Low temperature laser absorption spectra of methane in the near-infrared at 1.65 μm for lower state energy determination

Direct absorption spectra of the 2v3 band of methane （CH4） from 6038 to 6050 cm 1 were studied at different low temperatures using a newly developed cryogenic cell in combination with a distributed feedback （DFB） diode laser. The cryogenic cell can operate at any stabilized temperature ranging from room temperature down to 100 K with temperature fluctuation less than =t=1 K within 1 hour. In the present work, the CH4 spectra in the range of 6038-6050 cm-1 were recorded at 296, 266, 248, 223, 198, and 176 K. The lower state energy Ett and the rotational assignment of the angular momentum J were determined by a ＂2-low-temperature spectra method＂ using the spectra recorded at 198 and 176 K. The results were compared with the data from the GOSAT and the recently reported results from Campargue and co-workers using two spectra measured at room temperature and 81 K. We demonstrated that the use of a 2-low-temperature spectra method permits one to complete the Ett and J values missed in the previous studies.

Pd-M-TiO_(2)(M=Mn,Cu,Ce and Fe)as passive NO_(x) adsorber(PNA)at low temperature

A series of transition metal Mn,Cu,Ce and Fe were loaded on TiO_(2) by sol-gel method with noble metal Pd as promotor for the application of passive NO_(x) absorber.Experiments on adsorption and desorption of NO_(x) were conducted and characterization methods such as X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),transmission electron microscopy(TEM)and in situ Fourier transform infrared spectroscopy(in situ DRIFTS)were involved.The experimental results show that Mn-contained catalysts,Mn-Ti and Pd-Mn-Ti,performed excellent NO_(x) adsorbing ability and appropriate desorption temperature window.On the other hand,Ce-and Cu-contained samples were not suitable for the purpose of PNA.In addition to the low adsorption capacity,these two series of catalysts released massive amount of NO below 150℃.Characterization results indicated that Pd was highly dispersed on all catalysts.The loading of Pd lowered not only the valence states of transition metals but surface oxygen percentage as well.From in situ DRIFTS tests,the Pd had little influence on the types of adsorbed substances for Mn,Ce and Cu series.However,the storage forms of NO_(x) were obviously different on Pd-Fe-Ti and Fe-Ti.

Encapsulation of 2-amino-2-methyl-l-propanol with tetraethyl orthosilicate for C02 capture

Carbon capture is widely recognised as an essential strategy to meet global goals for climate protection.Although various C02 capture technologies including absorption,adsorption and membrane exist,they are not yet mature for post-combustion power plants mainly due to high energy penalty.Hence researchers are concentrating on developing non-aqueous solvents like ionic liquids,C 02-binding organic liquids,nanoparticle hybrid materials and microencapsulated sorbents to minimize the energy consumption for carbon capture.This research aims to develop a novel and efficient approach by encapsulating sorbents to capture C02 in a cold environment.The conventional emulsion technique was selected for the microcapsule formulation by using 2-amino-2-methyl-l-propanol(AMP)as the core sorbent and silicon dioxide as the shell.This paper reports the findings on the formulated microcapsules including key formulation parameters,microstructure,size distribution and thermal cycling stability.Furthermore,the effects of microcapsule quality and absorption temperature on the C02 loading capacity of the microcapsules were investigated using a self-developed pressure decay method.The preliminary results have shown that the AMP microcapsules are promising to replace conventional sorbents.