Adsorption on Ligand-Tethered Nanoparticles

We use coarse-grained molecular dynamics simulations to study adsorption on ligand-tethered particles. Nanoparticles with attached flexible and stiff ligands are considered. We discuss how the excess adsorption isotherm, the thickness of the polymer corona, and its morphology depend on the number of ligands, their length, the size of the core, and the interaction parameters. We investigate the adsorption-induced structural transitions of polymer coatings. The behavior of systems involving curved and flat “brushes” is compared.     

ZH-01吸附树脂对苯甲酸的吸附性能研究

比较了超高交联吸附树脂ZH-01与大孔吸附树脂AmberliteXAD-4对苯甲酸的静态吸附和动态吸附行为,并探讨了温度和起始浓度对平衡时间和吸附速率的影响.从静态平衡吸附行为及其热力学性质讨论吸附机理,动态吸附进一步验证聚苯乙烯超高交联吸附树脂对苯甲酸的吸附能力比AmberliteXAD-4强.结果表明:在288～3...     

间硝基酚在复合功能树脂上的吸附热力学及动力学研究

选用NDA-88、NDA-99、NDA-150、XAD-4几种吸附树脂对间硝基酚的静态吸附行为进行了研究,结果表明:间硝基酚在NDA-88、NDA-99复合功能树脂上的吸附效果较好。研究了NDA-88树脂对水溶液中间硝基酚的静态吸附等温线,并计算了吸附热力学函数,吸附行为符合Freundlich吸附等温方程,吸附量随温度升高而降低,表明为物理吸附。动力学研究结果表明:吸附速率随温度升高而增大。     

改性TiO2光催化降解水体中菲的研究

采用水热法制备粉末状N-Cd共掺杂TiO2催化剂,研究了催化剂对水体中菲的光催化降解反应,讨论了菲初始浓度、催化剂的投加量、H2O2的浓度、异丙醇以及呋喃甲醇对菲光降解反应的影响。结果表明:菲的光催化降解符合一级反应动力学,水体中菲初始浓度越高,其光降解率越低;催化剂和H2O2在一定范围内随投入量的增加,菲的光催化降解速率也增加,但当投入量较多时又降低了降解速率;异丙醇以及呋喃甲醇的加入可以推断出菲的光催化降解过程.OH是的主要活性物种,而1O2的作用较小。     

Predicting the Solubility of Solid Phenanthrene: A Combined Molecular Simulation and Group Contribution Approach

A simple correction to the infinite dilution activity coefficient computed via molecular simulation for a nonelectrolyte solid solute in solution is proposed. The methodology adopts the concept that the activity coefficient may be fundamentally interpreted as a product of a residual and combinatorial term. The residual contribution is assumed to be insensitive to concentration, and the combinatorial term is modeled using the athermal Flory–Huggins theory. The proposed method uses only properties for the solute computed at infinite dilution to estimate solution‐phase properties at finite concentrations. Properties of the pure solid solute are estimated using the group contribution method of Gani and coworkers, allowing for efficient blind solubility predictions to be made. The method is applied to predict the solubility of solid phenanthrene in 17 different solvents. For all cases, the combinatorial correction lowers the predicted solubility relative to the infinite dilution approximation, and in general, improves agreement with experiment. © 2013 American Institute of Chemical Engineers AIChE J, 59: 2647–2661, 2013     

大孔树脂对甘油的静态吸附及其热力学研究

研究了8种大孔树脂对甘油的静态吸附行为,根据吸附等温线研究了吸附热力学性质,在303~323 K和研究的浓度范围内,树脂HPD500对甘油的吸附平衡数据符合Freundlich吸附等温方程。实验结果表明,较大的比表面积和带有一定极性的树脂有利于吸附,吸附过程为放热的物理吸附,降低温度有利于吸附。并计算了甘油在大孔树脂HPD500上的吸附焓变、吉布斯自由能变、吸附熵变,并对吸附行为做了合理的解释。     

D392树脂对灵芝多糖色素吸附行为研究

在不同温度,不同树脂用量下进行吸附动力学实验,结果表明,D392阴离子交换树脂对色素的吸附等温线符合Freundlich模型＞符合Langmuir模型,它对色素的吸附可能是多分子层的,表现为吸热的化学吸附过程.此外,静态吸附速率曲线符合Lagergern一级速率方程,吸附速率受颗粒内扩散和膜扩散的共同控制.     

微塑料对水体中重金属吸附机理的研究

污染物中微塑料是一种新型的、分布十分广泛的颗粒物。对于微塑料已经有一部分学者研究确定其可以吸附污染物,但是对于微塑料在重金属方面的吸附作用相关研究尚少。通过从动力学以及热力学对聚苯乙烯吸附性进行分析:其吸附与二级动力学模型相符和Langumuir为单层吸附,吸附特性为化学吸附,温度变化会对反映造成正向影响。     

分子量及其分布对聚羧酸减水剂吸附行为的影响

从分子量及其分布角度研究聚羧酸系减水剂在水泥颗粒表面的吸附行为,分析了聚羧酸减水剂的吸附行为对其分散性、保坍性的影响.结果表明:平均分子量较高的减水剂在水泥表面的吸附量较高,减水剂分子中的高分子量部分优先吸附在水泥颗粒表面;对于同一减水剂,随其在水泥表面的吸附量增加,浆体的流动度增加,两者之间呈正相关性;而对于不同减水...     

端羟基超支化聚合物对水体中铁、铝离子吸附去除及热力学行为研究

采用“准一步法”,制备端羟基超支化聚合物（HPAE）,研究了HPAE在水溶液中对铁、铝离子的吸附去除,探讨了其吸附过程的热力学：在293-313K条件下,Langmuir等温方程呈现较好的拟合,不同温度下的△H〉0、△G〈0、△S〉0,表明该吸附反应是吸热、自发的、熵增的过程。     

分子筛吸附甲基丙烯酸甲酯中微量水分的研究

研究了3A，4A，5A和13X4种型号分子筛对甲基丙烯酸甲酯中微量水分的静态吸附的动力学性能，做出了4种型号分子筛的吸附动力学曲线；对其结果进行了分析讨论。并进一步研究了13X型分子筛的吸附温度和吸附剂用量对其饱和吸附量的影响。结果表明，13X型分子筛的吸附效果优于3A，4A和5A型分子筛；其在25℃时吸附效果最好，饱和吸附量最大，吸附速率也最快，分子筛的最佳用量为0．4g／mL。FTIR证明13X分子筛同时还吸附了一定量的对苯二酚。     

聚锑酸离子交换剂对锶的吸附行为研究

研究了聚锑酸离子交换剂吸附0.01 mol/L HNO_3溶液中锶的热力学特征,通过吸附动力学实验,初步探讨了温度对吸附过程的影响.结果表明,聚锑酸对0.01mol/L HNO_3溶液中锶的吸附符合Freundlich 经验公式,表现为吸热的化学吸附过程.根据毛细孔扩散模型,由平衡数据和动力学曲线计算了锶在聚锑酸离子交换剂颗粒内液相有效扩散系数为8.18×10~(-9)cm~2/s(20℃)和1.33×10~(-8)cm~2/s(30℃).     

Urinary and Faecal Excretion of Phenanthrene and Phenanthrols by Rats Following Oral,Intraperitoneal, or Intrapulmonary Application

Excretion of phenanthrene and its metabolites, 1–; 2–; 3–; 4– and 9–OH–phenanthrene after alkaline and acidic saponification of urine and faeces, has been studied in rats following oral, intraperitoneal and intrapulmonary application of phenanthrene. GC and GC/MS methods have been used as analytical techniques. In all cases 1,2-oxidation of phenanthrene was found to be the predominant pathway. Total excretion of 11–18% of the phenanthrene administered by the above routes was observed indicating the presence of water-soluble metabolites other than sulfates and glucuronides. Phenanthrene apparently is suitable for biologically monitoring polycyclic aromatic hydrocarbons. The reasons are:

a) the large amounts of phenanthrene and its metabolites excreted in the urine within a period of 3 days following intrapulmonary (1.3%), intraperitoneal (2.9%), or oral (4.1%) administration of phenanthrene, respectively;

b) varied metabolites are formed which can reflect qualitatively the regiospecific monooxygenase activities of the organism and;

c) the high concentration of phenanthrene in the environment.     

Alpha-Cypermethrin Pesticide Adsorption on Carbon Aerogel and Xerogel

Carbon aerogel (CA) and xerogel (CX) are proposed for pesticide adsorption as new carbon adsorbent materials. These materials are prepared by polycondensation of resorcinol and formaldehyde in Na₂CO₃ catalysis, followed by a drying step, in CO₂ supercritical or normal conditions to obtain organic aerogel or xerogel, and a pyrolytic step to obtain CA or CX. Adsorption experiments were carried out in batch conditions under magnetic stirring. Adsorbent quantity and grain size, pH, and temperature, and alpha-cypermethrin concentration influence on the adsorption efficiency were considered. The optimum parameters were established to be as follows: 0.01 g adsorbent, d < 0.025 mm, and 318 K. In all cases, CA proved to be more efficient than CX for alpha-cypermethrin removal from water samples. Equilibrium (Langmuir and Freundlich isotherms), kinetics (pseudo-first- and pseudo-second-order, intra-particle diffusion, and liquid film diffusion models) and thermodynamics of the considered adsorption process were discussed in detail. Equilibrium was best described by the Langmuir isotherm, while the kinetic of the process was best described by the pseudo-second-order model. Thermodynamic parameters showed that alpha-cypermethrin adsorption is an endothermic process.     

沙质滩涂颗粒物对磷酸盐的吸附过程研究

以沙质滩涂颗粒物对磷酸盐的吸附过程为对象,通过拟一级和拟二级方程进行吸附动力学研究,采用Langmuir和Freundlich方程描述平衡吸附等温线,并计算得到吸附热力学参数。结果表明:拟二级动力学模型能够较好拟合吸附过程,Langmuir模型能更好的描述吸附等温线,吸附是焓推动作用、自发且放热的过程。     

阴离子β-环糊精/Fe3O4磁性微球对Cu2+的吸附

通过对b-环糊精（b-CD）改性制备了阴离子b-环糊精/Fe₃O₄磁性微球（b-CDM）,并研究了b-CDM对Cu²⁺吸附的热力学、动力学及循环使用性能,借助数学拟合的方法得到了吸附热力学和动力学参数,探讨其吸附机理。研究表明,b-CDM对Cu²⁺的吸附是一个自发的放热过程,Langmuir与Freundlich等温吸附模型均适用于b-CDM对Cu²⁺的吸附研究,b-CDM对Cu²⁺的吸附经历颗粒外部扩散-孔隙扩散-吸附反应3个阶段,该吸附过程既存在物理吸附,又有化学吸附,在吸附温度298、308、318 K下得到的吸附速率常数分别为0.0906、0.1161、0.1674 g·mmol^-1·min^-1,吸附表观活化能为24.12 kJ·mol^-1,且随着介质中Cu²⁺平衡吸附量的增大,b-CDM对Cu²⁺的吸附驱动力由焓变转变为熵变。b-CDM重复利用8次后,对Cu²⁺的除去率由首次使用时的95.20%下降至88.21%。     

球粘土的制备及其吸附亚甲基蓝溶液的研究

以原矿粘土为原料,采用湿选工艺法制备了球粘土粉体,并通过X-射线荧光光谱仪(XRF)、扫描电镜(SEM)和比表面积及孔径分析仅等技术对样品的组成和结构进行表征.考察了球粘土作为吸附剂,在不同投加量下吸附亚甲基蓝(MB)溶液的吸附性能,结果表明,球粘土吸附剂对MB的吸附过程符合准二级吸附动力学模型和Langmuir吸附等温式.     

铝粉氧化对端羟基聚丁二烯界面吸附影响的分子模拟

为研究铝粉氧化对丁羟推进剂黏合剂界面吸附的影响,采用分子动力学方法和COMPASS力场,分别对端羟基聚丁二烯(HTPB)在Al和Al_2O_3不同晶面吸附进行了模拟计算,求得界面吸附能和静态力学性能(弹性系数、模量和泊松比),结合吸附能和径向分布函数揭示了界面相互作用本质.模拟结果表明,采用HTPB包覆后的Al和Al_2O_3刚度降低,弹性增强;HTPB在Al_2O_3的晶面吸附能远高于在Al晶面,HTPB与Al晶面只存在范德华力作用,而在Al_2O_3的界面吸附主要由静电作用引起.     

粉煤灰负载壳聚糖对磷吸附的热力学研究

以粉煤灰负载壳聚糖作为吸附剂,在静态吸附条件下,研究了其对磷的吸附行为,并对吸附过程的热力学进行了分析。结果表明,吸附平衡数据都能够较好地符合Langmuir和Freundlich吸附等温方程,但Langmuir方程能够更好地描述吸附等温线。在20～35℃范围内,磷在粉煤灰负载壳聚糖上的吸附是一个吸热过程,反应的吉布斯自由能变小,同时伴随着熵值的增加,吸附焓变为44.36 kJ/mol。