Syntheses and characterization of polystyrene‐supported 2,5‐dimercapto‐1,3,4‐thiodiazole and its sorption behavior for Pd(II), Pt(IV), and Au(III)

A type of chelating resin crosslinking polystyrene‐supported 2,5‐dimercapto‐1,3,4‐thiodiazole (also called bismuththiol I, BMT), containing sulfur and nitrogen atoms, was prepared. The structure of PS‐BMT was confirmed by FTIR, elemental analysis, and X‐ray photoelectron spectroscopy (XPS). Adsorption of Pd(II), Pt(IV), and Au(III) was investigated. The capacity of PS‐BMT to adsorb Pd(II) and Pt(IV) was 0.190 and 0.033 mmol/g, respectively. The adsorption dynamics of Pd(II) showed that adsorption was controlled by liquid film diffusion and that the apparent activation energy, E_a, was 32.67 kJ/mol. The Langmuir model was better than the Freundlich model in describing the isothermal process of Pd(II), and the ΔG, ΔH, and ΔS values calculated were ?0.33 kJ/mol, 26.29 kJ/mol, and 87.95 J mol^?1 K^?1, respectively. The mechanisms of adsorption of Pd(II), Pt(IV), and Au(III) were confirmed by XPS. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 631–637, 2006     

Synthesis and characterization of polystyrene‐supported glucosamine resin and its adsorption behavior for Au(III)

A novel chelating resin, crosslinking polystyrene‐supported glucosamine (PS‐GA), was prepared and its structure was confirmed by FTIR, elemental analysis, and X‐ray photoelectron spectroscopy. The adsorption properties of PS‐GA for Au(III) were investigated. PS‐GA resin possessed excellent enriching property to Au(III) ions and adsorption proportion E% could reach to about 90 shortly after 3 h. The adsorption dynamics of Au(III) showed that the adsorption was controlled by liquid film diffusion and the apparent activation energy E_a was 12.91 kJ mol^?1. Both Langmuir model and Freundlich model could describe the isothermal process of Au(III), and ΔG, ΔH, ΔS values were calculated. The mechanism of adsorption for Au(III) was confirmed by FTIR, SEM, and XPS. The results showed that redox reaction occurred and both coordination and ion‐exchange existed simultaneously in the adsorption. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4581–4586, 2006     

Modeling the PAAc‐AN‐TV surface using 134Cs and 152+154Eu sorption

A novel composite, composed of poly (acrylic acid (AAc), acrylonitrile, and titanium vanadate, was prepared by induced gamma irradiation route at 20 kGy to be used as a hybrid organic‐inorganic sorbent. 5–200 μm particle diameters of the composite were obtained. An average particle size of 75 μm of crystalline (17‐20) composite was used; it was thermally stable to 486°C. The distribution coefficients of Cs⁺ and Eu³⁺ were studied as a function of pH; 2350 mL·g^?1 and 645 mL·g^?1 were obtained in case of ^152+154Eu and ¹³⁴Cs at pH 6. 1.55 mmol·g^?1 and 1.85 mmol·g^?1 maximum loadings were accommodated for the same ions at the same pH. Different models were used to scan the surface of the exchanger, so that the topography of the surface was studied as a function of surface active site types, concentrations, and heterogeneity. Langmuir, Freundlich and D‐R models were used. Also, different kinetic models, as Lagergren pseudo first‐order, pseudo second‐order and Morris‐Weber intraparticle diffusion models were applied to study the possible mechanism of the sorption process; pseudo first‐order was exempted to investigate the mechanism. They proved that chemisorption and ion exchange mechanism with controlled diffusion are predominant, with their characteristic mean energies (8.731 kJ·mol^?1 and 9.310 kJ·mol^?1 for Cs⁺ and Eu³⁺, respectively). Double Shell Model was finally adopted to explain the suggested mechanism. Negative values of ΔG°, ?2.15 kJ·mol^?1 to ?7.92 kJ·mol^?1 in case of Cs⁺ and ?3.35 kJ·mol^?1 to ?9.67 kJ·mol^?1 in case of Eu³⁺adsorption at different temperatures, indicate the spontaneous nature of the reactions. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synergistic extraction of rare earths(III) from chloride medium with mixtures of 1‐phenyl‐3‐methyl‐4‐benzoyl‐pyrazalone‐5 and di‐(2‐ethylhexyl)‐2‐ethylhexylphosphonate

The synergistic effect of 1‐phenyl‐3‐methyl‐4‐benzoyl‐pyrazalone‐5 (HPMBP, HA) and di‐(2‐ethylhexyl)‐2‐ethylhexylphosphonate (DEHEHP, B) in the extraction of rare earths (RE) from chloride solutions has been investigated. Under the experimental conditions used, there was no detectable extraction when DEHEHP was used as a single extractant while the amount of RE(III) extracted by HPMBP alone was also low. But mixtures of the two extractants at a certain ratio had very high extractability for all the RE(III). For example, the synergistic enhancement coefficient was calculated to be 9.35 for Y³⁺, and taking Yb³⁺ and Y³⁺ as examples, RE³⁺ is extracted as RE(OH)A₂.B. The stoichiometry, extraction constants and thermodynamic functions such as Gibbs free energy change ΔG (?17.06 kJ mol^?1), enthalpy change ΔH (?35.08 kJ mol^?1) and entropy change ΔS (?60.47 J K^?1 mol^?1) for Y³⁺ at 298 K were determined. The separation factors (SF) for adjacent pairs of rare earths were calculated. Studies show that the binary extraction system not only enhances the extraction efficiency of RE(III) but also improves the selectivity, especially between La(III) and the other rare earth elements. Copyright © 2006 Society of Chemical Industry     

Synthesis and adsorption properties of macroporous cross‐linked polystyrene that contains an immobilizing 2,5‐dimercapto‐1,3,4‐thiodiazole with tetraethylene glycol spacers

A novel chelating resin macroporous cross‐linked polystyrene immobilizing 2,5‐dimercapto‐1,3,4‐thiodiazole via a hydrophilic tetraethylene glycol spacer (PS‐TEG‐BMT) is synthesized and the structure is characterized by means of Fourier transform infrared spectroscopy (FTIR), energy dispersive X‐ray microanalysis (EDX), and elementary analysis. Its adsorption capacity for several metal ions such as Hg²⁺, Ag⁺, Ni²⁺, Pb²⁺, Cd²⁺, Fe³⁺, Bi³⁺, Zn²⁺, and Cu²⁺ are investigated. The initial experimental result shows that this resin has higher adsorption selectivity for Hg²⁺ and Ni²⁺ than for the other metal ions and the introduction of hydrophilic TEG spacer is beneficial to increase adsorption capacities. The result also shows that the Langmuir model is better than the Freundlich model to describe the isothermal process of PS‐TEG‐BME resin for Hg²⁺. Five adsorption‐desorption cycles demonstrate that this resin are suitable for reuse without considerable change in adsorption capacity. POLYM. ENG. SCI., 45:1515–1521, 2005. © 2005 Society of Plastics Engineers     

Adsorptive removal of anionic and non‐ionic surfactants from aqueous phase using Posidonia oceanica (L.) marine biomass

BACKGROUND: In this study, the capability of low‐cost, renewable and abundant marine biomass Posidonia oceanica (L.) for adsorptive removal of anionic and non‐ionic surfactants from aqueous solutions have been carried out in batch mode. Several experimental key parameters were investigated including exposure time, pH, temperature and initial surfactant concentration. RESULTS: It was found that the highest surfactant adsorption capacities reached at 30 °C were determined as 2.77 mg g^?1 for anionic NaDBS and as 1.81 mg g^?1 for non‐ionic TX‐100, both at pH 2. The biosorption process was revealed as a thermo‐dependent phenomenon. Equilibrium data were well described by the Langmuir isotherm model, suggesting therefore a homogeneous sorption surface with active sites of similar affinities. The thermodynamic constants of the adsorption process (i.e. ΔG°, ΔH° and ΔS°) were respectively evaluated as ? 8.28 kJ mol^?1, 48.07 kJ mol^?1 and ? 42.38 J mol^?1 K^?1 for NaDBS and ? 9.67 kJ mol^?1, 95.13 kJ mol^?1 and ? 174.09 J mol^?1 K^?1 for TX‐100. CONCLUSION: Based on this research, valorization of highly available Posidonia oceanica biomass, as biological adsorbent to remove anionic and non‐ionic surfactants, seems to be a promising technique, since the sorption systems studied were found to be favourable, endothermic and spontaneous. Copyright © 2007 Society of Chemical Industry     

Kinetics of the liquid phase dehydration of 1‐octanol to di‐n‐octyl ether on Amberlyst 70

The kinetics of the liquid phase dehydration of 1‐octanol to di‐n‐octyl ether (DNOE) over Amberlyst 70 was studied at 413–453 K. Mechanistic rate models assuming water and 1‐octanol adsorbed on the resin, and the free sites fraction negligible, were selected from 1‐octanol dehydration experiments. Next, the influence of DNOE, water, and 1,4‐dioxane (solvent) concentration was evaluated. DNOE and 1,4‐dioxane do not affect significantly the reaction rate, while water inhibits it strongly. Water effect was quantified by splitting the rate constant into a “true one” and a correction factor related to the fraction of active sites blocked by water. The best kinetic model stemmed from an Eley‐Rideal mechanism with water adsorbed onto the resin and DNOE released directly to the liquid phase, with a correction factor for water inhibitory effect based on a Freundlich isotherm‐like function; activation energy being 110 ± 5 kJ·mol^?1, in line with literature data on homologous reactions. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3966–3978, 2017     

Toughening modification of (Acrylonitrile‐styrene‐acrylic copolymer)/(α‐Methylstyrene‐acrylonitrile copolymer) binary blend via using different impact modifiers

In this work, different impact modifiers such as acrylic resin impact modifier, chlorinated polyethylene (CPE), nitrile rubber, powdered nitrile rubber, and hydrogenated nitrile rubber, were chosen to improve the toughness of (acrylonitrile‐styrene‐acrylic copolymer)/(α‐methylstyrene‐acrylonitrile copolymer) (ASA/α‐MSAN) binary blend. The blend ratios of the ASA/(α‐MSAN)/(impact modifier) ternary system were 30/70/20 and 70/30/20 by mass, respectively. The results showed that the impact strength significantly increased, nearly 30 times (22.59 kJ·m^?2, 22.26 kJ·m^?2, and 25.24 kJ·m^?2) compared with that of control samples (0.80 kJ·m^?2) when nitrile rubber, powdered nitrile rubber, or hydrogenated nitrile rubber was added to the ASA/(α‐MSAN) (30/70) matrix, respectively. Moreover, the impact strength of ASA/(α‐MSAN) (70/30) was dramatically enhanced to 46 kJ·m^?2 with the addition of 20 parts by weight per hundred parts of resin of chlorinated polyethylene. The toughness of ASA/(α‐MSAN) with or without impact modifiers was also characterized via fracture energy calculated from stress‐strain curves. The results were perfectly consistent with that of impact strength. The results of dynamic mechanical analysis demonstrated the existence of α‐MSAN (glass transition temperature at approximately 140°C). The heat distortion temperature was barely changed, indicating the addition of impact modifiers barely affects the heat resistance. J. VINYL ADDIT. TECHNOL., 22:326–335, 2016. © 2014 Society of Plastics Engineers     

Studies on two‐dimensional coordination polymer cadmium phosphate and its high efficient adsorption of Pb(II) ions from aqueous solutions

The two‐dimensional coordination polymer cadmium phosphate with the morphology of rectangle layers was prepared by solid‐state template reaction at room temperature, and was characterized by XRD, FTIR, and TEM techniques. The as‐synthesized sample is a layered cadmium phosphate material, in which the structure is poly (CdPO₄^?) anion framework with ammonium ions and water species residing in the space between the layers, and cadmium ions are coordinated by the phosphate oxygen atoms. This article also presents the adsorption of Pb(II) ions from aqueous solution on the as‐synthesized coordination polymer cadmium phosphate, and the results showed that this inorganic polymer adsorbent had good adsorption capacity. It could reach to the saturation adsorption capacity within an hour, and its excellent adsorption capacity for Pb(II) was 5.50 mmol/g when the initial solution concentration was 1.68 × 10³ μg/mL at T = 278K. Moreover, the adsorption kinetics and adsorption isotherms were studied, it revealed that the adsorption kinetics can be modeled by pseudo second‐order rate equation wonderfully. The apparent activation energy (E_a), ΔG, ΔH, and ΔS were 3.16 kJ mol^?1, ?13.97 kJ mol^?1, ?11.84 kJ mol^?1, and 7.66 J mol^?1 K^?1, respectively. And it was found that Langmuir equation could well interpret the adsorption of the as‐synthesized coordination polymer cadmium phosphate for Pb(II) ions. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis,characterization, and properties for Hg2+ of new chelating resin containing sulfoxide and 3‐aminopyridine

A new chelating resin (PVESO‐AP) containing sulfoxide and 3‐aminopyridine (AP) was synthesized by using chloromethylated polystyrene‐co‐divinylbenzene (PS‐Cl) as material. Its structure was characterized by infrared spectra and elemental analysis. The adsorption capacities of the newly formed resin for Hg²⁺, Ag⁺, Cu²⁺, Zn²⁺, Cd²⁺, and Ni²⁺ were determined at pH 2 and 5. In addition, the adsorption selective coefficients for Hg²⁺ in several binary mixture systems were investigated by batch experiment method. The results showed that this resin had high adsorption selectivity for Hg²⁺. The adsorption kinetics and isothermal of PVESO‐AP for Hg²⁺ at different temperatures were also investigated. The adsorption kinetics showed that the apparent activation energy E_a was 13.71 kJ/mol. The results also showed that the Langmuir model was better than the Frundlich model to describe the isothermal process of PVESO‐AP resin for Hg²⁺. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Polystyrene composites of single‐walled carbon nanotubes‐graft‐polystyrene

Single‐walled carbon nanotubes (SWCNTs) dispersed in N‐methylpyrrolidone (NMP) were functionalized by addition of polystyryl radicals from 2,2,6,6‐tetramethyl‐1‐piperidinyloxy‐ended polystyrene (SWCNT‐g‐PS). The amount of polystyrene grafted to the nanotubes was in the range 20‐25 wt% irrespective of polystyrene number‐average molecular weight ranging from 2270 to 49 500 g mol^?1. In Raman spectra the ratios of D‐band to G‐band intensity were similar for all of the polystyrene‐grafted samples and for the starting SWCNTs. Numerous near‐infrared electronic transitions of the SWCNTs were retained after polymer grafting. Transmission electron microscopy images showed bundles of SWCNT‐g‐PS of various diameters with some of the polystyrene clumped on the bundle surfaces. Composites of SWCNT‐g‐PS in a commercial‐grade polystyrene were prepared by precipitation of mixtures of the components from NMP into water, i.e. the coagulation method of preparation. Electrical conductivities of the composites were about 10^?15 S cm^?1 and showed no percolation threshold with increasing SWCNT content. The glass transition temperature (T_g) of the composites increased at low filler loadings and remained constant with further nanotube addition irrespective of the length and number of grafted polystyrene chains. The change of heat capacity (ΔC_p) at T_g decreased with increasing amount of SWCNT‐g‐PS of 2850 g mol^?1, but ΔC_p changed very little with the amount of SWCNT‐g‐PS of higher molecular weight. The expected monotonic decrease in ΔC_p coupled with the plateau behavior of T_g suggests there is a limit to the amount that T_g of the matrix polymer can increase with increasing amount of nanotube filler. Copyright © 2012 Society of Chemical Industry     

Synergistic extraction and separation study of rare earth elements from nitrate medium by mixtures of sec‐nonylphenoxy acetic acid and 2,2′‐bipyridyl

BACKGROUND: Synergistic extraction has been proven to enhance extractability and selectivity. Numerous types of synergistic extraction systems have been applied to rare earth elements, among which sec‐nonylphenoxyacetic acid (CA100) has proved to be an excellent synergistic extractant. In this study, the synergistic enhancement of the extraction of holmium(III) from nitrate medium by mixtures of CA100 (H₂A₂) with 2,2′‐bipyridyl (bipy, B) in n‐heptane has been investigated. The extraction of all other lanthanides (except polonium) and yttrium by the mixtures in n‐heptane has also been studied. RESULTS: Mixtures of CA100 and bipy have significant synergistic effects on all rare earth elements, for example holmium(III) is extracted as Ho(NO₃)₂HA₂B with the mixture instead of HoH₂A₅, which is extracted by CA100 alone. The thermodynamic functions, ΔH^o, ΔG^o, and ΔS^o have been calculated as 2.96 kJ mol^?1, ? 6.23 kJ mol^?1, and 31.34 J mol^?1 K^?1, respectively. CONCLUSION: Methods of slope analysis and constant molar ratio have been successfully applied to study the synergistic extraction stoichiometries of holmium(III) by mixtures of CA100 and bipy. Mixtures of these extractants have also shown various synergistic effects with other rare earth elements, making it possible to separate them. Thus CA100 + bipy may be used to separate yttrium from other lanthanides at appropriate ratios of the extractants. Copyright © 2011 Society of Chemical Industry     

Preparation of poly(styrene‐b‐2‐hydroxyethyl acrylate) block copolymer using reverse iodine transfer polymerization

Reverse iodine transfer polymerizations (RITP) of 2‐h‐ydroxyethyl acrylate (HEA) were performed in N,N‐dimethylformamide at 75°C using AIBN as initiator. Poly(2‐hydroxyethyl acrylate) (PHEA) with M_n = 3300 g mol^?1 and M_w/M_n <1.5 were obtained. Homopolymerization of styrene in RITP was also carried out under similar conditions using toluene as solvent. The resulting iodo‐polystyrene (PS‐I) with (M_{n, SEC} = 607 g mol^?1, polydispersity index (PDI) = 1.31) was used as a macroinitiator for the synthesis of amphiphilic block copolymers based on HEA with controlled well‐defined structure. Poly(styrene‐b‐2‐hydroxyethyl acrylate) (PS‐b‐PHEA) with M_n = 13,000 g mol^?1 and polydispersity index (M_w/M_n) = 1.4 was obtained, copolymer composition was characterized using ¹H‐NMR and FTIR, whereas SEC and gradient HPLC were used to confirm the formation of block copolymer and the living character of polymer chains. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Extraction and Adsorption Behavior of Co(II) on HTTA-Impregnated Polyurethane Foam

Abstract

The batch extraction of Co(II) from aqueous solutions with open cell polyethertype HTTA-loaded polyurethane (PU) foam has been studied using a radiotracer technique. The effect of pH, shaking time, and loading capacity has been investigated. The membrane properties of loaded PU foam sorbent offer unique advantage of adsorption. The fundamental studies of adsorption show that the classical Freundlich and Langmuir isotherms are followed in the entire concentration range of a 10^?5 to 10^?2 M solution of cobalt. The sorption mean free energy from the Dubinin-Radushkevich isotherm is found to be 13.8 kJ·mol^?1 and the loading capacity 4.44 mg·g^?1, suggesting that the ion-exchange or chemisorption mechanism operates. The kinetic parameters of adsorption also support a chemisorption mechanism and the first-order rate law. The rate constants and activation energies of sorption and desorption have been evaluated. The thermodynamic function of adsorption of ΔH, ΔS, ΔG, and equilibrium constant K _c have been calculated. The process of adsorption is established to be endothermic and chemisorption, stabilized through thermodynamic functions.     

Synthesis and biological activity of medium range molecular weight polymers containing exo‐3,6‐epoxy‐1,2,3,6‐tetrahydrophthalimidocaproic acid

A new monomer, exo‐3,6‐epoxy‐1,2,3,6‐tetrahydrophthalimidocaproic acid (ETCA), was prepared by reaction of maleimidocaproic acid and furan. The homopolymer of ETCA and its copolymers with acrylic acid (AA) or with vinyl acetate (VAc) were obtained by photopolymerizations using 2,2‐dimethoxy‐2‐phenylacetophenone as an initiator at 25 °C. The synthesized ETCA and its polymers were identified by FTIR, ¹H NMR and ¹³C NMR spectroscopies. The apparent average molecular weights and polydispersity indices determined by gel permeation chromatography (GPC) were as follows: M_n = 9600 g mol^?1, M_w = 9800 g mol^?1, M_w/M_n = 1.1 for poly(ETCA); M_n = 14 300 g mol^?1, M_w = 16 200 g mol^?1, M_w/M_n = 1.2 for poly(ETCA‐co‐AA); M_n = 17 900 g mol^?1, M_w = 18 300 g mol^?1, M_w/M_n = 1.1 for poly(ETCA‐co‐VAc). The in vitro cytotoxicity of the synthesized compounds against mouse mammary carcinoma and human histiocytic lymphoma cancer cell lines decreased in the following order: 5‐fluorouracil (5‐FU) ≥ ETCA > polymers. The in vivo antitumour activity of the polymers against Balb/C mice bearing sarcoma 180 tumour cells was greater than that of 5‐FU at all doses tested. © 2001 Society of Chemical Industry     

Synthesis and biological activity of phthalimide‐based polymers containing 5‐fluorouracil

The attachment of anticancer agents to polymers is a promising approach towards reducing the toxic side‐effects and retaining the potent antitumour activity of these agents. A new tetrahydrophthalimido monomer containing 5‐fluorouracil (ETPFU) and its homopolymer and copolymers with acrylic acid (AA) and with vinyl acetate (VAc) have been synthesized and spectroscopically characterized. The ETPFU contents in poly(ETPFU‐co‐AA) and poly(ETPFU‐co‐VAc) obtained by elemental analysis were 21 mol% and 20 mol%, respectively. The average molecular weights of the polymers determined by gel permeation chromatography were as follows: M_n = 8900 g mol^?1, M_w = 13 300 g mol^?1, M_w/M_n = 1.5 for poly(ETPFU); M_n = 13 500 g mol^?1, M_w = 16 600 g mol^?1, M_w/M_n = 1.2 for poly(ETPFU‐co‐AA); M_n = 8300 g mol^?1, M_w = 11 600 g mol^?1, M_w/M_n = 1.4 poly(ETPFU‐co‐VAc). The in vitro cytotoxicity of the compounds against FM3A and U937 cancer cell lines increased in the following order: ETPFU > 5‐FU > poly(ETPFU) > poly(ETPFU‐co‐AA) > poly(ETPFU‐co‐VAc). The in vivo antitumour activities of all the polymers in Balb/C mice bearing the sarcoma 180 tumour cell line were greater than those of 5‐FU and monomer at the highest dose (800 mg kg^?1). © 2002 Society of Chemical Industry     

Studies on the solvent extraction of rare earths from nitrate media with a combination of di‐(2‐ethylhexyl)phosphoric acid and sec‐octylphenoxyacetic acid

BACKGROUND: Di‐(2‐ethylhexyl)phosphoric acid (D2EHPA, H₂A₂) has been used extensively in hydrometallurgy for the extraction of rare earths, but it has some limitations. Synergistic extraction has attracted much attention because of its enhanced extractabilities and selectivities. In the present study, sec‐octylphenoxyacetic acid (CA12, H₂B₂) was added into D2EHPA systems for the extraction and separation of rare earths. The extraction mechanism of lanthanum with the mixtures and the separation of lanthanoids and yttrium were investigated. RESULTS: The synergistic enhancement coefficient for La³⁺ extracted with D2EHPA + CA12 was calculated as 3.63. La³⁺ was extracted as La(NO₃)₂H₂A₂B with the mixture. The logarithm of the equilibrium constant was determined as 0.80. The thermodynamic functions, ΔH, ΔG, and ΔS were calculated to be 4.03 kJ mol^?1, ? 1.96 kJ mol^?1, and 20.46 J mol^?1 K^?1, respectively. The mixtures have synergistic effects on Ce³⁺, Nd³⁺, and Y³⁺, with an especially strong synergistic effect on Y³⁺. Neither synergistic nor antagonistic effects on Dy³⁺ and weak antagonistic effects on Lu³⁺ were found. CONCLUSION: Mixtures of D2EHPA and CA12 exhibit evident synergistic effects when used to extract La³⁺ from nitric solution. The stoichiometries of the extracted complexes have been determined by graphical and numerical methods to be La(NO₃)₂H₂A₂B with the mixture. The extraction is an endothermic process. The mixture exhibits different extraction effects on rare earths, which provides possibilities for the separation of Y³⁺ from Ln³⁺ at a proper ratio of D2EHPA and CA12. Copyright © 2008 Society of Chemical Industry     

Solvent extraction studies of Sm(III) from nitrate medium and separation factors of rare earth elements with mixtures of sec‐octylphenoxyacetic acid and 1,10‐phenthroline

BACKGROUND: Liquid–liquid extraction is widely used for the separation of rare earths, among which synergistic extraction has attracted more and more attention. Numerous types of synergistic extraction systems have been applied to rare earths with high extraction efficiency and selectivities. In the present study, mixtures of sec‐octylphenoxyacetic acid (CA12, H₂A₂) and 1,10‐phenanthroline (phen, B) have been used for the extraction of rare earths from nitrate medium. The stoichiometry of samarium(III) extraction has been studied using the methods of slope analysis and constant molar ratio. The possibility of using synergistic extraction effects to separate rare earths has also been studied. RESULTS: Mixtures of CA12 and phen display synergistic effects in the extraction of rare earth elements giving maximum enhancement coefficients of 5.5 (La); 13.7 (Nd); 15.9 (Sm); 24.5 (Tb); 45.4 (Yb) and 12.3 (Y). Samarium(III) is extracted as SmHA₄B₃ with mixtures of CA12 and phen instead of SmHA₄ when extracted with CA12 alone. The calculated logarithm of the equilibrium constant is 6.0 and the thermodynamic functions, ΔH, ΔG, and ΔS, have been calculated as 4.3 kJ mol^?1, ? 33.7 kJ mol^?1 and 129.7 J mol^?1 K^?1, respectively. CONCLUSION: Mixtures of CA12 and phen exhibit synergistic effects on rare earth elements. Graphical and numerical methods have been successfully used to determine their stoichiometries. The different synergistic effects may provide the possibility of separating yttrium from heavy lanthanoids at an appropriate ratio of CA12 and phen. Copyright © 2010 Society of Chemical Industry     

Study on adsorption performance of 2-amino-4-methylbenzothiazole onto chemical modification adsorption resins

A series of functional hyper-cross-linked resins were successfully synthesized by incorporating anhydride, sulfoacid and menthanone groups into post-cross-linked polymer. They were evaluated for adsorption of 2-amino-4-methylbenzothiazole (2A4MBT) from aqueous solution. The five resins were efficient for adsorption of 2A4MBT from aqueous solution. The adsorption process includes both physical adsorption and irreversible chemical adsorption. The absolute value of adsorption enthalpy had an order of PRLMR (3.24 kJ mol^?1) < IDLMR (7.96 kJ mol^?1) < TMAMR (9.72 kJ mol^?1) < PAMR (?13.1 kJ mol^?1) < SAMR (21.8 kJ mol^?1). Phthalic anhydride-modified resin could be regenerated by 10% HCl/methanol solution after adsorption equilibrium.     

Synthesis,characterization, conductivity,band gap,and kinetic of thermal degradation of poly‐4‐[(2‐mercaptophenyl) imino methyl] phenol

The oxidative polycondensation reaction conditions of 4‐[(2‐mercaptophenyl) imino methyl] phenol (2‐MPIMP) were studied in an aqueous acidic medium between 40 and 90°C by using oxidants such as air, H₂O₂, and NaOCl. The structures of the synthesized monomer and polymer were confirmed by FTIR, ¹H NMR, ¹³C NMR, and elemental analysis. The characterization was made by TGA‐DTA, size exclusion chromatography (SEC) and solubility tests. At the optimum reaction conditions, the yield of poly‐4‐[(2‐mercaptophenyl) imino methyl]phenol (P‐2‐MPIMP) was found to be 92% for NaOCl oxidant, 84% for H₂O₂ oxidant 54% for air oxidant. According to the SEC analysis, the number‐average molecular weight (M_n), weight‐average molecular weight (M_w), and polydispersity index values of P‐2‐MPIMP were found to be 1700 g mol^?1, 1900 g mol^?1, and 1.118, using H₂O₂; 3100 g mol^?1, 3400 g mol^?1, and 1.097, using air; and 6750 g mol^?1, 6900 g mol^?1, and 1.022, using NaOCl, respectively. According to TG analysis, the weight losses of 2‐MPIMP and P‐2‐MPIMP were found to be 95.93% and 76.41% at 1000°C, respectively. P‐2‐MPIMP showed higher stability against thermal decomposition. Also, electrical conductivity of the P‐2‐MPIMP was measured, showing that the polymer is a typical semiconductor. The highest occupied molecular orbital, the lowest unoccupied molecular orbital, and the electrochemical energy gaps (E′_g) of 2‐MPIMP and P‐2‐MPIMP were found to be ?6.13, ?6.09; ?2.65, ?2.67; and 3.48, 3.42 eV, respectively. Kinetic and thermodynamic parameters of these compounds investigated by MacCallum‐Tanner and van Krevelen methods. The values of the apparent activation energies of thermal decomposition (E_a), the reaction order (n), pre‐exponential factor (A), the entropy change (ΔS*), enthalpy change (ΔH*), and free energy change (ΔG*) were calculated from the TGA curves of compounds. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009