Weiman Li

Reactive adsorption of low concentration methyl mercaptan on a Cu-based MOF with controllable size and shape

A copper-based metal organic framework (MOF-199) with controllable size and shape was synthesized and used to remove gaseous methyl mercaptan (CH3SH). Characterizations of the synthesized MOF-199 samples before and after desulfurization were carried out by X-ray diffraction (XRD), Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS) to observe the adsorption mechanism of CH3SH on MOF-199. The adsorption performance of the synthesized MOF-199 materials and commercialized activated carbon (AC) and Cu loaded AC were evaluated by breakthrough experiments. All three synthesized MOF-199 materials show better performance than commercialized AC. The morphology and texture of MOF-199 materials have great influence on the performance of the adsorption process. The MOF-199 material synthesized by a hydrothermal method exhibited the highest sulfur compound capacity among the synthesized MOF-199 materials (74.7 mg of CH3SH/1 g MOF-199). The color change of MOF-199 during the CH3SH capturing process, indicated a strong interaction between the unsaturated copper sites and –SH group which finally formed CuS and gave rise to obvious damage to the MOF structure.

Promotion of transition metal oxides on the NH3-SCR performance of ZrO2-CeO2 catalyst

Chromium oxide and manganese oxide promoted ZrO2-CeO2 catalysts were prepared by a homogeneous precipitation method for the selective catalytic reduction of NOx with NH3. A series of characterization including X-ray diffraction (XRD), high-resolution transmission electron microscope (HR-TEM), Brunauer–Emmett–Teller (BET) surface area analysis, H2 temperatureprogrammed reduction (H2-TPR), and X-ray photoelectron spectroscopy (XPS) were used to evaluate the influence of the physicochemical properties on NH3-SCR activity. Cr-Zr-Ce and Mn-Zr-Ce catalysts are much more active than ZrO2-CeO2 binary oxide for the low temperature NH3-SCR, mainly because of the high specific surface area, more surface oxygen species, improved reducibility derived from synergistic effect among different elements. Mn-Zr-Ce catalyst exhibited high tolerance to SO2 and H2O. Cr-Zr-Ce mixed oxide exhibited>80% NOx conversion at a wide temperature window of 100°C–300°C. In situ DRIFT studies showed that the addition of Cr is beneficial to the formation of Bronsted acid sites and prevents the formation of stable nitrate species because of the presence of Cr6 +. The present mixed oxide can be a candidate for the low temperature abatement of NOx.

Removal of hydrophobic volatile organic compounds with sodium hypochlorite and surfactant in a co-current rotating packed bed

A co-current flow rotating packed bed was applied to remove volatile organic compounds (VOCs) by sodium hypochlorite (NaClO) and surfactant (sodium dodecyl benzene sulfonate, SDBS) from air stream. Xylene was used as a model VOC herein. The effect of pH, concentration of NaClO and SDBS solution, liquid flow rate, gas flow rate and rotational speed on xylene removal efficiency and overall mass transfer coefficient (KGa) were discussed. Then, a correlation for KGa of the co-current rotating packed bed was proposed by fitting the experimental data of KGa and independent variables of liquid/gas ratio, rotational speed, pH, NaClO concentration and treatment time, which was in good agreement with the experimental data (the deviation≤±30%).

Efficient removal of low concentration methyl mercaptan by HKUST-1 membrane constructed on porous alumina granules

A HKUST-1 metal–organic framework membrane was constructed on porous Al2O3 granules for the first time for the removal of low concentration CH3SH. The granules exhibited higher sulfur capacity than the pure HKUST-1 powders owing to the excellent dispersion of the MOF membrane on the Al2O3 substrate. The granules also showed good water resistibility.