Cation Absorption Research Articles

Absorption of strontium cations by a carbon nanomatrix

The structure and adsorption properties a new micro- and nanostructured carbon matrix are studied. The sorptional capacity of the matrix is 65 mg/g for strontium (II) cations; the moisture absorption is 285.7 mg/g. The matrix effectively removes the strontium cations from aqueous solution. This suggests that it might prove useful in the purification of industrial aqueous media.

Photoinduced One-Electron Oxidation of Benzyl Methyl Sulfides in Acetonitrile: Time-Resolved Spectroscopic Evidence for a Thionium Ion Intermediate.

The photo-oxidation of 4-methoxybenzyl methyl sulfide (1a), benzyl methyl sulfide (1b), and 4-cyanobenzyl methyl sulfide (1c) has been investigated in the presence of N-methoxy phenanthridinium hexafluorophosphate (MeOP(+)PF6(-)) under nitrogen in CH3CN. The steady-state photolysis experiments showed for the investigated sulfides exclusively the formation of the corresponding benzaldehyde as the oxidation product, reasonably due to a deprotonation of the sulfide radical cations. Photo-oxidation of 1a-1c occurs through an electron transfer process. Indeed, laser flash photolysis measurements showed an efficient formation of sulfide radical cations, detected in their dimeric form [(4-X-C6H4CH2SCH3)2(+•)] at ≈520 nm. At longer delay times, the absorption of the dimer radical cation was replaced by an absorption band assigned to the (α-thio)benzyl cation (thionium ion, λmax = 420-400 nm), formed by oxidation of the benzyl radical and not by that of the (α-thiomethyl)benzyl radical, as expected if a Cα-H bond cleavage is operative. This finding highlights a particular stability of this kind of cation never reported before, even though its involvement in one-electron oxidation mechanisms of various sulfides has already been invoked. Density functional theory calculations allowed identification of a significant charge and spin delocalization involving both the phenyl ring and the sulfur atom of the radical cations.

Selective Absorption of Hydrophobic Cations in Nanostructured Porous Materials from Crosslinked Hydrogen‐Bonded Columnar Liquid Crystals

A nanostructured porous material is obtained by crosslinking of a self‐assembled system consisting of columnar liquid crystals with polyamines and removal of the template. For this purpose, a columnar liquid crystal with liquid crystalline properties at room temperature is synthesized and fully characterized. The orthogonal self‐assembly of the columnar liquid crystal with polyamines (i.e., PPI dendrimers) results in the formation of nanosegregated structures. When crosslinked by photopolymerization a nanostructured crosslinked material is obtained. Partial removal of the polyamine template leads to a nanostructured porous material, which is characterized and the absorbent properties are investigated. The polarity of the porous material is probed and the porous material is used for the selective absorption of cationic dye molecules.

The [formula omitted] 2B3u ← [formula omitted] 2B2g electronic absorption spectrum of butatriene cation in a neon matrix

The C∼2B3u←X∼2B2g electronic absorption of butatriene cation (BT+) has been observed in a 6K neon matrix. The origin band lies at 511.9nm. The electronic transition assignment is based on comparison with the photoelectron spectrum of butatriene and the vibrational frequencies of BT+ calculated with the CASPT2 (5,6) method. Three vibrational modes of energy 207, 511 and 813cm−1, with their overtones and combinations, are active in the C∼2B3u state of BT+. It is shown that the emission observed from a glow discharge of 2-butyne at 491nm and attributed to the origin band of this electronic transition [1] of BT+ is due to another species, because the difference of 850cm−1 to the absorption spectrum is too large. No fluorescence of BT+ was detected in the matrix and it is expected that the C∼2B3u electronic state relaxes non-radiatively on a fs time scale.

Alginate/PVA Beads for Levan Production by Zymomonas mobilis

AbstractThe levan is a biopolymer of great importance to the food industry since it is capable of defining and modifying the structure of one food, acting as stabilizer, thickener, gelling agent and being largely responsible for the texture of processed foods. The levan production by bacterial cell immobilization may potentialize the results of these studies, having advantages such as: high cell concentrations inside the reactor, increase the substrate absorption rate, improve the performance and reduce the risk of microbial contamination. Thus, this study aims to evaluate the levan production by immobilized Zymomonas mobilis in hybrid system of alginate/polyvinyl alcohol (PVA) when submitted to different sucrose concentrations (5, 10, 25 and 30%), pH (5.7 and 7.0) and incubation temperature of 30C for 12, 18 and 24 h. The results showed that the best levan production rate was 18.66 g/L at 30% sucrose concentration, with productivity 1.55 g/L/h at pH 7.0.Practical ApplicationsThe biopolymer called levan is a nontoxic, nonmutagenic, odorless, tasteless and soluble dietary fiber; it has physiological effects that depend on its size and linkage type, and its fermentability. It can be produced by bacterial fermentation like Zymomonas mobilis. The administration of levan in human diet (5.5–6 g, twice a day) for 2–3 months reduced body weight and body fat mass. The input of levan showed in some studies an increase of divalent cation (Zn, Mg and Fe) and calcium absorption in rats. In the food industry, levan improves the rheological properties and functional characteristics of dairy products, such as yogurt. Its application includes use as a stabilizer, emulsifier, surface agent, encapsulating agent and flavor and fragrances carrier.

Mixed valence radical cations and intermolecular complexes derived from indenofluorene-extended tetrathiafulvalenes

Engineering of mixed-valence (MV) radical cations and intermolecular complexes based on π-extended tetrathiafulvalenes (TTFs) is central for the development of organic conductors. On another front, redox-controlled dimerization of radical cations has recently been recognized as an important tool in supramolecular chemistry. Here we show that π-extended TTFs based on the indenofluorene core, prepared by Horner–Wadsworth–Emmons reactions, undergo reversible and stepwise one-electron oxidations and that the detectable, intermediate radical cation forms remarkably strong intermolecular MV ([neutral·cation]) and π-dimer ([cation·cation]) complexes with near-infrared radical cation absorptions. The radical cation itself seems to be a so-called Class III MV species in the Robin–Day classification. The formation of MV dimers was corroborated by ESR spectroelectrochemical studies, revealing two slightly different ESR signals upon oxidation, one assigned to the MV dimer and the other to the cation monomer. Crystals of the radical cation with different anions (PF6−, BF4−, and TaF6−) were grown by electrocrystallization. Conductance studies revealed that the salts behave as semiconductors with the hexafluorotantalate salt exhibiting the highest conductance. Using a custom-built ESR spectrometer with sub-femtomole sensitivity, the magnetic properties of one crystal were investigated. While the spin-to-spin interaction between radical cations was negligible, a high cooperativity coupling to the microwave field was observed – as a result of an exceptionally narrow spin line width and high spin density. This could have great potential for applications in quantum computation where crystalline spin ensembles are exploited for their long coherence times.

Spectral and Kinetic Properties of Radical Cations Derived from Oxoisoaporphines: Relevance to Electron-Transfer Processes Involving Phytoalexins.

The thermally induced intermolecular electron transfer reaction in acetonitrile between the tetracyanoethylene (TCNE), a π-electron acceptor with a large electron affinity, and six oxoisoaporphines (2,3-dihydro-7H-dibenzo[de,h]quinolin-7-one, 5-methoxy-2,3-dihydro-7H-dibenzo[de,h]quinolin-7-one, 1-azabenzo[de]anthracen-7-one, 5-methoxy-1-azabenzo[de]anthracen-7-one, 7H-benzo[e]perimidin-7-one, and 2-methyl-7h-benzo[e]perimidin-7-one) is reported. Spectral and kinetic characteristics are presented for radical cations derived from these six oxoisoaporphines either generated by a thermal reaction or generated radiolytically in argon-saturated 1,2-dichloroethane, oxygen-saturated acetone, and acetonitrile. The radical cations of oxoisoaporphines are insensitive to oxygen and are mostly characterized by absorption maxima of their most intense bands located at λmax = 400-410 nm, except of the radical cations derived from 2,3-dihydrooxoisoaporphines. For the latter compounds, the absorption maxima of the most intense absorption bands are located at λmax = 290-295 nm. Their locations are independent of the presence of functional groups and the solvents used. They are formed in bimolecular processes with pseudo-first-order rate constants ranging from 2.1 × 105 to 1.5 × 106 s-1 (in solutions containing 10-4 M of the substrate), depending on the derivative and the solvent used. They are stable either when formed via the electron-transfer reaction with TCNE or when generated in isolation in pulse radiolysis of Ar-saturated 1,2-dichloroethane. In acetone and acetonitrile they decay predominantly by first-order kinetics with the first-order rate constants ranging from 2.3 × 104 to 5.1 × 104 s-1. Formation of dimeric radical cations for all of the oxoisoaporphines studied was observed in acetonitrile solutions, and for azaoxoisoaporphines also in acetone solutions. The experimental spectra show a reasonably good agreement with the ZINDO/S semiempirical quantum mechanical calculations of radical cation absorptions.

Mineral content and biochemical variables of Aloe vera L. under salt stress.

Despite the proven economic importance of Aloe vera, studies of saline stress and its effects on the biochemistry and mineral content in tissues of this plant are scarce. The objective of this study was to grow Aloe under NaCl stress of 0, 30, 60, 90 and 120 mM and compare: (1) proline, total protein, and enzyme phosphoenolpyruvate carboxylase (PEP-case) in chlorenchyma and parenchyma tissues, and (2) ion content (Na, K, Ca, Mg, Cl, Fe, P. N, Zn, B, Mn, and Cu) in roots, stems, leaves and sprouts. Proline and PEP-case increased as salinity increased in both parenchyma and chlorenchyma, while total protein increased in parenchyma and decreased in chlorenchyma, although at similar salt concentrations total protein was always higher in chlorenchyma. As salinity increased Na and Cl ions increased in roots, stems, leaves, while K decreased only significantly in sprouts. Salinity increases typically caused mineral content in tissue to decrease, or not change significantly. In roots, as salinity increased Mg decreased, while all other minerals failed to show a specific trend. In stems, the mineral concentrations that changed were Fe and P which increased with salinity while Cu decreased. In leaves, Mg, Mn, N, and B decreased with salinity, while Cu increased. In sprouts, the minerals that decreased with increasing salinity were Mg, Mn, and Cu. Zinc did not exhibit a trend in any of the tissues. The increase in protein, proline and PEP-case activity, as well as the absorption and accumulation of cations under moderate NaCl stress caused osmotic adjustment which kept the plant healthy. These results suggest that Aloe may be a viable crop for soil irrigated with hard water or affected by salinity at least at concentrations used in the present study.

Single-walled Carbon Nanohorn: Electronic Absorption Spectra in Neutral and Oxodized State

The electronic absorption spectrum of single-walled carbon nanohorn (SWCNH) shows a relatively broad absorption peak at 256–259 nm when suspended in tetradecane and in decalin. The electronic absorption spectrum is also characterized by a series of small bands recalling the spectra of C60 and C70 fullerenes. Surprisingly, SWCNH shows a minimal solubility in 1,2,4-trichlorobenzene. SWCNH is also dissolved and oxidized in oleum (fuming sulphuric acid with 20% free SO3), displaying a radical cation band in the near infrared at 1045 nm. The addition of ozone to a suspension of SWCNH in oleum enhances its dissolution and the relative radical cation absorption band.

Nitrogen‐fertilizer forms affect the nitrogen‐use efficiency in fertigated citrus groves

AbstractThe fertigated area of the Brazilian citrus industry has grown rapidly during recent years, and an efficient management of nitrogen (N) application at these sites is required for sustainable citrus production. Therefore, a field trial with Valencia orange trees [Citrus sinensis (L.) Osbeck] on Swingle citrumelo rootstock (Citrus paradise Macfad. x Poncirus trifoliata L. Raf.) was conducted for 8 years to evaluate the effects of N rates (80, 160, 240 and 320 kg ha–1 y–1) applied by fertigation, either as ammonium nitrate (AN) or calcium nitrate (CN), on soil solution dynamics, fruit yield, nutritional status, and N‐use efficiency (NUE) of trees. The maximum fruit yield was reached with 240 kg N ha–1 for AN, whereas a linear response and greater fruit yield was observed for N supplied as CN. The NUE was reduced for both N forms with increasing N rates. However, the NUE for CN was 14 to 38% greater than the NUE for AN. The lower fruit yield and NUE for AN compared to CN‐treated trees was associated with the increased acidification of the soil solution with increased AN rates (pH ≤ 4.0). This limited nitrification resulted in a high ammonium (NH$ _4^+ $) concentration in the soil solution and a reduction in the net absorption of cations by the trees, particularly calcium (Ca). Due to the improved ion balance as well as the higher pH of the soil solution (pH ≥ 6.3) and diminished NH$ _4^+ $ availability, gains in both fruit yield and NUE in fertigated citrus groves in tropical soils can be obtained with the use of CN as a source of N.

Characterization and performance study of sulfonated poly ether ether ketone/Fe3O4 nano composite membrane as electrolyte for microbial fuel cell

The influence of Fe3O4 in proton conductivity, oxygen crossover, water absorption and performance of Sulfonated Poly Ether Ether Ketone (SPEEK) matrix was studied in single chamber microbial fuel cell at various weight percentages (2.5%, 5%, 7.5%, 10%) of SPEEK/Fe3O4. The fabricated composite membranes were characterized by FT-IR, SEM, and XRD which were also tested for their surface roughness, water absorption, proton conductivity and transportation of cations were also studied for its suitability in microbial fuel cell operation. Escherichia coli (E. coli), an electrogenic bacteria, was used as the biocatalyst in anodic chamber and platinized carbon (Pt/C) was used as the catalyst in the air cathode. The low oxygen crossover, selective transfer of protons and water mediated proton hopping mechanism in Fe3O4 composite membrane (7.5% Fe3O4) resulted in a maximum power density of 104mWm−2 which was higher than that of the power density of Nafion® 117 (47mWm−2) under the same operating conditions. The results of the study suggested that SPEEK/Fe3O4 (7.5wt%) composite membrane would be more commercially viable and efficient than the existing Nafion membranes for use in microbial fuel cells.

Cation-Responsive Mechanisms of Oats to Alkali Stress

In a pot experiment, an alkali-tolerant oat variety, Vao-9, and an alkali-sensitive variety, Baiyan 5, were exposed to 25, 50, 75, and 100 mmol L-1 of alkali stress(molar ratio of Na2CO3:NaHCO3 = 1:1). The contents of Na+, K+, Ca2+, and Mg2+ absorbed by oat seedling and their distribution characteristics in root, stem, and leaf were measured after a short-term(14 d) or a long-term(28 d) stress treatment. The objective was to understand the physiological adaptation to alkali stress in oat in the view of ion balance absorption and distribution. After short-term stress, the cation contents in oat plants showed the variations of increased Na+, decreased K+, and minor changes in Ca2+ and Mg2+. Besides, the distribution proportions of the four ions in various organs were not significantly different between the two varieties. Compared to short-term stress, long-term stress resulted in larger increase of Na+ content and larger decreases of K+, Ca2+, and Mg2+ contents in all organs of both varieties. Vao-9 absorbed more Na+ and Ca2+ than Baiyan 5, and the absorptions of K+ and Mg2+ were not significantly different between varieties, but the distribution characteristics of the four ions in various organs were different between the two varieties. Under 100 mmol L-1 alkali stress, 5.9 percent Na+ in leaf were lower distributed and 13.5 percent K+, 28.9 Ca2+, 10.9 Mg2+ more distributed in Vao-9 than in Baiyan 5, 5.4 percent Na+ in stem higher and 9.8 K+ lower in Vao-9 than in Baiyan 5, 28.9 Ca2+, 10.9 Mg2+ in root were lower in Vao-9 than in Baiyan 5, As a result, the Na+ content and the ratios of Na+/K+, Na+/Ca2+, and Na+/Mg2+ in leaf were lower in Vao-9 than in Baiyan 5. Clearly, oat plant has the mechanism of selective absorption and distribution of various cations in different organs in response to alkali stress.

A Modified Method for Studying Behavioral Paradox of Antioxidants and Their Disproportionate Competitive Kinetic Effect to Scavenge the Peroxyl Radical Formation

We have described a modified method for evaluating inhibitor of peroxyl radicals, a well-recognized and -documented radical involved in cancer initiation and promotion as well as diseases related to oxidative stress and ageing. We are reporting hydrophilic and lipophilic as well as natural and synthetic forms of antioxidants revealing a diversified behaviour to peroxyl radical in a dose-dependent manner (1 nM–10 μM). A simple kinetic model for the competitive oxidation of an indicator molecule (ABTS) and a various antioxidant by a radical (ROO•) is described. The influences of both the concentration of antioxidant and duration of reaction (70 min) on the inhibition of the radical cation absorption are taken into account while determining the activity. The induction time of the reaction was also proposed as a parameter enabling determination of antioxidant content by optimizing and introducing other kinetic parameters in 96-well plate assays. The test evidently improves the original PRTC (peroxyl radical trapping capacity) assay in terms of the amount of chemical used, simultaneous tracking, that is, the generation of the radical taking place continually and the kinetic reduction technique (area under curve, peak value, slope, and V max).

Ursodeoxycholic and deoxycholic acids: A good and a bad bile acid for intestinal calcium absorption

The aim of this study was to investigate the effect of ursodeoxycholic acid (UDCA) on intestinal Ca2+ absorption and to find out whether the inhibition of this process caused by NaDOC could be prevented by UDCA. Chicks were employed and divided into four groups: (a) controls, (b) treated with 10mM NaDOC, (c) treated with 60μg UDCA/100g of b.w., and (d) treated with 10mM NaDOC and 60μg UDCA/100g of b.w. UDCA enhanced intestinal Ca2+ absorption, which was time and dose-dependent. UDCA avoided the inhibition of intestinal Ca2+ absorption caused by NaDOC. Both bile acids altered protein and gene expression of molecules involved in the transcellular pathway of intestinal Ca2+ absorption, but in the opposite way. UDCA aborted the oxidative stress produced by NaDOC in the intestine. UDCA and UDCA plus NaDOC increased vitamin D receptor protein expression. In conclusion, UDCA is a beneficial bile acid for intestinal Ca2+ absorption. Contrarily, NaDOC inhibits the intestinal cation absorption through triggering oxidative stress. The use of UDCA in patients with cholestasis would be benefited because of the protective effect on the intestinal Ca2+ absorption, avoiding the inhibition caused by hydrophobic bile acids and neutralizing the oxidative stress.

Organic Cation Transporter 1 (OCT1/mOct1) Is Localized in the Apical Membrane of Caco-2 Cell Monolayers and Enterocytes

Organic cation transporters (OCTs) are members of the solute carrier 22 family of transporter proteins that are involved in absorption, distribution, and excretion of organic cations. OCT3 is localized in the apical (AP) membrane of enterocytes, but the literature is ambiguous about OCT1 (mOct1) localization, with some evidence suggesting a basolateral (BL) localization in human and mouse enterocytes. This is contrary to our preliminary findings showing AP localization of OCT1 in Caco-2 cell monolayers, an established model of human intestinal epithelium. Therefore, this study aims at determining the localization of OCT1 (mOct1) in Caco-2 cells, and human and mouse enterocytes. Functional studies using OCT1-specific substrate pentamidine showed transporter-mediated AP but not BL uptake in Caco-2 cells and human and mouse intestinal tissues. OCT1 inhibition decreased AP uptake of pentamidine by ∼50% in all three systems with no effect on BL uptake. A short hairpin RNA-mediated OCT1 knockdown in Caco-2 cells decreased AP uptake of pentamidine by ∼50% but did not alter BL uptake. Immunostaining and confocal microscopy in all three systems confirmed AP localization of OCT1 (mOct1). Our studies unequivocally show AP membrane localization of OCT1 (mOct1) in Caco-2 cells and human and mouse intestine. These results are highly significant as they will require reinterpretation of previous drug disposition and drug-drug interaction studies where conclusions were drawn assuming BL localization of OCT1 in enterocytes. Most importantly, these results will require revision of the regulatory guidance for industry in the United States and elsewhere because it has stated that OCT1 is basolaterally localized in enterocytes.

Strength development in clay–fly ash geopolymer

This paper presents the role of influential factors on the strength development in a clay–fly ash geopolymer that a silty clay is used as fine aggregates and fly ash, FA is used as a pozzolanic material. A liquid alkaline activator, L is a mixture of sodium silicate solution (Na2SiO3) and sodium hydroxide solution (NaOH). The studied influential factors are Na2SiO3/NaOH ratio, L/FA ratio and heat conditions. The optimum ingredient for the clay–FA geopolymer is the Na2SiO3/NaOH ratio of 0.7 and the L/FA ratio of 0.6. The Na2SiO3/NaOH ratio required for the clay–FA geopolymer is less than that of the FA geopolymer because the clay has high cation absorption ability and then absorbs some of the input NaOH. For a given Na2SiO3/NaOH content, the strength increases with increasing the liquid alkaline activator. The excess input alkaline activator causes the precipitation at very early stage before the condensation process in geopolymerization and results in the cracks on the FA particles. The overheating (very high temperature) and excess heat duration cause the micro-cracks on the specimens. The relationship between the strength and heat energy is proposed to integrate the role of heat temperature and duration on the geopolymerization. The compressive strength increases with increasing heat energy up to a certain level. Beyond this level, the specimens shrink and crack due to the reduction in pore fluid, which results in the strength reduction. The relationship between strength and heat energy can be used as fundamental for further study on the strength development and the mix design method for the clay–FA geopolymer with different specimen dimensions, clay minerals, liquid alkaline activators, pozzolanic materials and clay:FA ratios.

Soil exchangeable base cations along a chronosequence of Caragana microphylla plantation in a semi-arid sandy land, China

As a pioneer leguminous shrub species for vegetation re-establishment, Caragana microphylla is widely distributed in the semi-fixed and fixed sandy lands of the Horqin region, North China. C. microphylla plantations modify organic carbon (SOC), nitrogen (N) and phosphorus dynamics, bulk density and water-holding capacity, and biological activities in soils, but little is known with regard to soil exchange properties. Variation in soil exchangeable base cations was examined under C. microphylla plantations with an age sequence of 0, 5, 10, and 22 years in the Horqin Sandy Land, and at the depth of 0–10, 10–20, and 20–30 cm, respectively. C. microphylla has been planted on the non-vegetated sand dunes with similar physical-chemical soil properties. The results showed that exchangeable calcium (Ca), magnesium (Mg), and potassium (K), and cation exchange capacity (CEC) were significantly increased, and Ca saturation tended to decrease, while Mg and K saturations were increased with the plantation years. No difference was observed for exchangeable sodium (Na) neither with plantation years nor at soil depths. Of all the base cations and soil layers, exchangeable K at the depth of 0–10 cm accumulated most quickly, and it increased by 1.76, 3.16, and 4.25 times, respectively after C. microphylla was planted for 5, 10, and 22 years. Exchangeable Ca, Mg, and K, and CEC were significantly (P<0.001) and positively correlated with SOC, total N, pH, and electrical conductivity (EC). Soil pH and SOC are regarded as the main factors influencing the variation in exchangeable cations, and the preferential absorption of cations by plants and different leaching rates of base cations that modify cation saturations under C. microphylla plantation. It is concluded that as a nitrogen-fixation species, C. microphylla plantation is beneficial to increasing exchangeable base cations and CEC in soils, and therefore can improve soil fertility and create favorable microenvironments for plants and creatures in the semi-arid sandy land ecosystems.

Electronic absorptions of the benzylium cation

The electronic transitions of the benzylium cation (Bz(+)) are investigated over the 250-550 nm range by monitoring the photodissociation of mass-selected C(7)H(7)(+)-Ar(n) (n = 1, 2) complexes in a tandem mass spectrometer. The Bz(+)-Ar spectrum displays two distinct band systems, the S(1)←S(0) band system extending from 370 to 530 nm with an origin at 19,067 ± 15 cm(-1), and a much stronger S(3)←S(0) band system extending from 270 to 320 nm with an origin at 32,035 ± 15 cm(-1). Whereas the S(1)←S(0) absorption exhibits well resolved vibrational progressions, the S(3)←S(0) absorption is broad and relatively structureless. Vibronic structure of the S(1)←S(0) system, which is interpreted with the aid of time-dependent density functional theory and Franck-Condon simulations, reflects the activity of four totally symmetric ring deformation modes (ν(5), ν(6), ν(9), ν(13)). We find no evidence for the ultraviolet absorption of the tropylium cation, which according to the neon matrix spectrum should occur over the 260 - 275 nm range [A. Nagy, J. Fulara, I. Garkusha, and J. Maier, Angew. Chem., Int. Ed. 50, 3022 (2011)].

Radical cations from diarylamino-substituted fluorenones

Chemical oxidation of diarylamino-substituted fluorenones gives highly persistent radical cations, some of which can be stored in the solid state for months. Solution UV–vis-NIR spectra show strong monoradical cation absorption bands in the 750–1700nm range, with minimum energy about 0.73eV. 2,7-Bis(dianisylamino)fluorenone exhibits strong absorptions at 1670 (monocation) and 873nm (dication). Fast intervalence electron transfer behavior between amine sites in the monocation is indicated by EPR spectroscopic and absorption spectral Hush analyses.

Absorption characterization of Ca2+, Na+, and K+ on irradiation crosslinked carboxymethyl sago pulp hydrogel

AbstractHydrogel of carboxymethyl sago pulp (CMSP) of various degree of substitution (DS) was prepared by electron beam irradiation of various radiation doses. The CMSP hydrogels were subjected to swelling in different ionic strength solutions of KCl, NaCl, and CaCl2. The CMSP hydrogels, due to its polyelectrolyte nature, were found to be highly sensitive to ionic strength of the medium. All the CMSP hydrogels showed the absorption of K+ and Ca2+ increases with the increase in the concentrations of the respective cation solutions. The cation absorption also decreases with DS and % gel fraction (%GF) of the CMSP hydrogels. Subjecting the CMSP hydrogels in NaCl results in deswelling and releases Na+ to swelling medium where the Na+ release increases with the increase of DS and %GF. The sorption capacity depends on the extent of crosslinking and decreases with the increase in the extent of crosslinking. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013