Study on the Diffusion Mechanism of Graphene Prepared by Chemical Vapor Deposition on Copper Substrates

自2004年石墨烯被机械剥离出来，2010年获诺贝尔物理学奖以后，石墨烯毋庸置疑的成为了一名炙手可热的明星材料，各种围绕石墨烯的研究热潮席卷而来。抛开石墨烯的诺奖光环不谈，石墨烯确实有很多令人瞩目的性质，如高机械强度、高透光性、高载流子迁移率、高热导和化学稳定等等。性质决定用途，所以石墨烯在平板显示、电子器件、储能器件和生物医药等领域有很多潜在的应用等待探索开发。而实现这些美好应用愿景的前提，是制备高质量的石墨烯。在科研工作人员探索出的各种石墨烯制备方法中，铜基底上的化学气相沉积法（ChemicalVaporDeposition，CVD法），因其制备质量高、生长可控、制备简单且可转移至任意基底...Since graphene was produced by mechanically exfoliating graphite in 2004 and got the Nobel Prize in Physics in 2010, graphene undoubtedly has become a hot star material, and set off a variety of research interests. Despite the Nobel aura, graphene does have a lot of eye-catching properties, such as high strength, high transmittance, high carrier mobility, high thermal conductivity, chemical stabil...学位：理学博士院系专业：物理科学与技术学院_凝聚态物理学号：1982013015424

电渗析阴离子交换膜污染机理及抗污染表面改性研究

电渗析技术具有浓缩倍数大、淡水回收率高、脱盐率可调等优点，在工业废水脱盐处理中具有广泛的应用前景，然而膜污染问题尤其是有机物对阴离子交换膜污染严重，成为限制工业废水电渗析脱盐技术大规模应用的&ldquo;瓶颈&rdquo;问题。本论文通过考察基膜性质、有机物分子结构和浓度等对阴离子交换膜有机污染的影响，探讨代表性有机物对阴离子交换膜的污染行为及其电化学性质的变化，揭示电渗析过程中阴离子交换膜有机污染的形成机理；进一步探讨通过表面改性提高阴离子交换膜的抗污染性能，研究修饰组分、改性方法和工艺条件等对改性膜性质的影响规律，获得膜表面改性的优化工艺，并制备具有良好抗污染性能的新型改性阴离子交换膜。主要研究内容及结果如下：（1）研究代表性有机物造成电渗析阴离子交换膜污染的性质及对离子跨膜迁移行为的影响。以十二烷基硫酸钠（SDS）作为模型污染物，浓度较低时，SDS在溶液中单分子分散，均匀分散吸附在阴离子交换膜表面或堵塞膜孔道，改变离子的跨膜迁移路径；当溶液中SDS浓度高于100 mg/L时，SDS分子在膜表面积聚形成胶束，导致其形成致密污染层附着在膜表面，造成膜面电阻急剧增大，几乎完全限制离子的跨膜迁移；膜清洗可以去除附着在膜表面的大部分SDS污染层，但堵塞在膜孔道的SDS不能完全去除。结果表明，SDS对阴离子交换膜造成不可逆污染，而且膜表面附着的污染层是导致其性能恶化及限制离子跨膜迁移的主要因素。（2）研究阴离子交换膜性质及有机物分子结构对阴离子交换膜有机污染的影响。发现模型污染物SDS造成不同阴离子交换膜的污染程度不同，其中均相膜（AMX）、半均相膜（AMA）和异相膜（HAEM）的脱盐性能分别下降42.3%、15.3%、9.2%，基膜结构越致密，膜污染越严重；对比不同有机物分子的膜污染特性，发现甲基磺酸钠（MS）对阴离子交换膜几乎没有污染，苯磺酸钠（BS）和2-萘酚-6-磺酸钠（NSS）造成轻微膜污染，十二烷基硫酸钠（SDS）和十二烷基苯磺酸钠（SDBS）都在膜表面形成致密污染层，造成严重膜污染。（3）探讨低温等离子体对阴离子交换膜进行表面改性，考察等离子体气氛对改性膜物理化学性质及抗污染性能的影响。结果表明，改性膜表面形成新极性基团，如N2等离子体改性膜表面形成酰亚胺基等、O2等离子体改性膜表面形成酯基/羧基、碳酸基等，而且O2等离子体改性膜比N2等离子体改性膜的表面负电荷密度的变化更显著，但其表面亲水性不如N2等离子体改性膜；比较两种改性膜的抗污染性能，发现O2等离子体改性膜的抗污染性能明显优于N2等离子体改性膜，表明等离子体改性膜表面负电荷密度比亲水性的改善更有利于提高其抗污染性能。（4）通过电沉积对阴离子交换膜进行表面改性，探讨不同修饰组分对改性膜物理化学性质及抗污染性能的影响。发现除聚乙烯醇（PVA）外，聚电解质聚苯乙烯磺酸钠（PSS）、聚乙烯磺酸钠（PVS）、聚丙烯酸钠（PAAS）都可以提高膜表面亲水性及负电荷密度，进而提高改性膜的抗污染性能，而且PSS、PVS修饰膜的抗污染性能优于PAAS修饰膜；表明膜表面改性提高负电荷密度对提高其抗污染性能起关键作用，带磺酸基团聚电解质对提高阴离子交换膜的抗污染性能作用显著，即聚电解质官能团的极性越强，越有利于提高改性膜的抗污染性能。（5）探讨电沉积与层层组装复合改性，考察阴离子交换膜表面沉积聚苯乙烯磺酸钠（PSS）/聚二甲基二烯丙基氯化铵（PDADMAC）多层聚电解质对改性膜抗污染性能的影响。发现随着膜表面沉积的PSS/PDADMAC双分子层数增加，改性膜表面负电荷密度及表面亲水性增大，显著提高其抗污染性能；当膜表面PSS/PDADMAC双分子层数高于4.5时，能阻止模型污染物SDS形成污染层，电化学阻抗谱分析和等效电路模拟表明，分散吸附在改性膜上的SDS使膜面电阻增大幅度显著降低，且不会限制离子的跨膜迁移，显著提高改性膜的抗污染性能。;Electrodialysis (ED) exhibits wide application potential in the desalination of industrial effluent because of its advantages such as high brine concentration, high desalted water recovery and adjustable desalination rate. In spite of such advantages, membrane fouling, especially the organic fouling of anion exchange membrane (AEM), has become the bottleneck problem which limits the large-scale application of ED in industrial effluent. In this work, the effects of membrane properties, organic molecular structure and organics concentration on fouling of AEM were investigated, and the organic fouling behavior on the AEM and the electrochemical properties changes of AEM were studied, then the organic fouling mechanism of AEM was elucidated. Based on the analysis of organic fouling mechanism, surface modification of AEM was explored in order to improve its antifouling performance. The effects of modifying agent, modified method and technical condition on properties of AEM were studied and the surface modification process was optimized, then the new modified AEM with better antifouling performance was prepared. The main research contents and results are as follows.(1) The effects of organic fouling on properties of AEM and ion transmembrane migration were studied with sodium dodecyl sulfate (SDS) as model foulant. In the low concentration, SDS molecule was distributed evenly in the feed solution, then SDS was adsorbed on the membrane surface or blocked in the membrane channel, resulting in the change of ion transmembrane migration. With 100 mg/L SDS or above in the feed solution, SDS molecule was accumulated to form micelle, then the dense SDS fouling layer was formed and adsorbed on the membrane surface, increasing membrane electrical resistance sharply and almost restricting ion transmembrane migration completely. After membrane cleaning, most of SDS fouling layer could be removed while SDS blocked in the membrane channel couldn&rsquo;t be removed completely. Results indicated that SDS caused irreversible fouling on the AEM and the dense fouling layer on the AEM was the main factor for deteriorating membrane and restricting ion transmembrane migration.(2) The effects of membrane properties and organic molecular structure on organic fouling of AEM were studied. SDS caused different fouling on the different AEMs. The desalination rate of homogeneous AEM (AMX), semi-homogeneous AEM (AMA) and heterogeneous AEM (HAEM) decreased by 42.3%, 15.3% and 9.2%, respectively, because of SDS in the feed solution. It indicated that the denser membrane structure caused severer membrane fouling. The fouling effects of different organics on the AEM were analyzed. Sodium methane sulfonate (MS) almost caused no fouling effect on the AEM, sodium benzene sulfonate (BS) and sodium 6-hydroxynaphthalene-2-sulfonate (NSS) caused slight fouling effect on the AEM, however, SDS and sodium dodecyl benzene sulfonate (SDBS) formed the dense fouling layer on the membrane, causing severe fouling effect on the AEM.(3) The AEM was modified by low temperature plasma and the effects of plasma gas on physicochemical properties and antifouling performance of modified AEM were studied. New polar group were formed on the modified AEM, such as imide group was formed on the N2-treated AEM and ester/carboxyl, carbonic acid groups were formed on the O2-treated AEM. O2 plasma treatment improved surface negative charge density of AEM more but surface hydrophilicity of AEM less than N2 plasma treatment. The antifouling performance of O2-treated AEM was better than that of N2-treated AEM. Results indicated that the increase of membrane surface negative charge density was more beneficial to the improvement of antifouling performance of AEM than the increase of membrane surface hydrophilicity.(4) The AEM was modified by electrodeposition and the effects of modifying agent on physicochemical properties and antifouling performance of modified AEM were investigated. Except poly(vinyl alcohol) (PVA), all the polyelectrolytes such as poly(sodium 4-styrene sulfonate) (PSS), poly(vinylsulfonic acid, sodium salt) (PVS) and poly(sodium acrylate) (PAAS) increased surface hydrophilicity and surface charge negative density of the modified AEM, contributing to the improvement of antifouling performance. The antifouling performance of PSS-modified AEM and PVS-modified AEM was better than that of PAAS-modified AEM. Results indicated that increasing membrane surface negative charge density by surface modification played a key role in improving antifouling performance and the polyelectrolytes with sulfonic group exhibited significant influence on the improvement of antifouling performance of AEM, meaning that the stronger polar group of polyelectrolytes was more beneficial to the improvement of antifouling performance.(5) The electrodeposition and layer-by-layer assembly was combined to modify the AEM and the effect of the deposition of (PSS)/poly(diallyldimethylammonium chloride) (PDADMAC) multilayer polyelectrolytes on the antifouling performance of modified AEM was studied. With the increase of PSS/PDADMAC bilayer number on the AEM, surface hydrophilicity and surface negative charge density of modified AEM also increased, which was more beneficial to the improvement of antifouling performance. As 4.5 PSS/PDADMAC bilayers or above was deposited on the AEM, the formation of SDS fouling layer could be prevented, therefore, SDS adsorbed dispersedly on the modified AEM increased membrane resistance slightly and didn&rsquo;t restrict the ion transmembrane migration according to the analysis of electrochemical impedance spectroscopy and fitting of equivalent circuit, and the antifouling performance of modified AEM was improved significantly.&nbsp;</p

Friedel盐对废水中低浓度Cd2＋的吸附动力学

以合成的Friedel盐（FS,3CaO·A12O3·CaCl2·10H2O）为吸附剂,研究了FS去除废水中Cd2＋的反应动力学和等温吸附特性.考察了FS盐用量、温度及Cd2＋初始浓度对Cd2＋去除的影响.结果表明,FS用量为0.03g/L时,在室温下对废水中初始浓度为10mg/L的Cd2＋的去除率大于94.34%,吸附容量可达301.9mg/g,吸附主要以离子交换吸附为主,最终形成Cd4Al2（OH）12Cl2（H2O）4xH2O及Cd4Al2（OH）12Cl24H2O化合物.利用一级动力学模型关联了反应动力学数据,得到速率常数k=0.049min-1,吸附行为较符合Langmuir等温吸附方程

Friedel盐对废水中低浓度Cd2＋的吸附动力学

以合成的Friedel盐（FS,3CaO·A12O3·CaCl2·10H2O）为吸附剂,研究了FS去除废水中Cd2＋的反应动力学和等温吸附特性.考察了FS盐用量、温度及Cd2＋初始浓度对Cd2＋去除的影响.结果表明,FS用量为0.03g/L时,在室温下对废水中初始浓度为10mg/L的Cd2＋的去除率大于94.34%,吸附容量可达301.9mg/g,吸附主要以离子交换吸附为主,最终形成Cd4Al2（OH）12Cl2（H2O）4xH2O及Cd4Al2（OH）12Cl24H2O化合物.利用一级动力学模型关联了反应动力学数据,得到速率常数k=0.049min-1,吸附行为较符合Langmuir等温吸附方程

Friedel盐对废水中低浓度Cd~(2+)的吸附动力学

以合成的Friedel盐(FS,3CaO&middot;A12O3&middot;CaCl2&middot;10H2O)为吸附剂,研究了FS去除废水中Cd2+的反应动力学和等温吸附特性.考察了FS盐用量、温度及Cd2+初始浓度对Cd2+去除的影响.结果表明,FS用量为0.03g/L时,在室温下对废水中初始浓度为10mg/L的Cd2+的去除率大于94.34%,吸附容量可达301.9mg/g,吸附主要以离子交换吸附为主,最终形成Cd4Al2(OH)12Cl2(H2O)4xH2O及Cd4Al2(OH)12Cl24H2O化合物.利用一级动力学模型关联了反应动力学数据,得到速率常数k=0.049min~(-1),吸附行为较符合Langmuir等温吸附方程

Friedel盐对废水中低浓度Cd~(2+)的吸附动力学

以合成的Friedel盐（FS,3CaO·A12O3·CaCl2·10H2O）为吸附剂,研究了FS去除废水中Cd2＋的反应动力学和等温吸附特性.考察了FS盐用量、温度及Cd2＋初始浓度对Cd2＋去除的影响.结果表明,FS用量为0.03g/L时,在室温下对废水中初始浓度为10mg/L的Cd2＋的去除率大于94.34%,吸附容量可达301.9mg/g,吸附主要以离子交换吸附为主,最终形成Cd4Al2（OH）12Cl2（H2O）4xH2O及Cd4Al2（OH）12Cl24H2O化合物.利用一级动力学模型关联了反应动力学数据,得到速率常数k=0.049min-1,吸附行为较符合Langmuir等温吸附方程

淡水刚毛藻目一新组合种及其系统发育分析

作者于2012-2014年先后在湖北省采集到4株刚毛藻目的丝状绿藻。经鉴定,其形态特征和莫拉瓦刚毛藻Cladophora moravica Gardavsky(1986)非常相似;但相较于刚毛藻属各个种的形态,4株藻体更接近黑孢藻科的分类特征。基于SSU和LSU rDNA序列构建的系统发育树显示,4株刚毛藻目的丝状绿藻均属于黑孢藻科拟湖球藻属(Aegagropilopsis)。据此,作者建议将该种名称作为一个新组合处理,即莫拉瓦拟湖球藻Aegagropilopsis moravica (Dvoak) Zhao et Liu com. nov。拟湖球藻属仅含有3个种:莫拉瓦拟湖球藻、硬枝拟湖球藻和棒状拟湖球藻,其形态特征与湖球藻相近且易混淆,故采用核基因组序列分析方法区分二者是非常有效的