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TiO2 exposed high energy crystal plane (001) was prepared by the sol-gel process using butyl titanate as the titanium source and hydrofluoric acid as the surface control agent. Ag-TiO2 was prepared by depositing Ag on the crystal plane of TiO2 (101) with a metal halide lamp. The surface morphology, interplanar spacing, crystal phase composition, ultraviolet absorption band, element composition, and valence state of the samples were characterized by using field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), X-ray diffraction (XRD), ultraviolet-visible absorption spectrum (UV-Vis-Abs), and X-ray photoelectron spectroscopy (XPS), respectively. The formation mechanism of high energy crystal plane (001) was discussed, and the photocatalytic activities were evaluated by following degradation of methyl orange. The results show that TiO2 exposed the (001) crystal plane with a ratio of 41.8%, and Ag can be uniformly deposited on the crystal plane of TiO2 (101) by means of metal halide lamp deposition. Under the same conditions, the degradation rate of methyl orange by deposited Ag-TiO2 reaches as much as 93.63% after 60 min using the metal halide lamp (300 W) as an illuminant, 81.89% by non-deposited samples and 75.20% by nano-TiO2, causing a certain blue shift in the light absorption band edge of TiO2. Ag-TiO2 has the best photocatalytic performance at a pH value of 2.

F&ndash, TiO2 was prepared by a simple precipitation method using titanium sulfate as the titanium source, hydrogen fluoride as the fluorine source and ammonia as the precipitant. CdS/F&ndash, TiO2 composites were prepared by hydrothermal synthesis of CdS and F&ndash, TiO2. The surface morphology, crystal phase composition, ultraviolet absorption band, fluorescence intensity, element composition, valence state, specific surface and pore structure of the samples were characterized by using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), ultraviolet visible absorption spectrum (UV-Vis-Abs), Molecular fluorescence spectrophotometer (PL) and X-Ray photoelectron spectroscopy (XPS) and Surface area analyzer (BET), respectively. The effects of the dosage of the photocatalyst, pH value, the concentration of methyl orange and the addition of H2O2 on the photocatalytic performance were investigated with methyl orange solution as the target degradation product. The results showed the optimum condition for photodegradation of methyl orange by 1% CdS/F&ndash, TiO2 is that the pH value, the solid-liquid ratio, the concentration of methyl orange and the dosage of H2O2 is 2, 2 g/L, 10 mg/L and 3%, respectively. Under the same conditions, the degradation rate of methyl orange by 1% CdS/F&ndash, TiO2 was 93.36% when 300 W metal halide lamp was irradiated for 20 minutes, which was significantly higher than that of F&ndash, TiO2. CdS has a significant effect on the morphology, crystallinity, grain size and the compound probability of electrons and holes after the F&ndash, TiO2 modification. The composite causes a significant red shift at the edge of the F&ndash, TiO2 light absorption band. The photocatalytic degradation of methyl orange by 1% CdS/F&ndash, TiO2 follows the Langmuir-Hinshelwood first-order kinetic model.

The violuric acid mediated chemical delignification system has a high delignification efficiency for pulp fibers and high delignification selectivity. The process conditions and effectiveness were carried out.The kinetics of electrochemical delignification has been investigated using the violuric acid (VIO) as the mediator. The reaction orders with respect to delignification, concentration of VIO and voltage of electrolytic cell were determined experimentally, which were dependent on the reaction conditions. The kinetic equation of electrochemical delignification and estimation function of kappa number were obtained respectively as follows: - dK/dt = A e-[VI1.031[2.197K6.25 , E=16.2KJ/mol, K(t)={2.89×10-7+5.25k [VI1.031[2.197t}-0.19.

The low molecular syringaldehyde was found to be a preferred natural mediator for pulp delignification in the electrochemically mediated delignification system (EMD-system). Electrochemical treatment of poplar kraft pulp with syringaldehyde results in the reduction of kappa number of about 28%, but the loss of viscosity is only 6.6%. During the process of electrochemically mediated delignification , the delignification efficiency is dependent on the voltage, the dosage of syringaldehyde , reaction temperature , pH value, reaction time and the composition of electrolyte solution. The optimum operating parameters of electrochemical delignification with syringaldehyde are obtained as follows: syringaldehyde 1mmol/l, voltage 1.8v, temperature 45°C, reaction time 4.5h, the pH-value in the range from 4.0 to 5.0, sodium sulfate 0.05mol/l.

There are lots of corn straws left on the farmland every year in China. At present, the technologies of taking full advantage of corn stalks are not mature. In this paper, the method of acidic hydrolysis was used to decompose hemicellulose of corn stalk into xylose, L-arabinose, fructose, etc. HPLC was used to detect the concentration of monosaccharides in the hydrolyzate, at the same time the hydrolysis conditions were also optimized. The results showed that the optimum conditions were: the concentration of corn stalks 15%, hydrolysis time 3h. There were xylose, L-arabinose, fructose and glucose were detected in the hydrolyzate of corn stalks. The max concentration of xylose 23.1mg/ml was obtained at temperature about 160°Cand the max concentration of L-arabinose 19.4mg/ml was obtained at a relatively low temperature 130°C. As the temperature rising, the concentration of glucose was increased at first and then decreased; the concentration of fructose was increased in a small range in the whole range of temperatures investigated.

Sodium hydroxide (NaOH) substituted by magnesium hydroxide (Mg(OH)2) as control agent and alkali source were investigated in chlorine dioxide bleaching and hydrogen peroxide bleaching of NaOH-AQ wheat straw pulp. The effects of alkali sources on pulp properties, including brightness and tensile strength, were investigated. The four experimental groups, including DNaOHPNaOH, DNaOHPMg(OH)2, D Mg(OH)2PNaOH and DMg(OH)2PMg(OH)2, were studied in this paper. The results showed that the brightness and tensile strength of DMg(OH)2PMg(OH)2 pulp was slightly lower than that of DNaOHPNaOH pulp. But there were more residual ClO2 and residual H2O2 in the effluents of DMg(OH)2PMg(OH)2 bleaching process than that in the effluents of DNaOHPNaOH bleaching process, which illustrated that DMg(OH)2PMg(OH)2 bleaching process had higher bleaching efficiency than DNaOHPNaOH bleaching process. The influence of Mg(OH)2 replacing NaOH was more obvious when it was used in the bleaching process of P stage than that in the D stage. The replacement of NaOH with Mg(OH)2 in D Stage can lower the dosage of alkali used in the following P stage.

The electrochemically mediated delignification of pulp fibers is one of the promising bleaching methods, which can give the delignified pulp with good subsequent bleachability and high pulp viscosity. Our previous work has shown that the poplar kraft pulp can be delignified to 45% delignification ratio with less than 10% pulp viscosity loss at the condition of 1% pulp consistency which limits the application of this method in pulp industry. The high-consistency electrochemical delignification of poplar kraft pulp was investigated in this paper. The delignification ratio, pulp viscosity loss and brightness were measured as well as the delignification conditions, such as pulp consistency, voltage of electrolysis cell, temperature, circulation of electrolysis liquor and time, were discussed. The results showed that at the 10% pulp consistency, the circulation of electrolysis liquor between pulp cell and electrolysis cell can efficiently improve the delignification ratio, and the pulp viscosity loss is less than 10%. The subsequent bleachability for H2O2 is similar as that of 1% consistency delignified pulp. The pulp also can be bleached to higher than 80% ISO with following EP stage at 2.5% H2O2 dosage.