Catalytic oxidation of anionic surfactants by electrochemical oxidation with CuO-Co2O3-PO4(3-) modified kaolin

A new catalytic oxidation of anionic surfactants by electrochemistry method was designed and used to investigate the removal of anionic surfactant from simulated wastewater. Synergetic effect on COD removal was studied when integrating the electrochemical reactor, using porous graphite as anode and cathode, with the effective CuO-Co2O3-PO4(3-) modified kaolin catalyst in a single undivided cell. The result showed that this combined process could effectively remove anionic surfactant. Its COD removal efficiency was much higher than those individual processes and could reach up to 90% in 60 min. The operating parameters such as initial pH, cell voltage, and current intensity were also investigated. Possible theory for COD removal was also proposed to predict the role of modified kaolin, electro-catalysis and oxidation in the combined process. The pollutants in wastewater could be decreased by the high reactive OH* that produced on the surface of catalyst by the decomposition of electrochemical generated H2O2. The result indicates that the catalytic oxidation by electrochemistry method is a promising wastewater treatment technique.     

Physicochemical treatments of anionic surfactants wastewater: Effect on aerobic biodegradability

The effect of different physicochemical treatments on the aerobic biodegradability of an industrial wastewater resulting from a cosmetic industry has been investigated. This industrial wastewater contains 11423 and 3148mgL(-1) of chemical oxygen demand (COD) and anionic surfactants, respectively. The concentration of COD and anionic surfactants were followed throughout the diverse physicochemical treatments and biodegradation experiments. Different pretreatments of this industrial wastewater using chemical flocculation process with lime and aluminium sulphate (alum), and also advanced oxidation process (electro-coagulation (Fe and Al) and electro-Fenton) led to important COD and anionic surfactants removals. The best results were obtained using electro-Fenton process, exceeding 98 and 80% of anionic surfactants and COD removals, respectively. The biological treatment by an isolated strain Citrobacter braakii of the surfactant wastewater, as well as the pretreated wastewater by the various physicochemical processes used in this study showed that the best results were obtained with electro-Fenton pretreated wastewater. The characterization of the treated surfactant wastewater by the integrated process (electro-coagulation or electro-Fenton)-biological showed that it respects Tunisian discharge standards.     

盐酸羟胺-铁试剂法测定水中阴离子表面活性剂的研究

本文通过实验来研究盐酸羟胺-铁试剂法测定水中阴离子表面活性剂,实验证明,该方法精密与准确性均达到监测要求,与国标亚甲基蓝法相比具有操作步骤简单,萃取剂用量少的优点,适用于各类清洁水质的监测和废水的快速监测。     

Occurrence of anionic surfactants in treated sewage: risk assessment to aquatic environment

A comparative evaluation of occurrence of and risk to aquatic environment due to anionic surfactants (AS) in treated effluents from three main treatment processes, i.e. activated sludge process (ASP), oxidation pond (OP), and upflow anaerobic sludge blanket reactor (UASBR) is presented. UASBR effluents contained substantial concentrations of AS (4.25–5.91 mg/L as average AS removal was not found to exceed 18%). Post-treatment of UASBR effluent using 1–1.6 days detention, anaerobic polishing ponds (PP) was also found quite ineffective. In UASBR–PP combine, AS reduced only up to 30%. Effluents from OP based sewage treatment plants (STPs) also contained significant concentrations of AS. On the contrary, effluent AS or linear alkylbenzene sulfonate (LAS) concentrations recorded in ASP effluents were quite low (less than 0.2 mg/L). Unlike UASBR, LAS or AS removals greater than 99% are achieved in ASP. Treated effluents from UASBR and OP based STPs when discharged to aquatic ecosystems are likely to cause substantial risk to aquatic environment due to the presence of AS while effluents from ASP are not supposed to pose risk. Need to find an effective aerobic post-treatment unit to UASBR for desired removal of AS is emphasized.     

硬脂酸对三氧化二铬疏水性改性研究

采用硬脂酸对三氧化二铬颗粒进行表面改性,探讨改性条件对改性效果的影响,并通过活化指数、接触角、红外光谱、X射线衍射、差热分析等测定对改性效果进行表征。结果表明,三氧化二铬表面改性的最佳工艺条件为:改性剂硬脂酸质量分数为2%,改性温度为80℃,改性时间为40 min;硬脂酸在三氧化二铬表面发生吸附键合,形成新的化学键,但未破坏三氧化二铬的晶体结构;改性后,三氧化二铬与水的接触角达145°,其表面性质由亲水变为疏水。     

The thermal conductivity of talc as a function of pressure and temperature

Talc is a commonly used pressure-transmitting and gasket material for high-temperature and -pressure applications. The thermal conductivity of talc at high pressures and temperatures is therefore valuable in the design of high-pressure experiments and apparatus. In this paper measurements of the thermal conductivity of fired and unfired talc are presented. Measurements were made at pressures ranging from 0 to 2.5 GPa and temperatures from 150 to 900 K. The thermal conductivity was measured with the hotwire technique. The thermal conductivity results for both the fired and the unfired talc show a slight increase with increasing pressure. The absolute value of the thermal conductivity of talc is lower in the fired material than in the unfired material. In both cases, the thermal conductivity varied less than 15% over the temperature range studied. X-Ray diffraction studies have shown talc to be highly disordered. The results are shown to be consistent with those expected for a disordered crystal.Paper presented at the Tenth Symposium on Thermophysical Properties, June 20–23, 1988, Gaithersburg, Maryland, U.S.A.     

纳米SiO2疏水改性研究及应用进展

由于与有机基体之间存在良好相容性,疏水纳米SiO2已成为一种广泛应用于有机材料中的重要无机纳米填料.介绍了纳米SiO2疏水改性的原理方法,综述了纳米SiO2疏水改性最新研究进展及其在硅橡胶、涂料、塑料、化妆品等领域的应用情况,并对今后的研究发展提出了建议.     

Extrusion of starch‐based loose‐fill packaging foams: effects of temperature,moisture and talc on physical properties

Starch‐based loose‐fill packaging foams were made in a single‐screw laboratory‐scale extruder. Corn starch was blended with polystyrene in the ratio of 70 : 30 and extruded into foams using talc and polycarbonate as additives. Extrusions were carried out at moisture contents of 16, 18 and 20% (dry basis), and at barrel temperatures of 140 and 160°C. The influences of extrusion temperature, moisture content of starch, talc and polycarbonate on the radial expansion and other selected physical properties of starch foams were investigated. The effects of moisture and talc contents on the radial expansion of foams were found to be critical, while the role of temperature was close to significant. The expansion ratio increased when the moisture content was increased from 16 to 18%, and then decreased when moisture content was increased to 20%. In general, the expansion ratios of foams were higher at 160°C as compared to 140°C. Although polycarbonate mixed well with the starch–polystyrene melt, it was not effective as a structural and anti‐shrinking agent, and it did not contribute to the radial expansion. In general, the bulk densities and unit densities of the starch foams decreased as the moisture content and extrusion temperature increased. Scanning electron microscope images showed that the addition of talc yielded foams with smaller‐sized cells, with less expansion of the foam melt, and thus a higher density. X‐ray diffractograms revealed that the crystallinity of starch foams increased post‐extrusion, and there was adequate dispersion of the starch and polystyrene polymers to make the foam water‐resistant. Copyright © 2008 John Wiley & Sons, Ltd.     

琼脂糖的疏水化改性及生物相容性

采用乙酸酐对琼脂糖进行疏水性改性,合成了具有生物活性的琼脂糖醋酸酯.通过红外光谱(FT-IR)、13C核磁共振(13C-NMR)、原子力显微镜和接触角仪对琼脂糖醋酸酯进行了表征.结果表明,琼脂糖C6上引入了乙酰基,随取代度增大,琼脂糖醋酸酯膜表面粗糙度增大,疏水性增强.纺成丝后在水中不溶胀,形态保持完好,吸湿率最小可达...     

低折射率疏水SiO_2薄膜的制备和表征

为了制备低折射率疏水SiO_2薄膜,将正硅酸乙酯(TEOS)和二甲基二乙氧基硅烷(DDS)在碱性条件下共水解缩聚,再以六甲基二氮硅烷(HMDS)做进一步的改性,采用提拉浸渍工艺在玻璃基底上制备单层增透膜。通过对溶胶粘度随老化时间的变化规律及HMDS添加对薄膜接触角影响等的分析与研究,制备了接触角最大的低折射率薄膜;同时对薄膜的红外特性、透过率、折射率进行了表征。结果表明:TEOS和DDS共水解缩聚提高了膜层疏水性,经HMDS改性后,薄膜的接触角为149°,折射率为1.12。     

疏水性光催化剂的制备及其催化动力学

采用十二烷基硫酸钠(SDS)为改性剂对TiO₂进行了疏水改性, FTIR表征表明催化剂表面具有CC和CH烷基疏水基团. 同时采用CuO对催化剂进行了可见光响应改性, UV-Vis表征表明催化剂具有良好的可见光响应性能, 吸收边红移至830nm以上. 三维荧光扫描发现随着CuO和SDS的加入,催化剂的空穴电子分离效果迅速提高. 以硝基苯为处理对象, 考察了体系pH值、污染物初始浓度、催化剂用量和光照强度对光催化反应过程的影响, 建立了动力学模型. 低浓度条件下, 通过模型计算的动力学常数相对误差范围为-16.5％～-4.5％; 高浓度条件下为-11.3％～4.6％.     

疏水性涂层的制备及防结霜性能

基于聚偏氟乙烯(PVDF)、纳米碳酸钙和十七氟癸基三甲氧基硅烷(FAS-17)制备了一种疏水性涂层。采用扫描电镜(SEM)分析,表明少量的FAS-17可改善CaCO3在PVDF中的分散状况和提高涂层表面与水滴的接触角,同时对涂层的力学性能没有影响。该疏水涂层可显著改善铜表面的防结霜性能。     

包覆双层表面活性剂Fe3O4纳米粒子的制备及性能研究

为制备稳定的水基磁流体,分别以月桂酸、油酸钠、十二烷基苯磺酸钠作为外层表面活性剂,对包油酸的Fe3O4粒子进行了再包覆.将得到的双层包覆的Fe3O4粒子分别分散在水中,发现以十二烷基苯磺酸钠为外层表面活性剂的磁粒子制成的水分散液的稳定性最佳.利用IR研究其吸附机理,结果显示:内层的油酸通过化学键合吸附在磁粒子表面,外层的十二烷基苯磺酸钠通过物理作用吸附在包油酸的Fe3O4粒子表面.     

Evaluation of thermal and dielectric behaviour of some anionic nylon 612 copolymers

The anionic nylon 612 copolymers consisting of ?-caprolactam and 0.0–50.0 wt.% of laurolactam comonomer were synthesized and some of their characteristics were compared. The melting temperature, degree of crystallinity (first and second heating scan) and crystallization temperature of the nylon 612 copolymers are influenced by the presence of comonomer (laurolactam) decreasing proportionally to the amount of the laurolactam in the initial monomer mixture. The thermal stability of the copolyamides is good and equal to that of PA 6. Dielectric measurements performed on the polymers under study, over a frequency range of 10⁰–10⁶ Hz, at temperatures from 173 to 373 K have evidenced that modification of the dielectric permittivity and dielectric loss values occur in concordance with increase/decrease of the homogeneity in the polymer chains structure induced by incorporation of laurolactam segments.     

高强度疏水缔合水凝胶的重塑性能机理

将丙烯酰胺和少量的疏水单体辛基酚聚氧乙烯(4)醚丙烯酸酯溶解于十二烷基硫酸钠水溶液中,采用胶束共聚的方法成功制备了疏水缔合水凝胶(HA-gels)。HA-gels除具有良好的力学性能以外,还具有重塑性能。为了研究HA-gels的重塑性能,对其应力松弛行为进行了表征。研究结果表明,HA-gels应力松弛过程可以分为四个阶段:第一阶段是交联点间亲水长链的应力松弛过程;第二阶段是交联点间亲水长链已经高度取向;第三阶段是交联网络的结构重排过程;第四阶段是HA-gels的应力完全消除。因此,HA-gels内的交联点在外力的作用下可以解缔合和重新缔合来实现交联网络的结构重组,从而赋予了HA-gels的重塑性能。     

Hydrophobic Hydrogels with Fruit‐Like Structure and Functions

Normally, a polymer network swells in a good solvent to form a gel but the gel shrinks in a poor solvent. Here, an abnormal phenomenon is reported: some hydrophobic gels significantly swell in water, reaching water content as high as 99.6 wt%. Such abnormal swelling behaviors in the nonsolvent water are observed universally for various hydrophobic organogels containing omniphilic organic solvents that have a higher affinity to water than to the hydrophobic polymers. The formation of a semipermeable skin layer due to rapid phase separation, and the asymmetric diffusion of water molecules into the gel driven by the high osmotic pressure of the organic solvent–water mixing, are found to be the reasons. As a result, the hydrophobic hydrogels have a fruit‐like structure, consisting of hydrophobic skin and water‐trapped micropores, to display various unique properties, such as significantly enhanced strength, surface hydrophobicity, and antidrying, despite their extremely high water content. Furthermore, the hydrophobic hydrogels exhibit selective water absorption from concentrated saline solutions and rapid water release at a small pressure like squeezing juices from fruits. These novel functions of hydrophobic hydrogels will find promising applications, e.g., as materials that can automatically take the fresh water from seawater.     

两种含高疏水基水性聚合物的制备

采用硅氢加成法,在反应温度为85℃~90℃,反应时间为3.5 h~4.0 h,催化剂含量为反应物总量0.005%~0.01%且无溶剂的条件下,同时将亲水基团烯丙基聚氧乙烯聚氧丙烯醚、疏水基团含氟单体或长链烷基酯分别引入到202低含氢硅油的侧链,成功制得两种高疏水基水性聚合物。采用红外光谱和透射电子显微镜对有关产物及其水分散物进行了结构分析,并系统研究了其水分散物的透光率、流变性、表面张力等性能,结果表明,两种含高疏水基水性聚合物都具有明显的降低表面张力效应,在质量分数为2%的产物的水分散物的表面张力降低至20 N/m~26 N/m,且具有剪切变稠现象。     

Light-Scattering Cross Section of Hydrophilic and Hydrophobic Silica Aggregates

The aggregation dynamics of solid particles in liquid media is currently determined by optical-based particle sizing methods. Because it can be used in situ and applied to a wide particle size range, turbidimetry is acknowledged as one of the best methods for this characterization. Although much work has been done on aggregation, some aspects are less known and require additional experimental and theoretical research. This is particularly the case of aggregation of hydrophobic particles. Corresponding aggregates are three-phase objects (solid-liquid-gas) the morphology and optical properties of which are not known. The present work rests on the turbidimetric study of hydrophilic and hydrophobic silica samples in stirred aqueous solutions. Modeling involves different aspects: aggregate morphology, aggregate optical properties, and aggregation dynamics. This article particularly emphasizes the second aspect. Fractal-like models are proved to be representative of the aggregate morphology even at small size. Light-scattering cross section of the aggregates is calculated from their averaged projected area; effective refractive index is proved to be a good parameter for modeling the optical properties of both hydrophilic and hydrophobic aggregates. Classical models of porous aggregate formation (Kusters theory) are used for describing the aggregation dynamics.     

表面活性剂对液膜法提取柠檬酸影响的研究

表面活性剂种类和浓度对液膜法提取柠檬酸的提取率和乳液溶胀都有一定影响 .在给定条件下 ,提取率随表面活性剂浓度的增大而提高 ,由LMA -1所制成的液膜对柠檬酸的提取率比Span -80高 ,且产生的乳液溶胀也比较小     

疏水性阳离子淀粉的制备与应用

采用环氧氯丙烷、乙二胺对可溶性淀粉进行交联改性,制备了疏水性阳离子淀粉(HCS)。通过红外光谱(IR)、X射线衍射(XRD)、扫描电镜(SEM)及紫外-可见光谱(UV)等测试手段对材料的微观相态结构和性能进行了表征。同时,比较了HCS与亲水性聚合氯化铝以及物理吸附剂活性炭的脱色率,考察了投料量、絮体沉降时间以及搅拌速度对脱色率的影响。结果表明,HCS为非定型态,且表面粗糙多孔的物质;投加量为2 g/L,沉降时间仅为20 min时,脱色率即可达到91%,其性能远优于聚合氯化铝和活性炭。