烷基磺酸盐搏收红柱石作用机理初探

研究了红柱石的浮性及其与捕收剂烷基磺酸盐的作用机理。通过红外光谱和电动电位的测定,以及解吸试验。确认红柱石与十二烷基苯磺到钠的相互作用,除了有物理吸附外,还有化学吸附。     

阳离子表面活性剂CTAB吸附机理的研究

本文测定了阳离子表面活性剂 CTAB(溴化十六烷基三甲基铵)水溶液在石英和甲基化石英表面的接触角、(?)电位及吸附等温线。讨论了在酸性溶液(PH=4.5)和碱性溶液(PH=8.5)情况下 CTAB 的吸附机理。研究结果表明:甲基化和非甲基化表面吸附机理的差别;甲基化表面在水溶液中长时间浸泡其表面由憎水向亲水方向转移是在作表面性能研究时必须严重关注的问题。     

石英与长石在酸性介质中的浮选分离研究

以十二烷基磺酸钠(SDS)和N-十二烷基-1,3-丙二胺(DN12)作为混合捕收剂,采用单矿浮选实验分离石英与长石,探究DN12和SDS对长石和石英浮选回收率的影响及其浮选分离的机理。结果表明,在p H为2.0,DN12浓度为4.739×10-4mol/L,SDS浓度为2.38×10-4mol/L时,长石和石英回收率的差值最大,达62.3%。紫外光谱的分析得出,SDS和DN12捕收剂在长石表面仅存在物理吸附,在石英表面不仅存在物理吸附,还存在化学吸附,表明该捕收剂对石英具有更强的捕收能力。     

十二烷基三甲氧基硅烷对十二胺浮选铝硅矿物的影响

通过单矿物浮选实验、动电位测定及红外光谱分析,研究了十二胺(DDA)和十二烷基三甲氧基硅烷(WD-10)2种浮选药剂对一水硬铝石和高岭石的浮选行为和作用机理.结果表明:在酸性条件下,十二胺单独使用时,高岭石的回收率略高于一水硬铝石,两种矿物的可浮性差异不大,不能有效实现高岭石与一水硬铝石的浮选分离;十二烷基三甲氧基硅烷单独使用时对高岭石和一水硬铝石均无捕收作用;与单用十二胺相比,DDA+WD-10的组合捕收剂对硅酸盐矿物浮选能力强,选择性好.在pH=4～5.5的范围及最佳药剂配比条件下,高岭石回收率在75%以上,而一水硬铝石回收率只有20%左右,能有效实现铝硅矿物的反浮选分离.     

十二烷基苯胺的合成

以十二烷基苯为原料，通过硝化、还原制得十二烷基苯胺，用非水滴定方法对产品含量进行了分析。     

连续法合成N-β-羟乙基乙二胺的研究

介绍了一种以乙二胺和环氧乙烷为原料，通过气液相快速接触反应合成N-β-羟乙基乙二胺的新技术，通过实验确定了含水量、进料比和环氧乙烷导入温度等条件对反应过程的影响，得出最佳工艺条件为：乙二胺中含水量为8％，乙二胺与环氧乙烷的进料量之体积比为1．8：1，环氧乙烷的导入温度为30℃．采用适合该反应的塔式精馏反应器，可使N—β—羟乙基乙二胺的收率达到86％，产品纯度达99％．     

阳离子表面活性剂在石英表面吸附行为的分子动力学模拟

为深入了解支链化对阳离子表面活性剂在水/石英界面吸附性质的影响,用分子动力学方法模拟十六烷基醚羟丙基季铵盐(C₁₆PC)和支链十六烷基醚羟丙基季铵盐(C_<sub>16GPC)在水/石英界面的单层和双层吸附行为,分析了不同浓度(即分子排列紧密程度)下表面活性分子的倾斜角、界面层厚度、水分子和尾端碳原子密度排布。结果表明：C_<sub>16GPC在较低浓度(分子平均占有面积0.466 nm²)形成紧密的吸附单层,明显低于C₁₆PC(0.272 nm²),说明支链结构有利于阳离子表面活性剂在水/石英界面的吸附,且在高浓度下C_<sub>16GPC被压缩的优先顺序依次为：主链>长支链>短支链。直链的C₁₆PC在较紧密的吸附单层上形成类似半胶束的双层结构;而支链的C_<sub>16GPC则是通过上下层长支链尾对尾的方式形成双层结构。     

十二烷基苯磺酸钠在硅藻土上的吸附热力学

用表态态法测定了２９３，３１３和３３Ｋ温度下，十二烷基苯磺酸自水溶液中在硅藻土上的吸附等温线。用二阶段吸附模型导出的吸附等温式拟合实验数据，求得模型参数Ｋ１，Ｋ２和ｎ的数值。计算值和实验值符合良好，表明二阶段吸附模型适合于该体系。     

三（十二烷基）膦的合成

三(十二烷基)膦可作为羰基钴的配位体.这种配位体配合物作为1-烯烃的氢甲酰化反应的催化剂比单独使用羰基钴时有很多优点.本文对三(十二烷基)膦的应用与合成方法作了介绍,取得了一定结果.三(十二烷基)膦的合成是通过格氏试剂与三氯化磷反应后水解制得粗膦再经精馏而制得的.     

Influence of surface roughness on flotation kinetics of quartz

Surface roughness of quartz particles was determined by measuring the specific surface area of particles. The wettability characteristics of particles were determined by measuring the flotation rate using a laboratory flotation cell. Experimental results show that the rod mill product has higher roughness than the ball mill product. For the particles with larger surface roughness, the flotation kinetics constant is also higher. Finally, empirical relationships between surface roughness (r) and the flotation kinetics constant (k) of quartz particles as k=A+Br+Cr ^0.5lnr+D/lnr+E/r and k=A+Br are presented, in which A, B, C, D and E are constants related to experimental conditions and mineralogical properties of mineral.     

有机氮化物在镍钼硫催化剂的表面吸附

加氢精制过程中,有机含氮化合物的存在会使得贵金属催化剂或酸性催化剂中毒,同时抑制加氢脱硫（HDS）催化剂的活性,因此研究含氮化合物在催化剂表面的吸附行为有助于了解含氮化合物对HDS反应的作用机理.本研究构建一个周期性的镍钼硫（NiMoS）催化剂超晶胞模型,应用密度泛函理论的方法计算了平行吸附和垂直吸附状态下的吡啶、喹啉、咔唑和吲哚在NiMoS催化剂表面的吸附构型和吸附能.结果表明：碱性分子吡啶和喹啉通过Ni-N键吸附在催化剂的表面上,主要表现为垂直吸附;而非碱性分子吲哚通过吡咯环的β-C键吸附在催化剂表面上,咔唑则主要通过苯环吸附在催化剂表面上,两者均以平行吸附为主.比较两类不同吸附构型的吸附能发现,在NiMoS催化剂表面碱性氮化物的吸附能比非碱性氮化物的吸附能高.氮化物在催化剂表面的吸附过程为放热过程.     

石英表面阳离子吸附膜结构的AFM研究

为了研究阳离子表面活性剂对固体表面的润湿性的影响,了解表面活性剂在石英表面的吸附机制,利用原子力显微镜(AFM)技术,考察了不同结构阳离子改性石英片与不同基团改性AFM探针间的拉脱力,从分子角度探索石英表面双层膜的结构特性.研究发现:直链烷基季铵盐CI6PC改性石英片与阴离子改性探针间的拉脱力随浓度增大在临界胶束浓度附...     

Adsorption characteristics of thiobacillus ferrooxidans on surface of sulfide minerals

1INTRODUCTION Thefeatureofmineralsurfaceismodifiedlike thecellsurfacebyfixingbacteriaonitssurface whilethefeatureofcellsurfaceisdeterminedbyits livingcondition[1].Thecomponentofbacterial surfaceplaysanimportantroleinthebacterialat tachmentonminerals[2,3].Itisprovedthatcell wallandoutermembraneareinvolvedintheadhe sionbetweenmineralsandmicrobes,whilethein nermembraneandotherorganelleshardlyhaveany influenceonthisprocess.Thesephysiological structuresofbacteria,especiallytheoutermem brane,af…     

Adsorption characteristics of thiobacillus ferrooxidans on surface of sulfide minerals

By using thiobacillus ferroxidans (T. f) from Qixiashan, Hubei Province, China, the adsorption characteristics of T. f on surface of sulfide mineral were studied. The influences of adsorption time, pH value, temperature, initial inoculated concentration of bacteria, concentration of sulfide mineral powder, and variety of minerals on the adsorption characteristics were firstly investigated by using the ninhydrin colorimetric method, and the changes of contact angles and Zeta potentials of mineral surface during the bacterial adsorption were then determined. The results show that when the leaching experiments are performed for a long time from several days to a month, the maximal quantity of adsorption of T f on the surface of pyrite is obtained under the following conditions: leaching for 20 d, pH value in range of 1–2 and temperature at 30 °C, respectively; when the bio-leaching experiments are performed for a shorter leaching time, the maximal quantity of adsorption is obtained under the conditions: bio-leaching for 2 h, at 2.4×10⁷ cell/mL of initial inoculated bacteria concentration, and at 10% of mineral powder concentration; and the adsorption quantities are different from one sulfide mineral to another, and the adsorption of T. f on the surface of sulfide minerals includes three phases: increasing phase, stationary phase and decreasing phase. Foundation item: Project(50321402) supported by the National Natural Science Foundation of China; project (2004CB619204) supported by the National Key Fundamental Research and Development Program of China     

Adsorption mechanism of polycarboxylate-based superplasticizer in CFBC ash-Portland cement paste

Circulating fluidized bed combustion （CFBC） ash exhibits the desirable pozzolanic activity which makes it a potential supplementary cementitious material to replace cement for concrete production. However, the high unburnt carbon content and porous surface structure of CFBC ash may adsorb water reducer and thereby significantly reduce the efficiency of water-reducing agents. The adsorption mechanism of polycarboxylate superplasticizer in CFBC ash-Portland cement paste was investigated by ultraviolet-visible spectrophotometer, and the conception of ＂invalid adsorption site＂ of CFBC ash was presented. The results show that the adsorption behavior of polycarboxylate superplasticizer in coal ash-Portland cement paste can be described by Langmuir isothermal adsorption equation. The adsorption capacity of CFBC ash-Portland cement paste is higher than that of pulverized coal combustion （PCC） fly ash-Portland cement paste. Moreover, the adsorption amount of polycarboxylate superplasticizer increases with the ratio of ash-to-cement in the paste. At last, the fluidity of CFBC ash-Portland cement paste is lower than that of the PCC fly ash paste. This work suggests that when CFBC ash is used as concrete admixture, the poor flowability of the cementitious system due to the high adsorption of water and water-reducing agent should be taken into consideration.     

Defect-free surface of quartz glass polished in elastic mode by chemical impact reaction

Removal of brittle materials in the brittle or ductile mode inevitably causes damaged or strained surface layers containing cracks, scratches or dislocations. Within elastic deformation, the arrangement of each atom can be recovered back to its original position without any defects introduced. Based on surface hydroxylation and chemisorption theory, material removal mechanism of quartz glass in the elastic mode is analyzed to obtain defect-free surface. Elastic contact condition between nanoparticle and quartz glass surface is confirmed from the Hertz contact theory model. Atoms on the quartz glass surface are removed by chemical bond generated by impact reaction in the elastic mode, so no defects are generated without mechanical process. Experiment was conducted on a numerically controlled system for nanoparticle jet polishing, and one flat quartz glass was polished in the elastic mode. Results show that scratches on the sample surface are completely removed away with no mechanical defects introduced, and microroughness（Ra） is decreased from 1.23 nm to 0.47 nm. Functional group Ce — O — Si on ceria nanoparticles after polishing was detected directly and indirectly by FTIR, XRD and XPS spectra analysis from which the chemical impact reaction is validated.     

蝗虫翅表面微观结构及疏水耦合机理

使用体视显微镜、扫描电子显微镜、傅立叶红外光谱仪和视频光学接触角测量仪,研究了4种蝗虫(黄胫小车蝗Oedaleus infernalis、异翅负蝗Atractomorpha heteroptera、花胫绿纹蝗Aiolopus tamulus、中华稻蝗Oxya chinensis)翅表面的微观结构、化学成分及疏水性,建立了蝗虫翅表面的微观结构疏水模型,分析了蝗虫翅表面疏水耦合机理。结果表明,蝗虫翅表面具有规则排列的微米级柱状乳突结构,乳突直径为1.6～2.3μm,高为2.3～3.2μm,间距为6.8～7.6μm。翅表面为长链烃类、脂肪酸酯和脂肪酸醇构成的蜡质层,是天然疏水表面,具有较强疏水性(接触角为139.0°～150.4°)。液滴与翅表面呈复合接触,符合Cassie方程。翅表面的高疏水性是微米级粗糙结构(结构耦元)与蜡质晶体(材料耦元)协同作用的结果。