正渗透膜对印染废水中铬的处理特性

利用水通道蛋白正渗透(FO)膜对含铬模拟废水和印染废水进行处理,分别研究了汲取液浓度和原料液pH对FO膜的水通量、盐返混通量及重金属铬截留效果的影响.结果表明,汲取液浓度对通量影响显著,处理模拟废水时,当氯化钠浓度从0.5 mol/L增加到2.0 mol/L时,膜的水通量从9.7 L/(m~2·h)增加到16.9 L/(m~2·h),盐返混通量从4.35 g/(m~2·h)增加到7.65 g/(m~2·h).而在处理印染实际废水的时候,膜的水通量从6.5 L/(m~2·h)增加到13.3 L/(m~2·h),截留率随汲取液浓度的增加而减小;另外随原料液pH的不断提高,对重金属铬的截留率也不断提高,在模拟废水的pH从3.0增加到11.0的过程中,对铬的截留率从98.8%增加到了99.7%,而对印染实际废水的处理中铬的截留率均高于99.5%,此外随着氯化钠浓度的提高,铬的截留率有所下降.这些数据可为FO应用于印染废水和重金属处理提供一定的参考.     

耐高温聚酰胺复合纳滤膜的染料脱盐性能研究

利用耐高温聚酰胺复合纳滤膜对偶氮染料酸性铬蓝K(ACBK)的含盐水溶液进行脱盐实验.研究了操作压力、盐水温度等对膜脱盐性能的影响,考察了复合膜在高温染料脱盐过程中的分离性能及热稳定性.结果表明,随着操作压力和温度上升,膜的通量都明显提高,对ACBK和NaCl的截留率则分别保持在100%和12%左右.在1.0MPa,80℃下复合膜可以高效地完成染料ACBK的脱盐净化.经过10d的高温染料脱盐实验,膜对染料的截留率基本不变,通量从260L/(m2·h)降低到约240L/(m2·h),经水冲洗后通量恢复到253L/(m2·h)左右.     

纳滤与反渗透膜处理含锰废水的初步研究

采用纳滤膜、反渗透膜分离技术对含锰废水进行了试验研究.考察了纳滤膜的操作压力、纯水/浓水比值、Mn2+浓缩倍数、Mn2+截留率及膜通量之间的关系.试验结果表明:纳滤膜对含锰废水有良好的处理效果,一级纳滤膜对Mn2+离子的平均截留率大于98％;浓缩倍数和膜通量随操作压力的升高而升高,2.0 MPa时,浓缩倍数可以达到8.2倍,膜通量可达到28～32 L/(m2·h).一级纳滤产生的纯水用反渗透膜进一步处理,反渗透膜对Mn2+离子的截留率在97％以上,纯水Mn2+离子浓度在0.5 mg/L以下,可以达标排放.     

海藻酸钙水凝胶过滤膜的制备及其对硫酸钙的截留

以尿素为致孔剂制备了海藻酸钙(CA)水凝胶过滤膜,测试了其通量、截留率和力学性能;通过扫描电子显微镜(SEM)观测其过滤硫酸钙前后的表面形貌。结果表明,增加尿素含量,均导致膜应力和应变的下降;而膜的纯水通量则迅速增大,尿素含量为3.0%(质量分数)时达到28.7 L/(m2·h),为最大;0.2 MPa下,过滤1.7 g/L硫酸钙时对Ca2+和SO2-4的截留率分别为83%和92%,稳定通量达到21.7 L/(m2·h)。     

耐高温聚芳醚酰胺超滤膜的研制与应用

以杂萘联苯聚芳醚酰胺(PPEA)为膜材料,N,N-二甲基乙酰胺(DMAc)为溶剂通过相转化法制备超滤膜.研究了添加剂种类,制膜过程中停留蒸发时间及凝胶浴温度对膜性能的影响.将PPEA超滤膜应用于硫化染料含盐粗产物水溶液的脱盐实验,膜的通量随操作压力或温度提高明显增加,而对染料的截留率保持在100%.在0.3MPa,80℃下经过3个循环约210min的恒容脱盐实验,染料溶液中的盐即可除净.在6h 5个循环的染料脱盐实验中,膜对染料的截留率基本不变,第五循环的初始通量约为260L/(m2·h),仅比第一循环时降低约10L/(m2·h).     

NF系列复合膜的制备及结构性能的研究

采用界面缩聚的方法制备了NF系列复合纳滤膜 ,并对其进行了表征 .在 0 6MPa下 ,NF - 1的水通量为 4 1L/(m2 ·h) ,对Na2 SO4 的截留率为 78% ,NF - 2的水通量为 6 0L/(m2 ·h) ,对Na2 SO4 的截留率为 94 % ,NF - 3的水通量为 2 6 5L/(m2 ·h) ,对Na2 SO4 的截留率为 94 % .通过红外光谱和原子力显微镜观察到NF系列复合纳滤膜的表层化学结构和表面形貌 ,探索了NF系列纳滤膜在染料工业的应用前景     

陶瓷膜法处理退浆废水工艺研究及工业化装置运行评价

针对以聚甲基丙烯酸甲酯为主要成分的退浆废水,采用孔径为50nm的陶瓷膜过滤,实现废水的资源化利用.采用两级串联先循环后浓缩的操作方式.循环过滤时,拟稳态通量为423L/(m2·h)和453L/(m2·h).循环结束后进行浓缩,浓缩倍数达到22倍时通量为66L/(m2·h)和54L/(m2·h);膜对COD的截留率为87.5%,产水浊度低于1NTU,废水中的氢氧化钠等小分子物质均透过膜层进入渗透液;膜污染是以聚甲基丙烯酸酯在膜表面形成滤饼为主;碱洗及酸洗膜通量恢复至新膜的95%以上.陶瓷膜出水回用于生产过程;工业化陶瓷膜运行稳定,经济效益显著.     

纳滤膜处理脱硫废水过程膜污染特性分析

利用纳滤装置对某电厂脱硫废水进行处理,判定主要污染物,研究纳滤膜污染特性.结果 表明,在运行过程中,纳滤膜通量在前18 h内由69.1 L/(m2·h)迅速降低至40.2 L/(m2·h),同时膜脱盐性能衰退,对Ca2+、SO42-和Mg2+的截留率呈现下降趋势.污染膜表面平均粗糙度从(5.94±2.13) nm增加至...     

凝固浴组分对双凝固浴法制备PVDF膜结构和性能的影响

在内外凝胶浴中添加不同含量的溶剂,采用双凝固浴法制备了PVDF/PVP/DMAc中空纤维膜.通过膜形貌扫描电镜( SEM)表征,纯水水通量和牛血清蛋白(BSA)截留率测试实验,分析评价了凝固浴中溶剂含量对PVDF中空纤维膜结构与性能的影响.结果表明,凝固浴中溶剂含量增大会导致皮层孔隙率增多,而对亚层结构的影响各不相同.膜的纯水渗透通量变化无明显规律性,但BSA截留率保持相对稳定.当内外凝固浴中溶剂体积分数分别为30％和70％时,膜内部大孔发育良好,亚层疏松多孔,水通量分别为270 L/(m2,h)和548 L/(m2·h),显示了良好的渗透性能.     

PA/PDA/PVDF复合纳滤膜的制备及其在模拟RB5染料废水处理中的应用研究

以聚偏氟乙烯(PVDF)超滤膜为基膜,通过多巴胺(DA)/聚乙烯亚胺(PEI)共沉积与交联剂均苯三甲酰氯(TMC)进行界面聚合组合的方法制备了聚酰胺/聚多巴胺/聚偏氟乙烯(PA/PDA/PVDF)复合纳滤膜。采用傅里叶变换红外光谱仪、原子力显微镜、场发射扫描电子显微镜对复合纳滤膜的结构、形貌进行了表征,考察了沉积时间、DA/PEI(质量浓度比)、PEI相对分子质量及DA+PEI沉积总量对复合纳滤膜微观结构与性能的影响,研究了复合纳滤膜对模拟活性黑5(RB5)染料废水的处理效果及运行稳定性。结果表明：最佳沉积时间为60min,随着PEI相对分子质量的减小,DA/PEI中PEI质量浓度的增加及DA与PEI沉积总量减小,复合纳滤膜的纯水通量增加。DA与PEI质量浓度比为1∶3时,PA/PDA/PVDF复合纳滤膜最大纯水通量达到3.11L/(m²·h·MPa),RB5染料废水通量为1.09L/(m²·h·MPa),截留率为95.89%;DA与PEI沉积总量为4g/L时,RB5染料废水最大截留率达到99.45%,纯水通量为1.34L/(m^2<...     

热交换器的分类及优缺点分析

热交换器是将不同温度介质之间的热量通过热传导的形式,由高温介质传递给低温介质,使介质达到生产所需温度的工艺设备,也可作为一种节能设备使用.通过对不同热交换器的结构分析,总结不同热交换器的优缺点、适用环境,为生产工艺设计人员及设备制造单位在选择可降低能耗、提高效率的设备上提供参考.     

聚苯胺及其复合物的制备和结构及形貌分析

通过化学氧化法分别制备盐酸,盐酸和十二烷基苯磺酸,碳纳米管(MWNTs-COOH)掺杂的聚苯胺,利用红外光谱,紫外光谱,扫描电子显微镜和透射电子显微镜对所制备聚苯胺的结构和形貌进行分析。分析不同掺杂物对聚苯胺的结构和形貌的影响;同时研究了超声波作用对聚苯胺形貌以及聚苯胺包裹MWNTs-COOH情况的影响。     

Modelling and computation of curing and damage of thermosets

The curing of thermosets is a complex process involving the transition from a fluid into a (visco-) elastic solid. This phase transition comes along with an increase in stiffness and a volume shrinkage of the polymer. The latter may lead to severe residual strains and stresses, which in turn can cause damage in the final, usually quasi-brittle material. In this contribution a constitutive model is developed which takes into account the curing of a thermosetting material together with the process-induced damage as resulting from curing shrinkage. The curing of the material is governed by a phenomenological hypoelastic constitutive equation which includes temporal evolutions for stiffness and volume shrinkage. Thermal and viscous effects are neglected in the present study. An isotropic gradient-enhanced damage model is adapted to describe the damage evolution. The curing-damage model is implemented into a finite element code and numerical examples for thermosetting materials demonstrate that the proposed model is capable to predict cure-induced damage in thermosets.     

Thermodynamic similarity and prediction of the properties and characteristics of substances and processes

Principles of the theory of thermodynamic similarity are considered in application to all aggregate states of a substance, including phase transitions, and to the change in dissipative structures in open systems.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 53, No. 5, pp. 709–716, November, 1987.     

Mechanisms of Corosion and Oxidation of Metals and Alloys

Selected topics in field of the study of the mechanisms of corrosion and of oxidation of metals or alloys are presented. The first part reports a new model for the mechanism of the breakaway oxidation of ferritic stainless steels in water vapour. The second part is devoted to the physico‐chemical aspects of oxidation and presents experimental methods useful in the kinetic modelling applied to two alloys, the zircalloy‐4 and an AlMg5 % in the liquid state. In the third part the physical and numerical modelling of the stress corrosion cracking behaviour in face‐centered cubic (fcc) alloys is detailed, which enables the study of the influence of macroscopic parameters (such as the temperature or hydrogen activity) on the fracture process.     

碳化硼陶瓷增韧补强和致密化研究现状及其展望

碳化硼陶瓷具有极高的硬度,然而其低韧性、低抗弯强度、难以致密化限制了它的广泛应用.已有一些研究集中于碳化硼陶瓷增韧补强和致密化,对这一方面国内外研究进展进行了归纳与评述,阐明各种增韧补强和致密化方法的优缺点,提出碳化硼陶瓷增韧补强和致密化研究值得发展的一些方向.     

Measurement and analysis of elastic and anelastic properties of alumina and silicon carbide

Measurements of dynamic Young's modulus, E, and damping as a function of temperature, T, were made for alumina and silicon carbide. The Young's modulus data were compared with some from the literature, and analysed in terms of a theoretical framework relating the Debye temperature, θD, with the elastic constants. For both materials this analysis yielded a ratio T₀/θ_D which was near 0.4, where T₀ is an empirical fitting constant for the plot of (E(0)−E)/T versus 1/T (E(0) is the value of E at 0 K). The analysis of the damping data in terms of an Arrhenius type dependence led to effective activation energies near kT, where k is Boltzmann's constant. This revised version was published online in November 2006 with corrections to the Cover Date.     

Preparation and characterization of phosphate and arsenate apatites of strontium and their solid solutions

Samples of phosphate and arsenate apatites of strontium and six of their solid solutions, spread over the entire compositional range, were prepared by a wet method. They were characterized by chemical, X-ray, electron microscopic and infrared analyses. The validity of Vegard's law established the homogeneity of the solid solutions.     

检定和校准证书的异同与应用

本文介绍了检定和校准以及证书的两点相同、五点不同之处,说明了对检定证书和校准证书的正确应用。