Polyphenylene sulfide‐based adsorption resins: synthesis,characterization and adsorption performance for Hg(II) and As(V)

A series of novel adsorption resins were synthesized via the chloromethylation of polyphenylene sulfide (PPS) resin and subsequent functional group conversion reaction. Their chemical structure, thermal stability, and morphology were systematically characterized by the Fourier transform infrared spectroscopy, elemental analysis, Raman spectroscopy, thermogravimetric analysis, scanning electron microscope, and energy dispersive spectrometer, respectively. The experimental results showed that the thioureido, mercapto, aminopyridine, and quaternary ammonium groups had been respectively introduced into PPS matrix, the functional group content of PPS‐based mercapto resin (HS‐PPS), aminopyridine resin (AP‐PPS), and quaternary ammonium resin (QA‐PPS) were about 2.20, 1.71, and 2.61 mmol g^?1, respectively. The adsorptive performance for Hg (II) and As (V) were studied by batch adsorptive method; the adsorption capacities of the HS‐PPS and AP‐PPS resin for Hg (II) were 210.65 and 169.06 mg g^?1. The adsorption capacity of the QA‐PPS resin was 88 mg g^?1 for As (V). Copyright © 2017 John Wiley & Sons, Ltd.     

Selective Pre-concentration and Solid Phase Extraction of Mercury（Ⅱ） from Natural Water by Silica Gel-loaded （E）-N-（1-Thien-2＇-ylethylidene）-1,2-phenylenediamine Phase

Silica gel-loaded （E）-N-（1-thien-2＇-ylethylidene）-1,2-phenylenediamine （TEPDA） phase was synthesized based on physical adsorption approaches. The stability of a chemically modified TEPDA especially in concentrated hydrochloric acid that was then used as a recycling and preconcentration reagent allowed the further uses of silica gel-loaded immobilized TEPDA phase. The application of this silica gel-loaded phase to sorption of a series of metal ions was performed by using different controlling factors such as the pH of the metal ion solution and the equilibration shaking time by the static technique. This difference was interpreted on the basis of selectivity incorporated in these sulfur containing silica gel-loaded TEPDA phases. Hg（Ⅱ） was found to exhibit the highest affinity towards extraction by these silica gel-loaded TEPDA phases. The pronounced selectivity was also confirmed by the determined distribution coefficients （Kd） of all the metal ions, showing the highest value reported for mercury（Ⅱ） extraction by the silica gel immobilized TEPDA phase. The potential applications of the silica gel immobilized TEPDA phase to selective extraction of mercury（Ⅱ） from aqueous solution were successfully accomplished and preconcentration of low concentration of Hg（Ⅱ） （30 pg·mL^-1） from natural tap water with a preconcentration factor of 200 for Hg（Ⅱ） off-line analysis was conducted by cold vapor atomic absorption analysis.     

Effective removal of 2,4,6‐trinitrophenol over hexagonal metal–organic framework NH2‐MIL‐88B(Fe)

A nanostructured organic–inorganic framework, hexagonal NH₂‐MIL‐88B, has been prepared through a facile one‐pot reflux reaction and then it was characterized using various techniques. The as‐prepared sample with high specific surface area (414 m² g^?1) showed excellent adsorption for 2,4,6‐trinitrophenol (TNP) in the liquid phase. Detailed studies of the adsorption kinetics, adsorption mechanism, adsorption isotherm, activation energy and various thermodynamic parameters were conducted. The adsorption mechanism of NH₂‐MIL‐88B for TNP may be ascribed to hydrogen bond interaction, and the complexation between ─OH in TNP and unsaturated Fe(III) on the surface of NH₂‐MIL‐88B. The maximum adsorption capacity of NH₂‐MIL‐88B for TNP based on the Langmuir isotherm was 163.66 mg g^?1. The as‐prepared NH₂‐MIL‐88B adsorbent seems to be a promising material in practice for TNP removal from aqueous solution.     

Synthesis and Application of Co‐Poly(2‐hydroxyethyl methacrylate‐ethylene dimethacrylate) Coupled with Alizarin Yellow for Preconcentration and Determination of Lead in Water Samples by Flame Atomic Absorption Spectrometry

Poly(2‐hydroxyethyl methacrylate‐ethylene dimethacrylate) (PHEMA‐EDMA) beads were produced by free radical co‐polymerization of 2‐hydroxyethyl methacrylate (HEMA) and ethylene dimethacrylate (EDMA). Then, metal complexing ligand alizarin yellow was covalently attached onto PHEMA‐EDMA beads. The resulting resin has been characterized by FT‐IR and studied for the preconcentration and determination of trace Pb(II) ion from solution samples. The optimum pH value for sorption of the metal ion was 5. The sorption capacity of functionalized resin is 100 mg.g^‐1. The chelating resin can be reused for 20 cycles of sorption‐desorption without any significant change in sorption capacity. A recovery of 96% was obtained for the metal ion with 0.1 M nitric acid as eluting agent. The equilibrium adsorption data of Pb(II) on modified resin were analyzed by Langmuir and Freundlich models. Based on equilibrium adsorption data the Langmuir and Freundlich constants were determined 2.571 and 418.7 at pH 5 and 25 °C. The method was applied for lead ions determination from well water sample.     

Adsorption of aqueous Hg (II) by a novel poly(aniline‐co‐o‐aminophenol)/mesoporous silica SBA‐15 composite

A novel poly(aniline‐co‐o‐aminophenol) (PAOA)/mesoporous silica SBA‐15 nanocomposite was synthesized and investigated for adsorption of Hg (II) from aqueous solutions of wide pH range. A chemical oxidation method was employed for polymerization of aniline and o‐aminophenol on an ordered SBA‐15 template to obtain a significantly enlarged BET surface area of the adsorbent. Efficiency study revealed that the PAOA/SBA‐15 could reach a maximum Hg (II) adsorption capacity of over 400 mg/g. Kinetic study showed that the Hg (II) adsorption by the PAOA/SBA‐15 fitted a pseudo‐second‐order kinetic model, indicating that the mercury adsorption process was predominantly controlled by chemical process. The results of this study also proved that the adsorbed Hg (II) could be effectively desorbed from the PAOA/SBA‐15 in 0.1M HCl and 5% sulfocarbonide solutions. Associated adsorption mechanism was also investigated by means of Fourier transform infrared (FTIR) and X‐ray photoelectron spectroscopy (XPS) techniques. Copyright © 2010 John Wiley & Sons, Ltd.     

Synthesis and application of modified poly (styrene‐alt‐maleic anhydride) networks as a nano chelating resin for uptake of heavy metal ions

A chelating resin based on modified poly (styrene‐alt‐maleic anhydride) with 3‐aminobenzoic acid was synthesized. This modified resin was further reacted by 1,2‐diaminoethane or 1,3‐diaminopropane in the presence of ultrasonic irradiation to prepare tridimensional chelating resin for the removal of heavy metal ions from aqueous solutions. The adsorption behavior of Fe(II), Cu(II), Zn(II) and Pb(II) ions was investigated by synthesized chelating resins in various pH. Among the synthesized resins, CSMA‐AB1 and CSMA‐AB2 demonstrated a high affinity for the selected metal ions compared to SMA‐AB, and the order of removal percentage changes as follow: Fe(II) > Cu(II) > Zn(II) > Pb(II). The adsorption of all metal ions in acidic medium was moderate, and it was favored at the pH value of 6 and 7. Also, the prepared resins were examined for removal of metal ions from industrial wastewater and were shown to have a very efficient adsorption in the case of Cu(II), Fe(II) and Pb(II); however, the adsorption of Zn(II) was lower than others. The resin was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X‐ray diffraction analysis and thermogravimetric analysis/derivative thermogravimetry. Copyright © 2012 John Wiley & Sons, Ltd.     

Surface‐initiated atom transfer radical polymerization of a new rhodanine‐based monomer for rapid magnetic removal of Co(II) ions from aqueous solutions

The present study reports synthesis and characterization of a new acrylamide‐based monomer containing rhodanine moiety, N‐3‐amino‐thiazolidine‐4‐one‐acrylamide (ATA). Poly(ATA)‐grafted magnetite nanoparticles (poly(ATA)‐g‐MNPs) were prepared using surface‐initiated atom transfer radical polymerization of the monomer on Fe₃O₄ nanoparticles. The grafted nanoparticles were characterized by Fourier transform infrared analysis, scanning electron microscopy, X‐ray diffraction, and vibrating sample magnetometry. The amount of the grafted polymer was 209 mg g⁻¹, as calculated from thermogravimetric analysis experiment. The capability of poly(ATA)‐g‐MNPs to remove Co(II) cations was shown under optimal conditions of contact time, pH, adsorbent dosage, and initial Co(II) concentration. About 86% of the Co(II) cations were removed over 7 minutes. The adsorption kinetics obeyed the pseudo–second‐order kinetic equation, and the Langmuir isotherm model best described the adsorption isotherm with a maximum adsorption capacity of 3.62 mg g⁻¹. The thermodynamic investigation showed spontaneous nature of the adsorption process (ΔG = −2.90 kJ mol⁻¹ at 25°C ± 1°C). In addition, the poly(ATA)‐g‐MNPs were regenerated by simply washing with an aqueous 0.1M HCl solution. The study of the reusability of the prepared magnetic sorbent revealed that the sorbent can be reused without a significant decrease in the extraction efficiency and be recovered by 95.4% after 7 cycles. These findings suggest that the grafted nanoparticles are stable and reusable adsorbent and can be potentially applied to water treatment in efficient removal of Co(II) cations.     

Bimetallic Ni–Co‐based metal–organic framework: An open metal site adsorbent for enhancing CO2 capture

An open metal site framework named UTSA‐16 was synthesized and modified as a high‐capacity adsorbent for reversible CO₂ capture. Partial substitution of intrinsic Co²⁺ sites of UTSA‐16 with Ni²⁺ centres was realized in the molar composition range 0–75% Ni with the aim of increasing CO₂ uptake. Synthesized bimetallic Nix‐UTSA‐16 (x = 0, 20, 50, 75) materials were characterized using various techniques to assess the influence of chemical composition on CO₂ binding affinity and any subsequent physical change in morphology, crystal size and porosity on the total uptake. Experimental isotherm adsorption studies showed the following trend for CO₂ adsorption capacity employing the Nix‐UTSA‐16 series: Ni20‐UTSA‐16 > UTSA‐16 > Ni50‐UTSA‐16 > Ni75‐UTSA‐16. According to the dynamic breakthrough CO₂ profiles measured for a mixture of CO₂ and CH₄ (15/85 molar ratio), Ni20‐UTSA‐16 exhibited 2 times the breakthrough time with 1.5 times the loading capacity at 75 Nml min^?1 feed flow rate, compared to the parent UTSA‐16. In addition, the Ni20‐UTSA‐16 bimetallic metal–organic framework exhibited lower isosteric heat of adsorption compared to UTSA‐16 (ΔH_ave = 28.54 versus 46.85 kJ mol^?1). As a result, more than 95% of its capacity was restored by applying a partial vacuum for only 1 h at room temperature without involving any other time‐ and energy‐consuming regenerative step.     

Azido chelating fiber: synthesis,characterization and adsorption performances towards Hg2+ and Pb2+ from water

Herein, we report the synthesis and adsorption property of a novel chelating fiber containing azido group. Firstly, the brominated fiber (PP‐St‐DVB‐Br) was obtained via the reaction of polypropylene‐(g)‐styrene‐divinylbenzene fiber (PP‐St‐DVB) with bromine in CH₂Cl₂ solution. Then, azido chelating fiber (PP‐St‐DVB‐N₃) was prepared by azidation of PP‐St‐DVB‐Br fiber. Its structure and properties were characterized by Fourier transform infrared, elemental analysis, thermogravimetric analysis, and chemical titration, respectively. The micromophology and functional group distribution in fibrous matrix were investigated by scanning electron microscopy‐energy dispersive spectroscopy. The results show that the chelating fiber has high functional group contents (2.11 mmol/g for PP‐St‐DVB‐N₃) and uniform distribution. Different from granulate chelating resin, the novel fibrous adsorbent possesses excellent adsorption ability for Hg(II) and Pb(II) ions (408.9 mg/g for Hg²⁺ and 334.4 mg/g for Pb²⁺), and the adsorption capacity of the fiber has no loss until five cycles. The novel absorbent material shows the potential application prospect in the treatment of heavy metal wastewater. Copyright © 2017 John Wiley & Sons, Ltd.     

Preparation of ferric nitrate–graphene nanocomposite and its adsorption of arsenic(V) from simulated arsenic‐containing wastewater

Ferric nitrate–graphene (FG) nanocomposites synthesized via the equivalent‐volume impregnation method were used for the removal of As(V) species from simulated arsenic‐containing wastewater. Effects of various factors were assessed, such as the reaction temperature, solution pH, adsorbent dosage, and reaction time. The results indicated that the As(V) removal efficiency was as high as 99%, and the concentration of arsenic‐containing wastewater after FG treatment was as low as 9.4 μg L^–1 as a result of the optimal absorption capacity and maximum specific surface area (171.766 m²/g) of this material. The equilibrium adsorption capacity of FG for As(V) was achieved in approximately 20 min, and the maximum adsorption capacity was calculated to be 112.4 mg g^–1 by Langmuir adsorption isotherm, which was higher than that of other adsorbents such as manganese‐incorporated iron(III) oxide–graphene (14.42 mg g^–1). Moreover, the removal efficiency of As(V) can be maintained above 95% under acidic and alkaline conditions. Brunauer–Emmett–Teller analysis showed that the modified FG pore structure was regular. Based on the characterizations by X‐ray diffraction, X‐ray photoelectron spectroscopy, and Fourier transform infrared, the products on the surface of the used FG were Fe(OH)₃, FeAsO₄, and other compounds, and As(V) was mainly removed by the formation of insoluble compounds and coprecipitation.     

Determination of 3‐chloro‐1,2‐propanediol in polyamideamine epichlorohydrin resin solution by reaction‐based headspace gas chromatography

We report on a headspace gas chromatographic method for determining the content of 3‐chloro‐1,2‐propanediol in polyamideamine epichlorohydrin resin solution. It was based on quantitatively converting 3‐chloro‐1,2‐propanediol to formaldehyde by periodate oxidation in a closed headspace sample vial at a room temperature for 10 min, and then to methanol by borohydride reduction at 90°C for 40 min followed by the headspace gas chromatographic measurement. The results showed that the present method has an excellent measurement precision (relative standard deviation < 2.60%) and accuracy (recoveries from 96.4–102%) in 3‐chloro‐1,2‐propanediol analysis. The limit of quantitation was 0.031 mg/mL. It is simple and suitable for determining the 3‐chloro‐1,2‐propanediol content in polyamideamine epichlorohydrin resin solution.     

Study of adsorption and preconcentration by using a new silica organomodified with [3‐(2,2′‐dipyridylamine)propyl] groups

In this work, a silica surface chemically modified with [3‐(2,2′‐dipyridylamine)propyl] groups, named [3‐(2,2′‐dipyridylamine)propyl]silica (Si‐Pr‐DPA) was prepared, characterized, and evaluated for its heavy metal adsorption characteristics from aqueous solution. To our knowledge, we are the first authors who have reported the present modification. The material was characterized using infrared spectroscopy, SEM, and NMR ²⁹Si and ¹³C solid state. Batch and column experiments were conducted to investigate for heavy metal removal from dilute aqueous solution by sorption onto Si‐Pr‐DPA. From a number of studies the affinity of various metal ions for the Si‐Pr‐DPA sorbent was determined to follow the order Fe(III) > Cr(III) >> Cu(II) > Cd(II) > Pb(II) > Ni(II). Two standard reference materials were used for checking the accuracy and precision of the method. The proposed method was successfully applied to the analysis of environmental samples. This ligand material has great advantage for adsorption of transition‐metal ions from aqueous medium due to its high degree of organofunctionalization associated with the large adsorption capacity, reutilization possibility, and rapidity in reaching the equilibrium.     

Poly(N‐phenylmaleimide‐co‐acrylic acid)–copper(II) and poly(N‐phenylmaleimide‐co‐acrylic acid)–cobalt(II) complexes: Synthesis,characterization, and thermal behavior

The free‐radical copolymerization of N‐phenylmaleimide (N‐PhMI) with acrylic acid was studied in the range of 25–75 mol % in the feed. The interactions of these copolymers with Cu(II) and Co(II) ions were investigated as a function of the pH and copolymer composition by the use of the ultrafiltration technique. The maximum retention capacity of the copolymers for Co(II) and Cu(II) ions varied from 200 to 250 mg/g and from 210 to 300 mg/g, respectively. The copolymers and polymer–metal complexes of divalent transition‐metal ions were characterized by elemental analysis, Fourier transform infrared, ¹H NMR spectroscopy, and cyclic voltammetry. The thermal behavior was investigated with differential scanning calorimetry (DSC) and thermogravimetry (TG). The TG and DSC measurements showed an increase in the glass‐transition temperature (T_g) and the thermal stability with an increase in the N‐PhMI concentration in the copolymers. T_g of poly(N‐PhMI‐co‐AA) with copolymer composition 46.5:53.5 mol % was found at 251 °C, and it decreased when the complexes of Co(II) and Cu(II) at pHs 3–7 were formed. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4933–4941, 2005     

Synthesis of Poly[(hydroxyethyl methacrylate)‐co‐(methacrylamidoalanine)] Membranes and Their Utilization as an Affinity Sorbent for Lysozyme Adsorption

Various adsorbent materials have been reported in the literature for protein separation. We have developed a novel and new approach to obtain high protein‐adsorption capacity utilizing a 2‐methacrylamidoalanine‐containing membrane. An amino acid ligand 2‐methacrylamidoalanine (MAAL) was synthesized from methacrylochloride and alanine. Then, poly[(2‐hydroxyethyl methacrylate)‐co‐(2‐methacrylamidoalanine)] [p(HEMA‐co‐MAAL)] membranes were prepared by UV‐initiated photopolymerization of HEMA and MAAL. The synthesized MAAL monomer was characterized by NMR spectrometry. p(HEMA‐co‐MAAL) membranes were characterized by swelling studies, porosimeter, scanning electron microscopy, FT‐IR spectroscopy and elemental analysis. These membranes have large pores; the micropore dimensions are around 5–10 μm. p(HEMA‐co‐MAAL) affinity membranes with a swelling ratio of 198.9%, and containing 23.9 (mmol MAAL)·m^–2 were used in the adsorption of lysozyme from aqueous media containing different amounts of lysozyme (0.1–3.0 mg·ml^–1) and at different pH values (4.0–8.0). The effect of Cu(II) incorporation on lysozyme adsorption was also studied. The non‐specific adsorption of lysozyme on the pHEMA membranes was 0.9 μg‐cm^–2. Incorporation of MAAL molecules into the polymeric structure significantly increased the lysozyme adsorption up to 2.96 mg·cm^–2. The lysozyme‐adsorption capacity of the membranes incorporated with Cu(II) (9.98 mg·cm^–2) was greater than that of the p(HEMA‐co‐MAAL) membranes. More than 85% of the adsorbed lysozyme was desorbed in 1 h in the desorption medium containing 1.0 M NaCl. The p(HEMA‐co‐MAAL) membranes are suitable for repeated use for more than 5 cycles without noticeable loss of capacity. These features make p(HEMA‐co‐MAAL) membrane a very good candidate for bioaffinity adsorption.     

Preparation of magnetic molecularly imprinted polymer nanoparticles by surface imprinting by a sol–gel process for the selective and rapid removal of di‐(2‐ethylhexyl) phthalate from aqueous solution

Magnetic molecularly imprinted polymer nanoparticles for di‐(2‐ethylhexyl) phthalate were synthesized by surface imprinting technology with a sol–gel process and used for the selective and rapid adsorption and removal of di‐(2‐ethylhexyl) phthalate from aqueous solution. The prepared magnetic molecularly imprinted polymer nanoparticles were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, and vibrating sample magnetometry. The adsorption of di‐(2‐ethylhexyl) phthalate onto the magnetic molecularly imprinted polymer was spontaneous and endothermic. The adsorption equilibrium was achieved within 1 h, the maximum adsorption capacity was 30.7 mg/g, and the adsorption process could be well described by Langmuir isotherm model and pseudo‐second‐order kinetic model. The magnetic molecularly imprinted polymer displayed a good adsorption selectivity for di‐(2‐ethylhexyl) phthalate with respect to dibutyl phthalate and di‐n‐octyl phthalate. The reusability of magnetic molecularly imprinted polymer was demonstrated for at least eight repeated cycles without significant loss in adsorption capacity. The adsorption efficiencies of the magnetic molecularly imprinted polymer toward di‐(2‐ethylhexyl) phthalate in real water samples were in the range of 98–100%. These results indicated that the prepared adsorbent could be used as an efficient and cost‐effective material for the removal of di‐(2‐ethylhexyl) phthalate from environmental water samples.     

Capillary electrophoresis for the investigation of two novel aminoalkanol derivatives of 1,7‐diethyl‐8,9‐diphenyl‐4‐azatricyclo[5.2.1.02,6] dec‐8‐ene‐3,5,10‐trione as potential anticancer drugs in water solution and serum

A simple, rapid, capillary zone electrophoresis method was developed and validated for the analysis of two novel aminoalkanol derivatives ( I ) and ( II ) of 1,7‐diethyl‐8,9‐diphenyl‐4‐azatricyclo[5.2.1.0^2,6]dec‐8‐ene‐3,5,10‐trione, which were found in earlier studies as potential anticancer drugs. Samples were analyzed to demonstrate the specificity and stability indicating ability of the developed method. The samples were extracted using n‐hexane‐ethyl acetate mixture in the ratio of 90:10. Electrophoretic separation was performed on a eCAP fused silica capillary (37 cm length, 50 µm inside diameter) with a 50 mM tetraborate buffer as a background electrolyte adjusted to pH = 2.5. The separation time of ( I ) and ( II ) was achieved within 7 min. In addition, analysis of the two compounds in the serum was conducted. Limits of detection of ( I ) and ( II ) by UV absorbance at 200 nm were achieved in the range of 87.4–92.1 ng/mL. The sufficient recovery was observed in the range of 90.3–99.8%. The quantification limits for the compounds ( I ) and ( II ) were in the range of 279.71–291.03 ng/mL, respectively. The method has been successfully applied to the analysis of compounds ( I ) and ( II ) in serum samples.     

Yolk–shell microspheres assembled from Preyssler‐type NaP5W30O11014− polyoxometalate and MIL‐101(Cr) metal–organic framework: A new inorganic–organic nanohybrid for fast and selective removal of cationic organic dyes from aqueous media

Novel inorganic–organic yolk–shell microspheres based on Preyssler‐type NaP₅W₃₀O₁₁₀^14? polyoxometalate and MIL‐101(Cr) metal–organic framework (P₅W₃₀/MIL‐101(Cr)) were synthesized by reaction of K_12.5Na_1.5[NaP₅W₃₀O₁₁₀], Cr(NO₃)₃·9H₂O and terephthalic acid under hydrothermal conditions at 200°C for 24 h. The as‐prepared yolk–shell microspheres were fully characterized using various techniques. All analyses confirmed the incorporation of the Preyssler‐type NaP₅W₃₀O₁₁₀^14? polyoxometalate into the three‐dimensional porous MIL‐101(Cr) metal–organic framework. The results revealed that P₅W₃₀/MIL‐101(Cr) demonstrated rapid adsorption of cationic methylene blue (MB) and rhodamine B (RhB) with ultrahigh efficiency and capacity, as well as achieving rapid and highly selective adsorption of MB from MB/MO (MO = methyl orange), MB/RhB and MB/RhB/MO mixtures. The P₅W₃₀/MIL‐101(Cr) adsorbent not only exhibited a high adsorption capacity of 212 mg g^?1, but also could quickly remove 100% of MB from a dye solution of 50 mg l^?1 within 8 min. The effects of some key parameters such as adsorbent dosage, initial dye concentration and initial pH on dye adsorption were investigated in detail. The equilibrium adsorption data were better fitted by the Langmuir isotherm. The adsorption kinetics was well modelled using a pseudo‐second‐order model. Also, the inorganic–organic hybrid yolk–shell microspheres could be easily separated from the reaction system and reused up to four times without any change in structure or adsorption ability. The stability and robustness of the adsorbent were confirmed using various techniques.     

Magnetic chitosan functionalized with β‐cyclodextrin as ultrasound‐assisted extraction adsorbents for the removal of methyl orange in wastewater coupled with high‐performance liquid chromatography

Three types of choline chloride based deep eutectic solvents were prepared and used to modify magnetic chitosan. The adsorption capacity of the three deep‐eutectic‐solvent‐modified magnetic chitosan/carboxymethyl‐β‐cyclodextrin for removing methyl orange from wastewater was examined. The different deep eutectic solvents were used to strengthen the adsorption capacity of magnetic chitosan. Deep‐eutectic‐solvent‐modified magnetic chitosan/carboxymethyl‐β‐cyclodextrin materials were characterized by Fourier transform infrared spectroscopy and Brunauer–Emmett–Teller surface area measurements. Among the three deep eutectic solvents, choline chloride/glycerol (1:2) modified magnetic chitosan/carboxymethyl‐β‐cyclodextrin showed the highest adsorption capacity to methyl orange. Therefore, choline chloride/glycerol (1:3, 1:4, 1:5, 1:6) deep eutectic solvents were prepared for the assay, and choline chloride/glycerol‐modified magnetic chitosan/carboxymethyl‐β‐cyclodextrin prepared with choline chloride/glycerol (1:3) (volume: 40 μg, contact time: 30 min, and pH: 6) had the best adsorption capacity over the concentration range of 10–200 μg/mL.     

Ion exchange of 90Sr and 137Cs into 1‐vinyl‐2‐pyrrolidone–divinylbenzene cation‐exchange resin

Radiotracer batch ion‐exchange experiments were employed to investigate the uptake of ⁹⁰Sr and ¹³⁷Cs radioisotopes by various cation‐exchanged forms of a 30% cross‐linked macroporous 1‐vinyl‐2‐pyrrolidone–divinylbenzene cation‐exchange resin with 1.37 ml g^?1 pore volume, 0.0232 µm pore diameter and 271.2 m² g^?1 surface area. The uptake of ⁹⁰Sr and ¹³⁷Cs was determined by taking liquid aliquots at various time intervals from solutions over solids. The volume‐to‐solid ratio was kept at 200. The results of kinetic experiments for the carrier‐free ⁹⁰Sr and ¹³⁷Cs were evident in all cationic forms of the resin. The percentage uptake and distribution coefficient K_d values with carrier (0.005 M SrCl₂ and 0.01 M CsCl) concentrations were also determined, and the best results were obtained from the Li⁺ and H⁺ forms of the resin. Cerenkov counting (β^?‐counting) was used to observe the initial and final radioactivity in the liquid phase. All the experiments were carried out at room temperature and the radioactivity in each case was corrected for the background counts. Copyright © 2005 John Wiley & Sons, Ltd.