Polymeric ions sorption

Solvents, UV cut-olf values, 70 Solvents, miscibility, 75 Solvophobic effect, 201,203 Solvophobic inleHlclidHk, IS2, 20i Solvophobic ion chromatography, 242 Solvophobic theory, 141,148,152,155, 158, 202, 203, 226, 228, 246 8omatostedn, 263,290 Sorbents, polymeric, 127 Sorption isottom, 159 Soiption kineties, efbet on column effi-cieney in RPC, 227 Speed of aepantion, optimization [Pg.172]

As mentioned above, many anionic ligands are trace contaminants in water and wastewater streams or bodies. Some metal ions can be anchored onto polymeric ion exchange resins to sorb (and thus remove) ligands. This sorption affinity can be substantially enhanced by appropriately modifying the interfacial chemistry of the ion exchanger, as shown in the following reaction scheme ... 

Kabanov, V.A. Efendiev, A.A. Orujev, D.D. Complex-forming polymeric sorbents with macromolecular arrangement favorable for ion sorption. J. Appl. Poly. Sci. 1979,... 

Ag ions sorption by nanocarbon Ag chemical reduction —> vinyl-pyrrolidone sorption vinylpyrrolidone polymerization. 

The third sorption phenomenon is that of ion-exchange. Here, the stationary phase is a permeable polymeric solid containing fixed charged groups and mobile counter-ions which can exchange with the ions of a solute as the mobile phase carries them through the structure. 

Functionalized polymers are of interest in a variety of applications including but not limited to fire retardants, selective sorption resins, chromatography media, controlled release devices and phase transfer catalysts. This research has been conducted in an effort to functionalize a polymer with a variety of different reactive sites for use in membrane applications. These membranes are to be used for the specific separation and removal of metal ions of interest. A porous support was used to obtain membranes of a specified thickness with the desired mechanical stability. The monomer employed in this study was vinylbenzyl chloride, and it was lightly crosslinked with divinylbenzene in a photopolymerization. Specific ligands incorporated into the membrane film include dimethyl phosphonate esters, isopropyl phosphonate esters, phosphonic acid, and triethyl ammonium chloride groups. Most of the functionalization reactions were conducted with the solid membrane and liquid reactants, however, the vinylbenzyl chloride monomer was transformed to vinylbenzyl triethyl ammonium chloride prior to polymerization in some cases. The reaction conditions and analysis tools for uniformly derivatizing the crosslinked vinylbenzyl chloride / divinyl benzene films are presented in detail. 

Besides phosphate, silica is known to commonly compete with As(V) for sorption/ion exchange sites on a wide variety of iron(III) and aluminum compounds (Clifford and Ghurye, 2002), 227 (Su and Puls, 2003), 2582 (Holm, 2002 Smith and Edwards, 2005 Zhang et al., 2004 McNeill, Chen and Edwards, 2002), 146. Silica may directly compete with arsenic for sites or polymerize on adsorbent surfaces and eliminate surface charges that are favorable for arsenic adsorption (Stollenwerk, 2003), 89. 

The fundamental step in SPE is recognizing that the hydrophobicity versus the polarity of an analyte controls the mechanism of sorption that may be selected. Thus, step one is to select a mechanism of sorption, and Figure 3.8 is a guide to this process. Part A shows the process for aqueous samples and part B for nonaqueous samples. With aqueous samples, the decision for the sorbent is based on the polarity and ionic character of the analyte. If the analyte is polar and ionic, then ion exchange is the preferred sorbent. If the analyte is polar but nonionic, then reversed phase by either C-18 or a polymeric phase is the best sorbent. If the analyte is nonpolar, then a reversed-phase sorbent such as C-8 or C-18 is chosen. 

The sorption process and the attainment of apparent equilibrium may be regarded then as involving essentially two kinds of sorbing species. There are a very small number of ionic plutonium species, including monomeric and low-molecular-weight polymeric hydrolysis products (1) which sorb relatively quickly and perhaps are involved in a true equilibrium, such as by ion exchange with silanol sites at the silica surface. There is evidence of such sorption of various types of univalent and multivalent cations on silica, and both chemisorption and physical adsorption processes have been deduced (13, 14, 15). Filtration of the desorbing plutonium with a 15-40-micron porous silica disc indicated that the very first material to desorb was essentially small, unfilterable Pu(IV). 

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