Advanced Materials Research Vols. 113-116

Abstract: The preparation of hydrophobic CaCO3-wood composite through a double-diffusive method using dodecanoic acid as organic substrate is demonstrated. The product was characterized by the contact angle analysis, X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM). The mechanical properties of the product were measured. The results show that the synthesized CaCO3 fills in the wood cell and covers the surface of wood. The CaCO3-wood composite is hydrophobic. The mechanical properties of wood composite have significantly increased.

Abstract: To optimize the conditions of modification and understand the absorption mechanism of activated carbon, the orthogonal test was used to select the best conditions of ammonia-modified activated carbon. The changes of activated carbon’s specific surface area, pore volume and surface acidic oxygen-containing functional groups were determined before and after modification by ammonia, and the equilibrium adsorption model for phenol was also explored. The results show that under the conditions of ammonia concentration of 10%, soaking time of 2h, activation time of 2.5h and activation temperature of 500°C, the best removal rate could be obtained. The specific surface area and pore volume of modified activated carbon were increased, whereas the acidic oxygen-containing groups of its surface were significantly reduced by 57.88% after modification. It means the surface polarity of carbon was decreased, and which was conducive to the adsorption of phenol, since phenol was a weakly polar substance. Both Freundlich and Langmuir model could reflect the adsorption behavior of modified activated carbon for phenol, while the Freundlich model was more properly, but for the unmodified activated carbon, Freundlich model was more suited to describe the adsorption behavior of phenol than Langmuir model.

Abstract: The high cost of the raw materials and non-recycling use are the two main problems which restrict the development and extension of the SLS rapid prototyping. Firstly this paper did some theoretical analysis on the characteristics of wood flour, hot melt adhesive and other components. Then, through experimental comparison, using SEM to do microcosmic study and actual processing in laser shaper, this paper got a new formula of WPC for SLS. It is proved by the experiments, the WPC according to this formula is green environmental protection, degradable and can be recycled. Also, it can meet the processing requirements of SLS. The shape precision of the formed parts is high, the relative warping rate is only 0.26%~0.45%, the roughness is less than 0.03mm, and the parts reached a certain mechanical index. The tensile strength can reach a maximum of 0.014MPa and shock strength can reach a maximum of 0.954kJ/m . It provides the basis for the further post-processing to enhance the mechanical properties.

Abstract: Traditional lime and sulfide dehairing process is a major source of the pollution, such as biochemical oxygen demand (BOD), chemical oxygen demand (COD), total dissolved solids (TDS), total suspended solids (TSS) and toxic H2S gas, etc. Enzymatic dehairing process is known to be cleaner but its dehairing effects are unsatisfactory. Hence, an attempt has been made to solve those two unhairing methods’ disadvantages through a biochemical approach. Several commercial enzyme formulations were chosen to research effects of hydrosulfide and peroxide on its activities, and then hair-saving enzymatic unhairing experiments with those two reagents were conducted in paste and pile method more effectively and cleanly. Results show that activity of enzyme 2709 is stabilized by the addition of hydrosulfide through activity measurements; Peroxide has some activation effect on protease 3942. Hair removal is found to be complete using scanning electron microscope (SEM) analysis. Those two processes enjoy a significant reduction in BOD, COD, TDS and TSS. The perfromances of the experimental leathers are also comparable to that of conventional ones. Therefore, those are cleaner processing technologies that could be chosen to solve traditional method’s disadvantage.

Abstract: In 1.0 mol/L H2SO4 solution, a rapid and simple flow—injection spectrophotometric method has been developed for Cr(Ⅵ) determination, based on the violet—red Cr(Ⅵ)—diphenylcarbazide chelates formed by reactions. The results show, under optimum conditions, the maximum absorption of the complex is at 540 nm and the detection limits of the method is 0.0136mg/L for Cr(Ⅵ) and Beer’s law is obeyed for Cr(Ⅵ) in the range of 0.03—1.60mg/L. The determination frequency is l00 times/h. The relative standard deviation of eleven replicates is less than 4.0%. The method has been applied to the determination of trace Cr(Ⅵ) in tanning wastewater with satisfactory results.

Abstract: The Zr-Cu-Ce/ZSM-5 catalysts prepared by the simultaneous ion-exchange showed high activity for NO decomposition in the presence of O2, the highest conversion of NO was up to 75%, indicating that the Ce and Zr addition can enhance the activity of catalysts. A new highly active site, which facilitates oxygen mobilization and desorption, could be formed in the sample due to the Ce and Zr addition. In addition, the Zr addition can significantly improve the thermal stability of the catalyst.

Abstract: ZnO nanorods have been successfully synthesized by employing ZnCl2, NaOH as the starting materials without surfactants, template supporting and structure-directing solvent at a low temperature (room temperature – 90 °C ). X-ray powder diffraction (XRD) and transmission electron microscopy (TEM) were used to analyze the crystal structure and surface morphology. XRD pattern analysis showed that the ZnO clusters are single hexagonal phase of wurtzite structure with no impurity of others. Also, TEM images revealed that the size of a single ZnO nanorod is between 32 – 60 nm in diameter and 470 – 740 nm in length. Furthermore, the ZnO nanorods exhibit significant optical properties in Raman spectrum, suggesting that they could be found promising potential for opto-electronic application.

Abstract: The present work deals with the synthesis of various imidazole ionic liquids [BMIM]Cl, [AMIM]Cl, [AEIM]Cl, [HeEIM]Cl and [HeVIM]Cl, the chemical structures of ionic liquids by FTIR and 1HNMR, the pretreatment of wood powder as extracted with a mixture of benzene/ethanol or activated with 25% (mass fraction) NaOH under normal temperature and pressure, microwave and high pressure, studies the solubility of ionic liquids on the wood powder by microwave (90°C, 400w), and analyses the microstructure of the wood before and after dissolution as measured by SEM. The result shows that all the ionic liquids can dissolve the wood fiber directly, ionic liquids containing hydroxyl group exhibit better solubility. Wood powder pretreated with 25% NaOH under high pressure has the lowest crystallinity (2.4%) and the highest dissolution rate. The solubility of [HeVIM]Cl is the best, which approach to 21.6%.

Abstract: Batch culture of dark fermentation was carried out to study the feasibility of biohydrogen production using bagasse as the substrate. In dark fermentation, hydrogen was produced by mixed culture using bagasse as the substrate. To establish favorable conditions for maximum hydrogen production, process parameters such as temperature and initial pH of the medium were investigated. Also, the component of biogas and liquid products of effluent by fermentation were analyzed by gas chromatography. The VFAs were mostly ethanol, acetic acid, propionic acid and butyric acid, and no valeric acid was observed. It is demonstrated that the hydrogen yield reached the maximum of 30.5mlH2/g bagasse while the temperature was 35°C in batch experiments under a series of temperature (25, 30, 35, 40°C) conditions. The initial pH ranged from 6.8 to 8.5, and the yield of hydrogen reached the maximum of 32mlH2/g bagasse with the initial pH of 8.5.

Abstract: In the present study we reported the feasibility of extracellular biopolymer(PF01) produced by Pseudomonas fluorescence as an alternative biosorbent to remove Cu(II) ions from environmental wastewater. The ability of PF01 to remove the Cu(II) ions was investigated by using batch biosorption procedure. The effects such as pH, dosage of biosorbent, Cu(II) initial concentration and sorbate–sorbent contact time on the adsorption were studied. The pseudo-second order kinetics and Langmuir isotherm models were noted be fit to the experimental data. The maximum Cu(II) adsorption capacity was 78.99 mg/g at pH 5.0 , at 28°C. The carboxyl , hydroxyl and amino groups of the PF01 were involved in chemical interaction with the Cu(II) ions depicted by Fourier transform infrared spectroscopic (FTIR). The study points to the potential of new use of extracellular biopolymer PF01 as an effective biosorbent for the removal of Cu(II) from environmental wastewater.