面向软化水处理的纳滤膜分离技术

很多领域需要软化水而并非脱盐水.利用纳滤膜对二价离子(Ca2 ,Mg2 ,SO42-)高截留和对单价离子(K ,Na ,Cl-)的低截留特性,可实现软化而不是完全脱盐,以适应各种领域对软化水的要求.阐述了纳滤膜的软水原理、软水用纳滤膜的性能与选用原则;介绍了水质、操作压力及产水率对纳滤膜软水性能的影响以及纳滤膜在制取软化的饮用水、工业软化水以及海水淡化等方面的应用;通过与石灰软化和离子交换软化的比较,分析了纳滤膜软水法的经济性.指出纳滤膜软水法是一种先进的经济的水软化技术,可克服反渗透的高能耗以及石灰软化和离子交换软化产生的废渣和废水对环境的污染.因此纳滤膜软水法具有很强的竞争力,广泛采用纳滤技术制取各种用途的软化水具有十分广阔的前景.     

纳滤处理模拟电镀废水

分别以硫酸铜、氯化铜、硝酸铜溶液为模拟电镀废水进行了纳滤实验,所采用纳滤膜为Osmonics的DK、DL膜和日东电工的NTR-7450膜.实验表明,三种膜通量大小顺序为DL>DK>NTR-7450,随原料液浓度的增大膜通量降低,而膜对铜离子的截留率有升高的趋势;纳滤膜对各盐的截留率大小排序为硫酸盐>氯盐>硝酸盐.实验还考察了添加其它离子对纳滤膜通量和截留率的影响.结果表明,加入CaCl2后,对DL膜性能影响不显著;加入Na2SO4后,DL膜的通量变化不明显,截留率略有升高;加入EDTA能明显提高DL膜通量和对铜离子的截留率.     

纳滤膜脱盐及其在海水软化中的应用

采用卷式纳滤膜进行了MgSO4、K2SO4、MgCl2等5种物质的脱盐性能研究,考察了进料操作压力和浓度对表现截留率和膜通量的影响,在此基础上研究了操作压力对海水脱盐性能的影响.实验表明,纳滤膜性能稳定,能除去海水中90％以上的SO42-以及50％以上的Mg2+和Ca2+,大幅度降低了海水的硬度,可解决传统上海水淡化过程中易结垢离子对膜的污染问题;纳滤膜软化海水可以降低海水淡化后期处理的成本和能耗;采用纳滤膜软化海水在技术上是可行的.     

大黄素等天然药物的纳滤行为

以NF270纳滤复合膜对几种不同分子量的天然药物(如大黄素、咖啡因)进行了纳滤行为研究,并考察了操作压力、浓度、pH、离子浓度等因素对纳滤膜截留行为的影响.结果表明,NF270纳滤复合膜截留分子量在300左右(例如对相对分子质量为270.23的大黄素几乎100%截留,对相对分子质量较小的咖啡因截留率小于60%);随着pH的增大,纳滤膜对大黄素的截留率稍有下降,对其他三种药物的截留率略有升高;改变溶液的离子浓度,纳滤膜的截留率和通量均下降.选择适宜的操作条件可以实现天然药物的提取、分离和浓缩.     

PA/PVDF中空纤维复合纳滤膜的研究(Ⅱ)复合纳滤膜性能表征

对自制的芳香聚酰胺(PA)/聚偏氟乙烯(PVDF)中空纤维纳滤膜进行了膜性能表征,讨论了自制的PA/PVDF中空纤维纳滤膜的结构和接触角,探讨了不同操作条件以及物料性质对中空纤维纳滤膜分离性能的影响.实验结果表明,自制的PA/PVDF中空纤维复合纳滤膜对多价盐和分子量在300以上的有机分子的截留率较高,符合纳滤膜的分离范围.     

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.     

纳滤膜对染料截留行为的研究

通过一系列实验 ,考察了几种纳滤膜在不同操作条件下对几种不同的染料的截留行为 .发现不同的纳滤膜对不同的染料的截留行为不同 ;反之 ,染料的品种和分子结构对纳滤膜的盐截留率、染料截留率和水通量也有影响 ,同时 ,操作条件如进料浓度、pH、压力对截留效果的影响也很大 .实验结果和结论可作为染料清洁生产实际应用的参考 .     

高浓度含盐蔗糖溶液的纳滤分离实验研究

为探讨运用纳滤(NF)过程实现高浓度二糖和一、二价无机盐分离的可能性,选用商业纳滤膜NF270对高浓度蔗糖与一、二价盐离子的单组分和混合组分溶液开展了分离实验研究.首先,研究了物料浓度、操作压力等因素对高浓度蔗糖与盐的单组分体系分离效果的影响,明确了NF270膜对不同的单组分溶液的透过和截留性能;其次,探究了NF270纳滤膜对高浓度蔗糖/NaCl和蔗糖/Na_2SO_4混合体系的分离效果.实验结果说明,操作压力的降低和盐浓度的升高均能显著降低混合溶液的溶剂透过通量,且高浓度盐离子的存在会影响蔗糖的截留率,而蔗糖对无机盐截留率影响不明显.在高操作压力下,NF270膜可实现对高浓度蔗糖/NaCl混合体系的高效分离.     

纳滤膜材质对高含盐体系中有机物截留性能的影响研究

为获得纳滤膜材质对高含盐体系中有机物截留性能的影响规律,采用截留分子量相近的有机纳滤膜和陶瓷纳滤膜对模拟高含盐体系中有机物的截留性能进行研究比较,考察运行时间、盐浓度、跨膜压差、有机物浓度等因素对截留效果的影响.结果表明,两种纳滤膜运行30 min后截留性能即可稳定;随着盐浓度的增加,膜的渗透通量和膜对有机物的截留率都下降,其中陶瓷纳滤膜对有机物的截留效果优于有机纳滤膜;有机物浓度和跨膜压差对两种膜的截留性能影响较小.因此,在高含盐体系中,截留分子量相近的陶瓷纳滤膜相比于有机纳滤膜,前者具有更大的通量和更高的有机物截留率.     

染料的纳滤分离性能和机理

考察了醋酸纤维素纳滤膜对染料溶液的分离性能,纳滤膜对染料溶液有很好的分离效果,其分离过程中筛分起主导作用;试验不同孔径的醋酸纤维素纳滤膜对萘系衍生物．以及不同材料的纳滤膜对相同分子量有机物的截留效果,其分离性能是由有机物性质和范德华引力共同作用的;分析磺化聚醚砜膜对有机物的截留和染料与膜材料界面力数据,结果表明纳滤膜分离性能是由膜、溶液和溶质三者共同决定的．     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.     

新闻(英文)

正China and Greece Sign the Standardization Cooperation Agreement Witnessed by Chinese Premier Li Keqiang and Greek Prime Minister Antonis Samaras,AQSIQ Minister Zhi Shuping and ELOT Chairman and Executive Director Angelos Tolkas signed the SAC-ELOT Standardization Cooperation Agreement.The Agreement is one of the critical cooperation documents signed during Li Keqiang’s visit in Greece,encouraging China and Greece to