Tổng hợp và nghiên cứu hoạt tính xúc tác của hệ Cu/bentonit chống lớp cho phản ứng oxi hóa CO

Montmorillonite clay was intercalated and pillared by polycation Al, then used as a support for copper and cerium oxides catalytic systems. The pillared bentonite as well as pillared bentonite supported-catalysts was characterized by means of XRD, SEM, BET and TGA. The prepared catalysts were tested for the oxidation process of CO. The pillared bentonite is proved to make a better support than parent clay since it can improve the CO conversion from 13 % over Ce-Cu/Bent-TC to 70 % over Ce-Cu/Bent-Al with the same amount of the active oxides. By introducing 2 % Ce (Ce-Cu/Bent-Al), a higher CO conversion was found at temperature as low as 250 oC in comparison to that over Cu/Bent-Al sample. In addition, the impregnation method had created a more active Ce than Ce adding direct into the intercalation solution, the catalyst not only showed its activity at a lower temperature but also gave a higher CO conversion. The catalyst was then tested for 3 times and showed a potential in reuse

Hoạt tính xúc tác của Cu trong phản ứng phân hủy N2O

The focus of the performed studies is Cu containing catalysts for nitrous oxide decomposition in the temperature range of 200÷600 oC. Catalytic samples have been synthesized by wet impregnation method. Prepared materials are characterized by means of XRD and N2 adsorption/desorption. The obtained results reveal that Cu or Fe supported catalysts, especially Cu (or Fe)/ZSM-5, exhibit very promising activity and they are good catalysts for decomposition of N2O. An optimal copper loading of 5 wt% is found. Further increase of Cu-loading to 7 % results in the formation of segregate and less active phase. Of the three supports, ZnO, Al2O3 and ZSM-5 used, H-ZSM-5 produces the most effective catalyst for N2O decomposition due to acid nature, high surface area and high order pore structure. The decomposition of N2O follows two stages. At low temperatures, N2O decomposes to N2 and surface oxygen atoms. The second high temperature stage involves the formation of O2 and the rate of oxygen formation correlates with catalytic activity. Fast desorption of O2 increases the number of effective sites and therefore the catalyst is regenerated. Keywords. Decomposition, N2O, copper, ZSM-5, Al2O3

PHÂN TÍCH NGUYÊN TỐ VẾT LẮNG ĐỌNG TRONG KHÔNG KHÍ QUA RÊU BARBULA INDICA TẠI THÀNH PHỐ BẢO LỘC SỬ DỤNG KỸ THUẬT HUỲNH QUANG TIA X PHẢN XẠ TOÀN PHẦN

In this investigation, the Total Reflection X-ray Fluorescence (TXRF) technique detected 24 elements: Al, P, S, Cl, K, Sr, Sc, Ti, Mn, Fe, Co, Cu, Zn, As, Br, Ba, La, Eu, Tb, Dy, Ta, Pb, Th, and U in Barbula indica moss collected at Baoloc (Vietnam) from November 2019 to March 2020. Factor analysis was used to explain contamination sources at the sampling sites. This study showed that the passive moss biomonitoring and TXRF techniques are efficient and very suitable for detecting trace elements due to atmospheric deposition in developing countries, especially Vietnam and some Asian countries.Trong nghiên cứu này, kỹ thuật huỳnh quang tia X phản xạ toàn phần (TXRF) được ứng dụng đã xác định được 24 nguyên tố, bao gồm: Al, P, S, Cl, K, Sr, Sc, Ti, Mn, Fe, Co, Cu, Zn, As, Br, Ba, La, Eu, Tb, Dy, Ta, Pb, Th, và U trên rêu Barbula Indica tại thành phố Bảo Lộc (Việt Nam) từ tháng mười một năm 2019 đến tháng ba năm 2020. Kết quả cũng đã dự đoán những nguồn ô nhiễm mang lại. Ở nghiên cứu này cho thấy việc sử dụng mẫu rêu có sẵn, và kỹ thuật TXRF là hiệu quả, rất thuận lợi để xác định sự lắng động các nguyên tố vết trong không khí cho những quốc gia đang phát triển, đặc biệt là Việt Nam và các nước Châu Á