Sorption procedures

Harmia,T., Speiser, P, and Kreuter, J. (1986), Optimization of pilocarpine loading onto nanoparticles by sorption procedures, Int. J. Pharm., 33(1-3), 45-54. 

Equilibrium Sorption Procedure. The sorption (binding) of 8-galactosidase by the various modified and unreacted collagen membranes was measured by the method of equilibrium sorption (18, 13). In this procedure, collagen membrane was impregnated with the purified enzyme (8-galactosidase, J2. coli K12) as a function of enzyme bath concentrations. Enzyme solutions containing 0.023 0.012, 0.0074, 0.0047) 0.0031 and 0.0021 pmole/ml of enzyme in phosphate buffer (0.02H) at pH 7-0 were employed as the sorption baths. All sorption studies were carried out at 4°C for a twenty four hour period. Transient state sorption data established that the system had equilibrated within the twenty four hour period. 

The extraction cycles lead to the production of various aqueous and organic waste solutions, mainly from solvent clean-up and washing. Some of the aqueous LLW solutions may be released directly into the environment if their activity is low enough. Others are decontaminated by precipitation, coprecipitation, ion exchange or sorption procedures. The general tendency in handling liquid wastes is to reduce the volume as far as possible and to transform LLW into MLW, as already mentioned. Liquid organic wastes are either incinerated or the radionuclides contained therein are separated by precipitation or other procedures. 

Despite the great potentials of using FI liquid-liquid extraction for achieving analyte preconcentrations for flame AAS. the number of applications are surprisingly few compared to sorption column preconcentration procedures. The performance of some published procedures 114,38,39] are shown in Table 3.2. Despite the additional enhancement effects from the organic solvents, the concentration efficiencies and consumptive indices generally tend to be inferior to those achievable by sorption procedures (cf. Sec. 

Differential solvent vapor sorption procedures to measure % and the activities of solvent in uncross-linked and cross-linked polymers are described in this Section A schematic diagram of the apparatus designed by Yen and Eichinger is reproduced... 

Thermal Transitions A recent study has compared the thermal behavior of 5 form and e form films, obtained by similar solvent sorption procedures starting from a same y form film, by using several different techniques [44]. 

An oxidant-sorption procedure was used by Ojio and Miyata [338] for the fabrication of P(Py)/PVA (Poly(Vinyl Alcohol)) composites. PVA, of M 22,000, was dissolved with FeClj (the oxidant) in water, a film cast from this solution onto a PET film substrate. This oxidant-saturated host-polymer film was then exposed, in a desiccator at low temperature and in a deoxygenated atmosphere, to monomer (pyrrole) and water vapor for 0.5 to 24 h, with the resulting composite films, ca. 2 jam thick, dried in vacuum. Conductivities and transmission values saturated at about 1 h exposure time, to ca. 1 S/cm and 40% ( 550 nm) for a 70 30 w/w ratio PVA/FeClj. Transmission of the film was down to ca. 55% within 0.5 h, (with conductivity ca. 0.1 S/cm) for the same PVA/FeClj ratio. Higher PVA/FeClj ratios (90 10, 95 5) gave not only higher transmissions with minimal conductivity reduction, but also more homogeneous films as evidenced by SEM. 

In the absence of dyes, APA- and AdPA-grafted silica bind La(III) with, respectively, 0.20 and 0.27 mmol/g sorption capacity, resulting in formation of 1 2 (La L) complexes. 50% of introduced cation is bonded at pH=5 (APA), pH=6.1 (AdPA) and complete adsorption occurs at pH=6 (APA), pH=6.5 (AdPA). The grafted support in absence of La adsorbs the chosen dyes at pH<4 due to the electrostatic interaction with the -NH, groups on the surface, present as a result of grafting procedure. The adsorption of dyes at pH>4 is insignificant. 

Theoretical and applied aspects of microwave heating, as well as the advantages of its application are discussed for the individual analytical processes and also for the sample preparation procedures. Special attention is paid to the various preconcentration techniques, in part, sorption and extraction. Improvement of microwave-assisted solution preconcentration is shown on the example of separation of noble metals from matrix components by complexing sorbents. Advantages of microwave-assisted extraction and principles of choice of appropriate solvent are considered for the extraction of organic contaminants from solutions and solid samples by alcohols and room-temperature ionic liquids (RTILs). 

Several selective interactions by MIP membrane systems have been reported. For example, an L-phenylalanine imprinted membrane prepared by in-situ crosslinking polymerization showed different fluxes for various amino acids [44]. Yoshikawa et al. [51] have prepared molecular imprinted membranes from a membrane material which bears a tetrapeptide residue (DIDE resin (7)), using the dry phase inversion procedure. It was found that a membrane which contains an oligopeptide residue from an L-amino acid and is imprinted with an L-amino acid derivative, recognizes the L-isomer in preference to the corresponding D-isomer, and vice versa. Exceptional difference in sorption selectivity between theophylline and caffeine was observed for poly(acrylonitrile-co-acrylic acid) blend membranes prepared by the wet phase inversion technique [53]. 

A procedure for characterizing the rates of the volume change of gels has not been uniformly adopted. Often, the kinetics are simply presented as empirical sorption/desorption curves without quantitative analysis. In other cases, only the time required for a sample of given dimensions to reach a certain percentage of equilibrium is cited. One means of reducing sorption/desorption curves to empirical parameters is to fit the first 60% of the sorption curve to the empirical expression [119,141]... 

Monte Carlo simulations and energy minimization procedures of the non-bonding interactions between rigid molecules and fixed zeolite framework provide a reasonable structural picture of DPP occluded in acidic ZSM-5. Molecular simulations carried out for DPB provide evidence of DPB sorption into the void space of zeolites and the preferred locations lay in straight channels in the vicinity of the intersection with the zigzag channel in interaction with H+ cation (figure 1). 

Perkins [18] carried out radium and radiobarium measurements in seawater by sorption and direct multidimensional gamma-ray spectrometry. The procedure described includes the removal of radium and barium from water samples on sorption beds of barium sulfate impregnated alumina (0.5-1 cm thick) and direct counting of these beds on a multidimensional y-ray spectrometer. The radioisotopes can be removed at Unear flow rates of sample of up to 1 m/min. 

A speciation calculation including one of the sorption models described above, or a combination of two or more sorption models, can be evaluated numerically following a procedure that parallels the technique described in Chapter 4. We begin as before by identifying the nonlinear portion of the problem to form the reduced basis,... 

In order to validate the hypothesis mentioned above, the Ni retention capacity of the Lac Tio waste rock was estimated using a batch sorption test performed on a fresh (C1) and weathered (C4) sample, followed by a 3-step Sequential Extraction Procedure (or SEP). The batch sorption test was done using a 10 mg/L Ni solution with an initial pH of 6, an ionic force adjusted to 0.05 M with NaN03 and with a liquid/solid ratio of 25. Some of the batch sorption results are presented in Figure 3. 

Simonich et al. [ 11 ] compared the concentration of 16 FMs in wastewater influent collected from 12 U.S. treatment plants and five treatment plants from the U.K. and The Netherlands (see Table 4). It is important to characterize FMs in influent because it is a good representation of the relative amounts of FMs being used by consumers and there is minimal opportunity for biodegradation, sorption, and/or volatilization in transit to the wastewater treatment plant. In addition, because the same analytical methods were used by the same laboratory to measure U.S. and European influent in the Simonich et al. [ 11] study, we can directly compare concentrations between the U.S. and Europe without questioning differences in laboratory procedures or analytical methodology. 

Sorption. The sorption properties of aluminum-deficient mordenite are strongly affected by the dealumination procedure used and by the degree of dealumination. Materials prepared by procedures that do not involve high temperature treatments show a relatively high sorption capacity for water (15,70), due to the presence of silanol groups, which are hydrophilic centers. However, aluminum-deficient mordenite zeolites prepared by methods requiring heat treatment show a lower sorption capacity for water due to fewer silanol groups. This was shown by Chen (71), who studied the sorption properties of aluminum-deficient mordenite prepared by the two-step method. 

The surfactant bioconcentration data available in the literature show considerable variability, due mainly to the different compounds, species, environmental characteristics and analytical procedures used to determine the BCF. Physicochemical properties of surfactants, such as molecular structure, molecular weight, partitioning coefficients (Kom Kqc), water solubility and sorption rate constants all influence their BCF [47]. 

Generally, there is no simple and easy theoretical procedure which can provide exact or nearly precise quantitative predictions of what and how much will be adsorbed/desorbed by any solid phase over a period of time [9, 136-139]. Understanding sorption/desorption characteristics of any solid phase materials requires two main laboratory experimental techniques (a) batch equilibrium testing, and (b) continuous solid phase column-leaching testing. These involve... 

Sorption and desorption of contaminants into, onto, or from subsurface soils, bottom sediments, and suspended solids constitute a consideration in the characterization of the nature of both solid phases and contaminants. There is no simple and easy theoretical procedure that provides an exact quantitative prediction of what and how much of what will be sorbed/desorbed by a certain solid phase over a period of time, and to predict the sorption/desorption-time relationship and the fate of contaminants once they are released into the environment. 

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