H2O2∕UV-C and Fe2+∕H2O2∕UV-C versus TiO2∕UV-A Treatment for Reactive Dye Wastewater

This study investigated the advanced oxidation of commonly used reactive dyestuffs in exhausted dye-bath effluents in homogeneous (H2O2∕UV-C and photo-Fenton) and heterogeneous (TiO2∕UV-A) media. Photocatalytic treatment efficiencies of two different TiO2 powders (PC 500 and Mikroanatas) and the platinized Degussa P25 were compared with that of the more well-known Degussa P25 in varying pH media. Treatment performance was strongly affected by the initial H2O2 concentration for H2O2∕UV-C and photo-Fenton oxidation systems, whereas for the TiO2∕UV-A process only PC 500 TiO2 powder, an anatase crystal phase of the semiconductor, exhibited a significantly pH-dependent reaction efficiency. The decolorization rate followed the order of Fenton∕UV-C > Pt-P25∕UV-A > Mikroanatas∕UV-A > P25∕UV-A > PC 500∕UV-A > H2O2∕UV-C, whereas the decreasing order for total organic carbon reduction was Fenton∕UV-C > H2O2∕UV-C > Mikroanatas∕UV-A > Pt-P25∕UV-A > P25∕UV-A > PC 500∕UV-A for the studied reaction conditions. Removal of optical density at 254-nm wavelength ranged between 75 and 96%.     

Treatment of MTBE-Contaminated Water in Fluidized Bed Bioreactor

Methyl tertiary-butyl ether (MTBE) biodegradation was evaluated in a laboratory-scale granular activated carbon (GAC)-based fluidized bed bioreactor system. The reactor was operated in seven distinct phases during which the MTBE loading rate, hydraulic retention time, cocontaminant loading [butyl, toluene, ethylbenzene, and xylene (BTEX) and tertiary-butyl alcohol (TBA)] and temperature were varied. The reactor was able to treat MTBE to less than 20 ug/L at 25°C and total organic carbon (TOC) loading rates between 0.01 and 1.1 kg/m3 of expanded GAC bed per day (kg/m3?day). Net biomass yield in the reactor under high loading conditions was approximately 0.55 g of total suspended solids (TSS) per gram of TOC consumed. This high yield under the higher loading rates necessitated that biomass be removed from the reactor to control bed expansion. At a loading rate of 1.5 kg/m3?day, MTBE effluents exceeded 20 ug/L. Reactor performance decreased as the reactor temperature was reduced from 25 to 15°C, but even at the lower temperatures MTBE removal efficiency exceeded 99%. Methyl tertiary-butyl ether treatment efficiency was not affected by the addition of TBA or BTEX under the conditions evaluated. Results of this study demonstrate that fluid bed bioreactors inoculated with an appropriate microbial culture can efficiently treat MTBE-contaminated water.     

含钛中碳钢中钛氧化物析出热力学分析

摘要：以含钛中碳钢为研究对象,从热力学的角度分析了含钛中碳钢中钛氧化物析出行为,结果表明：浇注温度为（1535±10）℃且钢中溶解氧含量大于0.003%（质量分数,余同）时,低钛中碳钢中的溶解Ti可与钢中的溶解氧反应生成Ti3O5、Ti2O3,生成TiO2、TiO夹杂的可能性较小;高钛中碳钢中的溶解Ti可与钢中的溶解氧反应生成Ti3O5、Ti2O3、TiO2和TiO夹杂;同时钢中的溶解Ti能够还原钢中的SiO2、MnO、Cr2O3夹杂物并生成TiO2夹杂;低钛中碳钢中不会生成TiC、TiN、TiS和Ti4C2S2夹杂;高钛中碳钢中可能会生成TiN和Ti4C2S2夹杂。对于低钛中碳钢,控制钢中较低的溶解氧含量（<0.002%）,对于高钛中碳钢,控制钢中较低的溶解氧含量（<0.0007%）及较少的Cr2O3、MnO、SiO2夹杂数量,可有效抑制含钛中碳钢中高熔点含钛夹杂物的生成,实现中碳钢低成本钛合金化及相关连铸工艺开发。     

Preparation and Photocatalytic Behaviors of Nanoporous Polyoxotungstate-Anatase TiO2 Composites

Nanoporous anatase TiO2 crystalline particles coupled with Keggin or Wells-Dawson unit, H3PW12O40/TiO2 or H6P2W18O62/TiO2, were prepared at a low temperature （200℃ ） using sol-gel method combined with hydrothermal treatment at programmed temperature. The as-prepared composites have uniform anatase phase, and they exhibit both micrand mesoporosities with pore sizes of 0.6 and 4.0 nm, respectively, and their average size is lower than 10 nm. Photocatalytic tests show the composites exhibit relatively higher photocatalytic activities to decompose the organocholorine pesticide hexachlorobenzene（HCB） than anatase TiO2, the starting polyoxotungstates, and EuEOa/TiO2 prepared by using sol-gel method, and this was attributed to （ 1 ） the synergistic effect of photoactive anatase TiO2 with the polyoxotungstate, and （2） the fascinating physical and chemical properties of the porous materials.     

Anoxic∕Oxic Biodegradation of Aminobenzene

Biodegradation of aminobenzene, which is used as the only source of carbon and nitrogen, is evaluated in a single fluidized bed reactor operated in a temporal, anoxic∕oxic mode. The experimental evidence indicates that total organic carbon (TOC) is removed with >91% efficiency at a feed concentration of 100 mg∕L and a dilution rate of 2.4 day?1. Moreover, about 53–63% of feed total Kjeldahl nitrogen (TKN) is also removed, confirming that effective removal of nitrogenous matter in aminobenzene (i.e., the ?NH2 group) is achievable in a temporal, anoxic∕oxic environment. The kinetic analysis shows that TOC removal in oxic cycles is rapid and substantial, which enables nitrification to proceed at a discernible rate. In addition, the data on TOC and NO3?-N removal in anoxic cycles reveal that carbonaceous matter in aminobenzene and∕or its intermediate metabolites is effectively utilized for denitrification. The best treatment performance, in terms of carbon and nitrogen removal and potential savings in aeration costs, is obtained by coupling a 6 h oxic cycle with a 6 h anoxic cycle. All reaction rates estimated in anoxic∕oxic experiments remain relatively constant over the range of conditions tested.     

TiO2／活性炭的制备与光催化性能

以活性炭(AC)为载体，采用Sol-Gel法制备纳米TiO2／AC复合催化剂，利用SEM，TG-DTA，XRD等对其组成、结构、尺寸等进行分析和表征；并用紫外灯为光源，通过可溶性罗丹明B的光催化降解反映对其光催化活性进行研究。结果表明，TiO2纳米粒子的尺寸范围在30nm～60nm之间，其中TiO2的晶型主要为锐钛矿；活性炭载体与TiO2结合牢固，TiO2纳米颗粒不发生二维粘结；TiO2／AC复合体的比表面积比活性炭载体的大，对罗丹明B在200min内达到完全降解，而P25需要5h，TiO2／AC复合体具有很强的光催化活性，并且制备的TiO2／AC复合体催化剂容易从溶液中分离。     

纳米TiO2负载钯催化剂的性能研究

采用浸渍法制备了纳米TiO2负载钯催化剂,以乙炔选择催化加氢制备乙烯为反应模型考察了稀土元素La、空速对纳米Pd／TiO2催化剂性能的影响,并与纳米SiO2为载体的Pd—La／SiO2催化剂的性能做了比较。实验结果表明,纳米Pd／TiO2催化剂具有良好的催化活性和性能稳定性,La的加入显著提高了乙烯的选择性、增幅达加％左右。与Pd—La／SiO2催化剂相比,Pd—La／TiO2催化剂具有更高的选择性。     

Process Optimization of an Aerobic Upflow Sludge Blanket Reactor System

Response of an aerobic upflow sludge blanket (AUSB) reactor system to the changes in operating conditions was investigated by varying two principle operating variables: the oxygenation pressure and the flow recirculation rate. The oxygenation pressure was varied between 0 and 25?psig (relative), while flow recirculation rates were between 1,300 and 600% correspondingly. The AUSB reactor system was able to handle a volumetric loading of as high as 3.8?kg total organic carbon (TOC)/m3?day, with a removal efficiency of 92%. The rate of TOC removal by AUSB was highest at a pressure of 20?psig and it decreased when the pressure was increased to 25?psig and the flow recirculation rate was reduced to 600%. The TOC removal rate also decreased when the operating pressure was reduced to 0 and 15?psig, with corresponding increase in flow recirculation rates to 1,300 and 1,000%, respectively. Maintenance of a high dissolved oxygen level and a high flow recirculation rate was found to improve the substrate removal capacity of the AUSB system. The AUSB system was extremely effective in retaining the produced biomass despite a high upflow velocity and the overall sludge yield was only 0.24–0.32?g VSS/g TOC removed. However, the effluent TOC was relatively high due to the system’s operation at a high organic loading.     

高温热震对具有SiC涂层的C/C复合材料压缩性能的影响

采用化学气相反应法在C/C复合材料表面制备SiC涂层,对SiC涂层C/C复合材料试样进行热震实验。利用X射线衍射仪(XRD)、扫描电镜(SEM)及能谱分析等研究涂层的形貌和结构,采用压缩性能试验研究热震次数及热震温度对SiC涂层C/C复合材料试样压缩性能的影响。结果表明:试样的抗压强度在197.9~237.0 MPa之间,平均抗压强度为210.4 MPa。在1 100℃下进行热震实验,抗压强度随热震次数增加呈近似线性降低趋势;当热震次数一定时(15次循环热震),在900~1 500℃温度范围内,抗压强度随热震温度升高逐渐降低。热震温度为1 500℃时,热震后试样的抗压强度略有升高,主要与热震过程中氧化形成的SiO2玻璃的高温自愈合作用有关。     

Adsorption Equilibrium Modeling of Space Station Wastewaters

An adsorption equilibrium model was developed for predicting the total organic carbon (TOC) removal by the International Space Station water processor's multifiltration beds. Ideal adsorbed solution theory is used to describe the competitive interactions between fictive components (FCs) that make up the TOC. The FC physical properties were based on several identified compounds to represent the distribution adsorbing compounds in the wastewaters. The TOC isotherms were performed using the wastewaters on three absorbents (a coconut-based granular activated carbon, a coal-based granular activated carbon, and a polymeric-based resin), which are contained in the multifiltration beds. The isotherms were used to validate the model for all three adsorbents. The FCs were determined in such a way that they can describe the TOC concentration for multiple beds in series.     

Effect of Y2 （CO3）3 and Surfactants on Electrorheological Performance of SiO2 Particle Materials

The SiO2 particle material has weak electrorheological (ER) activity. The ER performance of the SiO2 particlescan be ameliorated after adsorbing Y2(CO3)3. In this paper, the effect of Y2(CO3)3 and different surfactants on the ER performance of the SiO2 particle materials is investigated. The results show lhat anionic or cationic surfactants maybe enhance the ER activity of SiO2 material, and nonionic surfactants cannot when surfactants are added during the process of the SiO2 particle preparation, only the anionic surfactant, AES, can enhance markedly the ER performance of the material. The surface area, pore volume and pore diameter of the particles were measured. The effect of Y2(CO3)3 and the surfactants on the microstructure of SiO2 materials and the relationship between ER effect and the microstructure are described.     

含钛高炉渣结晶规律的研究

用差热分析和淬冷法配合岩相分析,研究了SiO_2和TiO_2对CaO-SiO_2-TiO_2-Al_2O_3-MgO五元合成渣系结晶规律的影响,绘制出该渣系在改变SiO_2和TiO_2含量时的两个矿物结晶区域图,并确定了钙钛矿和黑钛石的结晶区域。测定了在中性气氛下,不同条件时,渣中钙钛矿和黑钛石的结晶量。为采用结晶分离法降低含钛高炉渣中的TiO_2含量及其利用提供了必要的理论基础。     

Photoelectrocatalytic Wastewater Treatment Using TiO2/ITO Bilayers Prepared on Optical Fibers by Pulsed Laser Deposition

Advanced oxidation processes (AOPs), on the basis of photoelectrochemical reactions, constitute a good alternative for treating wastewaters contaminated with refractory organic compounds such as dyes. For this purpose, different approaches have been explored to develop novel photoanodes that can be efficiently used in these systems. In this context, this study deals with a comparison of indium tin oxide (ITO) thin films deposited at room temperature by pulsed laser deposition on flat glass and on silica optical fiber (SiO2 core, 600?μm diameter) substrates. Characterization data reveal that nanostructured ITO thin films with resistivity values from 4.4×10-2 to 5.6×10-4??Ω·cm were obtained. To build the photoanode, the ITO thin films were coated with a TiO2 layer deposited by using the electrophoretic method. The prepared TiO2/ITO bilayers on optical fibers showed a better photocatalytic performance than those deposited on flat glass substrates according to TOC and color removal measurements from dye contaminated water samples. These results suggest that the deposited materials exhibit suitable properties for their application in photoelectrocatalytic devices that, employing optical fiber as support and light transmitter, can be efficiently used for the elimination of organic contaminants in industrial wastewaters.     

Grain Size and Wettability of TiO2/SiO2 Photocatalytic Composite Thin Films

The uniform transparent TiO2/SiO2 photocatalytic composite thin films are prepared by sol-gel method on the soda lime glass substrates, and characterized by UV-visible spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), BET surface area, FTIR spectroscopy and X-ray photoelectron spectroscopy (XPS). It was found that the addition of SiO2 to TiO2 thin films can suppress the grain growth of TiO2 crystal, increase the hydroxyl content on the surface of TiO2 films, lower the contact angle for water on TiO2 films and enhance the hydrophilic property of TiO2 films. The super-hydrophilic TiO2/SiO2 photocatalytic composite thin films with the contact angle of 0-° are obtained by the addition of 10%-20% SiO2 in mole fraction.     

化学包覆法制备TiO_2/SiO_2复合物

与TiO2光催化剂相比,以SiO2为载体或内核制备的TiO2/SiO2复合催化剂,其表面活性、光催化活性和热稳定性都更高。以粉煤灰为原料制备的沉淀SiO2为硅源,钛酸四丁酯为钛源,采用化学包覆法制备TiO2/SiO2复合物,采用扫描电镜(XRD)、红外光谱(FT-IR)和差热分析(TG-DTA)等测试手段对该复合物进行表征。FT-IR和TG-DTA分析证实,SiO2被TiO2有效包覆。复合物热稳定性较高,经700℃焙烧4 h后,SiO2仍为无定形,TiO2以锐钛矿相为主;在900℃焙烧后,TiO2大部分由锐钛矿相转变为金红石相。     

溶胶凝胶法制备TiO_2–SiO_2复合薄膜及特性表征

以钛酸丁酯和正硅酸乙酯为原料,采用溶胶–凝胶法制备TiO_2–SiO_2复合薄膜,通过热重分析、X射线衍射、红外光谱、原子力显微镜和接触角测试等方法对样品进行表征。结果表明,TiO_2–SiO_2复合薄膜中存在Ti–O–Si化学键,薄膜具有较好的热稳定性,内部结构均匀且具有较高的孔隙率,平均孔径为50.2 nm;加入SiO_2使复合膜表面酸性提高从而吸附更多的羟基,表现出更强的亲水性能;当TiO_2:SiO_2=3:2(摩尔比)时,复合膜表面亲水性能良好。     

不同造孔剂对SiCp/Al复合材料中多孔预制体性能的影响

采用无压浸渗法制备SiCp/Al复合材料,主要分析了淀粉、硬脂酸和石墨三种不同造孔剂对多孔预制体组织结构和性能的影响。结果表明:三种不同造孔剂对预制件的孔隙分布影响很小;以石墨为造孔剂的预制件有一部分SiC颗粒在高温下氧化生成SiO2,形成的烧结颈,氧化生成的SiO2膜层对SiC颗粒起到一定的连接作用,使得预制件的强度增大。     

矿石中SiO2、TiO2、P、Mn的联合测定

采用碱熔法处理样品,用同一母液对矿石产品中的SiO2、TiO2、P、Mn进行了联合测定。通过控制测定的酸度,各元素线性良好,测得SiO2、TiO2、P、Mn的相对标准偏差分别小于3．70％、4．00％、4．44％、1．79％。该方法用于不同含量标准物质的测定,精密度和准确度高,结果令人满意。     

Separation and Recovery of Phosphorus from P-bear-ing Steelmaking Slag

In order to recycle the phosphorus from P-bearing steelmaking slag, the influences of magnetic field inten- sities, slag particle sizes and slag compositions were investigated by magnetic separation experiments. SiO2, A1203 and TiO2 melting modification of converter slag was made respectively and phosphorus-rich phase was extracted by magnetic separation. The results show that MgO, MnO, Na2 0 and CaF2 have little effect on the phosphorus recovery, whereas the addition of SiO2, Al2 03, and TiO2 has great effect on phosphorus enrichment in slag and magnetic separation. With adding the reagent of SiO2 Al2 03 and TiO2, recycled non-magnetic substances are increased obviously and P2 05 content in nowmagnetic substances and phosphorus recovery rate are also increased. The phosphorus recovery rates of modified slag No. 8 （SiO2 modification）, slag No. 10 （AI2 03 modification） and slag No. 11 （TiO2 modification） are 84.75 %, 82.16 % and 74.46 %, respectively. Then, most of phosphorus was recycled.     

Impact of Membrane Surface Modification on the Treatment of Surface Water

New polyethersulfone (PES) based membranes for ultrafiltration (UF) were developed by blending a surface-modifying macromolecule (SMM) in the casting solution, in an attempt to minimize the impact of fouling. Fouling was evaluated using concentrated Ottawa River water (CORW), either unfractionated or fractionated via UF. These membranes also included some polyvinylpyrrolidone (PVP), a pore forming additive. A statistical analysis was conducted to evaluate the impact of some variables on the treatment of the surface water. The independent variables included PVP/PES ratio in the casting solution, with and without SMM, and the nature of the feed CORW [low molecular weight (LMW) fraction, unfractionated, high molecular weight (HMW) fraction]. The performance variables studied were total organic carbon (TOC) removal, the foulant accumulation at the membrane surface after filtration, the flux reduction, and the final permeate flux. The most important variable was the feed water. Filtration of LMW had a higher final flux, less fouling, but slightly lower TOC removal. The SMM did not significantly impact the membrane performance. TOC removal was high, compared with results reported in the literature for UF membranes.