Synthesis Of 3DOM Metal Oxide Desulfurizer And Desulfurization Performance At Ambient Temperature

With increasing depletion of fossil fuels and increasingly serious environmental issues, the research and development of novel technologies with high efficiency, energy saving, environmental friendly features has been imminent. The emerging fuel cell technology is one of typical representatives.The deep and ultra-deep desulfurization of hydrogen gas stream is the key technology area that must be addressed in the process of FC. With the change in the above technologies, it is required that desulfurization is conducted at low or ambient temperature. Metal oxides chemical absorption method is very effective and commonly used methods of desulfurization due to the strong bond between the metal and sulfur. ZnO and CuO have high desulfurization efficiency because of their favorable thermodynamics of the sulfudization. However, their sulfur capacities at room temperature are generally low. Thus, the improvement of capacity has been the research focus for enhancing the performance of desulfurization.In the study, series of 3DOM zinc-silicon and copper-silicon composite desulfurizer are prepared by PS colloidal crystal template method and used for hydrogen sulfide (H2S) removal at room temperature for the first time. The performances of desulfurization were evaluated by dynamic breakthrough testing in a fixed bed. The samples before and after adsorption were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption, and X-ray photoelectron spectroscopy (XPS). The changes of its phase composition, micro-morphology as well as texture were studied and been associated with the mechanism and performance of desulfurization at room temperature.The results of characterization show that the prepared 3DOM composites have orderly three-dimensional macroporous structure, uniform large pore size and highly order level in long range, close-packed macropores interconnected through small windows. The incorporation of silica and structure effects of 3DOM promoted the highly dispersion of ZnO and CuO in the composites, at the same time, silica also play a supporting role for the 3DOM structure. The phase composition and micro-morphology of samples before and after desulfurization have the significant changes, ZnO and CuO converted to ZnS and CuS respectively after desulfurization reaction. And the BET surface as well as pore volume of composites after desulfurization decreased obviously, indicating that the process of sulfidation is a process of transformation of open to close in internal pores. Texture plays an important role in the process of desulfurization.The performance of 3DOM zinc-silicon and copper-silicon composites were evaluated at room temperature in a fixed bed. The results show that their desulfurization performance are superior to the corresponding commercial desulfurizer and composite desufurizer without 3DOM. The improvement of desulfurization performance was attributed to the special structure features of 3DOM:the well-ordered interconnected macroporous, high surface areas and nano-crystal. Calcination temperature and the ratio of the metal oxide and silicon dioxide directly affects the performance of 3 DOM composite desulfurizater. In addition, the study also found that water vapor has a great promoting role in desulfurization at room temperature. The performance of 3DOM composites was improved significantly through ammoniated, indicating that surface properties play a key role in desulfurization at ambient temperature.In the experiment, the regeneration performance of 3DOM composites was also studied. The sulfur capacities decreased after regeneration, but compared with commercial desulfurizer, its generation level was considerable and the performance was stable. The 3 DOM structure was no obvious damage and collapse.