Electrodialysis with Bipolar Membranes for Valorization of Brines

Several industrial processes, such as desalination or neutralization, generate brines defined as concentrated solutions of salts in water, usually NaCl, typically discharged in the vicinities of the desalination plant or factory. To reduce the environmental impact and promote the valorization of the wasted resources, alternatives must be sought. Among sustainable alternatives for the recovery of brines, the possibility of using Electrodialysis with Bipolar Membranes (EDBM) is of interest, because it allows recovering brines as useful acids and bases. This review focuses on the discussion of the technical aspects of the EDBM as a means to treat streams rich in NaCl from reverse osmosis desalination and industrial processes in order to complete the direct delivery of chemicals for self-supply. The main environmental issues associated with desalination brine disposal are presented. The state-of-the-art of valorization of brines by EDBM to acids and bases is completed. This work concludes with an in-depth discussion of the technical, techno-economic and economic barriers that prevent the widespread use of EDBM technology.     

Chemometric analysis of disubstituent effects on the 13C chemical shifts of the carboxyl carbons (deltaCO) of benzoic acids. A comparative study of the substituent effects on the strength of benzoic acids in apolar aprotic media

The results of measurements of substituent induced chemical shifts of carboxyl carbons (deltaCO) of dichloro- and difluorobenzoic acids, including the monosubstituted ones with substituents at meta- and/or ortho- positions, in chloroform-d and strengths of these acids (log K) in chlorobenzene show an anomalous reverse trend between deltaCO and log K, while the electron density at carboxyl carbons should influence similarly both deltaCO and log K. A detailed chemometric analysis of comparison of disubstituent effects between deltaCO and log K on the basis of Fujita-Nishioka's multiparameter approach and assumption of additivity of substituent effects shows a dominance of the localized pi-polarization mechanism relative to simple electrostatic effects upon deltaCO. Further, steric factors play a significant role in determining deltaCO whereas with respect to log K they were insignificant. The overall anomaly has been rationalized keeping in mind that, while log K is a gross measure of energy differences between the ionized and unionized forms of the acids, deltaCO is a very sensitive probe for determining changes in electron density at the carboxyl carbon of the unionized acid.     

半导体纳米粒子在反胶束中的合成及其与芘分子间的跨相电子转移

本文在AOT/异辛烷反胶束中合成了CdS和ZnS半导体纳米粒子。粒子的荧光量子产率随胶束水含量的增大而减小。这可以归结为水含量增大导致胶粒表面Cd²⁺或Zn²⁺离子浓度降低,因为这两种离子在胶粒表面富集有利于形成硫空位,从而增大光生电子-空穴对的发光复合。研究发现,Ag⁺离子可以有效猝灭CdS和ZnS纳米粒子的荧光发射,该猝灭过程可以用Ag⁺离子在胶束中的Poisson分布来描述。以溶解在有机相中的pyrene作电子给体,在光激发下可以向CdS粒子注入电子,而和ZnS粒子间没有电荷转移发生,这可以解释为两种半导体的导带边相对于pyrene激发态氧化电位所处的位置不同。Cu²⁺或Ag⁺离子在ZnS颗粒表面吸附,可以形成Cu_xZn_1-xS或Ag_2xZn_1-xS复合粒子,降低ZnS粒子的导带位置,从而使之能够接受来自pyrene激发态的电子。实验结果证实了这种论点。     

反胶束系统及萃取蛋白质的分子热力学模型1: 反胶束系统的分 子热力学模型

以反胶束系统稳定性的热力学分析为基础,综合分析了反胶束系统的三大效应,即低界面张力效应、界面弯矩效应、混合熵效应,提出了一个分子热力学模型,模型所预言的反胶束水分含量随无机盐种类、浓度、表面活性剂浓度以及助表面活性剂含量的变化与所获实验规律定量相符,还能预言反胶束内表面处电势值、表面活性剂解离度。     

冠醚芳酸菁染料的合成及其逆光致变色性

1　引言光致变色是一个或几个物种在吸收光谱显著改变的两个状态之间的可逆性变化,这种变化至少在一个方向是由光的照射引起的,而在另一方向通常则是自发的热变化过程[1]。若颜色较深的物种是热不稳定物种,则该体系称为“正”向光致变色体系,否则称为“逆”向光致变色体系。逆向光致变色体系化合物由于其有色体比较稳定,便于研究其有色体的构造、构型及变色机理,对于探索有机光致变色化合物在光信息存储等高科技领域的应用具有一定意义。我们用冠醚菁染料2-甲基-3-烷基-5,6-并-(15-冠-5)苯并噻唑季铵盐与方酸缩合得到了四个未见文献报道的光…     

Alkaline hydrolysis of ethylp-nitrophenyl chloromethylphosphonate in the reverse micellar AOT—decane—water system

The influence of cluster formation of micelles on the rate of alkaline hydrolysis of ethylp-nitrophenyl chloromethylphosphonate in the reverse micellar sodium bis(2-ethylhexyl) sulfosuccinate (AOT)—decane—water system was found. The applicability of the pseudo-phase model of micellar catalysis below and above the percolation threshold was shown. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2266–2270, December, 1999.     

吨染料与反胶束体系中CdS的光敏电子转移

用ＡＯＴ／异辛烷／水反胶束体系制备出了不同尺寸大小的纳米ＣｄＳ,并以曙红（ＥＯ）和孟加拉玫瑰红（ＲＢ）为探针分子,研究了它们与硫化镉微粒间的光致电荷转移相互作用,用光照实验和ＥＳＲ技术研究了这些染料向ＣｄＳ的导带注入电子的过程并讨论了作用机理     

5.6 Cellulose acetate in separation technology

Cellulose acetate has been utilized in a variety of separation and purification processes. In membrane separation, cellulosics, in particular cellulose acetate, have played important roles. Hemodialysis and desalination are the established fields where acetate membranes have been applied. Recently, a new application, that is the purification of drinking water, is growing. The history of cellulosic membranes, preparation of acetate membranes, and applications will be reviewed. Cellulose acetate is also useful in chromatography and related separation technologies. These application will also be reviewed and the relationship between the superstructure of cellulose triacetate and its adsorptive behavior is briefly mentioned.     

一种可溶性氯铟酞菁化合物的光限幅性能研究

本工作通过无中心金属酞菁合成了可溶性金属酞菁化合物--四-α-(2-乙基丁氧基)氯铟酞菁,用纳秒脉冲激光在532 nm处检测了它在四氢呋喃溶液中的光限幅过程,发现该化合物具有非常明显的光限幅性能.在很低的入射光能量下,输出能量即开始偏离Beer定律,透过率随着入射光能量的增加迅速下降.这一效应归因于酞菁分子的反饱和吸收.通过纳秒激光闪光光解实验测定了上述化合物在四氢呋喃溶液中的瞬态吸收光谱及三线态寿命,实验结果表明在很宽的波长范围内分子具有较强的激发态吸收性能.