Advanced Materials Research Vols. 236-238

Abstract: Sm-doped TiO₂ photocatalysts were prepared by doping samarium ions into TiO₂ nanoparticles in a sol-gel process. The samples were characterized using transmission electron microscopy (TEM) and ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS). Their photocatalytic activities were evaluated by photodegradation of methyl orange (MO) in water under UV or stimulant solar light irradiation. The kinetics of MO photodegradation was further studied using multi-variable grey model. The experimental results indicated that the Sm³⁺ doping reduced the crystallite size, and appropriate doping induced red-shift of the absorption profile of TiO₂. It was also found that the red-shift and absorptivity decreased in the range of 350-500 nm with the increase of Sm³⁺ doping and the optimal doping concentration was 0.05 mol%. Furthermore, the effects of Sm³⁺ doping concentration, the calcinating temperature of the samples, and the illuminating light on the photocatalytic activity of TiO₂ were well simulated using multi-variable grey model.

Abstract: Four Chinese coals were oxidized with NaOCl aqueous solution under mild conditions. The reaction mixture was extracted with diethyl ether, carbon disulfide, petroleum ether, acetic ester and benzene sequentially. A series of organosulfur compounds (OSCs) were identified in the carbon disulfide fraction from the oxidized coals by GC/MS analysis but no OSCs were detected from other fractions except for 3 thiophene polycarboxylic acids found in ether-extraction. Some new types of sulfur function groups were also detected in the coal oxidation products which were not previously reported from coals. The results revealed that macromolecule OSCs in coals can be effectively degraded to water soluble small molecules with NaOCl aqueous solution, which can be enriched by carbon disulfide. Understanding the distribution of OSCs forms in coals matrix is useful in high value-added utilization of coals and coal desulphurization technologies.

Abstract: The objectives of this study were to convert marigold dregs to a cationic metal ions and dye adsorbent and further to investigate the potential of using the adsorbent for the removal of copper(Ⅱ) and methylene blue (MB) from effluents. The base washed marigold dregs and citric acid (CA) modified marigold dregs (MMD) were prepared and the structure were investigated by fourier transform infrared, emission scanning electron microscope and X-ray photoelectron spectroscopy. The results show that the modification did not significantly change the morphology of the dregs surface structure but the esterificated reaction could increase the carboxyl groups and hydroxyl groups on the surface of the adsorbent. The adsorption ability are also evaluated by MB and copper(Ⅱ) and the results show the MMD is an excellent adsorbent. Due to the high adsorption quantity, it may be used as a low cost alternate adsorbent for the elimination of metal and dye ions form effluents.

Abstract: Concentrations of miglitol on the adsorptive capacity effect of resin were investigated.The pseudo first and second order equations were used to describe the kinetic process of ion exchange. The results showed that adsorption of miglitol onto resin is fast and can reach approximate equilibrium after 2.5h. Langmuir model is suitable to describe the equilibrium adsorption.By linear fit of the pseudo first and second order equation and comparing the R² value of correlation coefficient, it finds that the R² value of the pseudo second order equation is bigger, and concludes that the ion exchange process is described by the pseudo second order equation.

Abstract: In order to research on the inhibition of Cu²⁺ to removal of U(Ⅵ) by sulfate reducing bacteria(SRB), the experiment investigated the removal of U(Ⅵ) by SRB through H₂S reduction process, elecrton transfer process and adsorption process respectively. The results showed that the electron transfer was the main process in removing of U(Ⅵ) by SRB, It accounted for 80% of the total removal. Extracellular polymeric substances (EPS) adsorption of U(Ⅵ) had little effect. When the concentration of Cu²⁺ was 5mg/L, Cu²⁺ had little effect on the removal U(Ⅵ) by SRB; It inhibited the removal of U(Ⅵ) significantly when the concentration was 15mg/L because of the competition of H₂S and the electronics of lactic acid between Cu²⁺ and U(Ⅵ); When the concentration of Cu²⁺ exceeded 25mg/L, it would damage the integrity of SRB’s membrane and the removal of U(Ⅵ) was completely inhibited.

Abstract: A L-lysine modified semi-crosslinked chitosan (LMCCT) beads was synthesized and demonstrated to be an excellent enzyme support by studying the enzymatic properties of glucose oxidases (GODs) immobilized on it. The prepared LMCCT beads have very larger BET specific surface ( 403 m²/g) and excellent chemical stability due to the semi-crosslinking of chitosan backbones. The insertion of the flexible L-lysine spacers between chitosan backbone and the active amino groups increases the activity of immobilized GODs (I-GODs) and improves the affinity of I-GODs towards the substrate, which was testified by the smaller Michaealis constant, K_m and larger reactive rate, V_m of I-GODs on LMCCT than that on crosslinked chitosan. Further studies of I-GOD activity at varied temperature and pH also indicated that I-GOD on LMCCT has an excellent stability.

Abstract: To investigate the antioxidant effect in vitro of JiangHuang JiangZhi capsule, different concentrations of content of capsule were determinated by DPPH assay method. Results showed Jianghuang Jiangzhi capsule had antioxidant capacity on eliminating DPPH free radicals.

Abstract: This paper deals with the extraction of L-theanine containing Aliquat 336 and Di(2-ethylhexyl)phosphate(P204) as combined carriers and cyclohexane as solvent across bulk liquid membrane. A mathematical model of transport process was deduced, the forward and the backward interfacial reaction rate constants between the feed phase, the receiving phase and the membrane phase were taken into account. Using the experimental results, several parameters of the proposed model have been achieved by a nonlinear fitting method. It is a simply mathematical model which can be easily used to predict the concentration of the extraction process.

Abstract: The alkaline-pretreated wheat straw was used as raw materials, and the fed-batch simultaneous saccharification and fermentation (SSF) process for ethanol production with higher substrate loading (up to 16% (w/v)) was investigated. Firstly, the Fed-batch SSF with different feeding strategy was optimized. The highest ethanol concentration reached to 37.9 g/L with an initial substrate loading of 10% (w/v), and equal substrate addition (3%) at 8h and 16h respectively. Then the effects of Tween-20 were also investigated. The results showed that Tween-20 addition with 2.0 g/L can improved the ethanol production. Furthermore, a nonisothermal fed-batch SSF was proposed, and the ethanol concentration of 41.5 g/L, corresponds to 81.0 % of the theoretical yield was achieved within 72 h.

Abstract: Glucose oxidase (GOD) and catalase (CAT) were co-immobilized on the cross-linked chitosan microsphere containing L-Lysine (CCL) by the method of absorption-crosslink, with cross-linking agent of glutaraldehyde. The optimized conditions of the co-immobilization are as follows: activity ratio of GOD and CAT is 0.78:1, concentration of glutaraldehyde is 0.17mmol/L, and the immobilizing process last for 3 hours. The enzyme activity of co-immobilized enzyme is 15.3U/mg and activity recovery is 50.1%. The half life is 231 days, 2.4 times of immobilized GOD.