Advanced Materials Research Vols. 113-116

Abstract: A technology was studied to prepare -alumina from fly ash, and the integrated process flow including sintering with sulfuric acid, leaching, recrystallization, calcination was established in this paper. The influences including the particle size of fly ash, sintering temperature, sintering time and the mass ratio of sulfuric acid to fly ash on the extraction ratio of alumina were investigated and discussed during sintering process, and the optimal parameters were determined. The product of -alumina was examined by chemical analysis, XRD and SEM, and the results show that α-alumina reach the national standards.

Abstract: Under visible light, the catalytic properties of heteropoly acid supported {(NH4)6 H5[Mo4V9O40]•23H2O/TiO2} by sol-gel method are studied and characterized. By exploring different amount of catalyst and oxidant for degrading dye wastewater analog, photocatalytic decolorization rate of the neutral red solution is investigated, and those main effects on the efficiency of catalytic degradation are discussed. The results show that photo-degradation efficiency relies on the amount of catalysts and oxidants, the catalyst is recoverable and readily to recycle.

Abstract: Nowadays drinking water resource has been polluted, while the conventional treatment process cannot effectively remove polluted matters. In order to tackle this problem, the granular activated carbon (GAC) and ultrafiltration membrane (UF) were introduced into drinking water treatment process. The results revealed that when treat the micro-polluted water the effluent water quality of turbidity, permanganate index and color can reach 0.1NTU, 1.3mg/L-2.3mg/L and 5 degree respectively with GAC-UF process. And the total removal efficiency of turbidity, permanganate index and color can reach 98%-99%, 70%~75% and 60% respectively. The GAC can effectively remove organic matters, while the UF membrane can effectively remove suspended solids, colloids. The GAC-UF combined process can get a good water quality when treat the micro-polluted water.

Abstract: In order to avoid the damage on mesostructure by the high temperature treatment, inorganic titanium species were used as the precursors for the preparation of mesoporous TiO2 of crystalline framework at mild conditions. The influences of the precursor, additive, reaction pH and temperature on phase and textural structures of the products were investigated. The samples were characterized by XRD, N2 adsorption/desorption, FT-IR and SEM. The results show that anatase mesoporous TiO2 with large surface area could be obtained without calcination with Ti(SO4)2 as precursor or TiCl4 when SO42- was added. And the template could be completely removed by Soxhlet extraction.

Abstract: In the membrane bioreactor (MBR) treating municipal wastewater, the effect of sludge retention time (SRT) on the contents of the extracellular polymeric substances (EPS), tightly bound EPS (TB) and loosely bound EPS (LB) and the ratios of protein and polysaccharide in TB and LB was studied. With the extension of SRT the EPS increased and the ratios of protein and polysaccharide in TB and LB changed. The above changes influenced the charge distribution of bacterial surface, increased the proportion of hydrophilicity and hydrophobicity on the bacterial surface, changed the bacteria from the instable (R-type) to the stable (S-type), decreased the Zeta potential and increased the values of sludge volume index (SVI). The correlation analysis for the main parameters of fouling resistance was performed by SPSS software, and it was found that the correlation coefficient (rp) was -0.818 for Zeta potential, 0.853 for the content of suspended solids in supernatant and 0.832 for relative hydrophobicity, respectively. SRT of the MBR should be controlled below 120 times of the minimum generation-time of dominant bacteria considering the membrane fouling and sludge characteristics.

Abstract: Substrate concentration effects on H2 production performance in a continuous stirred-tank reactor (CSTR) were investigated. Using molasses as the feeding, the CSTR system was operated at chemical oxygen demand (COD) of 2000-8000 mg/L to identify the optimal working substrate concentration. Increasing substrate concentration (2000~6000 mg/L) gave better biomass content and hydrogen production, signifying that the average cellular activity for H2 production may be enhanced as the substrate concentration increased. The overall maximal biogas and hydrogen production yield were 18.69 L and 6.01 L, respectively, both of them occurred at 6000 mg/L. The gas phase H2 content did not vary considerably regardless of changes in substrate concentration. This reflects that the CSTR was a relatively stable H2-producing system. The major soluble products from hydrogen fermentation were ethanol and acetic acid, accounting for 59% and 23% of total liquid fermentation products, respectively. Thus, the dominant H2 producers in the mixed culture belonged to acidogenic bacteria that underwent ethanol-type fermentation. However, the biomass content and hydrogen production yield tended to decrease as the substrate concentration increased to 8000 mg/L, suggesting that granular sludge formation and cellular activity for H2 production may be inhibited at high substrate concentration. Ethanol, acetic, butyric and propionic were the main liquid fermentation products with the percentages of 31%, 24%, 20% and 18%, which formed the mixed-type fermentation.

Abstract: The electrochemically mediated delignification (EM) of lignocellulosic fibers is one of new methods for fiber pulp delignification and bleaching. The choice of mediator is a key to the foundation of the delignification system. In this paper, violuric acid (VIO) was selected as a mediator to catalyze this delignification process, and the catalyzing delignification was carried out as well as subsequent bleachability of delignified pulps. The catalyzing delignification efficiency was evaluated according to pulp kappa number and viscosity. The pollution loads of bleaching effuluents were discussed. The results showed that VIO is a suitable mediator for the electrochemical delignification system. At the optimum conditions, the kappa number reduces by 5.4, from 17.4 to 11.7, and viscosity decreases from 1144cm3/g to 1059cm3/g. The alkali treatment after EM can further reduce kappa number and increase brightness of resulting pulp. The kappa number of pulp treated with EME can be reduced to 8.9 with the delignification rate of 48.8% and viscosity only decreases to 1065 cm3/g. The brightness of EM E treated pulp increases from original 39.2% ISO to 50.7% ISO. The EM treated pulps can be bleached to 80%ISO with the subsequent QP or EQP bleaching sequences at 2.0% H2O2 charge. The bleaching effluents of EMQP have lower COD and BOD than that of OQP which is considered as environmental friendly bleaching sequence.

Abstract: A new kind of bio-based composite panel with veneer material and performance of decorative material was produced by process of dissection, staining, weaving and collage. The bio-based composite panel was instructed with art design using the wheat straw as raw material. The facing technology of the bio-based composite panel with wheat straw veneer material was investigated and no previous research using pretreated wheat straw to produce the veneer material with characteristic of decorative function. The bonding strength was measured and it reached 0.75 MPa. It is demonstrated that pretreated wheat straw can be used for furniture manufacturing and decorative applications directly.

Abstract: Based on (3-methacryloxypropyl)-Polyhedral oligomeric silsesquioxane (MP-POSS) (MP), vinyl-POSS (VP), (3-glycidoxypropyl)-POSS (GP) and modified with 10, 20 and 30 wt-% titanium tetrabutoxide (TTB), three hybrid nanofilms (f-MPT, f-VPT and f-GPT) were prepared using hydrolytic condensation and crosslinking. The average transparency (AT) and absorption coefficients (AC) of the films were measured in the ranges of 280-2500 nm. The average transparency (AT) values of three films were about 10-11% (280-320 nm), 78-80% (320-400 nm) and 85-89% (750-2500 nm), which implies that these films indeed can provide a physical barrier for blocking the UV-B absorbed into greenhouse, indicating functionality of the POSS/TiO2 materials as the sun protection ingredients. The AT values of three films were in the order of f-MPT>f-GPT>f-VPT due to complete-cage structures of building blocks (POSS) and the size of organic branches covalently bonded to the silica network in the molecular structures. This indicates that VPT powder might be significantly better to selected for the sun protection factor (SPF). Lower mtransparency of the films containing 30 wt-% TTB fractions is ascribed to more amounts of TTB in the modified films.

Abstract: The study herein investigated the bond strength of original veneer, dyeing veneer and fixative veneer in terms of moisture content. The test results were shown that: bond strength of untreated veneer, dyeing veneer and fixation veneer were all decreased with moisture content increasing. Furthermore, wet strength of these three kind of veneers were lower than the dry strength themselves evidently. The study also found that dry strength and wet strength of original veneer were all bigger than those of dyeing veneer and fixative veneer evidently.