Synthesis and Dyes Adsorption Properties of Calix[4]crown-grafted Chitosan Chelating Polymer

By the Schiff-base condensation of formacyl calix[4]crown(2) with raw chitosan, a novel calix[4]crown- grafted chitosan chelating polymer(3) was conveniently prepared in good yield. The structure of polymer 3 was confirmed by elemental analysis, infrared(IR) spectrometry and X-ray diffraction(XRD) analysis. The elemental analysis suggests that the grafting degree of calixcrown unit was 22% on the amino groups of chitosan. The morphological characteristic of polymer 3 was studied by scanning electron microscopy(SEM). Polymer 3 possessed loose porous and smooth morphology of surface. The dyes adsorption abilities of polymer 3 for a series of organic dyes[Orange I(OI), Neutral red(NR), Victoria blue B(VB) and Brilliant green(BG)] were studied by solid-liquid adsorption experiments. The adsorption percentages increased from 45%―60%(raw chitosan for dyes) to 75%―90%(polymer 3 for dyes). The highest adsorption percentage reached 89% for VB. The saturated adsorption capacities for OI, NR, VB and BG were as high as 622, 564, 854 and 781 mg/g, respectively. The adsorption abilities kept stable at 70%―90% in the scope of pH=5―9. The adsorption abilities for anionic dye(OI) decreased gradually with the increase of pH and the opposite trend was observed for cationic dyes(NR, BG, VB). The adsorption percentages were 70%―90% after five times' cycles for adsorption.     

Synthesis and characterization of a new phase of zirconium phosphate for the separation of metal ions

The tetravalent metal acid (TMA) salt amorphous zirconium phosphate (ZP), an inorganic ion exchanger, has been synthesized by sol-gel method. The material has been characterized by elemental analysis (ICP-AES), thermal analysis (TGA, DSC), FT-IR and X-ray diffraction studies. Chemical resistivity of the material in various media-acids, bases and organic solvents has been assessed. The Na⁺ ion exchange capacity (IEC) and the effect of heating on the IEC have been determined, and showed the distribution and elution behavior of ZP towards several metal ions in different electrolyte media/concentrations. Based on the distribution studies, a few binary metal ion separations have been achieved.     

Sorption of basic dyes onto granulated pillared clays: thermodynamic and kinetic studies

Effect of the granulation process onto the thermodynamic and kinetic sorption parameters of two basic dyes (Basic Yellow 28-BY 28 and Basic Green 4-BG 4) was evaluated in the present work. The charge surface properties of the surfactant-modified aluminium-pillared clay (CTAB-Al-Mont-PILC) particles were not modified, and the isoelectric point remains constant after high shear wet granulation. The Gibbs free energy of both BY 28 and BG 4 sorption was negative and decreased with the granulation; the endothermic nature of the sorption process was confirmed by the positive values of ΔH°. Adsorption kinetics of the two dyes, studied at pH 6 and 150 mg L(-1), follow the pseudo-first order kinetic model with observed rate constants of 2.5-4.2×10(-2) min(-1). The intraparticle diffusion model, proposed by Weber and Morris, was applied, and the intraparticle plots revealed three distinct sections representing external mass transfer, intraparticle diffusion and adsorption/desorption equilibrium. Diffusion coefficients, calculated from the Boyd kinetic equation, increased with the granulation and the particle size. Pseudo-first order kinetic constants, intraparticle diffusion rate constants and diffusion coefficients were determined for two other initial concentrations (50 and 100 mg L(-1)) and include in a statistical study to evaluate the impact of granulation and initial concentration on the kinetic parameters. Kruskal-Wallis tests, Spearman's rank order correlation and factor analysis revealed a correlation between (i) the diffusion coefficients and granulation, and between (ii) the intraparticle diffusion rate constants and initial concentration.     

Biosorption of Basic Green 4 from aqueous solution by Ananas comosus (pineapple) leaf powder

Biosorption characteristics of Ananas comosus (pineapple) leaf powder was investigated for decolorization of Basic Green 4 (BG 4), a cationic dye from its aqueous solutions employing a batch experimental set-up. Parameters that influence the sorption process such as pH, biosorbent dosage, contact time, initial dye concentration and temperature were systematically studied. The optimum conditions for removal of BG 4 were found to be pH 9.0, contact time=150 min, biosorbent dosage=5.0 g L(-1), initial dye concentration=50 mg L(-1). The temperature had a strong influence on the biosorption process. Further, the biosorbent was characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and Brunauer, Emmett, Teller (BET) surface area and pore size analysis. Experimental biosorption data were modeled by Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherms. The biosorption process followed the Langmuir isotherm model with high coefficients of correlation (R(2)>0.99) at different temperatures. The pseudo second order kinetic model fitted well in correlation to the experimental results. Activation energy of the biosorption process (E(a)) was found to be 45.79 kJ mol(-1) by using the Arrhenius equation, indicating chemisorption nature of BG 4 sorption onto pineapple leaf powder. Thermodynamic parameters suggest that the biosorption process is spontaneous and exothermic in nature. Overall, the present findings suggest that this environmentally friendly, efficient and low-cost biosorbent may be useful for the removal of BG 4 from aqueous media.     

无溶剂条件下磷酸锆纳米粒子作为固体酸催化剂催化苯酚选择性烷基化(英文)

A facile synthesis of α-zirconium phosphate(ZP) nanoparticles as an effective, eco-friendly, and recyclable solid acid catalyst is reported. Polyvinylpyrrolidone(PVP) and polyvinyl alcohol(PVA) were used as organic matrix as dispersing agents and served as a template for the nanoparticles. Hydrogen bonds between ZP and PVA or PVP, along the polymer chains, appear to play an important role for improving the dispersion of in situ formed ZP. Following calcination of PVA/ZP or PVP/ZP, pure hexagonal ZP nanoparticles were obtained. The catalysts were characterized by nitrogen sorption, inductively coupled plasma optical emission spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy(FTIR), scanning electron microscopy, and transmission electron microscopy. Pyridine-FTIR and temperature-programmed desorption of NH3 suggest the presence of Brnsted acid sites. The acidic properties of the catalyst were studied in Friedel-Crafts alkylation of phenol by tert-butanol, producing 2-tert-butylphenol, 4-tert-butylphenol, and 2,4-ditert-butylphenol. The alkylation reaction was performed in the presence of catalysts P2O5/Al2O3, P2O5/SiO2, α-ZrP(prepared in the absence of the polymers), and various ionic liquids. The use of the hexagonal ZP nanoparticle catalyst afforded an excellent phenol conversion(86%) and selectivity towards 4-tert-butylphenol(83%) under optimized reaction conditions. The catalyst was easily recovered from the reaction mixture, regenerated, and reused at least four times without significant loss in the catalytic activity.     

Sorption of organic dyes by polyurethane foam

The sorption of fifty-nine organic dyes, indicators and stains by polyester and polyether-type polyurethane foams was investigated by use of aqueous solutions and powdered foam material. Comparisons were made with sorption from 50% methanol solutions for some dyes and also with solvent extractions done with diethyl ether or ethyl acetate for several dyes. The R(f) values for the dyes run on cellulose TLC plates in water or a mixed solvent mobile phase were compared to the distribution coefficients with polyurethane foam. The relationship between the structure of the test substances and their sorption is discussed.     

一步法制备聚脲多孔材料及其对染料的吸附

以甲苯二异氰酸酯为单体, 在水和丙酮混合溶剂中不用致孔剂且无需任何高分子改性一步法合成了聚脲多孔材料(PPU), 通过扫描电镜和BET氮气吸附法对其表面形貌和孔参数进行了表征. 以酸品红(AF)溶液模拟染料废水, 对其在PPU上的吸附进行了研究, 讨论了pH、 吸附时间、 AF初始浓度及吸附剂用量对吸附过程的影响, 优化了吸附条件. 结果表明, PPU对染料AF具有优异的吸附效果. PPU在30℃, pH=3时对AF的最大吸附量为44.60 mg/g. PPU对AF的吸附过程更接近于Langmuir等温吸附的单分子层吸附机理. PPU对水溶性染料刚果红(CR)也有很好的吸附能力. 使用水、 乙醇和水混合溶剂以及NaOH水溶液对染料吸附后的解吸附结果表明, 乙醇和水混合溶剂对吸附染料的解吸效率最高, 对2种染料的解吸附都达90%以上. 解吸后PPU的再吸附能力略有下降, 但第三次吸附量仍达到首次吸附的80%以上.     

Synthesis and characterization of zinc sensors based on a monosubstituted fluorescein platform

The synthesis of a new fluorescein carboxaldehyde asymmetrically substituted on the xanthene (top) ring is reported. This molecule is a key precursor for two of three monofunctionally derivatized fluorescein-based Zn(II) sensors presented in this work. Detailed preparative routes to, and photophysical characterization of, these sensors are described. The sensors are based on the previously reported ZP4 motif (Burdette, S. C.; Frederickson, C. J.; Bu, W.; Lippard, S. J. J. Am. Chem. Soc. 2003, 125, 1778-1787) and incorporate a di(2-picolyl)amine-containing aniline-derivatized ligand framework. By varying the nature of the substituent (X) para to the aniline nitrogen atom, which is responsible for PET quenching of the unbound ZP dye, we investigated the extent to which such electronic tuning might improve the fluorescent properties of asymmetrical ZP sensors. Although a comparison of probes with X = H, F, Cl, OMe reveals that the photophysical behavior of these dyes is not readily predictable, our methodology illustrates the ease with which aniline-based ligands may be linked to fluorescein dyes.     

Organelle-specific zinc detection using zinpyr-labeled fusion proteins in live cells

A protein labeling approach is employed for the localization of a zinc-responsive fluorescent probe in the mitochondria and in the Golgi apparatus of living cells. ZP1, a zinc sensor of the Zinpyr family, was functionalized with a benzylguanine moiety and thus converted into a substrate (ZP1BG) for the human DNA repair enzyme alkylguaninetransferase (AGT or SNAP-Tag). The labeling reaction of purified glutathione S-transferase tagged AGT with ZP1BG and the zinc response of the resulting protein-bound sensor were confirmed in vitro. The new detection system, which combines a protein labeling methodology with a zinc fluorescent sensor, was tested in live HeLa cells expressing AGT in specific locations. The enzyme was genetically fused to site-directing proteins that anchor the probe onto targeted organelles. Localization of the zinc sensors in the Golgi apparatus and in the mitochondria was demonstrated by fluorescence microscopy. The protein-bound fluorescence detection system is zinc-responsive in living cells.     

Treatment of direct blending dye wastewater and recycling of dye sludge

A new sorbent material, barium sulfate-Direct Blending Yellow D-3RNL hybrid (BSD), was synthesized and characterized by various methods. Both the anionic dyes, Reactive Brilliant Red X-3B and Weak Acid Green GS were hardly adsorbed by the BSD material, while the sorption of Ethyl Violet (EV) and Victoria Blue B were extremely obvious. The sorption of cationic dyes obeyed the Langmuir isotherm model, which depended on the electric charge attraction. The saturation amount of EV adsorbed onto the BSD material approached to 39.36 mg/g. The sorption of EV changed little with pH from 3 to 12 while it increased with increasing levels of electrolyte. A dye wastewater sampled from Jinjiang Chemicals was treated, and the color removal rate was more than the COD removal rate. In addition, the cationic dye-BSD sludge was utilized as a colorant fill-in coating. The light stability and thermal stability of the colorant was measured and exhibited good features. This work provided a simple and eco-friendly method for dye wastewater treatment with recycling of waste.     

6-methylpyridyl for pyridyl substitution tunes the properties of fluorescent zinc sensors of the Zinpyr family

To prepare fluorescent zinc sensors with binding affinities lower than that of the parent 9-(o-carboxyphenyl)-2,7-dichloro-4,5-bis(bis(2-pyridylmethyl)methylaminomethyl)-6-hydroxy-3-xanthenone (ZP1), dimethylated and tetramethylated derivatives were synthesized having either two or four of the pyridyl subunits methylated at the 6-position. Like the parent ZP1, both Me(2)ZP1 and Me(4)ZP1 exhibit increased fluorescence in the presence of Zn(2+). The integrated emission of Me(2)ZP1 increases 4-fold in the presence of excess zinc, whereas Me(4)ZP1 displays 2.5-fold enhanced fluorescence for Zn(2+). Methylating the 6-positions of the pyridyl rings raises the dissociation constant of the sensors and lowers the pK(a) values associated with the tertiary amine ligands in a systematic manner. The properties of the dimethylated Me(2)ZP1 dye resemble those of ZP1, but the tetramethylated Me(4)ZP1 differs greatly from ZP1 in terms of its brightness, affinity toward Zn(2+), exchange kinetics, and metal sensitivity. Both Me(2)ZP1 and Me(4)ZP1 can enter HeLa cells and signal the presence of Zn(2+). Staining caused by both dyes is punctate, with localization patterns resembling that observed for ZP1.     

Preparation and sorption performance of magnetic 18-crown-6/Fe3O4 nanocomposite for uranium(VI) in solution

A new magnetic nanocomposite material, magnetic 18-crown-6/Fe₃O₄ nanocomposite (MCFN), was prepared for the removal of U(VI) from aqueous solution. The MCFN was composed of Fe₃O₄ nanoparticales modified by covalent attachment of 18-crown-6, which can help the material to be removed easily from solution by magnetic force. As a new adsorbent for U(VI) removal, MCFN was characterized by infrared radiation, scanning electron microscopy with energy dispersive X-ray spectroscopy, vibrating sample magnetometer and thermal gravimetric analysis. Those factors affecting the sorption behavior of U(VI), such as acidity, temperature, initial concentration of U(VI) and the amount of crown ethers were studied by orthogonal experiments. A maximum U(VI) sorption capacity of 91.12 mg g^?1 was achieved at 45 °C, pH 5.5 for 30 min. The experimental results showed that MCFN had great sorption capacity, high selectivity and strong potentiality of enrichment and recovery for U(VI). In summary, MCFN is a promising candidate for U(VI) separation in future practical applications.     

Water treatment to remove acid and basic dyes by biosorption on polysaccharide composites

A composite material based on cross-linked cationic starch and sodium alginate was synthesized and studied. The composite is an effective biosorbent for removing various types of synthetic dyes from water. The influence exerted on adsorption of a basic dye (Methylene Blue) and an acid dye (Methyl Orange) by temperature, pH, solution ionic strength, and biosorbent amount was examined, and the dye adsorption kinetics was studied. The adsorption isotherms were analyzed using various models of sorption equilibrium.     

Sorption of food dyes on polyurethane foam and aluminum oxide

The sorption of food dyes Sunset Yellow (E-110), Tartrazine (E 102), Ponceau 4R (E-124), Fast Green FCF (E-143) on polyether-based polyurethane foam, and α-Al₂O₃ from water solutions has been studied. It has been found that the maximum sorption is observed in the range of 0.2 M HCl-pH 2 on polyurethane foam and at pH 2–4 on aluminum oxide. Under the optimal conditions the recoveries on polyurethane foam and α-Al₂O₃ are 20–30% and 70–80%, respectively. It has been shown by diffuse reflectance spectroscopy that, for all dyes except for Fast Green FCF, only one form of the dye that dominates under these conditions in the aqueous solution is extracted on the sorbents in the range of 0.5 M HCl, pH 8.0. Possible models of the interaction between the dyes and the sorbent surface are proposed.     

PHOTOOXYGENATION OF METHYL LINOLEATE SENSITIZED BY PORPHYRINS AND DYES IN ACETONITRILE SOLUTION AND AQUEOUS EMULSION SYSTEMS

Photooxygenation reaction of an unsaturated fatty acid ester, methyl linoleate (methyl 9- cis. 12- cis -octadecadienoate, ML-H), sensitized by porphyrins and several types of dyes has been studied in aqueous emulsion and acetonitrile solution under air at 40°C. The oxygen (O₂) uptake proceeded slowly in the absence of sensitizers upon irradiation of an aqueous emulsion and an acetonitrile solution of ML-H (20 m M ) at ℷ_ex > 290 nm (11.4 and 6.1 μmol h^-1, respectively). The rate of O₂ uptake was enhanced by a catalytic amount (0.1 m M ) of porphyrins and dyes; hematoporphyrin (HP), zinc tetrakis(N-methyl-4-pyridiniumyi)porphyrin (ZnTMPyP), methylene blue (MB), rose bengal (RB), acridine orange (AO), and acriflavine (AF). In both systems, the sensitized photooxidation of ML-H by O₂ proceeded equimolarly to produce isomeric mixture of C9 and C13 hydroperoxides having the trans,cis and trans,trans conjugated diene configurations, independent of the types of the sensitizers used. The yield ratio of trans,trans/ trans,cis products in the MB-sensitized photooxygenation in acetonitrile and aqueous emulsion were almost equal (0.32 and 0.35. respectively). The sensitizing activity of the sensitizers, as measured by the quantum yield of O₂ uptake, increased in the order: MB (≃ 0) < ZnTMPyP < RB < HP < AF < AO in the aqueous emulsion and AO < AF < HP < RB = MB in the acetonitrile solution. The order in homogeneous acetonitrile solution was interpreted by the sensitizing ability of the dyes to produce singlet oxygen, while that in heterogeneous aqueous emulsion was correlated to the lipophilicity of dyes as well as the singlet-oxygen-producing ability.     

Insight into the nonlinear absorbance of two related series of two-photon absorbing chromophores

A comprehensive photophysical study of the linear and nonlinear absorption properties has been carried out on two series of two-photon absorbing dyes to gain insight into how structure-property relationships influence observed nonlinear absorption. The materials studied consist of an electron accepting benzothiazole group connected to an electron donating diphenylamine via a fluorene bridging group. Two series differ from each other by the addition of one phenyl group and for each series one-arm (dipolar, AF240 and AF270), two-arm (quadrupolar, AF287 and AF295), and three-arm (octupolar, AF350 and AF380) versions were studied. Overall the AF240 series exhibits higher intrinsic two-photon absorption (TPA) cross-sections than the AF270 series as well as enhanced nanosecond nonlinear absorption, with an increase with number of branches. The enhanced nanosecond nonlinearity is understood by taking into account the contribution from the singlet and triplet excited states and was verified by a two-photon assisted excited-state absorption model that satisfactorily predicts the nonlinear absorption of the chromophores.     

Effect of quaternary ammonium cations on dye sorption to fly ash from aqueous media

The efficacy of the surface modification of fly ash by quarternary ammonium cations in the removal of dyes from aqueous solution is demonstrated. A series of organo-fly ash materials were synthesized by treating fly ash with quarternary ammonium cations such as tetraethylammonium, hexadecyltrimethylammonium, and benzyldimethyltetradecylammonium (TEA, HDTMA, and BDTDA). Two types of dyes were used for the investigation, disperse and anionic dyes. The effects of initial dye concentration, contact time, temperature, and the mechanism of dye sorption were investigated. The sorption was found to be affected by the structure and size of the quaternary ammonium cations as well as that of the dyes. Sorption of dyes was considerably enhanced by the surface modification. Thermodynamic parameters such as free energy (DeltaG0), enthalpy (DeltaH0), and entropy (DeltaS0) for the sorption process were also calculated.     

Proton-conducting zirconium phosphate/poly(vinyl acetate)/glycerine gel electrolytes

This work reports on a proton gel electrolyte composed of zirconium phosphate (ZP) particles suspended in a poly(vinyl acetate)/glycerine matrix. The material was studied by X-ray powder diffraction, differential scanning calorimetry, impedance spectroscopy, and spectrophotometry. It had a proton conductivity of 1–0.1 mS/cm at room temperature and remained stable and transparent up to at least 110 °C; it therefore appears suitable for uses in electrochromic devices. The structure of the ZP powder and of the gel is discussed in terms of water removal from interplanar spaces by heating or exfoliation. It is suggested that an exfoliation of the layered structure of ZP by intercalation of glycerine produces a dispersion of ZP nanoparticles in the poly(vinyl acetate)/glycerine matrix.     

An optical chemical sensor based on functional polymer films for controlling sulfur dioxide in the air of the working area: Acrylonitrile and alkyl methacrylate copolymers with brilliant green styrene sulfonate

The effects of the chemical and phase composition of acrylonitrile and alkyl methacrylate (Alkyl-MA) copolymers with styrene sulfonates (SS) of triphenylmethane dye cations on the gas permeability and sensing properties of their films were studied for developing an optical chemical sensor (OCS) for sulfur dioxide (SO₂) on the basis of functional polymers. Of the three triphenylmethane dyes tested, namely, fuchsine, Crystal Violet, and Brilliant Green (BG), only the last dye was selected for molecular design. It was shown that the copolymer of Decyl-MA with SS—BG with the degree of modification DM = 0.10 is the best material among the studied ones from the viewpoints of sensitivity, response time, and time stability of sensor characteristics. The conditions for fabricating polymer films and the parameters of their functioning in OCSs for SO₂ were optimized. The effect of annealing conditions on the sensitivity of spectra to SO₂ was studied. Working temperature, working wavelength, and the conditions for the regeneration of the initial spectral parameters were optimized. Calibration characteristics of OCSs for the dynamic admittance of SO₂—air mixtures were obtained. The calculated detection limit for SO₂ in an air flow for a sensor with a sensing film fabricated of the decyl-MA—SS—BG copolymer with DM = 0.10 was 0.16 vol %, or 4160 mg/m³. This points to the necessity of searching for more sensitive sensing materials among other classes of functional polymers.Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 3, 2005, pp. 307–315.Original Russian Text Copyright © 2005 by Soborover, Tverskoi, Tokarev.