鞣质、果胶污染膜的清洗初步研究

采用常用的膜的清洗方法及清洗剂,清洗被鞣质、果胶污染后的中空纤维膜。结果表明,用几种清洗剂依次交替清洗,能使膜通量有较好的恢复,且实验重复性好。     

分离膜材料的污染与清洗

分析了膜分离技术中存在的膜污染与影响膜污染的因素，介绍了膜的清洗及影响清洗的因素，清洗剂及使用范围。     

UF处理生活污水过程中的膜污染和膜清洗研究

采用多种化学清洗剂对UF处理生活污水过程中被污染的UF膜进行了清洗研究，初步分析了产生膜污染的因素．结果表明，在被污染的膜上，有机物和无机盐垢相互覆盖，用次氯酸钠和酸交替清洗膜可以获得较好的清洗效果，     

茶叶深加工中污染微滤膜高效清洗技术研究

以微滤澄清技术在茶叶深加工中的推广应用为目标,在中试规模的基础上,以茶叶深加工工业化生产中的浸提方法和微滤澄清方法制备污染微滤膜,研究了NaClO、HNO3、NaOH或其组合等多种清洗剂对污染微滤膜清洗效果的影响,并实现了较优清洗剂下的清洗时间、膜面压力、清洗温度的筛选.结果表明,在各种清洗剂的清洗效果上,由好到差的清洗剂依次为0.6%NaClO、0.6%NaOH 0.6%NaClO、0.6%NaOH、0.6%NaClO洗后 pH=2的HNO3洗p、H=2的HNO3.采用0.6%NaClO作为清洗剂,在温度为50℃、无压力条件下清洗45 min,污染微滤膜的膜通量恢复率达99.40%,此方法可作为应用于茶叶深加工中的高效、简便、快速的污染微滤膜再生方法.     

红霉素发酵液纳滤膜污染与再生

超滤-纳滤双膜法作为新型分离技术应用于红霉素发酵液的过滤和浓缩.双膜法是指行先用陶瓷或金属超滤膜对发酵液进行预处理,之后树脂脱色,再进入纳滤膜浓缩.详细分析与总结了纳滤膜的膜污染,根据污染物的特性,选用专业清洗剂和清洗方法,给出最佳的再生方案:在0.37MPa,38~45℃下,采用专业清洗剂碱酸清洗法清洗和定期采用酶碱酸清洗法相结合的清洗方法.在保持同样通量下,专业清洗剂清洗后的一级膜进口压力比片碱、柠檬酸清洗后的一级膜进口压力降低约20%.     

农药废液处理工艺中反渗透膜污染与清洗研究

以农药废液处理工艺中的反渗透膜为研究对象,通过表观分析、烧失量分析、扫描电子显微镜与能谱仪(SEM-EDS)、傅里叶红外光谱仪(FTIR)、X射线衍射仪(XRD)分析和表征反渗透膜的污染状态,通过不同清洗实验探讨膜通量恢复率并确定最优清洗方案.结果表明,膜污染由有机污染和无机污染组成,有机污染占总污染的50%左右,主要来源于废液中的二甲戊灵、灭草松、灭菌唑等农药有效成分;无机污染主要为Ca、Mg、Al的无机盐、硅酸盐和少量的磷酸盐.最优清洗方案为专用碱性清洗剂+十二烷基苯磺酸钠+专用酸性清洗剂的组合,膜通量恢复率达86%.     

油水乳液污染纳米TiO_2改性Al_2O_3陶瓷膜的化学清洗

研究了采用碱性复合清洗剂通过一次清洗工艺对油水乳化液污染的纳米TiO2改性Al2O3陶瓷微滤膜进行化学清洗的可行性.通过通量恢复率、油截留率、SEM和FT-IR等分析手段表征了制备的复合清洗剂对改性陶瓷膜的清洗效果及化学清洗对纳米TiO2改性效果的影响.结果表明,采用制备的复合清洗剂对油水乳化液污染的改性陶瓷膜进行清洗后,可有效去除膜污染物,表现出良好的清洗效果,且清洗过程不会明显影响纳米TiO2对Al2O3陶瓷膜的改性效果.工业应用试验表明,冷轧乳化液含油废水污染的改性陶瓷膜,经碱性复合清洗剂清洗后,膜纯水通量恢复率和油水渗透通量恢复率分别可达到96.9%和98.1%.     

油水污染炭膜清洗方法的放大实验研究

采用自制的孔径为0．6～2．5μm的单根和多根管状炭膜，用原油和水经超声波乳化而成的油水乳化液为原料，用不同的清洗方法及清洗条件，通过比较膜的通量恢复率，考察单管和七管规模下的清洗规律．实验结果表明，在单管和七管条件下，用单一清洗剂清洗的效果都不理想；而采用酸洗和碱洗的组合清洗方式效果较好；为达到满意的清洗效果，七管时清洗剂的浓度需要比单管时增加一倍；清洗时间加长为单管的2．5倍．这些数据可为在工业规模下炭膜的清洗恢复提供依据．     

硝基苯电化学还原合成对氨基苯酚过程中被污染离子膜的清洗再生

对电还原硝基苯(NB)合成对氨基苯酚(PAP)过程中受到污染的Nafion425型阳离子交换膜进行了清洗再生研究.筛选出的较佳清洗剂成分是:脂肪醇聚氧乙烯醚磺酸钠(AES)、十二烷基磺酸钠(ABS)、脂肪醇聚氧乙烯醚琥珀酸单酯磺酸二钠(R-3)、脂肪醇聚氧乙烯醚(JFC)、烷基多糖苷(APG-10)、Tween-60及异丙醇,质量分数分别为:0.15,0.17,0.10,0.05,0.10,0.02及0.05,余量为水;其在线清洗适宜工艺条件为:清洗剂稀释倍数为300,清洗温度60℃,清洗液pH值10~11,清洗时间2~2.5 h.实验结果表明,清洗后的膜电阻降为4.8Ω/cm2左右,与新膜基本相同,膜强度基本不变,扫描电镜(SEM)观察显示其表面形貌与新膜也几乎相同,用于电合成PAP的槽电压降为3.03 V左右,与新膜相关数据十分接近.     

陶瓷微滤膜回收偏钛酸过程中膜清洗的研究

对陶瓷微滤膜回收偏钛酸过程中膜清洗方法进行了研究。考察了不同清洗剂的清洗效果，研究了清洗时间、外压脉冲等不同清洗方式对清洗效果的影响，并结合ＳＥＭ和ＥＤＸ等检测结果，分析了清洗机理，同时对清洗重复性进行了考察；确定了效果好且稳定的清洗方法，将此过程向工业化应用又推进了一步。     

Evaluation of cleaning methods for granite based on petrographic examinations

The decay of granite blocks in buildings results in microfracturing, mineral alteration and salt crystallisation. The conservation of granite historic buildings involves the application of cleaning methods to reduce these effects and to improve the general condition of the stone. Strong cleaners applied without any control have sometimes caused damage to the materials. This study determines the effect of various cleaning methods on microfractures, mineralogy and soluble salt content in granite. Samples of weathered granite from buildings in Trinity College, Dublin and unweathered freshly-quarried granite were cleaned by physical and chemical methods. The condition of the granite was assessed before and after cleaning by examining thin sections under a petrographic microscope. Fracturing, mineral transformation and soluble salt content were used as indicators of the condition of the stone. This paper concludes that the cleaning methods tested do not significantly alter the intensity and depth of fracturing in weathered granite. It also concludes that chemical cleaning does not cause significant mineralogical alteration to weathered granite and that salts remaining after cleaning are remnant weathering products and not reaction products. Finally, the paper highlights the effectiveness of a poultice containing detergent and chelating agents in removing salts from weathered granite.     

药液超滤过程中的膜污染及其防治

超滤过程中存在的膜污染问题极大地影响了超滤技术在生产实际中的应用。本文介绍了药液超滤过程中膜污染的机理及影响因素、已污染超滤膜的物理和化学清洗方法及超滤时膜污染的防止及控制等方面近来来国内的研究状况,以便推动超滤技术在各个领域特别是在医药生产中得到更广泛应用。     

Degradation of chemical warfare agent simulants using gas-liquid pulsed streamer discharges

This study determines the effectiveness of pulsed streamer discharges (PSD), a type of advanced oxidation technology (AOT) to clean water contaminated with chemical agents. For the purpose of this study, experiments were conducted with G and H agent simulants to determine the degradation kinetics and to determine the effects of various electrical and chemical parameters in the degradation of these contaminants. The energy efficiency of contaminant degradation shows that pulsed streamer discharges can be an efficient technology in treating water contaminated with chemical agents. The maximum energy yields of degradation of H and G agent simulants by the pulsed corona discharges are 0.029 and 0.008 molecules/100 eV, respectively, in the series configuration with ferrous sulfate salt in solution.     

Soil washing for metal removal: a review of physical/chemical technologies and field applications

Soil washing is one of the few permanent treatment alternatives to remove metal contaminants from soils. This paper reviews the various technology types and pilot/full-scale field applications of soil washing applicable to soils highly contaminated with heavy metals. The physical separation technologies, the chemical extraction processes and the integrated processes that combine both physical and chemical methods are discussed separately. This paper reviews basic principles, applicability, advantages and limitations, methods of predicting and improving performance of each physical/chemical technology. The discussion is based on a review of 30 recent laboratory investigations and 37 field applications of soil washing systems which have been undertaken, mostly in the US, for the period 1990-2007. This paper also examines and compares the status of soil washing technology for remediation of soils contaminated with metals in the US, in Canada and in Europe.     

超声波清洗在替代ODS清洗工艺技术中的独特作用

文章通过分析超声清洗技术的原理、特点及其所具有的环保优势，并将超声清洗技术与其它清洗技术进行对比，阐述了超声波清洗在替代ODS清洗工艺技术中的独特作用；通过分析影响超声清洗效果的主要因素，如超声的声强、频率和声场分布，清洗液的粘滞系数、表面张力和流动性，清洗介质的理化性质与清洗能力等，提出了确定超声空化强度和选择清洗介质的基本原则；介绍了超声清洗方式的分类与选择，以及用超声清洗技术替代ODS清洗技术时应该注意的一些问题，指出大功率超声参量与清洗介质物理化学性能参量之间的相互作用对清洗效果有着重要的影响。     

聚丙烯微孔膜亲水改性及其对力学性能影响的研究进展

聚丙烯微孔膜因其比表面积大、性能优异、价格合理等优点而被广泛应用;但其亲水性差、易被污染,因此需要进行亲水改性。根据是否发生化学变化将亲水改性方法归纳为:物理法、化学法和物理化学法;改性之后膜的亲水性得到了改善。分类论述了各种亲水改性方法对聚丙烯微孔膜力学性能的影响及其对膜亲水性能的改善程度同时对亲水改性方法的改进进行了展望。     

超滤法提纯茶多酚的研究

对比考察了几种不同膜材质、不同截留分子量和不同构型的膜系统对茶叶水提液中茶多酚的分离效果,比较了不同清洗剂对膜污染的清除效果.结果表明,Ultra-flo超滤系统适于茶多酚的提纯,尤其是聚偏氟乙烯膜UF-602-5和聚砜膜UF-610,膜通量较大,茶多酚透析率高.膜污染后,碱性清洗剂对茶叶污染物具有一定的去除能力,酸性清洗剂几乎没有任何效果,氧化性清洗剂去污性虽很强,但易对膜造成损伤.选用UF-602-5膜连续做了5个批次的重复超滤实验,结果显示,加水套洗可提高茶多酚的收率,改善分离效果,但随实验批次的增加,膜通量逐渐衰减.     

Biofouling: lessons from nature

Biofouling is generally undesirable for many applications. An overview of the medical, marine and industrial fields susceptible to fouling is presented. Two types of fouling include biofouling from organism colonization and inorganic fouling from non-living particles. Nature offers many solutions to control fouling through various physical and chemical control mechanisms. Examples include low drag, low adhesion, wettability (water repellency and attraction), microtexture, grooming, sloughing, various miscellaneous behaviours and chemical secretions. A survey of nature's flora and fauna was taken in order to discover new antifouling methods that could be mimicked for engineering applications. Antifouling methods currently employed, ranging from coatings to cleaning techniques, are described. New antifouling methods will presumably incorporate a combination of physical and chemical controls.     

退火温度对宽带脉冲压缩光栅载体金属/介质多层高反膜的影响

分别以金(Au)作为金属层材料, 氧化铪(HfO₂)与氧化硅(SiO₂)作为高低折射率层材料, 利用物理气相沉积方法制备了用于宽带脉冲压缩光栅制作的金属/介质多层高反膜, 研究了退火温度对其表面均方根粗糙度、反射率及抗化学清洗破坏能力的影响。实验结果表明: 退火前后样品表面均方根粗糙度变化很小; 提高退火温度能提高金属/介质多层膜的抗化学清洗破坏能力, 但反射率会随之下降。250℃退火10 h后金属/介质多层膜不仅可以承受住化学清洗过程, 而且反射率下降也比较小, 可以作为金属/介质多层膜的最佳退火工艺。