화학공학소재연구정보센터
Industrial & Engineering Chemistry Research, Vol.57, No.44, 15122-15131, 2018
Adsorption of Trace Phosphine in Circular Hydrogen of a Polysilicon Chemical Vapor Deposition Stove by Cu/gamma-Al2O3
In our previous studies, CuCl2 showed excellent removal efficiency for trace phosphine in circular hydrogen of a polysilicon chemical vapor decomposition (CVD) stove. In this study, the investigation of properties and performances of CuCl2 supported on gamma-Al2O3 with high surface area were conducted. Various characterization techniques including BET, XRD, TPR, SEM, TGA, and XPS were used to identify the copper species and discuss the adsorption mechanism. The results illustrated that y-Al2O3 maintained the mesoporous structure and high specific surface area and it was well dispersed on the channel of y-Al2O3 after impregnation of CuCl2. There are two forms of copper species, copper aluminate and amorphous CuCl2, generated according to the copper loading. In the adsorption experiment, the virgin y-Al2O3 has no adsorption capacity for PH3. Copper aluminate showed weak adsorption performance, while amorphous CuCl2 exhibited high reactivity for PH3 capture. The adsorption capacity of 7.4% Cu/gamma-Al2O3 was 32.09 mg/g with an inlet concentration of 50 ppm at 20 degrees C. Moreover, the chemical adsorption efficiencies of Cu/gamma-Al2O3 increased with increasing the adsorption temperature ranging from 15 to 50 degrees C, but decreased by increasing the concentration of HC1 in the inlet gas. After capturing PH3 in N-2, the transformation of PH3 followed the sequence of PH3 -> H2P-OH -> HO-P=0 -> H3PO4 or P2O5. At the same time, Cu2+ was reduced to Cu+. Ultimately, H3PO4 and P2O5 were produced and CuC12 was regenerated by exposing the spent sample to ambient air for a long time. Partial water molecule may be involved in the adsorption process. The adsorbent can be renewed well by thermal treatment in air atmosphere, and the cumulative adsorption capacity for four cycles is 146.1 mg/g. Cu/gamma-Al2O3 can be effectively used as a trace phosphine adsorbent at room temperature.