The decoloration mechanism of Methylene Blue in a CuO/TiO2-H2O2 photocatalytic system

A CuO/TiO2 photocatalyst is prepared using the hydrolysis method. It exhibites excellent photocatalytic activity under both UV and Vis light. After investigating the quantity of hydroxyl radicals and the decoloration rate under different pH sit     

Preparation and photocatalytic properties of Pt and Crco doped Nano TiO2 films 

Pt and Cr co doped Nano TiO2 film was prepared by the sol gel method. The film was characterized by AFM, XRD and UV Vis. The experiment showed that when the average TiO2 film diameter is 32 nm and the film thickness is 290 nm, the rate of photodegradation is 95% in 2.5 hours. Additionally, when the optimal co doping ratio for Pt Cr is n(Pt): n(TiO2) equals 0.03% and n(Cr):n(TiO2) equals 0.4%, the photodegradation of methylene blue for Nano TiO2 film can be enhanced. The photocatalytic properties of Pt and Cr co doped Nano TiO2 film is better than that of pure TiO2 and Pt, Cr separately doped TiO2 film.     

Microwave assisted preparation of spherical monodispersed TiO2

Spherical titania (TiO2) with narrow size distribution and nice dispersibility has been obtained by hydrolysis in the mixed solvent of 1-propanol to de-ionized water using microwave as heat source. Parameters like precursor concentration, heating method, microwave power, and pH value have been investigated. The results show that the high quality TiO2 can be synthesized using PVP as surfactant when the volume ratio of 1-propanol to de-ionized water is 1DK〗∶1. The results display that size and size distribution of the particles are affected by heating method, precursor concentration and pH value. However, the effect of microwave power is comparatively less obvious.     

Analysis on Cd 2+ adsorption capability of activated carbon modified by HNO3

In order to improve the absorption ability of Cd 2+, the activated carbon is modified by HNO3. Additionally, the structure changes of activated carbon with and without treatment are studied in virtue of BET, Boehm and other instruments. The research demonstrates that the specific surface area and the number of activated carbon surface functional groups dramatically change after treatment, and the specific surface area and the figure of acid functional groups after HNO3 oxidizing increase. It is worth mentioning that under the condition of pH with 7.00, the removal rate of Cd 2+ by raw activated carbon is approximately 10%, in contrast, the removal efficiency reached 41% by 10% N-GAC and 57% by 70% N-GAC, the removal effects of Cd 2+ could be improved after modification. With the dosing quantity of modified activated carbon increased, the removal effects of Cd 2+ are also increased. PH is the biggest influence factor of removing Cd 2+. As the pH of solution increases, the removal rates of three kinds of adsorbent for Cd 2+ increases. Adsorption kinetic research shows that the adsorption reaction of Cd 2+ on 10% N-GAC is suitable to Lagergren pseudo-first-order (PFO) reaction in the former 20 min and more suitable to Lagergren pseudo-second-order (PSO) reaction after 20 min.     

The effect of TiO2 nanofilms’ water sensitivity on the contamination resistance of coating

To improve the coating stain resistant performance using the photocatalytic activity of TiO2 is a hot research topic in recent years. In the article,hydrophilic TiO2 and hydrophobic TiO2 are prepared by hydrothermal method. The samples are characterized by X-ray diffraction(XRD) and transmission electron microscope(TEM). The results show that both the hydrophilic-TiO2 and hydrophobic-TiO2 are anatase,and the particle size of hydrophilic-TiO2 is 40 nm,while hydrophobic-TiO2 is only 7 nm. Moreover,the samples are employed for super-hydrophilic and super-hydrophobic coatings,respectively. The contact angle measurement is used to characterize the as-synthesized TiO2 coatings. The effect of the water contact angle on the contamination resistance is investigated. It is shown that the synthesized the hydrophilic TiO2 and hydrophobic TiO2 coatings both can remarkably improve the contamination resistance of the paint and the latter exhibited the better performance.     

Catalytic Performance of H3PW12O40-TiO2/bentonite in Photocatalytic Degradation of Methyl Orange

H3PW12O40Ti(OH)4 hydrogel was prepared by the sol-gel method, and then H3PW12O40TiO2/bentonite was prepared through the intercalation of H3PW12O40Ti(OH)4 into interlayer space. The characterization of XRD, SEM and EDS showed that H3PW12O40TiO2 species were successfully immobilized on bentonite, and the layer strucure of bentonite was changed. The discrete anatase TiO2 existed on the bentonite. H3PW12O40TiO2/bentonite was a composite material with the different particle size and th loose structure. The photocatalytic degradation of methyl orange showed that the photocatalytic activity of catalyst had been better by doping H3PW12O40, and the H3PW12O40/TiO2/bentonite had a wide applicable range of pH value. Moreover, H3PW12O40TiO2/bentonite had a good catalytic stability. Based on the results of characterization analysis and catalytic performance, the schematic procedure for the action mechanism of H3PW12O40TiO2/Bentonite in photocatalysis was presented.     

Growth of Potassium Perchlorate Single Crystals in Gels

Gel growth is the best method for growth of potassium perchlorate single crystals.The effect of concentration of reactants,concentration of gel,temperature,pH value of gel on crystal nucleation density,size,form and quality has been studied by experiments.The best growth parameters for growth of large size,well defined and transparent potassium perchlorate single crystals are obtained.The crystal morphology and the relative importance of crystal faces of potassium perchlorate single crystals are quantitatively analyzed for the first time,and the results are in satisfactory agreement with experimental observations.The theory of periodic bond chain(PBC) is verified in the experiment.     

Preparation of Series of Ti based Electrode and Electro catalytic Oxidation of Dye Wastewater

Series of Ti based electrodes of Ti/PbO2, Ti/SnO2 Sb2O3/PbO2, Ti/SnO2 Sb2O3/PbO2 Cu, Ti/SnO2 Sb2O3/PbO2 Ni and Ti/SnO2 Sb2O3/PbO2 Fe were prepared by thermal decomposition method. And with these electrodes as anodes and the acid fuchsin as simulated dye wastewater, the electro catalytic oxidations of the simulated dye wastewater were performed. With the comparison of effects and reaction rate of different electrodes and the analysis of acid fuchsin oxidation process, it is shown that the electro catalytic abilities of the Fe modified electrode Ti/SnO2 Sb2O3/PbO2 Fe and Ni modified electrode Ti/SnO2 Sb2O3/PbO2 Ni have higher removal efficiency and removal ratio while the Cu modified electrode Ti/SnO2 Sb2O3/PbO2 Cu did not present a obvious modified effect compared with those by Ti/PbO2 and Ti/SnO2 Sb2O3/PbO2. Based on the test data, first order kinetic models of these five electrodes were established. From the UV VIS spectra of the Ti/SnO2 Sb2O3/PbO2 Fe electrode generated under the condition of 100 mg/L of initial concentration of acid fuchsin, 75 mA/cm2 of the density and 12 g/L of the electrolyte concentration (Na2SO4), it is found that the characteristic absorption peak of acid fuchsin at λmax =545 nm nearly disappeared in 60 min and the acid fuchsin was removed. However, some small molecular intermediate products were generated in the electro catalytic oxidation.     

Fabrication and thermal expansion properties of particle reinforced Al matrix composites

Aimed at electronic packaging application, the different types of particles of Al2O3, AlN and SiC which the mean size is about 4 μm are selected and three types of composites are fabricated by squeeze casting method with the particle volume fraction is 40%. The results show that the microstructure of composites is dense and free of pores with the particle distribute uniformly. The mean linear coefficient of thermal expansion (CTE) of composites ranges from 11.51×10-6~18.62×10-6/K and increases with increasing temperature. The measured coefficient of thermal expansion of SiCp/2024 is lower than that of AlNp/6061 and Al2O3p/2024. The measured CTE values of Al2O3p/2024 composites agreed well with Kerner’s model, the CTE of AlNp/6061 is closer to the prediction by ROM, and the CTE of SiCp/2024 varies from lower limit to upper limit of Shapery’s model.     

Effects of different preparation methods onphotocatalytic activity of Fe3+/TiO2

Two kinds of Fe3+/TiO2 catalysts are prepared by Sol-gel method and hydrolysis method. XRD, UV-Vis, BET, curves of N 2 adsorption-desorption and 3D fluorescence are used to analyze the structures and properties of the catalysts, and their photocatalytic activities are investigated through degradation of DBP. The results show that two kinds of catalysts are anatase TiO 2. The band gap of the Fe3+/TiO 2 catalysts prepared by Sol-gel and hydrolysis method are 2.6 eV and 3.2 eV respectively, and the former with an absorption edge at 477 nm, while the latter with no redshift. The curves of N 2 adsorption-desorption of the Fe3+/TiO 2 catalysts prepared by Sol-gel and hydrolysis method are type Ⅳ and Ⅴ, their BET specific surface areas are 57.03 m2/g and 10.94 m2/g, and the hysteresis loop of the latter shifts to the high relative pressure region with a smaller pore volume and a bigger average pore diameter. Two kinds of catalysts can reduce photoluminescence properties of TiO 2 at various degrees, and the catalyst prepared by Sol-gel method shows a weaker photoluminescence property. The results of degradation experiment show the degradation rate of DBP by catalyst prepared by Sol-gel method and hydrolysis method are 60.53% and 31.83% respectively after 2 h.     

Numerical simulation of NO and N2O emission in fluidized bed reactor

Both NO and N2O emission in fluidized bed reactor are studied by numerical simulation. The effects of excess air ratio, coal composition and co combustion of coal and biomass are researched. The results show that NO and N2O are the main products of the NOx in the fluidized bed reactor combustion, and the emission of NO and N2O increases with the excess air ratio increasing. The NOx production has strong relationship with coal composition. The nitrogen content of the coal plays an important role in the production of NO and N2O, as well as oxygen to nitrogen mass ratio and hydrogen to nitrogen mass ratio. In the co combustion process of coal and biomass, carboxyl group have remarkable effect on HCN production, which reduces the content of NO and NO2. The co combustion of coal and biomass can reduce the emission of NO and N2O.     

Chemical structural characteristics of microbial flocculant

Active bacteria from activated sludge in Tangjiaqiao sewage treatment plant were enriched, cultivated, separated and purified, and their degree of activity tested. Structural characteristics of the microbial flocculant produced by the activated bacteria were analyzed using coloration reaction and Fourier transform infrared spectrometry. The results show that the most active bacterium is saccharomycetes with a flocculation ratio reaching as high as 95%. Yellow crystal microbial flocculent was obtained through fermentation cultivation, separation and purification from these saccharomycetes. Results of the coloration reaction and infrared absorption spectrometry indicate this microbial flocculent is a type of sugar in which there are numerous functional groups.     

Particle Size Analysis of Clay by Malvern Laser Particle Analyzer

In order to study the particle size distribution of fine grained soil, the Malvern Mastersizer 2000 laser diffraction grain size analyzer and traditional densimeter method were used to test the clay in Hefei. According to the work principle and affecting factors of laser method, the parameters, such as the refractive index, concentration, ultrasonic displacement and time, pumping speed of the apparatus, were altered in turn. Then the influence of these control parameters on the particle size was investigated, and the best parameters for the clay in Hefei were identified. The grain size distributions measured by laser method under the best condition and traditional densimeter method were compared, which shows that laser method has a wider measuring range, higher accuracy and better repetitiveness in measuring the particle size distribution of fine grained soil.     

Influence of compound retarders on the hydration process of FGD building gypsum and its retarding mechanism

The effect of compound retardant powder P on the hydration process,ion concentration in liuquid and supersaturation degree,and crystal morphology of dehydrate of FGD building gypsum is investigated.Furthormore,by using the SEM,its retarding mechanism is also studied.The results indicate that the addition of powder P retardant the early hydration of FGD building gypsum,which leads to delay of hydration heat evolution.It can also decrease the hydration ratio at early stage and prolong induction period of FGD building gypsum.Powder P has a major effect on the crystal morphology of dehydrate,moreover it enlarges crystal sizes.Retardation effect of powder P is worked by a variety of ways. The ionization of calcium ion from the hydroxyl carboxylic acid calcium salt definitely impedes the early dissolution of hemihydrate FGD building gypsum, delay the formation of nucleus.Also the selective absorption of groups composed of carboxyl and hydroxyl inhibits the growth of nucleus.Moreover the protein also plays a colloid coated role for gypsum,inhibiting the growth of nucleus.     

Application of a Particle Swarm Optimization Algorithm in Truss Structure Optimal Design

The particle swarm optimization (PSO) algorithm developed in recent years is a stochastic optimization algorithm based on swarm intelligence. It possesses advantages such as being a simple concept, ease of implementation and low resource occupation. The PSO algorithm was adopted to solve the problem of size optimization of truss structures with stress and displacement constraints. We present the basic principle of the original PSO algorithm in detail, and then introduce a constriction coefficient to modify it. Moreover, reasonable values of the coefficients are proposed for the modified PSO algorithm. Several classical problems are solved using the modified PSO algorithm, and the results compared with those using traditional optimization algorithms and genetic algorithms. Numerical results show that the modified PSO algorithm has good convergence and stability, and can be applied to the size optimization of truss structures.     

Comparison Analysis of Sludge Nitrification Activity Before and After Micro bulking with Low Dissolved Oxygen

In order to investigate the variation of sludge nitrification activity before and after micro bulking with low dissolved oxygen(DO), with mean DO value of 0.6mg/L-0.9 mg/L,the sequence batch reactor (SBR) was employed to test the oxygen consumption velocity curves before and after micro bulking. The results showed that COD removal ability increased, whereas the ammonia nitrogen removal effect was decreased with micro bulking of sludge. The oxygen consumption velocity curves before and after micro bulking showed that the total activity of activated sludge was 67.72 mgO2/gVSS·h before micro bulking, of which nitrification activity was 43.12 mgO2/gVSS·h, that is, 63.67% of the total activity. And the total activity of activated sludge was 90.49 mgO2/gVSS·h after micro bulking, of which nitrification activity was 23.98 mgO2/gVSS·h, that is, 26.51% of the total activity. The low DO value was the limited substrates for microorganism growth. When activated sludge was in the state of micro bulking, the filamentous bacteria were the dominant bacteria, whereas the nitrification bacteria were subordinate. Thus the total nitrification activity of activated sludge decreased.     

Study on flammability and flame-retardant mechanism of modified asphalt for tunnel pavement synergisticly flame retarded by BFR-Ti and ZB

Tunnel fire resistant asphalt can be prepared by mixing SBS modified asphalt and BFR-Ti/ZB. The combustion performances of the SBS modified asphalt/BFR-Ti/ZB and the synergism mechanism of the BFR-Ti and ZB are studied systematically through different methods, such as oxygen index (LOI) method, density of smoke, cone calorimetry, thermogravimetric analysis, etc. The result indicates that compared with SBS modifiedasphalt/BFR-Ti, BFR-Ti/ZB has synergistic effect which can make smoke density, heat release rate(HRR), mass loss rate(MLR) and effective heat of combustion(EHC) of SBS modified asphalt/BFR-Ti/ZB systems significantly decrease while the oxygen index of the SBS modified asphalt/BFR-Ti/ZB and the practice carbon content increase. SBS modified asphalt/BFR-Ti system has significant endothermic-antiflaming mechanism and condensed phase flame-retardance character. SBS modified-asphalt / BFR-Ti/ZB is based on the condensed phase flame-retardance mechanism while with synergistic flame-retardance and endothermic-antiflaming mechanism.     

Investigations of the particle motion characteristics in the gas solid two phase wake of leeward side circular cylinder

This paper investigates the characteristics of the particle motion in circular cylinder wake flow of leeward side by simulating the micro particle flow around circular cylinder using Euler two fluid model combined with Reynolds stress model. It compares the particle velocity and concentration of different particle size in the leeward area. The results show that the vortex is formed after the gas flowed passing the cylinder, and the concentration and velocity of particles are affected by the turbulent intensity in the leeward side. Gas entrainment vortex and particles own inertia decide the flow form of fine particle around the cylinder. Both effects impact the particle concentration distribution of different size particles in the leeward area. With the increase of particle size, the particle concentration increases at the beginning and then decreases in the leeward area.     

conductivity of a TiO2 cathode in the FFC process and analysis of its influencing factors

The conductivity of a TiO2 cathode in the FFC process was studied by sintering and electrolyzing experiments. Sintered TiO2 cathode and electrochemical reduction of TiO2 were measured using X ray diffraction. Results show that changing the energy band structure of TiO2 via high temperature sintering can cause electric conduction vacancy. An electric double layer can be formed in molten salt. Ionization of oxygen atoms leads to formation of TiO2 x ionic structures. The ions infiltrate to the electrode in molten salt, increasing the number of conduction ions. The electrolyzing process proceeds smoothly, based on the integrated mechanism of activating the TiO2 cathode. The activated TiO2 cathode can be obtained by forming electric conduction vacancy at high temperature sintering, the TiO2 x ionic structure by electric double layer, and ions infiltrating to the interior of the electrode.