Hydrogels as fire-resistant materials have attracted great attention due to their high water content and tailored shapes that can cover various surfaces.
One Datong (China) coal was deashed by a mixture of hydrofluoric acid (HF), hydrochloric acid (HCl) and distilled water. The textures of the coal samples were investigated by N2 adsorption at 77 K. The surface groups on coals were characterized by X-ray photoelectron spectroscopy (XPS). The results showed that the coal texture has been changed after deashing treatment. The XPS results showed that the dominant forms of carbon on the surface of raw coal are C-C and C-H, the dominant forms of oxygen are COO-and C-O, and dominant forms of sulphur is thiophenes sulphur. The de-ashing treatments resulted in the elimination of sulphur and a decrease of oxygen adsorbed on the coal surface.
Pure form,single phase and high crystalline zeolite 4A samples were synthesized during hydrothermal treatment of by-products in polysilicon production process. The effects of the different crystallization time on the degree of crystallinity, skeleton structure, morphology, size of the particle and its distribution of zeolite 4A samples were investigated using XRD,FT-IR,SEM and Zetasizer. The results indicated that the zeolite 4A sample featured high crystallinity degree, excellent dispersivity, high purity and single structure.
One bituminous coal was modified with H2O2, (NH4)2S2O8 and HNO3 respectively, to prepare coal samples with different surface properties. The oxygen groups on coal surface were characterized by X-ray photoelectron spectroscopy (XPS). The textures of the coal samples were investigated by N2 adsorption at 77 K. The methane adsorption behaviors of the coal samples were measured at 303 K in pressure range of 0-5.3 MPa by a volumetric method. The methane adsorption data were fitted to the Langmuir model. It was observed that there was, in general, a positive correlation between the methane adsorption capacity and the SBET of coals while a negative correlation between methane saturated adsorption capacity and the Ototal/Ctotal. The methane adsorption capacity was determined by the coal surface chemistry when the microporosity parameters of two samples were similar. Coal with a higher amount of oxygen surface groups, and consequently with a less hydrophobic character, had lower methane adsorption capacity.
In this work, one activated carbon (AC) was modified with H2O2, (NH4)2S2O8saturated solution and H2SO4/(NH4)2S2O8mixture respectively. The oxygen groups on ACs surface were characterized by Boehm titration. The textures of the ACs were investigated by N2adsorption at 77 K. The influence of surface oxygen groups on methane adsorption on ACs has been studied. The results of Boehm titration showed that the concentration of acidic oxygen functional groups on the AC surface increased after modification. N2adsorption data showed that the specific surface areaSBETand the micropore volumeVmicof AC were changed lightly after modification. It was observed that there was, in general, a positive correlation between the methane saturated adsorption capacity and theSBETof ACs while a negative correlation between methane saturated adsorption capacity and the total surface acidic groups. The methane saturated adsorption capacity was determined by the ACs surface chemistry when the microporosity parameters of two samples were similar. AC with a higher amount of oxygen surface groups, and consequently with a less hydrophobic character, had lower methane adsorption capacity.
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