Adsorption resins

Chemical precipitation Chemical oxidation/re duction Air and/or steam stripping Activated carbon adsorption Resin adsorption Ion exchange Ultrafiltra-tion and/or reverse osmosis Flo atation / ph ase separation... 

The main characteristic properties of asbestos fibers that can be exploited in industrial appHcations (8) are their thermal, electrical, and sound insulation nonflammabiUty matrix reinforcement (cement, plastic, and resins) adsorption capacity (filtration, Hquid sterilization) wear and friction properties (friction materials) and chemical inertia (except in acids). These properties have led to several main classes of industrial products or appHcations... 

Resin adsorption Aqueous solutions typical concentration < 8 % SS < 50 ppm no oxidants Adsorbate on resin always chemically regenerated... 

Centrifugation Integrated adsorption Resin adsorption Ozonation Chemical oxidation Aerobic decomposition Thermal emulsion breaking... 

In addition to these three treatment options, several alternative technologies are applicable to the treatment of oily wastewater. These include coalescing, flotation, centrifugation, integrated adsorption, resin adsorption, ozonation, chemical oxidation, aerobic decomposition, and thermal emulsion breaking.18-20... 

Several methods are available to remove gasoline constituents from water, such as air stripping, biorestoration, activated carbon adsorption, reverse osmosis, ozonation, oxidation, resin adsorption, oxidation with hydrogen peroxide, ultraviolet irradiation, flotation, and land treatment. 

Suspension Model of Interaction of Asphaltene and Oil This model is based upon the concept that asphaltenes exist as particles suspended in oil. Their suspension is assisted by resins (heavy and mostly aromatic molecules) adsorbed to the surface of asphaltenes and keeping them afloat because of the repulsive forces between resin molecules in the solution and the adsorbed resins on the asphaltene surface (see Figure 4). Stability of such a suspension is considered to be a function of the concentration of resins in solution, the fraction of asphaltene surface sites occupied by resin molecules, and the equilibrium conditions between the resins in solution and on the asphaltene surface. Utilization of this model requires the following (12) 1. Resin chemical potential calculation based on the statistical mechanical theory of polymer solutions. 2. Studies regarding resin adsorption on asphaltene particle surface and... 

Molybdenum Anion exchange resin adsorption (Biorad Agl-X8), elution Graphite furnace AAS <10p,g/l... 

There are six primary in-plant control methods for removal of priority pollutants and pesticides in pesticide manufacturing plants. These methods include steam-stripping, activated carbon adsorption, chemical oxidation, resin adsorption, hydrolysis, and heavy metals separation. Steam-stripping can remove volatile organic compounds (VOCs) activated carbon can remove semi volatile organic compounds and many pesticides and resin adsorption, chemical oxidation, and hydrolysis can treat selected pesticides [7]. Heavy metals separation can reduce toxicity to downstream biological treatment systems. Discussion of each of these methods follows. 

The USEPA surveys identified four resin adsorption systems in the pesticide industry [7]. Phenol, pesticide, and diene compounds are all effectively removed by these systems. At least one system realized a significant product recovery via regeneration and distillation. The design surface loading rates vary from 1.0 to 4.0 gpm/ft with empty bed contact times of 7.5 to 30 minutes. 

In the pesticide industry, neutralization is provided prior to GAC and resin adsorption, pesticide hydrolysis, and biological treatment. The neutralization basin is sized on the basis of an average retention time of 6 minutes and 70 horsepower per million gallons for mixing requirements [7]. 

Solutions must be concentrated or the constituents must be isolated before trace amounts of the various organics present as complex mixtures in environmental water samples can be chemically analyzed or tested for toxicity. A major objective is to concentrate or isolate the constituents with minimum chemical alteration to optimize the generation of useful information. Factors to be considered in selecting a concentration technique include the nature of the constituents (e.g., volatile, nonvolatile), volume of the sample, and analytical or test system to be used. The principal methods currently in use involve (1) concentration processes to remove water from the samples (e.g., lyophilization, vacuum distillation, and passage through a membrane) and (2) isolation processes to separate the chemicals from the water (e.g., solvent extraction and resin adsorption). Selected methods are reviewed and evaluated. 

Analysis of aqueous solutions of the polar compounds (DCP, TCP, CA, and DCB) at concentrations of 1-10 ppm was easily accomplished by direct aqueous injection liquid chromatography. The Hamilton PRP-1 reverse-phase column gave a better resolution of these compounds than the conventional reverse-phase columns. Acetonitrile/water mixtures have been found to be as effective as the buffered mobile phases recommended by the manufacturer (28). Analyses of the nonpolar compounds (BHC and DEHP) at concentrations of 25-100 ppb were achieved by XAD resin adsorption-desorption, concentration, and GC techniques. 

In accordance with conversations with the USEPA, it was necessary to repeat the lead study at pH 6-7 to evaluate the resin under conditions similar to those used for resin adsorption (pH 7). Previous experiments... 

The concentrations of the solutions were selected to give a realistic level of total organic carbon (i.e., approximately 3 mg/L). The solutions were adjusted to pH 6.2 with phosphate buffer. They were then chlorinated for 24 h at room temperature in the dark with sodium hypochlorite to a residual of <1 mg/L of total available chlorine. The chlorine demand of the solutions was determined in preliminary experiments prior to chlorination of larger samples for concentration by XAD-2 resin adsorption and mutagenicity testing. Corresponding extracts of unchlorinated solutions of the model compounds were also prepared and tested. 

Amer, F., Bouldin, D. R., and Black, C. A. (1955). Characterization of soil phosphorus by anion exchange resin adsorption and 32P equilibration. Plant Soil 6, 391-394. 

Synthetic organic chemicals have been isolated by either resin adsorption or direct methylene chloride liquid—liquid extraction. Analyses for 48 distinct chemical entities in river water from a river located in North Carolina s Piedmont area were carried out. The river was sampled at three locations several times during a 13-month period (41). Most frequendy included among the 48 chemicals found were atrazine, methyl atraton (triazine herbicides), dimethyl dioxane, 1,2,4-trichlorobenzene, tributylphosphate, triethylphosphate, trimethylindolinone, and tris(chloropropyl) phosphate. Many of these chemicals are indigenous to industrial and agricultural activities in Piedmont. The concentrations were in the ng/L to mg/L range. 

Needs, E.C., Ford, G.D., Owen, A.J., Tuckley, B., Anderson, M. 1983. A method for the quantitative determination of individual free fatty acids in milk by ion exchange resin adsorption and gas-liquid chromatography. J. Dairy Res. 50, 321-329. 

Resin adsorption. The resin adsorption is a good option for the selective removal of waste. This technique is normally used for the removal of ther-molabile organic solutes from aqueous waste streams. The solute concentration of solution ranges fiwm 1 to 8 percent. Moreover, synthetic cationic and anionic resins may be used to remove a hydrophobic, hydrophihc, or neutral solute, which can also be recovered by chemical methods. These resins are also used with a high concentration of dissolved inorganic salts in the waste stream. Their appUcations include phenol, fat, organics, and color removal from wastewater. They can be apphed for the removal of pesticides, carcinogens, and chlorofluoro compounds. 

P. H. Boening, D. D. Beckmann, V. L. Snoeyink, Activated carbon varsus resin adsorption of Humic Substances, JAWWA, 72, 1, 54-59(1980). 

Table 1. Results of Cation Exchange Resin Adsorption...

Bleomycin was isolated from the culture filtrate of Streptomyces verticillus by ion exchange resin adsorption, alumina and Sephadex column chromatography. Bleomycin thus obtained was a mixture of more than 10 components, which can be separated on a CM-Sephadex column by elution with a linear gradient of ammonium formate5) (see Fig. 1). Later, it was found that they are different from one another in... 

M(II), M(11I), M(IV),... Basification Activated carbon Ion-exchange chromatography (including chelating resins) Polystyrene-supported ligands Precipitation Adsorption to carbon Adsorption to resin Adsorption to resin... 

Leenheer and Huffman (1976) designed a hydrophobic classification of dissolved organic carbon using resin adsorption as a means of fractionation. The procedure is based on adsorption chromatography onto XAD resins. Those organic substances that adsorb onto the resins with pH adjustment (low pH for acids and neutral pH for bases) are termed hydrophobic those organic substances that do not absorb are hydrophilic. Fulvic and humic acids are classified as hydrophobic substances. This classification procedure makes it possible to measure indirectly the amount of humic substances in water. A more detailed explanation of this procedure is presented by Leenheer (1981). 

A persuasive argument for fractionating aquatic humic substances before concentration is the minimization of aggregation resulting from intermolecu-lar interactions discussed in the previous section. The resin-adsorption concentration procedures discussed by Aiken in Chapter 14 of this book also accomplish compound group fractionation at ambient concentrations. Most fractionation procedures can be performed at ambient concentrations if detection of the analyte is sufficiently sensitive or if the fractionating medium concentrates the analyte. However, preconcentration needs to be used if a preparative fractionation is desired where the analyte is not concentrated on the fractionating medium. 

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