Advanced Materials Research Vols. 197-198

Abstract: The effects of different activators on compressive strength of fly ash-based geopolymers have been studied. It is discovered that, alkali solution doesn’t have obvious effect, while Na₂SiO₃ solution has visible effect, the strength of samples rise with the increase of Na₂SiO₃ solution concentration. The effect of K₂SiO₃ solution is more obvious than Na₂SiO₃ solution, the strength of samples tend to first increase and then decrease with the increase of K₂SiO₃ solution concentration. The K₂SiO₃ solution with concentration of 2 M is the best activator to prepare geopolymers, which has compressive strength of 28.8 MPa at 28 d. When water glass are used as activators, the best modulus and solid content for Na-water glass (Na₂O•nSiO₂) are 1.2 and 32%, respectively. On this condition the sample’s compressive strength at 28 d is 38.9 MPa. However crystal calcium oxide is harmful for the compressive strength development, which is different with the conclusion accepted abroad.

Abstract: To improve the photocatalytic application performances of TiO₂, in this work, firstly CdS modified Degussa P25 TiO₂ (CdS/TiO₂) composites were prepared, then they were loaded on activated carbon fibers(ACFs) by dip-coating method. The composites were characterized by XRD, UV-vis, SEM, EDS and BET. Their photocatalytic activities under daylight were investigated by the degradation of gaseous toluene. The results showed that CdS/TiO₂ composites mainly composed of anatase TiO₂ and little CdS phases; CdS/TiO₂ absorption edge had a pronounced “red shift”, the corresponding absorption edge wavelength of CdS/TiO₂ composites were extended to 740 nm, respectively. From EDS spectrum, the main elements of CdS/TiO₂/ACFs were Ti and O and a small quantities of S and Cd. CdS/TiO₂ loaded on ACFs was in the form of small clusters, but not very uniform; compared with original ACFs, the surface area and pore volume of CdS/TiO₂/ACFs decreased slightly, while the average size remained unchanged. The photodegradation rate of toluene by CdS/TiO₂/ACFs composites under daylight irradiation was markedly higher than that by TiO₂/ACFs, the maximal increasing rate reached as high as 18%.

Abstract: In this paper, the indicators of multi-component bamboo blended knitted fabric style were obtained by FAST meters, and the relationship between the performance and the blend ratio of the bamboo fiber was analyzed. The results indicated that the value of fabric surface thickness, bending rigidity, the formability and shear stiffness linearly decreased with the bamboo fiber content increasing.

Abstract: Using zirconium oxychloride hydrate ( ZrOCl₂•8H₂O) and ammonia water (NH₃•H₂O) as raw materials, and ammonium dihydrogen phosphate (NH₄H₂PO₄) as additives, tetragonal zirconia (t-ZrO₂) with size range of 8–12 nm were prepared by coprecipitation method under hydrothermal conditions. The influence factors on phase transformation and the particle size such as phosphor loading, hydrothermal temperature and calcination temperature were studied by X-ray diffraction (XRD), Fourier transform Roman spectra (FT-Roman), the Brunauer-Emmett-Teller (BET) method and X-ray photoelectron spectroscopy (XPS) techniques etc. Research results show that a small amount of phosphor has been incorporated into the framework of ZrO₂ crystals, producing a certain amount of oxygen vacancies. Phosphor can effectively restrain crystal particles growth and improve the thermal stability of metastable t-ZrO₂. The phosphor doped t-ZrO₂ had a high surface area (244.2 m²/g). In contrast to the pure ZrO₂ particles readily aggregating, the phosphor species deposited on the framework of ZrO₂ crystals prevented the agglomeration of the primary particles during calcinations.

Abstract: Cu doping zinc oxides (ZnOs) were prepared by a post doping process with CuCl₂ at high temperature. With the increase of the dopant loading, the lattice constant c decreased firstly and then increased, which indicated that the doped Cu atoms substituted for Zn atoms at lower loading and extra dopant of the Cu atoms existed as interstitial atoms. UV-Vis diffuse reflectance spectra (UV-DRS) illustrated that the energy band gap was effectively narrowed after Cu doping. The photocatalytic production of hydroxyl radical (•OH) and superoxide anion (O₂^-) were determined by terephthalic acid with fluorescence spectrophotometer and nitroblue tetrazolium with UV-Vis spectrophotometer respectively, and the results showed that both the photocatalytic production of •OH and O₂^- were deceased with the increase of the dopant concentration, which indicated that the recombination centers were formed in the samples.

Abstract: In this paper, a magnetic hollow fly ash microsphere(MHFM) was prepared by citrate sol-gel method and the Cu doped TiO₂ nanopowder were prepared by sol-gel process at which the novel magnetic Cu-doped TiO₂ photocatalyst (M-Cu/TiO₂) was prepared by coating-calcining process. The crystal phase and morphology of M-Cu/TiO₂ were investigated by Scanning electron microscopy(SEM), X-ray diffraction(XRD), The photocatalytic activities of the prepared photocatalyst under different preparation conditions were evaluated by the degradation of methyl orange (MO). Results showed that these TiO₂ photocatalysts were highly efficient for the destruction of methylene orange in water. In addition, the multi-coating procedure made it possible to effectively control the physical properties of TiO₂ layer such as the coating thickness, amount of TiO₂ and photocatalytic activity. The floating catalyst made by this method could also be separated easily from the reaction system. And the multilayer film has higher photocatalytic activity than TiO₂ film under visible light irradiation.

Abstract: Combining with the production practice in the particular consortium of the paper mill, power plant and calcium carbonate fines factory, a new kind of united treatment technology is designed. The technology is mixing the waste pulp and waste scum with coal to finish the in-furnace desulphurization, spraying waste water to the flue gas to finished flue gas desulphurization and using waste hydrogen of calcium as absorb material. This method can comprehensive use of resource to reach a better economic effective and social benefit. It reduces the processing cost and avoids city environment pollution. The three factories have mutually pleasant business. The technology opens up a new effective approach of desulphurization and can be good example to the same enterprises. An economical benefit is analyzed.

Abstract: This paper synthesis a new purifying agent on a rapid semidry process, using a natural guar gum as basic material, which was carboxymethyl guar. The factors which affect degree of substitution (DS) of carboxymethyl guar, such as the reaction temperature, the reaction time, the consumption of chloroacetic acid, and the consumption of sodium hydroxide etc were studied. The best synthesis condition was concluded. The flocculating property of the produced purifying agent was studied. Then the experiment analysis the structure and thermal stability through IR and DTA. The experiment results showed that the turbidity ratio of the micro-polluted water was better than other purifying agents. The synthetic purifying agent should have potential applications in the wastewater market.

Abstract: This paper studied the stability and regeneration mechanism of photocatalyst Bi₂₀TiO₃₂. There is no change in the XRD of the catalyst after reaction, which indicates that photocatalyst Bi₂₀TiO₃₂ has stable structure. The comparison of XPS between used and fresh catalyst, shows that the major cause of the deactivation is the competitive adsorption of intermediates onto the surface active sites of the catalyst. Simple cleaning by deionized water, light irradiation, acid or base purging can not refresh the catalyst. However, ethanol with ultrasonic vibration can recover its activity well, as further demonstrates that the deactivation is because of that active sites are occupied by organic intermediates. Calcination is an effective way to recover the catalyst activity.

Abstract: Ce-Y-palygorskite catalysts were prepared by chemical blending method. The effect of preparation conditions on catalytic performance of Ce-Y-palygorskite catalyst for NO decomposition was investigated in a fixed bed flow reactor. The characteristics of the Ce-Y-palygorskite catalysts were studied by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The obtained results provided substantial evidence that the catalysts preparation conditions would have strong effect on the catalytic activity for NO decomposition. The Ce-Y-palygorskite catalyst prepared under the optimal conditions: rare earth content, Ce/Y, pH value of the chemical blending and calcination treatment temperature was 3%, Ce_xY_(1-x)(x=0.9), 7 and 350°C, respectively, was identified as the most active catalyst for the NO decomposition, and the denitration rate could be up to 67.3% under the experimental reaction conditions.