苯乙烯丙烯酸共聚物分散剂在氟铃脲颗粒界面的吸附性能

利用残余质量浓度法、ζ电位测定、红外光谱和XPS法系统地研究了苯乙烯丙烯酸共聚物(MOTAS)分散剂在氟铃脲颗粒界面的吸附量、吸附状态、ζ电位、吸附作用力和吸附层厚度等性能. 实验结果表明, MOTAS分散剂在氟铃脲界面的吸附符合Langmuir吸附等温式, 其饱和吸附量和吸附平衡常数k、ζ电位和吸附层厚度均随MOTAS分散剂相对分子量增加而增大, MOTAS分散剂在氟铃脲界面呈多点吸附, 氢键是分散剂分子与氟铃脲界面结合的重要作用力. 分析实验结果发现, MOTAS分散剂在氟铃脲颗粒界面吸附后具有静电排斥和空间位阻双重作用.     

四环素在海洋沉积物上的吸附

研究了四环素在不同pH、盐度、温度下在海洋沉积物上的吸附特征. 结果表明, 在实验浓度范围内吸附行为都可以用线性等温式进行描述. 通过一种包含四环素3种形态与沉积物界面相互作用的模型对不同pH下的吸附常数进行拟合, 发现四环素正价态的吸附常数K_d⁺远大于中性态的K_d⁰与负价态的K_d^-. 随着盐度的减小四环素在海洋沉积物上的吸附增强, 而温度的升高则不利于吸附的进行. 热力学计算结果得出, ΔG^0-=-9.746~-9.713 kJ/mol; ΔH^0-=-10.056 kJ/mol; ΔS^0-<0, 表明该吸附过程是一个自发的、放热的熵减过程.     

改性层状双氢氧化物对铜离子(Ⅱ)和双酚A的协同吸附

采用离子交换法制备了十二烷基苯磺酸根(DBS^-)和柠檬酸根(Cit^3-)复合改性层状双氢氧化物(LDHs),简写为DBS-Cit-LDHs。 利用粉末X射线衍射分析、红外光谱分析、比表面积测定以及元素分析等技术手段对样品进行了表征。 结果表明,DBS^-和Cit^3-已柱撑进入LDHs层间。 研究了DBS-Cit-LDHs对水中重金属离子Cu²⁺和有机污染物双酚A(BPA)的协同吸附性能。 吸附实验结果表明,DBS-Cit-LDHs能同时高效去除Cu²⁺和BPA;对Cu²⁺的强吸附能力缘于DBS-Cit-LDHs层间Cit^3-与Cu²⁺形成了稳定配合物;对BPA的强吸附能力缘于分配作用,且吸附能力与样品比表面积无关。 DBS-Cit-LDHs对Cu²⁺的吸附动力学和热力学分别符合准二级动力学方程和Freundlich等温式;对BPA的吸附分别符合准一级动力学方程和Linear等温式。 二者吸附过程的ΔG^o和ΔH^o均为负值,表明吸附为自发放热过程。     

聚合物分散剂对氟虫脲水悬浮剂分散稳定性的影响

通过测定药物颗粒界面Zeta电位和平均粒径, 研究了聚合物分散剂苯乙烯磺酸聚合物钠盐(GY-D08)用量、pH和盐离子对氟虫脲水悬浮剂分散稳定性的影响, 研究结果表明, 分散剂GY-D08的加入量与水悬浮剂分散效果密切相关, 制备质量分数为5%氟虫脲水悬浮剂的GY-D08最佳用量为2%, GY-D08用量过多或过少都会使分散效果下降; pH影响分散剂GY-D08在水中的电离能力, 当pH=9时, GY-D08分子完全电离, 能为颗粒提供较大的静电位阻, 水悬浮剂分散稳定性最好; Mg²⁺或Ca²⁺压缩颗粒界面的双电层, 降低Zeta电位, 使颗粒因带电量减少而聚结, 导致水悬浮剂分散稳定性变差, 且Mg²⁺或Ca²⁺浓度愈大, 其分散稳定性愈差; 当离子浓度相同时, Ca²⁺压缩双电层的能力比Mg²⁺强, 添加Ca²⁺后的水悬浮剂的分散稳定性更差.     

基于等温滴定量热法表征的红细胞凝集反应热动力学特性研究

采用等温滴定量热法研究植物凝集素(PHA)作用于20%家兔血红细胞(RBC)的凝集反应过程, 以生物热动力学参数表达凝集反应动力学特征. 结果表明, PHA与家兔血红细胞凝集反应的平衡常数K为3.24×10⁵ L•mol^－1, 反应焓变( )为－238.548 kJ•mol^－1, 反应自由能( )为－32.722 kJ•mol^－1, 反应熵变( )为－0.664 kJ•mol^－1•K^－1. 反应为放热反应(Q＞0), 可自发进行(ΔG＜0), 反应为焓驱动、熵减过程(ΔH＜0, ΔS＜0, |ΔH|＞|TΔS|), 由化学键合作用、氢键和范德华力推动, 反应体系最终处于稳定有序状态. 所建立的微量量热法可以客观表征凝集反应的热动力学过程, 也为其他抗原抗体类型反应的过程评价方法提供新的技术参考.     

高容量亚胺基二乙酸型螯合树脂的制备及吸附性能

以甲基丙烯酸缩水甘油酯(GMA)为单体, 氯甲基化的交联聚苯乙烯树脂(CMCPS)为大分子引发剂, CuBr/2,2'-联吡啶(Bpy)为催化剂, 采用表面引发原子转移自由基聚合(SI-ATRP)技术, 使甲基丙烯酸缩水甘油酯聚合在CMCPS树脂表面, 制得了环氧化聚合物. 将该聚合物与亚胺基二乙酸(IDA)反应, 制备了高容量亚胺基二乙酸型螯合树脂(IDA-PGMA-CMCPS), 用元素分析对其进行了表征. 考察了螯合树脂对Cu²⁺的吸附性能及动力学和热力学参数. 该螯合树脂表面IDA接枝密度达8.15 mg/m². 研究结果表明, 树脂对Cu²⁺的吸附量随离子浓度和温度的升高而增加, 当pH值为2.2时, 对Cu²⁺离子的吸附效果最佳. 树脂的静态饱和吸附容量为1339.66 mg/g, Langmuir和Freundlich方程均呈现良好的拟合度. 通过热力学平衡方程计算ΔG<0, ΔH=270.60 kJ/mol, ΔS>0, 表明该吸附过程是自发、 吸热、 熵增加的过程. 动力学研究结果表明, 准二级动力学方程能较好拟合动力学实验结果, 该过程符合准二级动力学模型.     

磁性多壁碳纳米管对水中三种硝基咪唑类药物的吸附行为

在制备磁性多壁碳纳米管(MWCNTs)并且对其表征的基础上, 将磁性MWCNTs用于吸附水溶液中的三种硝基咪唑类药物(甲硝唑、奥硝唑、替硝唑). 研究了溶液pH值、吸附剂量、吸附时间和温度对吸附过程的影响. 结果表明, 当磁性MWCNTs投加量为5 g·L^-1, 溶液pH值为7, 吸附时间为300 min时, 甲硝唑、奥硝唑、替硝唑的去除率分别达到92.86%, 94.44%, 94.91%. 吸附动力学分析证实准二级模型准确地反映了吸附过程的动力学, 而Freundlich模型很好地描述了不同温度下的吸附等温线. 吸附过程的总速度受到外部质量传递和粒子内扩散的影响, 但主导因素是粒子内扩散. 吸附机理可能是由MWCNTs和硝基咪唑类化合物之间的静电引力及π-π堆积作用产生的. 对热力学参数(ΔH⁰, ΔS⁰, ΔG⁰)的计算揭示, 在实验的温度范围, 硝基咪唑类药物的吸附是自发、放热的物理过程. 最后考察了吸附材料中Fe的溢出情况, 发现在中性pH下Fe的溢出仅是0.96 mg·L^-1, 表明磁性MWCNTs在中性水体中是相当稳定的.     

多重吸附同步净化-气相色谱-质谱法测定干性样品中丁烯氟虫腈的残留量

建立了干性样品中丁烯氟虫腈残留量的多重吸附同步净化(MASP)-气相色谱-质谱检测方法。前处理以1%乙酸-乙腈提取样品,应用MASP法对样品同时进行提取、盐析和净化,并利用气相色谱-质谱仪在选择离子扫描(SIM)模式下进行检测,以基质匹配标准溶液外标法定量。结果表明:丁烯氟虫腈在2~100 μg/L范围内线性关系良好,相关系数(r²)不小于0.999;在2~10 μg/kg添加水平范围内,丁烯氟虫腈的平均回收率为92.2%~97.5%,相对标准偏差(RSD, n=6)为2.69%~5.21%;方法检出限(S/N=3)为2 μg/kg;定量限(S/N=10)为6 μg/kg。本方法操作简便、快速、准确,可用于干性样品中丁烯氟虫腈的日常检测。同时,对丁烯氟虫腈的裂解机理进行了探讨。     

双硫腙包覆钛酸锶钡粉体对水中铅的吸附行为

用草酸化学共沉淀法合成了钛酸锶钡(BST)粉体, 以双硫腙为表面修饰剂, 采用静态浸渍法对钛酸锶钡粉体进行表面包覆修饰, 制备出新型固态粉体吸附剂. 利用X射线衍射(XRD)、扫描电镜(SEM)和傅立叶变换红外光谱(FTIR)进行了表征. 研究了该吸附剂对水中铅的吸附行为. 结果表明: 双硫腙通过与钛酸锶钡表面羟基形成氢键作用包覆于该粉体上; 当吸附介质pH值大于4时, 该吸附剂对水中的铅有较强的吸附能力; 室温下, 5 min内吸附达到平衡. 其吸附行为符合Langmuir吸附等温模型和HO准二级动力学方程式, 吸附焓变(ΔH)为19.42 kJ•mol^－1, 活化能(E_a)为22.187 kJ•mol^－1, 该吸附过程是吸热的物理过程. 吸附在双硫腙包覆钛酸锶钡粉体上的铅, 可用1 mol•L^－1的硝酸溶液进行洗脱. 建立了吸附富集、火焰原子吸收法测定水中铅的新方法, 应用于地表水和自来水中铅的测定, 取得了令人满意的结果.     

木质素磺酸盐在烯酰吗啉颗粒表面的吸附特性

考察了常用分散剂木质素磺酸钠(Sodium Lignosulfonate, SLS)在烯酰吗啉(Dimethomorph, DMM)上的吸附性能, 并测试了吸附SLS后DMM颗粒表面Zeta电位和接触角的变化, 从理论上探讨了分散剂的吸附对农药颗粒表面物化性能的影响, 指导农药分散剂的开发. 结果显示, 浓度为0~10 g/L时, SLS在DMM表面呈现双层吸附; 低浓度(0~1.0 g/L)时, 吸附等温线符合Langmuir方程. SLS在DMM表面上的吸附属于自发、 放热吸附过程, 吸附力主要包括疏水作用、 范德华力和氢键作用力. SLS在DMM表面吸附后提高了其Zeta电位, 且SLS磺化度越高其提高作用越明显. 随着SLS溶液浓度增大, DMM在SLS溶液中的接触角先减小后增大, 到70º~80º后趋于稳定.     

Adsorption Properties of Comb-Shaped Polycarboxylate Dispersant onto Different Crystal Pyraclostrobin Particle Surfaces

The stability of the suspension system of the two crystal forms of pyraclostrobin is evaluated using multiple light technology, and the adsorption performance of polycarboxylate dispersant on the surface of two different crystalline pyraclostrobin particles is compared in combination with XRD, FTIR, XPS, and SEM from the microscopic view. The adsorption kinetics and thermodynamics studies of 2700 on the surfaces of different crystalline forms of pyraclostrobin particles show that the adsorption process of 2700 on the surfaces of pyraclostrobin crystal forms II and IV conform to pseudo-second-order kinetic adsorption model. The Ea values for crystal forms II and IV are 12.93 and 14.39 kJ∙mol⁻¹, respectively, which indicates that both adsorption processes are physical adsorption. The adsorption models of 2700 on the surfaces of pyraclostrobin crystal forms II and IV are in accordance with Langmuir adsorption isotherms. The ∆G_ad values of crystal forms II and IV are negative and the ∆S_ad values are positive at different temperatures. Therefore, the adsorption processes are spontaneous and accompanied by entropy increase. The results of this study provide an important theoretical basis for the selection of polycarboxylate dispersants in the suspension of pyraclostrobin. This study also provides a reference for the research of polycrystalline pesticide suspension concentrate.     

SiCp/ Al复合材料与化学镀镍层结合机理研究

根据结构化学理论，用SEM, EDAX和XPS等测试手段研究了镀层和碳化硅颗粒增强铝基复合材料(SiC_p/ Al)的表面、断面形貌及界面的结合状态，分析了镀层和基体之间的结合机理。结果表明，Ni镀层与复合材料界面有良好的结合，在复合材料表面的SiC-Al界面，初期沉积物Ni按Al的晶格外延生长出现微晶层，然后吸附原子扩散迁移、碰撞结合并与界面上的SiC晶格匹配生长，在镍层中诱发了拉伸应力。镍晶格和基体粒子之间产生了键合作用，形成的键显示出共价键和离子键的混合性质。     

Studies on the adsorption behaviors of Pb(II) onto an acyl-thiourea resin

In this paper, an acyl-thiourea resin (PIDTR) was synthesized and its adsorption performances to Pb(II) were investigated by adsorption tests, scanning electron microscopy (SEM), Fourier transform infrared spectra (FTIR), and X-ray photoelectron spectroscopy (XPS) analyses. A pH of 6.0 was found to be the optimum pH to obtain the maximum adsorption capacity in 12 hours of equilibration time. The Langmuir model was well fitted to the adsorption data with adsorption capacity of 0.756?mmol?·?g^?1. The adsorption kinetics showed that the adsorption process experienced liquid film diffusion and chemical reaction. The thermodynamic studies indicated that the adsorption for Pb(II) was spontaneous and endothermic. The results of SEM suggested that Pb(II) adsorbed on the surface of PIDTR. The FTIR and XPS analyses further confirmed Pb(II) might chemisorb onto PIDTR surfaces and N–Pb, O–Pb, and S–Pb were formed with the breakage of C?O, C?S, and N-H bonds in the PIDTR molecule.     

Adsorption-desorption mechanism of phosphate by immobilized nano-sized magnetite layer: interface and bulk interactions

Phosphate adsorption mechanism by a homogenous porous layer of nano-sized magnetite particles immobilized onto granular activated carbon (nFe-GAC) was studied for both interface and bulk structures. X-ray Photoelectron Spectroscopy (XPS) analysis revealed phosphate bonding to the nFe-GAC predominantly through bidentate surface complexes. It was established that phosphate was adsorbed to the magnetite surface mainly via ligand exchange mechanism. Initially, phosphate was adsorbed by the active sites on the magnetite surface, after which it diffused into the interior of the nano-magnetite layer, as indicated by intraparticle diffusion model. This diffusion process continues regardless of interface interactions, revealing some of the outer magnetite binding sites for further phosphate uptake. Desorption, using NaOH solution, was found to be predominantly a surface reaction, at which hydroxyl ions replace the adsorbed phosphate ions only at the surface outer biding sites. Five successive fix-bed adsorption/regeneration cycles were successfully applied, without significant reduction in the nFe-GAC adsorption capacity and at high regeneration efficiency.     

PS colloidal particles stabilized by graphene oxide

Exfoliated graphene oxide (GO) sheets with hydrophilic functional groups on the surface were prepared by the oxidation of graphite. Because of the hydrophilic groups on the sheets and the hydrophobic carbon surface, GO sheets were located at the oil-water interface and could be used as a stabilizer in Pickering emulsions. After the Pickering emulsion polymerization of styrene, PS colloidal particles with GO sheets on the surface were prepared. The size of the GO sheets exerts an important influence on the preparation of PS colloidal particles. Small GO sheets located at the liquid-liquid interface and GO-stabilized PS colloidal particles were prepared; however, for large GO sheets, smaller PS colloidal particles prepared on the GO surface were observed. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) were used to characterize the structure and morphology of the colloidal particles. TEM, SEM, and XPS results all suggest the successful preparation of GO-stabilized PS colloidal particles.     

An Experimental and Theoretical Approach to Investigate the Effect of Chain Length on Aminothiol Adsorption and Assembly on Gold

Despite the numerous studies on the self‐assembled monolayers (SAMs) of alkylthiols on gold, the mechanisms involved, especially the nature and influence of the thiol–gold interface are still under debate. In this work the adsorption of aminothiols on Au(111) surfaces has been studied by using surface IR and X‐ray photoelectron spectroscopy (XPS) as well as by density functional theory (DFT) modeling. Two aminothiols were used, cysteamine (CEA) and mercaptoundecylamine (MUAM), which contain two and eleven carbon atoms, respectively. By combining experimental and theoretical methods, it was possible to draw a molecular picture of the thiol–gold interface. The long‐chain aminothiol produced better ordered SAMs, but, interestingly, the XPS data showed different sulfur binding environments depending on the alkyl chain length; an additional peak at low binding energy was observed upon CEA adsorption, which indicates the presence of sulfur in a different environment. DFT modeling showed that the positions of the sulfur atoms in the SAMs on gold with similar unit cells [(2√3×2√3)R30°] depended on the length of the alkyl chain. Short‐chain alkylthiol SAMs were adsorbed more strongly than long‐chain thiol SAMs and were shown to induce surface reconstruction by extracting atoms from the surface, possibly forming adatom/vacancy combinations that lead to the additional XPS peak. In the case of short alkylthiols, the thiol–gold interface governs the layer, CEA adsorbs strongly, and the mechanism is closer to single‐molecule adsorption than self‐assembly, whereas for long chains, interactions between alkyl chains drive the system to self‐assembly, leading to a higher level of SAM organization and restricting the influence of the sulfur–gold interface.     

Chemical and physical adsorption of polymers containing thiophosphate,amino, or polysiloxane groups at the oil/metal interface under extreme pressure

Thiophosphate‐ and amino‐containing polymers—poly[diethyl 2‐(methacryloyloxy) ethyl phosphate‐stearyl acrylate] (PPS) and poly(2‐dimethylaminoethylacrylate‐stearyl acrylate) (PNS)—were synthesized, and their characteristics at an oil/metal interface under a high load and rotary velocity were investigated by the measurement of the temperature of the oil, the frictional coefficient, and the electrical contact resistance between the two metal surfaces. The experimental results indicated that PNS most effectively limited the increase of the oil temperature and the frictional coefficient at low temperatures. However, PNS reduced the oil temperature and frictional coefficient less effectively than the base oil at high temperatures, whereas PPS most effectively reduced the oil temperature and frictional coefficient and increased the electrical resistance at high temperatures. Moreover, the adsorption layers of PPS could be directly observed with scanning electron microscopy (SEM). These adsorption layers were analyzed by energy‐dispersible spectrometry to determine the phosphorus content and by electron spectroscopy for chemical analysis to demonstrate the existence of ferric or ferrous ions of sulfide or sulfate. The results of this study suggested that the adsorption layer of the thiophosphate‐containing polymer resulted in chemisorption by a reaction of the thiophosphate group on a metal surface. In contrast, an amino‐containing polymer was physically adsorbed onto a metal surface at low temperature, although no adsorption layer was observed at a high temperature with SEM. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 106–115, 2003     

Coating of Y2O3:Eu3+ particles with alumina by a humid solid state reaction at room temperature

Humid solid state reaction at room temperature was utilized for the first time to coat Y(2)O(3):Eu(3+) particles with alumina. The particles were studied with an X-ray photoelectron spectrometer (XPS), a scanning electron microscope (SEM), and an energy dispersive spectrometer (EDS). XPS results show that the yttrium and europium contents are decreased and that the aluminum content is the highest except for that of oxygen after coating. SEM and EDS results show that particles are coated with a thin shell of alumina.     

Preparation and Research of Butylene Fipronil Microencapsulation by Layer-by-Layer Polyelectrolyte Self-Assembly

This paper introduced the preparation of butylene fipronil-loaded microcapsules with oppositely charged chitosan and sodium lignosulfonate as shell materials. It summed up the performance, preparation methods of microcapsules and sketched the application status of layer-by-layer self-assembly. The whole progress of the preparation was controlled by measuring the change of the Zeta potential and the morphology of microcapsules was characterized by microscope and SEM. Entrapment efficiency and slow release performance of the microcapsule were determined as measurement index. The results of experiment showed that the surface of the microcapsules was rougher than the butylene fipronil particles. With the increasing layer number of assembly, the entrapment efficiency reduced while the slow release performance increased. After encapsulation, the photodegradation rate of butylene fipronil under the UV decreased obviously. Results showed that the condition of preparation was the best when NaCl with the concentration of 0.5 mol/L and PH of 5.0.