Materials Science Forum Vols. 743-744

Abstract: Four novel boron containing ores/epoxy composites were prepared by using nature ludwigite green ore (NLGO), artificial ores including boron containing iron ore concentrate (BCIOC), boron rich slag (BRS) and boron mud (BM) as neutron absorbers, which were obtained by dressing from NLGO, blast furnace separation from BCIOC and borax production, respectively. The microstructure of the composites was investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FT-IR). Shielding properties of the composites against thermal and Cf-252 fast neutron were measured. Factors affecting the shielding properties were investigated. Energy deposition, absorbed dose and half value layers of the composites against neutron penetration were simulated by Monte Carlo method, and a simulated function was obtained. The results showed that the composites were compact and the particles of ores were homogeneous. Ascending boron mole numbers per unit volume (n_B) in the composites can obviously enhance the macroscopic absorbing cross section (Σ_thermal) and improve the shielding properties for thermal neutron. The relationship of Σ_thermal and n_B follows the equation of Σ_thermal=0.218+450.490n_B. And the relationship of average atomic number (Z) of boron containing ores composites and the macroscopic removal cross section for fast neutron follows the equation of Σ_removal=0.042exp (-Z/5.70)+0.032. Enhancement of the shielding abilities against Cf-252 fast neutron can be achieved by using the composites with low average atomic number.

Abstract: Spherical and octahedral Cu₂O nanocrystals were prepared by reducing copper acetate monohydrate (Cu (CH₃COO)₂·H₂O) with hydrazine hydrate (N₂H₄·H₂O) at ambient temperature and pressure. The influence of solution composition on the morphology and microstructure of Cu₂O nanocrystals were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Ultraviolet and visible light spectrometer (UVvis) was employed to investigate the photocatalysis behavior of the Cu₂O samples. The results show that Cu (OH)₂ was initially formed with the addition of NaOH and then reduced into Cu₂O by N₂H₄·H₂O. At the same time, a portion of Cu₂O particles were further reduced to Cu, but the increasing of O₂ contents in the solution under vigorous stirring reconvert Cu into Cu₂O whichlead to the formation of pure Cu₂O nanocrystals. The alkaline condition which provided by NaOH was the prerequisite for obtaining spherical and octahedral Cu₂O crystals. The facile method was provided to fabricate Cu₂O nanocrystals with outstanding photocatalysis performance at low temperature, which may play an important role in sewage treatment and organic pollutants decomposition.

Abstract: Multi-channel tubular macroporous ceramic membrane supports were successfully prepared via a plastic extrusion method, using α-Al₂O₃ with a purity of 94wt% and aluminum hydroxide as starting materials, the ash of burned rice hull as the pore-forming agent and a small amount of talc and kaolin as sintering aids. The effects of the kinds of sintering aids, content of aluminum hydroxide and ash of burned rice hull on the porosity, pore size and distribution, compressive strength, acid and alkali corrosion resistance and permeability of the new multi-channel ceramic membrane supports were investigated. The results showed that aluminum hydroxide effectively improved the mechanical strength, and the support sintered at 1450°C for 4h with the aluminum hydroxide content of 20wt% exhibited higher performance: average pore size diameter and porosity were nearly 5μm and 50% respectively, the compressive strength was around 7MPa, the pure water flux was 26m³/m²h at 0.1MPa and changed to nearly 20m³/m²h after the acid and alkali treatment at 90°C for 48h. The support possesses excellent corrosion resistance and can be used in the water treatment process with large range of pH value.

Abstract: The adsorption of acetamiprid and phenol in water onto the resin of ZHP02 modified with proline based on NDA150 was investigated from the static experiment at different temperatures in single component system and binary components system. The adsorption capacities and adsorption selectivity for acetamiprid and phenol in waste water were tested. The results showed that the adsorption was fitted by Freundlich model, and the adsorption of acetamiprid or phenol on ZHP02 was an exothermic process. The cooperative adsorption existed in binary components system when the equilibrium concentration was higher. The adsorption of acetamiprid onto ZHP02 had little change in the presence of phenol, but the adsorption of phenol onto ZHP02 was weakened significantly in the presence of acetamiprid. The electrostatic force between acetamiprid and adsorbent was stronger than phenols, so acetamiprid was adsorbed preferentially onto ZHP02.

Abstract: The natural soil-contact method was used to investigate the toxicity of poly (butylene succinate-co-caprolactone) (P(BS-co-CL)) copolymers with different number-average molecular weight (Mn) on the protein content, cellulose enzyme activity and peroxidase activity in earthworm extraction. The results showed that: during the first two weeks, both cellulose enzyme activity and peroxidase activity of earthworms treated by polymer (Mn is 8.0×10³), decreased with the increase of polymer content. In the polymer (Mn is 1.6×10⁴) group, in the end (28 and 42 d), cellulose enzyme and peroxidase activity decreased with the increase of the polymer concentration. However, the polymer (Mn is 2.8×10⁴) had no significant effect on the cellulose enzyme activity and peroxidase activity of earthworms. In addition, in the beginning (7 and 14 d) of the three treatments, the protein content increased with the raising of polymer concentration. Nevertheless, in the test treated by copolymers with high Mn, there was no significant changing.

Abstract: Lipase Novozym 435 was used as catalyst to degrade P(BS-co-DGS), which was a kind of PBS-based copolyester modified with diethylene glycol (DEG), in a THF/toluene mixed solvent system. P(BS-co-DGS) copolyesters were synthesized by copolymerization and characterized by ¹H NMR. GPC and TGA were used to investigate average molecular weight and thermal property before and after degradation, respectively. After degraded by N435 for 30 h, the M_n of P(BS-co-DGS)10 (DEG content 10%) decreased from 8.33×10⁴ to 3.52×10⁴ g·mol^-1 with some yellow oil droplets of oligomers appearing. And the initial decomposition temperature (the temperature at 5% mass loss) of P(BS-co-DGS)10 changed from 300.6 to 178.9. MALDI-TOF-MS results showed that none of DEG oligomers appeared in P(BS-co-DGS)10 degradation products. However, when the DEG content increased to 20%, there were the DEG circle oligomers as well as linear oligomers in the degradation products.

Abstract: The reclaimed water reuse is certainly the most effective method to alleviate the shortage of water resources in China at present. The reclaimed water reuse technique is now in the exploration and development stage in the urban area. At the present the reuse ratio is still low, the reasons may be that not only the processing system is very costly, but also a lot of fossil fuel is used, and a large amount of new solid waste and the second sludge will be produced during the reclaimed water reuse. In order to make the endurance of the environment meets the more severe challenges the soil infiltration method, based on ecology principle, through the use of sewage treatment combination process in soil infiltration method has been developed in the present study to solve the above problems. This paper emphasizing on the analysis of the advantages and disadvantages of the soil infiltration method in reclaimed water reuse technique to treat sewage, and provides a new idea and method for the development of water reuse technology.

Abstract: The bionic structure nanoporous TiO₂ materials were prepared using aquatic plants as biological templates. The X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), nitrogen adsorption method and ultraviolet-visible light spectrometer were employed to characterize the structure of samples and the degradation performance of methylene blue solution under the visible light. The results showed that TiO₂ sample inherited the porous structure of original template. Such bionic material was composed of ultra-thin piece layers which were full of TiO₂ nanoparticles with size of about 10 nm. The product was studded with piled pores which had a few to dozens of nanoaperture. The material was doped with a small number of bionic legacy elements which can enhance the absorption of 400-800 nm range of the visible light, thus the bionic nanoporous TiO₂ materials had better photocatalytic degradation effects of methylene blue solution in the sun.

Abstract: Five novel coagulants, DC-491, Fennofix K97, BWD-01, MD-03 and MD-04 were chosen to treat reactive brilliant red X-3B simulated wastewater by jar tests. The results showed that the decolorization efficiencies were all higher than 75% at initial pH 8.2 and temperature 20 after 20 minutes of reaction. Then, two typical coagulants, BWD-01 and MD-04 which had better performance were chosen to study the effect of dye removal of X-3B at different operating parameters, including coagulant dosage, pH, sedimentaion time and reaction temperature of simulated wastewater. Decolorization efficiency of MD-04 for X-3B solution was higher than 80% in pH range from 3 to 9, while for BWD-01, efficiency increased from 37.3% to 82.3% in this pH range. For both BWD-01 and MD-04, the color removal efficiency increased as the solution temperature increased and the maximum efficiency was over 94% at 40. Small changes in the color removal efficiency were observed after 1 hour sedimentation for both coagulants.

Abstract: Using coagulant aid to increase the organics removal is one of the main methods to improve the coagulation effect. The development of new coagulant aids has vital significance to water supply and sewage treatment. This paper develops two kinds of new seaweeds coagulant aids- Enteromorpha extract (EE) and sodium alginate (SA), and then the two coagulant aids were used together with ferric chloride (FC) in humic acid - kaolin water sample. The coagulation aid effect of EE and SA were studied through the comparation of coagulation effects before and after the application of them. Meanwhile, the growth, breakage and regrowth of flocs were investigated by use of a laser diffraction particle sizing device. The experimental results showed that Ee had significant coagulant aid effect while the aid role of SA was not obvious, but when used together with FC, flocs showed larger particle sizes and growth rates no matter which coagulant aid was selected. Meanwhile the strength and recovery ability of flocs showed a corresponding increase.