L-B膜

L-B膜即 Langmuir-Blodgett单分子膜,它是人为地利用分子间相互作用而建立起来的特殊分子体系。在L-B膜中分子是有序的准晶体排列,其性质有别于固体和晶体,因而有人将其称为物质的第五相。用米制备L-B膜的技术称为L-B技术。

水面单分子层膜的原位光谱测定方法

将溶于挥发性有机溶剂的双亲性分子溶液小心地滴加在平静的水面上,待溶剂挥发后,沿横向压缩使分子以亲水基与水接触、疏水基远离水面的形式整齐地排列在水-空气界面上,形成缀密的单分子膜-Langmuir 膜。这类界面

Co,Mo在Al_2O_3和K在Co-Mo催化剂上的吸附和分布

钴离子在γ-Al_2O_3上的吸附速度比钼酸根离子的慢,但钴离子的视扩散系数比钼酸根的大(25℃下D_(Co)=1.2×10~(-5)cm~2/s,D_(Mo)=4.4×10~(-6)cm~2/s)。钴的吸附等温线符合Langmuir等温式,而钼的符合Freundlich等温式。在等孔容积共浸法制备催化剂时,低pH值下由于Al_2O_3吸附Mo较多而导致Co、Mo在颗粒中分布不均;在高pH值下由于Mo的吸附量锐减,可用共浸法得到分布均匀的催化剂。K_2CO_3在均匀型Co-Mo/Al_2O_3催化剂上的吸附等温线符合Langmuir等温式,虽然吸附量较大,但在浸渍液中含量足够时也可得到均匀分布的结果。

Bi-Ce二元氧化物催化剂上丙烯氧化脱氢二聚的动力学与反应机理

丙烯在氧化物催化剂上氧化脱氢二聚反应的研究,文献上主要是在Bi-Sn系催化剂上进行的,不同研究者根据各自的结果,对这一步反应提出了两种不同的机理:一种认为是催化剂表面上吸附丙烯间的二聚(Langmuir-Hinshelwood型机)理;另一种认为是气相丙烯与吸附丙烯间的二聚(Eley-Rideal型机理).我们发现Bi-Ce二元氧化物显示出与Bi-

In vitro assembly of R-phycoerythrin from marine red alga Polysiphonia urceolata

Scanning tunneling microscope was used to investigate the in vitro assembly of R-phycoerythrin (R-PE) from the marine red alga Polysiphonia urceolata. The results showed that R-PE molecules assembled together by disc-to-disc while absorbing on HOPG surface, which just looked like the rods in the phycobilisomes. When the water-soluble R-PE was dissolved in 2% ethanol/water spreading solution, they could form monolayer film at the air/water interface. Similar disc-to-disc array of R-PE was constituted in the two-dimensional Langmuir-Blodgett film by the external force. It could be concluded that, apart from the key role of time linker polypeptides, the in vivo assembly of phycobiliproteins into phycobilisomes is also dependent on the endogenous properties of phycobiliprotein themselves.

A new model of phycobilisome in Spirulina platensis

Phycobilisomes (PBS) were isolated from blue-green alga Spirulina platensis. Scanning tunneling microscope was used to investigate the three-dimensional structure of PBS deposited on freshly cleaved highly oriented pyrolytic graphite (HOPG) in ambient condition at room temperature. The results showed that the rods of PBS radiated from the core to different directions in the space other than arrayed in one plane, which was different from the typical hemi-discoidal model structure. The diameter of PBS was up to 70 nm, and the rod was approximately 50 nm in length. Similar results were observed in Langmuir-Blodgett (LB) film of PBS. The dissociated PBS could reaggregate into rod-like structures and easily form two-dimensional membrane while being absorbed on HOPG, however, no intact PBS was observed. The filling-space model structure of PBS in Spirulina platensis with STM from three-dimensional real space at nanometer scale was found, which showed that this new structural model of PBS surely exists in blue-green algae and red algae. The function of this structural model of PBS was also discussed.

Effect of Stokes drift on upper ocean mixing

Stokes drift is the main source of vertical vorticity in the ocean mixed layer. In the ways of Coriolis - Stokes forcing and Langmuir circulations, Stokes drift can substantially affect the whole mixed layer. A modified Mellor-Yamada 2.5 level turbulence closure model is used to parameterize its effect on upper ocean mixing conventionally. Results show that comparing surface heating with wave breaking, Stokes drift plays the most important role in the entire ocean mixed layer, especially in the subsurface layer. As expected, Stokes drift elevates both the dissipation rate and the turbulence energy in the upper ocean mixing. Also, influence of the surface heating, wave breaking and wind speed on Stokes drift is investigated respectively. Research shows that it is significant and important to assessing the Stokes drift into ocean mixed layer studying. The laboratory observations are supporting numerical experiments quantitatively.

烟酸、吖啶、黄连素对热浸镀钢材的缓蚀作用及其量化构效关系

为了找到在热浸镀钢材表面清洗处理过程中替代铬酸的缓蚀、清洗剂，本论文通过量子化学计算方法、失重实验、电化学测试和扫描电镜分析等方法系统研究了环境友好型缓蚀剂——烟酸、吖啶和黄连素对热浸镀锌、5%铝-锌和55%铝-锌钢材在盐酸介质中的缓蚀作用及其量化构效关系。 量化计算结果表明，这三种杂环化合物均具有多个吸附活性中心的平面结构。Mulliken电荷、最高占据轨道（HOMO）能量和最低空轨道（LUMO）能量分布显示活性中心主要集中在氧原子、氮原子和杂环周围。三种化合物可能通过这些活性中心吸附在镀层表面以阻止镀层电极反应，且其前线轨道同镀层表面锌原子的前线轨道能够相互作用，使得杂环化合物分子可通过在镀层钢材表面形成吸附膜而阻止镀层表面锌在盐酸介质中的溶解。 失重和电化学测试的结果表明，三种化合物对三种热浸镀钢材在盐酸介质中均是高效的环境友好型缓蚀剂，最高缓蚀效率可达99%以上；其中黄连素的缓蚀效果最好，在浓度为1.0×10-4M时缓蚀效率就已达到80%以上。实验结果同时表明，三种缓蚀剂通过单分子层的化学吸附方式吸附在镀层表面以阻滞酸液对镀层的腐蚀，其吸附遵从Langmuir吸附等温式。扫描电镜分析结果也显示了在盐酸介质中三种缓蚀剂能够很好地抑制镀层的腐蚀。几种实验方法得到的结果能够很好地吻合，同时又都验证了量子化学计算的推测。 另外，通过恒电量方法和量化构效关系(QSAR)研究了盐酸介质中烟酸、吖啶和黄连素对热浸镀钢材的缓蚀机理。恒电量实验验证了失重实验和电化学测试的结果：烟酸、吖啶和黄连素是混合型缓蚀剂，三种缓蚀剂通过活性中心吸附在镀层材料表面，同时抑制镀层的阴阳极反应以减缓镀层在盐酸溶液中的腐蚀。量化构效关系显示缓蚀效率与最高占据轨道能量（EHOMO）成正相关关系，与前线轨道能量差ΔE（ELUMO-EHOMO）成负相关关系；三种缓蚀剂通过提供电子与镀层材料表面锌原子相互作用而起到缓蚀作用。 最后，以铬酸清洗方法作参照，使用缓蚀酸液清洗方法对热浸镀钢材的腐蚀产物进行去除，结果显示，缓蚀酸液清洗方法可替代铬酸对热浸镀钢材进行腐蚀产物去除和绿色清洗。

水处理纳米材料的制备、性能及应用研究

工业的高速发展使地球上有限的水资源受到日益严重的污染，去除水中的有毒、有害化学物质已成为环保领域的一项重要工作。纳米材料与技术的开发应用为实现高效、低成本的水处理开辟了新的途径。 本课题组开发的纳米-亚纳米功能新材料（生态宝）可用作养殖生态环境改良剂，它对“三氮”、硫化物、CODCr、BOD5、重金属等有害物质具有很好的去除能力。生态宝用于养殖幼参，有显著的促生长、增加成活率的作用。生态宝用于养殖对虾，对虾体内重金属含量有明显降低。 以粉末状P25型纳米TiO2为光催化剂，系统的研究了它对染料AB80的光催化降解。在紫外光照射下，光催化反应75min，染料AB80溶液完全脱色，光催化反应135min，染料溶液完全矿化；AB80的光催化脱色反应遵从准一级反应动力学；催化剂的最佳剂量为1.0g/L。AB80在TiO2颗粒表面的吸附符合Langmuir方程式，随着pH值的增加吸附量迅速减少；pH值在反应中起着重要的作用，碱性溶液中的反应速度比酸性溶液的大，pH=10.0初始反应速度最大；电子捕获剂（H2O2）的加入能够显著的提高反应速率，H2O2浓度为5mmol/L时，反应速度变为原来的2.78倍。 以硅藻土为载体，采用溶胶-凝胶法制备了负载型的纳米TiO2，SEM分析结果表明，TiO2的包覆量对负载光催化剂的形貌有很大影响，TiO2包覆量较低(14.5%)的复合物无团聚现象发生。XRD分析结果表明，所制备的TiO2为锐钛矿和金红石混晶型，平均粒径11nm。FT-IR分析结果表明，TiO2和硅藻土之间没有生成化学键。以染料AB80和B-2BF为模型污染物，利用制备的光催化剂复合物进行了吸附-光催化试验，结果表明，TiO2包覆量为14.5%的复合物具有较高的吸附-光催化活性，对模型污染物的降解效果好于德国Degussa公司的商品纳米P25-TiO2。溶液pH对TiO2/硅藻土复合物光催化活性影响很大，弱酸性条件有利于反应的进行。TiO2/硅藻土对实际印染废水有较好的降解效果，试验条件下，废水光催化反应3.5h，色度去除率为100%。研究了液固多相光催化反应的催化剂失活原因及再生手段，提出TiO2/硅藻土复合物再生的方法为酸洗和高温烧结。对于模拟印染废水来说，光催化剂重复使用对光催化活性几乎没有影响，重复使用15次后，催化活性仅降低了12%。而对实际印染废水来说，重复使用对光催化活性有影响，光催化剂复合物重复使用7次后，催化活性降低了41%。TiO2/硅藻土复合光催化剂成本低，简便易行，光催化效果好，有望在环境污染物治理中得到广泛的应用。 采用CuCl水解法制得了硅藻土负载的纳米Cu2O，并利用XRD、SEM等手段对其进行表征。研究了负载的纳米Cu2O对B-2BF和AB80染料废水的光催化降解，发现纳米Cu2O经过负载后，团聚减少，分散性好，对染料废水的光催化降解效率成倍增长。纳米Cu2O包覆量为31.3%的光催化剂复合物光催化活性最好，其光催化效率是纯的Cu2O的6倍。负载的纳米Cu2O可以有效的利用太阳光进行光催化反应，而且太阳光下纳米Cu2O的光催化活性比纳米TiO2的强。太阳能是取之不尽、用之不竭的清洁能源，利用太阳能来处理染料废水成本低、无污染，是一种非常有发展前景的环境治理新技术。pH 5-pH 7是负载纳米Cu2O光催化降解B-2BF的最佳反应范围。负载的纳米Cu2O光催化剂有较好的稳定性，重复使用8次以后，其脱色率仍能达到75%以上。

藻体对水环境中N、P及重金属Cu2+、Pb2+、Cd2+、Cr6+的吸附特征研究

随着全球生态环境的恶化，各国日益重视对水体中各种污染物的治理。利用藻类的吸收、富集和降解作用，可以去除污水中的营养物质、重金属离子和有机污染物，与其他物理、化学及工程的方法相比，该技术具有以下优点：成本低、能耗小、治理效果较好，对环境污染小，有利于资源化，有利于整体生态环境的改善，是治理水质污染的新途径。 本文利用几种大型海藻对富营养化海水进行处理，结果发现孔石莼、刚毛藻均有很强的吸收N、P的能力，吸收能力依次为褶曲刚毛藻>束生刚毛藻>孔石莼。水体中褶曲刚毛藻3 g/L含量，在3～5小时之内，可把中等以上富营养化海水中的N、P降低至一类海水水平。利用刚毛藻处理富营养化地下海水和养殖废水，进行海参和大菱鲆养殖试验，探索藻类净化水质和废水循环利用的新模式，使水体保持较低的营养盐状态，减轻养殖废水对环境的影响，实现了海水养殖业与环境的可持续发展。 刚毛藻在我国近海滩涂分布广泛，利用它来处理富营养化水体，并和水产养殖业相结合，既净化水体，使养殖废水能循环利用，满足水产养殖的需求，又改善水产业生态环境。同时，将回收藻体生产优质饲料、食品和药物等，实现藻类资源的高值利用。刚毛藻营养丰富，用其替代鼠尾藻作海参饲料，资源丰富，成本低，效果好，是一种值得加以开发利用的宝贵资源，具有广泛的应用前景。 生物吸附法是一种经济有效的移除废水中有害重金属离子的方法。由于藻类细胞壁中的多聚糖可提供吸附重金属的位点，廉价而蕴藏丰富的海藻对多种重金属表现出很强的吸附能力。所以本文通过分批实验，研究了非活体刚毛藻对水体中重金属Cu2+、Pb2+和Cd2+的吸附影响因子、吸附热力学、吸附动力学及吸附机理，得到了平衡等温线及动力学数据。吸附过程的最佳pH值为5.0，吸附量随温度的升高而增加，水体中常见的Na+、K+、Ca2+、Mg2+阳离子及Cl-、NO3-、SO42-、C2O42-等阴离子的存在对吸附的影响并不显著。EDTA存在时，吸附百分率大大降低。吸附等温线符合Langmuir和Freundlich方程。刚毛藻对重金属Cu2+、Pb2+和Cd2+的吸附容量很高，25℃时，对Cu2+、Pb2+和Cd2+的最大吸附容量分别为1.61 mmol/g、0.96 mmol/g和0.98 mmol/g，且吸附过程为吸热反应。刚毛藻对重金属Cu2+、Pb2+和Cd2+的吸附过程为化学吸附，在吸附过程中藻体表面的官能团可能与金属离子发生了螯合作用。吸附动力学过程符合pseudo-二级动力学模型，在初始的30min内，吸附速率很快，随后速率逐渐降低。解吸试验表明，用EDTA可以对重金属进行回收，刚毛藻可以循环利用。实验结果表明刚毛藻是一种高效、经济实用的生物吸附材料，可用来吸附回收水体中的重金属Cu2+、Pb2+和Cd2+等。 通过非活体刚毛藻对重金属Cr6+的吸附影响因子、吸附动力学、吸附机理的研究发现，刚毛藻对Cr6+具有很强的还原能力，对电镀废水中的Cr6+的还原去除提供了非常好的方法。吸附过程的最佳pH值为2～3，实际电镀废水通常在此pH范围，因此处理实际废水时，首先在原酸性条件下，对Cr6+进行还原去除，然后调废水pH至5.0，继续进行吸附，去除其他二价离子及被还原的三价Cr离子，实现了利用同一材料还原Cr6+为Cr3+，并将Cr3+和其他重金属离子同时去除。通过对机理的讨论，认为刚毛藻对Cr6+的生物吸附过程不是一个简单的“离子交换过程”，而是一个“吸附还原过程”。在海藻量足够的前提下，只要时间足够长，Cr6+可被彻底还原去除。 利用工业废弃物褐藻渣，对水体中重金属离子Cu2+、Pb2+、Cd2+及Cr6+的生物吸附特性分别进行了讨论，结果表明褐藻渣对重金属离子的吸附特性与刚毛藻一致，吸附等温线符合Langmuir和Freundlich方程，在25℃时，pH为5.0时，由Langmuir方程求出褐藻渣对Cu2+、Pb2+和Cd2+的最大吸附容量分别为4.20 mmol/g、3.13 mmol/g和2.97 mmol/g。褐藻渣对低、高浓度的重金属Cr6+都具有很强的吸附能力，且移除效果比较彻底。实际应用结果表明，褐藻渣是一种高效、经济实用的生物吸附材料，可用来吸附回收水体中的重金属离子，具有广泛的应用前景。

Photocatalytic degradation of CI Acid Blue 80 in aqueous suspensions of titanium dioxide under sunlight

The dye C.I. Acid Blue 80 (AB80) was easily degraded by TiO2-P25 assisted photocatalysis in aqueous dispersion under irradiation of sunlight. The optimal reaction conditions were [TiO2] = 2.0 g/L, pH = 10, [H2O2] = 5 mmol/L. The photocatalytic reaction followed pseudo-first order kinetics. The adsorption of AB80 onto TiO2 was in accord with Langmuir equation.

Biosorption and desorption of Cd2+ from wastewater by dehydrated shreds of Cladophora fascicularis

The adsorption and desorption of algae Cladophora fascicularis and their relation with initial Cd2+ concentration, initial pH, and co-existing ions were studied. Adsorption equilibrium and biosorption kinetics were established from batch experiments. The adsorption equilibrium was adequately described by the Langmuir isotherm, and biosorption kinetics was in pseudo-second order model. The experiment on co-existing ions showed that the biosorption capacity of biomass decreased with an increasing concentration of competing ions. Desorption experiments indicated that EDTA was efficient desorbent for recovery from Cd2+. With high capacities of metal biosorption and desorption, the biomass of Cladophora fascicularis is promising as a cost-effective biosorbent for the removal of Cd2+ from wastewater.

Biosorption of copper(II) from aqueous solutions by green alga Cladophora fascicularis

Biosorption is an effective means of removal of heavy metals from wastewater. In this work the biosorption behavior of Cladophora fascicularis was investigated as a function of pH, amount of biosorbent, initial Cu2+ concentration, temperature, and co-existing ions. Adsorption equilibria were well described by Langmuir isotherm models. The enthalpy change for the biosorption process was found to be 6.86 kJ mol(-1) by use of the Langmuir constant b. The biosorption process was found to be rapid in the first 30 min. The presence of co-existing cations such as Na+, K+, Mg2+, and Ca2+ and anions such as chloride, nitrate, sulfate, and acetate did not significantly affect uptake of Cu2+ whereas EDTA substantially affected adsorption of the metal. When experiments were performed with different desorbents the results indicated that EDTA was an efficient desorbent for the recovery of Cu2+ from biomass. IR spectral analysis suggested amido or hydroxy, C=O, and C-O could combine strongly with Cu2+.

Sorption and desorption of lead (II) from wastewater by green algae Cladophora fascicularis

Biosorption is an effective method to remove heavy metals from wastewater. In this work, adsorption features of Cladophora fascicularis were investigated as a function of time, initial pH, initial Pb(II) concentrations, temperature and co-existing ions. Kinetics and equilibria were obtained from batch experiments. The biosorption kinetics followed the pseudo-second order model. Adsorption equilibria were well described by the Langmuir and Freundlich isotherm models. The maximum adsorption capacity was 198.5 mg/g at 298 K and pH 5.0. The adsorption processes were endothermic and the biosorption heat was 29.6 kJ/mol. Desorption experiments indicated that 0.01 mol/L Na(2)EDTA was an efficient desorbent for the recovery of Pb(II) from biomass. IR spectrum analysis suggested amido or hydroxy, C=O and C-O could combine intensively with Pb(II). (C) 2006 Elsevier B.V. All rights reserved.

Biosorption of copper (II) and lead (II) from aqueous solutions by nonliving green algae Cladophora fascicularis: Equilibrium, kinetics and environmental effects

Biosorption of Cu2+ and Pb2+ by Cladophora fascicularis was investigated as a function of initial pH, initial heavy metal concentrations, temperature and other co-existing ions. Adsorption equilibriums were well described by Langmuir and Freundlich isotherm models. The maximum adsorption capacities were 1.61 mmol/ g for Cu2+ and 0.96 mmol/ g for Pb2+ at 298K and pH 5.0. The adsorption processes were endothermic and biosorption heats calculated by the Langmuir constant b were 39.0 and 29.6 kJ/ mol for Cu2+ and Pb2+, respectively. The biosorption kinetics followed the pseudo- second order model. No significant effect on the uptake of Cu2+ and Pb2+ by co-existing cations and anions was observed, except EDTA. Desorption experiments indicated that Na(2)EDTA was an efficient desorbent for the recovery of Cu2+ and Pb2+ from biomass. The results showed that Cladophora fascicularis was an effective and economical biosorbent material for the removal and recovery of heavy metal ions from wastewater.