Papers by Author: Qin Shuai

Abstract: Geopolymer have gradually become an alternative materials for hazardous and radioactive waste immobilization. However, the compatibility between radioactive waste and geopolymer in various extreme conditions are still not clear. In this study, the thermal stability of geopolymer solidified product of Sr contaminated zeolite A was investigated. For this purpose, the specimens after standard curing were subjected to temperatures of 600, 700 and 800 degrees C for 2h. Freeze-thaw cycles were also employed to test the thermal stability of geopolymer matrices. Meanwhile, changes in the leaching characteristics and physical properties were analyzed. Analysis showed that geopolymer - Sr contaminated zeolite A blends exhibited excellent thermal stability. Although elevated temperature and freeze-thaw cycles led to the deterioration of geopolymer matrices, the leaching rate and mechanical properties of solidified product were still acceptable. The resluts obtained indicated that geopolymer appeared to be very suitable for radioactive waste immobilization.

Abstract: The volatilization behavior of Seleenium in coal / coal char was studied by determining the concentration of Se with AFS at H₂O(Ar) atmosphere in high-temperature tube furnace. The inhibition effects on the volatilization of Se with calcium-based material (CaO) and nano materials Fe₃O₄ as absorbents were studied during coal gasification. The results show that the volatilization rates of Se, rising with the temperature of gasification, can be effectively controlled with the absorbent of CaO. Because CaO can reacts with Se produce CaSeO₄, a more stable compoud. Nano-Fe₃O₄ can enhance the ability of CaO to inhibit the volatilization of selenium, it is because not only can promote more CaSeO₄, while also reducing the possibility of its decomposition.

Abstract: A new catalyst of gold supported on nanometal oxide for oxidation of SO2 was developed. Deposition-precipitation method was used to prepare gold-based catalysts. The catalytic activity of the catalysts was evaluated by determining the concentration of SO2 with gas chromatography under reaction temperature from 100 to 700°C. The results showed that there was an enhancement of catalytic activity when gold nanoparticles were dispersed on the surface of nano-metal oxides, furthermore, γ-Fe2O3 showed the highest activity as the support of the colloidal gold supported catalysts among the nanometal oxides including γ-Fe2O3, Fe2O3, ZnO, and Al2O3. It was also found that water vapour in the reaction enhanced the catalytic activity of Au/γ-Fe2O3. The Au/γ-Fe2O3 was characterized by XRD and FTIR methods, which indicated that the gold nanoparticles were dispersed on the γ-Fe2O3 support and sulfate species were formed on the surface of catalysts.

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.