Adsorption of large macromolecules on fine colloidal particles

A simple model of adsorption of large macromolecules on ultra-fine colloidal particles is presented. The basic assumption of the model is that the number of particles attached to a single molecule is a random quantity. Both the reversible and irreversible polymerparticle binding is considered. Also, effects of the non-ideal mixing of polymer solution with suspension and of the polymer/particle size ratio on the shape of the adsorption isotherm are examined. The predictions of the model are confronted with experimental results of the study on the adsorption of very high molecular weight polyacrylamide on fine AgI colloidal particles.     

扩张床吸附技术

扩张床是流化床的一种特例。它具有流化床的特点,能处理含悬浮颗粒的液体。又具有固定床的优点,流动成活塞流;返混程度低,分离效率高。作为蛋白质的初步分离方法,它能取代固液分离、浓缩和初步纯化等三步操作。具有提高收率、降低投资费用、缩短操作时间等优点,成为生物工程下游过程的研究热点。本文综述了近年来扩张床吸附技术的发展。包括：1、原理：床层的分层稳定性、吸附剂和吸附柱;2、操作：吸附、洗涤、洗脱和再生4个步骤;3、流动动力学特性：床层扩展特征和停留时间分布;4．在蛋白质纯化中的应用。     

Extraction of Pb(II), Cd(II), and Hg(II) from aqueous solution by nitrogen and thiol functionality grafted to silica gel measured by calorimetry

The reaction of ethylene sulfide with 3-aminopropyltrimethoxysilane gave a new silylating agent, which was anchored onto a silica surface via the sol–gel procedure. This surface displayed a chelating moiety containing nitrogen and two sulfur basic centers potentially capable of extracting cations from aqueous solutions. The process of metal extraction was followed by a batch method, and fitted to a modified Langmuir equation. The maximum adsorption capacities found were: 2.06 ± 0.01, 3.72 ± 0.02, and 5.14 ± 0.02 mmol g⁻¹ for Pb(II), Cd(II), and Hg(II), respectively. The enthalpies of bending are: −1.16 ± 0.04, −3.60 ± 0.10, and −8.94 ± 0.03 kJ mol⁻¹ for Cd(II), Pb(II), and Hg(II), respectively. The Gibbs free energies of binding agree with the spontaneity of the proposed reactions between cations and basic centers.     

Eco-dyeing and functional finishing of wool fabric based on Portulaca oleracea L. as colorant and Musa basjoo as natural mordant

Biomass energy is the most acknowledged renewable resource due to its universality, richness, and renewability. This study utilized a Portulaca oleracea L. plant as a natural colorant for wool fabric dyeing with a high color yield at optimum extraction and dyeing conditions. To evaluate the dyeing mechanism and feasibility of the extracted dyes, we analyzed and characterized the molecular structure and nano-level particle size. The dyeing kinetics and the morphology of dyed fabrics were integratedly explored; the adsorption process of wool fabric on natural colorant molecules was increasingly in line with the pseudo-second-order kinetic adsorption model. Further, the dyeing effects of wool fabrics were compared to that of Musa basjoo mordant and synthetic dyes to confirm the superior color depth (K/S value 23.53), biological function as anti-ultraviolet (UPF value 253.47), and anti-bacterial activity (antibacterial rate of Staphylococcus aureus/Escherichia coli was 71.3%/37%). Our findings provide a feasible scheme for providing deep color and biological activity to wool fabrics. This has broad application prospects in the field of eco-friendly textile materials.     

Adsorption of crude oil on anhydrous and hydrophobized vermiculite

This publication reports the adsorption of crude oil on vermiculite samples, expanded and hydrophobized with carnauba (Copernícia Cerífera) wax. The adsorption studies were performed by using columns filled with the vermiculite matrices and by dispersion of the vermiculite samples in an oil-water (50 ppm of oil) emulsion. The hydrate vermiculite exhibits a very low adsorption capacity against crude oil. On the other hand, anhydrous (expanded) and hydrophobized matrices show a high adsorption capacity. The 10% hydrophobized matrix show a 50% increased adsorption capacity, in comparison with the expanded one. For adsorption performed in the water-oil emulsion, saturation of the solid hydrophobized matrix is achieved after 60 min. The hydrophobized samples exhibit adsorption factors in the 0.7-1.0 range.     

Adsorption of oligooxypropylenated amines at the aqueous solution—air interface: Homologous series of piperidine and morpholine derivatives

The surface tension isotherms for pure oligooxypropylenated piperidine and morpholine at the aqueous solution—air interface were determined and interpreted. The surface excess concentration, Γ, the surface area per molecule, A, and the standard free energy of adsorption, ΔG°, were calculated according to a new empirical adsorption equation. The standard free energy contribution for the oxypropylene group (PO) in morpholine derivatives,ΔG° (PO) = −3.34 kJ mol⁻¹, is substantially lower than that for the PO group located in the piperidine derivatives, i.e. ΔG° (PO)= −3.12 kJ mol⁻¹.     

Multilayer adsorption with variable thickness at solid-liquid interfaces

 The multilayer adsorption on the solid/liquid interface in binary mixtures was studied by adsorption space filling with constant and variable layer thickness. Adsorption from benzene/n-heptane mixtures was examined on hydrophilic and hydro-phobic surfaces. The free enthalpy of adsorption, Δ₂₁ G=f (x ₁), was calculated from the adsorption excess isotherm by integration of the Gibbs equation. Supposing that the free enthalpy is mainly due to adsorption in the first layer, the composition of this layer can be calculated from the Δ₂₁ G=f (x ₁) function. It was established that the adsorption layer thickness in benzene/heptane mixtures increases significantly with increasing benzene content. This statement was supported by X-ray diffraction on hydrophobic clay minerals. Received: 2 April 1997 Accepted: 10 June 1997     

氧原子在Pt低指数面上的吸附和振动

应用原子和表面簇合物相互作用的5参数Morse势方法（简称5-MP）对O-Pt低指数表面体系进行了研究,并获得了全部临界点特性.计算结果表明,氧原子在Pt(100)面上只存在四重吸附态.在缺行重构的(110)面上,氧原子仍吸附于三重位,随着覆盖度的增加还会嵌切吸附于长桥位;通过分析三重态振动指纹性质的遗传和遗变,确认实验观察到的59.49和40.90 meV损失谱分别为氧原子在三重位和长桥位吸附态的表面垂直振动.     

活性炭的Zeta电位对其吸附达旦黄规律的影响

The effect of pH on the adsorption of anionic dye Titan yellow on the activated carbon from aqueous solution has been studied. It has been found that the Zeta potential of the activated carbon has a great effect on adsorption capacity of Titan yellow. The kinetic and the thermodynamic parameters of adsorption as a function of pH has been evaluated. The mechanism for adsorption of anionic dye Titan yellow on the activated carbon has also been discussed.     

Gas-Chromatographic Studies of the Interaction between Water and Methanol Molecules and the Surface of Carbon Materials

The gas-chromatographic method is used to study the interaction of water and methanol molecules with active hydrophilic centres existing at the surface of thermally exfoliated graphite and graphitized thermal carbon black. The concentration of carboxyl and phenol hydroxyl groups at the surface of these sorbents is determined, and heats of adsorption of the studied molecules are shown to be and 28−25 kJ/mol, respectively. It is also shown that adsorption of water at the hydrophilic centres at lowest relative pressure values takes place with formation of clusters consisting of n = 2 water molecules.