMA+ cations enter into the interlayer space of vermiculite crystal layers only without exchange with the cations in the interlayer space of phlogopite crystal layers, and that the arrangement models of HDTMA+ cations in the interlayer space of vermiculite crystal layers varies with the added amount of HDTMAB. When the added amount is small, the arrangement model of HDTMA+ cations in the interlayer space of vermiculite crystal layers is lateral-bilayer, and when the added amount is larger, the arrangement model is paraffin-type monolayer.
Abstract: The catalytic activities of various nanometer metal oxides (ZnO, CeO2, ZrO2, Al2O3, Co3O4, MgO) supported colloidal gold catalysts with self-designed equipment were evaluated and compared for benzene catalytic oxidation. The results showed that ZnO was the most activive support of the colloidal gold among these nanometer metal oxides. The effects of Au/ZnO on the activity for benzene oxidation were investigated at 50- 300°C. The optimal gold loading was 2 wt%. The Au/ZnO was characterized using BET, XRD, and TEM methods. The XRD patterns and TEM image showed that gold nanoparticles were well dispersed on the surface of ZnO, and the mean diameter was 3.1±0.81 nm. The gaseous products of benzene oxidation and the adsorbed species on Au/ZnO catalyst surface were characterized with FTIR and GC-MS. It was proved that benzene was completely oxidized into CO2 and H2O over the Au/ZnO catalyst at low temperature.
Abstract: Aimed at the problem of low purity and poor electrochemical activity of natural MnO2, acid-treatment was applied to pre-treat natural MnO2. Three factors, such as H2SO4 concentration, bathing temperature and reaction time, were accessed. The best acid treatment conditions of natural MnO2 were determined through an orthogonal experiment of 3 factors and 3 levels, using the initial discharge capacity at 0.2C rate as an index, that is, H2SO4 concentration 2mol•L-1, bathing temperature 30oC, reaction time 4h. Lithiated manganese dioxide-Li0.3MnO2 was prepared by melt-impregnation method using the MnO2 pre-treated under the optimal acid-treatment conditions, which showed an initial discharge capacity of 186.7 mAh•g-1 at 0.2C rate and little capacity degradation after 300 cycles at 20%DOD.
Abstract: Multiple copper-zinc alloy was used to treat water in order to restrict the formation of hard scale during heating process. Trace amounts of metal ions were dissolved from the alloy under the action of tiny battery corrosion, which took part in the crystallization of calcium carbonate crystal. The ion migration rules and its effect on the crystal structure of water scale were studied. The ICP test results show that after immersion in the water for 20 min, the zinc ion concentration increased to 0.35 mg•L-1 compared with contrast group. The simulating experiment of the scale crystal growth demonstrated that the calcium carbonate scale after treated with the alloy showed a transformation from calcite to aragonite, and the ratio of calcite to aragonite changed from 1:0.125 to 1:2.30. Meanwhile, the heat transfer efficiency was increased to 2.19%.
Abstract: Effect of acute toxicity and chronic toxicity on attapulgite for animal was studied by Kunming mice and SD rats experiment through administering intragastrically with large dose of attapulgite suspension. The results showed that the mice were normal and grew well, and they did not appear death and toxicity symptoms when they received the same amount as 286 times of the adult dose, indicating that attapulgite mineral powders did not contain acute toxicity and administering intragastrically with large dose of attapulgite suspension had no obvious influence on blood environment and normal growth of rats, and attapulgite did not contain chronic toxicity.
Abstract: The cationic surfactant-octadecyl trimethyl ammonium chloride was added to the mixture of sepiolite powders and water with mechanical stirring. The effect of cationic surfactant on the defibering of fiber bundles was studied. The samples were characterized by X-Ray diffraction (XRD), bulk density, scanning electron microscope (SEM), FT-IR spectrum (FTIR) and thermal conductivity. The results indicated that the surface active agent could protect the structure of sepiolite fibers effectively, the bulk density and the thermal conductivity of the fibers could reach 0.06g/cm3 and 0.042W/(m.K), respectively.