Aqueous solution adsorption

Adsorption kinetic and adsorption isotherm of pesticide metobromuron at the high area ACC were investigated in relation to water treatment. The ACC used in this study seems to be quite effective in adsorption of metobromnron from aqueous solutions. Adsorption of that pesticide was found to follow second-order kinetic model and the adsorption isotherm is well represented by Frenndlich model. 

Waszczuk etal. [173] have performed radiometric and voltammetric studies of benzoic acid adsorption on a pc-Ag electrode in contact with 0.1 M HCIO4 solution. The electrodes were obtained by electroplating Ag black onto a vacuum-deposited silver substrate. Benzoic acid appeared to be surface active in the entire range of potentials available at Ag in aqueous solutions. Adsorption of benzoic acid increased as the potential became more positive and this surface process was... 

Adsorption isotherm An equation or distribution on a graph representing the concentration of an adsorbed chemical species as a function of its concentration in an associated aqueous solution. Adsorption isotherms are measured in systems that are at equilibrium and where temperature, pressure, and possibly other conditions are held constant. Isotherms are often described with linear, Freundlich, or Langmuir equations. 

The present stu(fy shows that the coir pith carbon is an effective adsorbent for the removal of methylene blue from aqueous solution. Adsorption follows Langmuir isotherm. Kinetic data follow second order kinetic model. The adsorption capacity was found to be 5.87mg/g. The results would be useful for the fabrication and designing of wastewater treatment plants for the removal of dye. As the raw material, coir pith is discarded as waste in coir industries, the treatment method using coir pith carbon is expected to be economical. 

Natan M. J., Thackeray J. W. and Wrighton M. S. (1986), Interaction of thiols with n-type cadmium sulfide and n-type cadmium selenide in aqueous solutions adsorption of thiolate anion and efficient photoelectrochemical oxidation to disulfides , J. Phys. Chem. 90, 4089-4098. 

All animal fibrous proteins tested accumulated gold-cyanide ion from aqueous solution. Adsorption was highest at pH 2 accumulations were up to 9.8% of the DW for wool, 8.6% for eggshell membrane, 7.1% for chicken feathers, and <3.9% for other materials. In the case of eggshell membrane, adsorbed gold was desorbed with 0.1 M NaOH and the material can be used repeatedly. Eggshell membrane could remove gold-cyanide ion at concentrations near 1.0p,g/L. 

M. J. Natan, J. W. Thackeray, M. S. Wrigh-ton. Interaction of Thiols with n-Type Cadmium Sulfide and n-Type Cadmimn Selenide in Aqueous Solutions Adsorption of Thiolate Anion and Efficient Photoelectrochemical Oxidation to Disulfides, . Phys. Chem. 1986, 90,4089-4098. 

This book presents coverage of the dynamics, preparation, application and physico-chemical properties of polymer solutions and colloids. It also covers the adsorption characteristics at and the adhesion properties of polymer surfaces. It is written by 23 contemporary experts within their field. Main headings include Structural ordering in polymer solutions Influence of surface Structure on polymer surface behaviour Advances in preparations and appUcations of polymeric microspheres Latex particle heterogeneity origins, detection, and consequences Electrokinetic behaviour of polymer colloids Interaction of polymer latices with other inorganic colloids Thermodynamic and kinetic aspects of bridging flocculation Metal complexation in polymer systems Adsorption of quaternary ammonium compounds art polymer surfaces Adsorption onto polytetrafluoroethylene from aqueous solutions Adsorption from polymer mixtures at the interface with solids Polymer adsorption at oxide surface Preparation of oxide-coated cellulose fibre The evaluation of acid-base properties of polymer surfaces by wettability measurements. Each chapter is well referenced. 

Saleem, M., et al.. Adsorption characteristics of organic dyes on alumina powder from aqueous solutions, Adsorpt, Sci, Technol., 11(2), 95-104 (1994). 

Another consequence of surface activity is the fact that at low concentrations in aqueous solution, adsorption losses on glassware can be very substantial. At concentrations of lO"" mol/l and lower, particularly... 

An often-quoted mechanism for mixtures of hydrophobic oils and particles is that due to Kulkarni et al. [53, 207]. These authors claimed that the oil spreads over the air-water surface exposing the particles to the aqueous solution. Adsorption of surfactant onto the surface of the particles is then supposed to occur, rendering the particle hydrophilic so that particles are progressively extracted from the oil into the aqueous phase. Rapid local depletion of surfactant in the aqueous film is then, in turn, supposed to produce a surface stress that renders the foam film unstable so that rupture occurs. 

Figure-16 Theoretical plot of cxjntact angle 0 and ji, modification through surfactant aqueous solution adsorption on polar surfaces, for the case of surfactant ions of charge opposite to that of the surface. (From Ref. 37.)...

Cansado IPP, Galacho C, Nunes AS, Carrott MLR, Carrott PJM (2010) Adsorption properties of activated carbons prepared from recycled PET in the removal of organic pollutants from aqueous solutions. Adsorpt Sci Technol 28(8-9) 807-821... 

We have considered the surface tension behavior of several types of systems, and now it is desirable to discuss in slightly more detail the very important case of aqueous mixtures. If the surface tensions of the separate pure liquids differ appreciably, as in the case of alcohol-water mixtures, then the addition of small amounts of the second component generally results in a marked decrease in surface tension from that of the pure water. The case of ethanol and water is shown in Fig. III-9c. As seen in Section III-5, this effect may be accounted for in terms of selective adsorption of the alcohol at the interface. Dilute aqueous solutions of organic substances can be treated with a semiempirical equation attributed to von Szyszkowski [89,90]... 

STM has been used to study adsorption on surfaces as it relates to corrosion phenomena [6, 7]. Sulfiir is a well known corrosion agent and is often found in air (SO2, FI2S) and in aqueous solution as dissolved anions ( HSO7) or dissolved gas (FI2S). By studying the interaction of sulfur with surfaces, insights can be gained into... 

Biggs S, Mulvaney P, Zukoski C F and Grieser F 1994 Study of anion adsorption at the gold-aqueous solution interface by atomic force microscopy J. Am. Chem. Soc. 116 9150... 

Cationic monomers are used to enhance adsorption on waste soHds and faciHtate flocculation (31). One of the first used in water treatment processes (10) is obtained by the cyclization of dimethyldiallylammonium chloride in 60—70 wt % aqueous solution (43) (see Water). Another cationic water-soluble polymer, poly(dimethylarnine-fi9-epichlorohydrin) (11), prepared by the step-growth... 

Hydrophilic and Hydrophobic Surfaces. Water is a small, highly polar molecular and it is therefore strongly adsorbed on a polar surface as a result of the large contribution from the electrostatic forces. Polar adsorbents such as most zeoHtes, siUca gel, or activated alumina therefore adsorb water more strongly than they adsorb organic species, and, as a result, such adsorbents are commonly called hydrophilic. In contrast, on a nonpolar surface where there is no electrostatic interaction water is held only very weakly and is easily displaced by organics. Such adsorbents, which are the only practical choice for adsorption of organics from aqueous solutions, are termed hydrophobic. 

The most common hydrophobic adsorbents are activated carbon and siUcahte. The latter is of particular interest since the affinity for water is very low indeed the heat of adsorption is even smaller than the latent heat of vaporization (3). It seems clear that the channel stmcture of siUcahte must inhibit the hydrogen bonding between occluded water molecules, thus enhancing the hydrophobic nature of the adsorbent. As a result, siUcahte has some potential as a selective adsorbent for the separation of alcohols and other organics from dilute aqueous solutions (4). 

Fructose—Dextrose Separation. Emctose—dextrose separation is an example of the appHcation of adsorption to nonhydrocarbon systems. An aqueous solution of the isomeric monosaccharide sugars, C H 2Dg, fmctose and dextrose (glucose), accompanied by minor quantities of polysaccharides, is produced commercially under the designation of "high" fmctose com symp by the enzymatic conversion of cornstarch. Because fmctose has about double the sweetness index of dextrose, the separation of fmctose from this mixture and the recycling of dextrose for further enzymatic conversion to fmctose is of commercial interest (see Sugar Sweeteners). 

SPME has been utilized for deterrnination of pollutants in aqueous solution by the adsorption of analyte onto stationary-phase coated fused-siUca fibers, followed by thermal desorption in the injection system of a capillary gas chromatograph (34). EuU automation can be achieved using an autosampler. Eiber coated with 7- and 100-p.m film thickness and a nitrogen—phosphoms flame thermionic detector were used to evaluate the adsorption and desorption of four j -triazines. The gc peaks resulting from desorption of fibers were shown to be comparable to those obtained using manual injection. 

Another standard industry method for surface area is based on the adsorption of cetyltrimethylammonium bromide (CTAB) from aqueous solution. This is ASTM method D3765-85 (2). This method measures the specific surface area of carbon black exclusive of the internal area contained in micropores that are too small to admit the large CTAB molecules. Eor mbber-grade nonporous blacks the CTAB method gives excellent agreement with nitrogen surface areas. 

The test-techniques of hydrargyrum (II) and zincum (II) ions determination in aqueous solutions with the use of congo red and brilliant green adsorbed on polyurethane foam accordingly are desighed on the basis of received data for organic reagents adsorption on it s. 

Starek, J., Zukal, A. and Rathousky, J., Comparison of the adsorption of humic acids from aqueous solutions on active carbon and activated charcoal cloths. Carbon, 1994, 32(2), 207 211. 

Brasquet, C., Subrenat, E. and Le Cloirec, P., Selective adsorption on fibrous activated carbon of organics from aqueous solution Correlation between adsorption and moleeular strueture. Water Sci. Technol., 1997, 35(7), 251 259. 

The following are some of the typical industrial applications for liquid-phase carbon adsorption. Generally liquid-phase carbon adsorbents are used to decolorize or purify liquids, solutions, and liquefiable materials such as waxes. Specific industrial applications include the decolorization of sugar syrups the removal of sulfurous, phenolic, and hydrocarbon contaminants from wastewater the purification of various aqueous solutions of acids, alkalies, amines, glycols, salts, gelatin, vinegar, fruit juices, pectin, glycerol, and alcoholic spirits dechlorination the removal of... 

Two other methods worth discussing are wet air oxidation and regeneration by steam. Wet oxidation may be defined as a process in which a substance in aqueous solution or suspension is oxidized by oxygen transferred from a gas phase in intimate contact with the liquid phase. The substance may be organic or inorganic in nature. In this broad definition, both the well known oxidation of ferrous salts to ferric salts by exposure of a solution to air at room temperature and the adsorption of oxygen by alkaline pyrogallol in the classical Orsat gas analysis would be considered wet oxidations. 

Carbon adsorption Aqueous solutions typical concentration < 1 % SS < 50 ppm Adsorbate on carbon usually regenerated thermally or chemically... 

---