膜分离技术用于非电解质除杂

介绍电渗析装置工艺及基本原理，提出使用离子选择性透过膜的依据及极限电流的确定方法．论述了不同方法对冷冻液与ＮａＳＣＮ分离效果影响，指出采用电渗析法分离冷冻液中的ＮａＳＣＮ，使除杂率可达９５％以上。本工艺为腈纶冷冻液除杂及防治污染提供了新途径。     

San copolymer membranes with ion exchangers for Cu(II) removal from synthetic wastewater by electrodialysis

Heterogeneous membranes were obtained by using styrene-acrylonitrile copolymer (SAN) blends with low content of ion-exchanger particles (5 wt.%). The membranes obtained by phase inversion were used for the removal of copper ions from synthetic wastewater solutions by electrodialytic separation. The electrodialysis was conducted in a three cell unit, without electrolyte recirculation. The process, under potentiostatic or galvanostatic control, was followed by pH and conductivity measurements in the solution. The electrodialytic performance, evaluated in terms of extraction removal degree (rd) of copper ions, was better under potentiostatic control then by the galvanostatic one and the highest (over 70%) was attained at 8 V. The membrane efficiency at small ion-exchanger load was explained by the migration of resin particles toward the pores surface during the phase inversion. The prepared membranes were characterized by various techniques i.e. optical microscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis and differential thermal analysis and contact angle measurements.     

黑液电渗析碱回收的研究

针对造纸黑液的碱性及污染严重的特点，采用单阳膜电渗析法对黑液中的碱加以回收．并研究了电渗析操作中如电流密度，黑液浓度，温度等因素的影响．综合考虑得到电流密度３５０Ａ／ｍ２，电流效率８５％～９０％，碱回收率７０％～７５％，耗电量５０００～６０００ＫＷＨ／ｔ碱的结论     

电渗析预处理测定水中溶解性有机氮浓度的研究

当水样中无机氮(DIN)与总溶解性氮(TDN)质量浓度的比大于0.6时,溶解性有机氮(DON)浓度测定的准确度和标准偏差会受到很大影响。研究了电渗析预处理方式去除水样中部分无机氮离子,对DON浓度测定的影响。结果表明,使用CJM-2型离子交换膜时,并且在对水样适当酸化后溶解性有机碳(DOC)的损失率较小,长江水水样的DOC损失率为5.3%。在最佳工作条下,40 min内对自配水的脱盐率在97%以上。在15 min时,长江水水样中ρ(DIN)/ρ(TDN)0.6,测定出的DON浓度与没有经过电渗析预处理水样相比更加接近真实值,多次测量值(n=4)的标准偏差分别从18.65%下降到3.25%。     

含盐废水电渗析膜分离处理工艺研究

在水资源日益紧张、含盐废水排放量日益增多的大趋势下,寻求经济有效的含盐废水处理技术已成为重要的研究课题。以厦门某食品企业水产品加工腌泡环节含盐废水为研究对象。含盐废水经氨水沉淀、离子交换树脂软化处理,废水中钙镁离子被有效脱除,出水钙镁质量浓度已经降为10．4mg·L-1,达到软水水质标准。软化后的废水经4‰聚丙烯酰胺（PAM）絮凝并通过活性炭吸附,污染密度指数值（SDI）降低至0．41,完全达到膜分离装置进水水质的要求。预处理液再经电渗析膜进一步浓缩分离后,氯化钠质量浓度可由7351mg·L-1提升到78156mg·L-1,对盐分浓缩了10倍以上,达到废水和盐分的处理回收利用。本处理工艺流程简洁,药耗少、能耗低,比较适合小规模含盐废水的综合处理。     

Fluoride removal from secondary effluent of the graphite industry using electrodialysis: Optimization with response surface methodology

RSM was utilized to optimize and model influential parameters on fluoride removal. Regression models involving independent variables and main response were developed. Interactive effects and optimum of process factors were illuminated and determined. Fluoride removal efficiency of 99.69% was observed in optimal process conditions. Response surface methodology was utilized to model and optimize the operational variables for defluoridation using an electrodialysis process as the treatment of secondary effluent of the graphite industry. Experiments were conducted using a Box-Behnken surface statistical design in order to evaluate the effects and the interaction of the influential variables including the operational voltage, initial fluoride concentration and flow rate. The regression models for defluoridation and energy consumption responses were statistically validated using analysis of variance (ANOVA); high coefficient of determination values (R² = 0.9772 and R² = 0.9814; respectively) were obtained. The quadratic model exhibited high reproducibility and a good fit of the experimental data. The optimum values of the initial fluoride concentration, voltage and flow rate were found to be 13.9 mg/L, 13.4 V, 102.5 L/h, respectively. A fluoride removal efficiency of 99.69% was observed under optimum conditions for the treatment of the secondary effluent of the graphite industry.     

Amine reclaiming technologies in post-combustion carbon dioxide capture

Amine scrubbing is the most developed technology for carbon dioxide (CO₂) capture. Degradation of amine solvents due to the presence of high levels of oxygen and other impurities in flue gas causes increasing costs and deterioration in long term performance, and therefore purification of the solvents is needed to overcome these problems. This review presents the reclaiming of amine solvents used for post combustion CO₂ capture (PCC). Thermal reclaiming, ion exchange, and electrodialysis, although principally developed for sour gas sweetening, have also been tested for CO₂ capture from flue gas. The three technologies all have their strengths and weaknesses, and further development is needed to reduce energy usage and costs. An expected future trend for amine reclamation is to focus on process integration of the current reclaiming technologies into the PCC process in order to drive down costs.     

Changes in chromium distribution during the electrodialytic remediation of a Cr (VI)-contaminated soil

A laboratory study has been carried out to determine the feasibility of in situ remediation of chromium (VI)-contaminated soil using electrodialysis in relation to its speciation in soil. This technique is best suited for low-permeability soils or sediments, which may be difficult to remediate by other means and implies the application of a low-intensity direct current to the soil, which is separated from the electrode compartments by ion-exchange membranes. A clayey soil was prepared for use in the experiments and was characterized before being mixed with a solution of potassium dichromate for several days to produce a final Cr content of 4,056 mg/kg of soil dry wt. Remediation tests were carried out under constant-voltage conditions for periods of 7–14 days and the evolution of applied current to the cell, pH, and conductivity of the electrolytes were recorded periodically. Fractionation of chromium was determined for soil samples before and after remediation using a standardized four-step sequential extraction procedure (SEP) with acetic acid, hydroxylamine, hydrogen peroxide, and aqua regia solutions. Results show that chromium is mobilized from the most labile phases (soluble/exchangeable/carbonate). In a 15 V test, SEP results show that the amount of chromium extracted in the first step drops from 80% to 9%, but also that changes in the total chromium distribution occur during the treatment with some transferred to other soil phases that are more difficult to mobilize.     

国外化学镀镍老化液处理现状

介绍了国外目前应用的化学镀镍老化液处理方法，着重推荐了沉淀法、电解法、离于交换法和电渗析法     

钠碱脱硫吸收液膜电解再生的基础研究

介绍了阴离子膜电解技术对烟气脱硫吸收液进行再生的机理。应用二室阴离子膜电解装置研究了电流密度、吸收富液的组成对脱硫吸收液再生的影响规律。实验结果表明,随着电流密度的增大,再生液的硫迁移比、硫酸浓缩倍率增大,电流效率降低。膜电解法可以有效地再生钠碱法脱除低浓度SO2燃煤烟气的含硫富液。