Adsorption of thorium(IV) from aqueous solutions by poly(cyclotriphosphazene-co-4,4′-diaminodiphenyl ether) microspheres

Journal of Radioanalytical and Nuclear Chemistry - Poly(cyclotriphosphazene-co-4,4′-diaminodiphenyl ether) microspheres (PZA) was based on hexachlorocyclotriphosphazene (HCCP) and...     

Modified nanoporous magnetic cellulose–chitosan microspheres for efficient removal of Pb(II) and methylene blue from aqueous solution

Pyromellitic dianhydride-modified nanoporous magnetic cellulose–chitosan microspheres (PNMCMs) were designed and synthesized to introduce abundant carboxyl groups onto the basic microstructure. The novel microspheres were studied by scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis, thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). Subsequently, a batch technique was applied to investigate various environmental parameters that could affect the adsorption behavior of the PNMCMs. Due to its nanoporous structure and large quantity of carboxyl groups, the cellulose/chitosan-based bioadsorbent exhibited excellent adsorption performance for removal of Pb(II) ions and methylene blue (MB) from aqueous solution, with maximum adsorption capacity of 384.6 and 833.3 mg/g, respectively. Furthermore, the adsorption kinetics and isotherms of Pb(II) ions and MB on PNMCMs obeyed the pseudo-second-order and Langmuir isotherm models, and the rate of adsorption was found to be controlled by film diffusion. Finally, the PNMCMs with adsorbed Pb(II) and MB could be easily regenerated using HCl, retaining removal capacity of almost 89% after six repeated uses.     

Efficient simultaneous removal of U(VI) and Cu(II) from aqueous solution using core–shell nZVI@SA/CMC-Ca beads

Core–shell nanoscale zero-valent iron@alginate/carboxymethyl cellulose sodium composite loaded with calcium (nZVI@SA/CMC-Ca) beads were synthesized in this study using coaxial electronic injection method. The adsorbent structure was characterized via FT-IR, SEM, EDX and XPS. The adsorption behavior of U(VI) and Cu(II) on core–shell nZVI@SA/CMC-Ca beads was studied under various experimental parameters like pH, contact time and temperature. The isotherm and the kinetic data, pertaining to the adsorption of U(VI) and Cu(II) by core–shell nZVI@SA/CMC-Ca beads obeyed both the Langmuir and Freundlich isotherms model and the pseudo-second-order kinetics model, respectively. The thermodynamic parameters revealed the spontaneous and endothermic nature of the adsorption. The experiment of regeneration and reusability suggested core–shell nZVI@SA/CMC-Ca bead was a regenerated material.     

Erratum on “Ozonated graphene oxides as high efficient sorbents for Sr(II) and U(VI) removal from aqueous solutions”

Science China Chemistry - We regret that our article “Ozonated graphene oxides as high efficient sorbents for Sr(II) and U(VI) removal from aqueous solutions ” (Sci China Chem, 2016,...     

Solvent extraction of uranium(VI) and thorium(IV) by N,N′-di-p-tolylpyridine-2,6-dicarboxamide from nitric acid solution

Synthesis and characterization of N,N′-di-p-tolylpyridine-2,6-dicarboxamide (DTPDA) was carried out and used for extraction of U(VI) and Th(IV) from nitric acid solutions. The processes of extraction were determined by the slope analysis and by analyzing a function that allows the simultaneous treatment of all the experimental points obtained in different conditions. The different factors affecting the extraction distribution ratio(D) of U(VI) and Th(IV) (extraction concentration, concentrations of nitric acid, salting-out agent NaNO₃ concentration, equilibration time and temperature) were investigated. The results obtained indicated that the extraction species of U(VI) and Th(IV) are mainly extracted as UO₂(NO₃)₂·1.5DTPDA and Th(NO₃)₄·1.5DTPDA. The related thermodynamic functions were calculated. Back-extraction of U(VI) and Th(IV) from organic phases was also studied.     

Extraction and separation performance of rhenium(VII) and uranium(VI) from nitric acid medium using N,N′-dimethyl-N,N′-dioctyldiglycolamide

Journal of Radioanalytical and Nuclear Chemistry - The extraction behavior and separation performance of Re(VII) and U(VI) from the nitric acid medium were studied respectively, in which an...     

Ozonated graphene oxides as high efficient sorbents for Sr(Ⅱ) and U(Ⅵ) removal from aqueous solutions

Ozone was used to oxidize graphene oxides(GO) to generate ozonated graphene oxides(OGO) with higher oxygen-containing functional groups. The as-prepared OGO was characterized by Fourier transformed infrared spectroscopy(FTIR), scanning electron microscopy(SEM) and X-ray photoelectron spectroscopy(XPS). Based on the results of potentiometric acid-base titrations, the total carboxylic acid concentration on OGO surface was calculated to be 3.92 mmol/g, which was much higher than that on GO surface. The results of adsorption experiments indicated that the adsorption capacities of OGO for Sr(II) and U(VI) removal were improved significantly after ozonization.     

Extraction of technetium(VII) from uranium(VI) in nitric acid system by primary amine — n-heptane solution

Separation of technetium(VII) from uranium(VI) has been studied through experiments on the coprecipitation of technetium(VII) with precipitation of ammonium diuranate, and on the extraction of technetium(VII) from a 3M aqueous nitric acid solution using, as extractant, a primary amine (Primene JMT) dissolved in either chloroform or n-heptane solution. Ammonium diuranate precipitation proved to provide the most satisfactory means of separating technetium(VII) from uranium(VI) in solution. Extraction of technetium(VII) contained in nitric acid solution using Primene JMT dissolved in n-heptane solution proved to be quantitative after several cycles of the procedure and alternatively, upon raising to 51 the volume ratio between the organic phase containing the extractant and the aqueous phase containing technetium(VII). Stripping of technetium(VII) into 2M aqueous ammonium carbonate solution was enhanced to quantitative level by repetition of the stripping procedure, and alternatively, by adding the ammonium carbonate in a volume ratio of 51 with respect to the organic phase containing technetium(VII).     

Cesium removal from solution using PAN-based potassium nickel hexacyanoferrate (II) composite spheres

A polyacrylonitrile–potassium nickel hexacyanoferrates composite adsorbent was prepared to remove cesium ion in aqueous solution. The dual nozzle technique was applied to prepare a composite sphere. The physicochemical behavior of the ion exchanger was specified with different techniques including Fourier transform infrared spectroscopy, X-ray powder diffraction, specific surface analysis, scanning electron microscopy, and X-ray fluorescence spectroscopy analysis. The effects of contact time, solution initial pH, presence of various cations and initial cesium concentration on the adsorption was also investigated and the optimum conditions for separation of cesium were determined. In addition, adsorption kinetics and adsorption mechanism were studied by modeling the experimental data and related parameters were also evaluated, which showed that sorption data fitted to pseudo-second-order and film diffusion models. Adsorption isotherm in batch experiments showed that the sorption data were successfully fitted with Langmuir model. Finally the adsorption dynamic capacities of the synthesized composite in column experiments were evaluated at 139.925 and 119.539 mg/g for flow rate of 1 and 3 BV/min, respectively.     

Sequestration of naphthenic acids from aqueous solution using β-cyclodextrin-based polyurethanes

The sorption characteristics of naphthenic acids (NAs) in their anion form with β-cyclodextrin (β-CD) based polyurethanes, as sorbents, from aqueous solutions that simulate the conditions of oil sands process water (OSPW) are presented. The copolymer sorbents were synthesized at various β-CD:diisocyanate monomer mole ratios (e.g., 1:1, 1:2, and 1:3) with diisocyanates of variable molecular size and degree of unsaturation. The equilibrium sorption properties of the copolymer sorbents were characterized using sorption isotherms in aqueous solution at pH 9.00 with electrospray ionization mass spectrometry to monitor the equilibrium unbound fraction of anionic NAs in the aqueous phase. The copolymer sorbents were characterized in the solid state using (13)C CP-MAS NMR spectroscopy, IR spectroscopy and elemental analysis. The sorption results of the copolymer sorbents with anion forms of NAs in solution were compared with a commercially available carbonaceous standard: granular activated carbon (GAC). The monolayer sorption capacities of the sorbents (Q(m)) were obtained from either the Langmuir or the Sips isotherm model used to characterize the sorption characteristics of each copolymer sorbent. The estimated sorption capacity for GAC was 142 mg NAs per g sorbent whereas the polymeric materials ranged from 0-75 mg NAs per g sorbent over the experimental conditions investigated. In general, significant differences in the sorption capacities between GAC and the copolymer sorbents were related to the differences in the accessible surface areas and pore structure characteristics of the sorbents. The Sips parameter (K(eq)) for GAC and the copolymer materials reveal differences in the relative binding affinity of NAs to the sorbent framework in accordance with the synthetic ratios and the value of Q(m). The diisocyanate linker plays a secondary role in the sorption mechanism, whereas the β-CD macrocycle in the copolymer framework is the main sorption site for NAs because of the formation of inclusion complexes with β-CD.     

Synthesis and characterization of poly(phthalazinone biphenyl ether sulfone ketone)s from 4,4′-dichlorobenzophenone

A series of poly(aryl ether sulfone ketone)s containing phthalazinone and biphenyl moieties were synthesized by aromatic nucleophilic displacement polycondensation of 4-(4-hydroxylphenyl)(2H)-phthalazin-1-one (DHPZ), 4,4′-dichlorobenzophenone (DCB), 4,4′-dichlorodiphenyl sulfone (DCS) and 4,4′-biphenol (BP) in different molar ratios. The obtained copolymers were characterized by different instrumental techniques (FTIR, TGA, DSC, WAXD, etc.). The inherent viscosities of these polymers were in the range of 0.43–0.56 dL g⁻¹. They were amorphous and had good solubility in polar aprotic organic solvents. The copolymers exhibited high glass transition temperatures (T _gs) between 225°C and 256°C and excellent thermal stability up to 517–526°C (thermal decomposition temperatures for 5% weight loss, T _{d, 5%}) in nitrogen. The tensile strength and elongation at break of the polymers ranged from 63 MPa to 71 MPa and from 18% to 21%, respectively. The processability of the material was effectively improved by the introduction of biphenyl group into polymer backbone.     

Liquid–liquid extraction of uranium(VI) using cyanex 272 in toluene from sodium salicylate medium

Liquid–liquid extraction and separation studies of uranium have been carried out from sodium salicylate media using cyanex 272 in toluene. Uranium was quantitatively extracted by 1 × 10⁻³ M sodium salicylate with 5 × 10⁻⁴ M cyanex 272 in toluene. The extracted uranium(VI) was stripped out quantitatively from the organic phase with 1.0 M hydrochloric acid and determined spectrophotometrically with arsenazo(III) at 660 nm. The effect of concentration of sodium salicylate, extractant, diluents, metal ion and strippants has been studied. Separation of uranium(VI) from other elements was achieved from binary as well as from multicomponent mixtures. The method was extended for the separation and determination of uranium(VI) in geological samples. The method is simple, rapid and selective with good reproducibility (approximately ± 2%).     

Liquid–liquid extraction of mercury(II) from aqueous solution using furosemide in benzyl alcohol

Journal of Radioanalytical and Nuclear Chemistry - A simple, efficient and economical liquid–liquid extraction method has been developed for quantitative extraction of mercury(II) from...     

Poly（vinylpyridine） adsorbent for the removal of SIPA from its aqueous solution

Poly(vinylpyridine) WH-225 resin was prepared and characterized.Compared with the commercial hypercrosslinked adsorbent NDA-100 and macroporous adsorbent XAD-4 resins,the newly synthesized poly(vinylpyridine) WH-225 resin exhibited the highest adsorption capacity toward SIPA from aqueous solution.     

Highly efficient removal of Cr(Ⅵ)from wastewater via adsorption with novel magnetic Fe_3O_4@C@MgAl-layered double-hydroxide

Novel magnetic Fe_3O_4@C@MgAl-layerecl double-hydroxide(LDH) nanoparticles have been successfully prepared by the chemical self-assembly methods.The properties of surface functional groups,crystal structure,magnetism and surface morphology of magnetic nanoparticles were characterized by Fourier transform infrared spectroscopy(FT-IR),X-ray diffraction(XRD),thermal gravity-differential thermal gravity(TG-DTG),scanning electron microscopy(SEM),and transmission electron microscopy(TEM).The adsorption studies of the novel adsorbent in removing heavy metals Cr(Ⅵ) from waste water showed that the maximum absorption amount of Cr(Ⅵ) was 152.0 mg/g at 40℃ and pH 6.0.The excellent adsorption capacity of the Fe_3O_4@C@MgAl-LDH nano-absorbents plus their easy separation,environmentally friendly composition and reusability makes them more suitable adsorbents for the removal of metal ions from waste water.     

The removal of endotoxins from protein solutions using column packings with aminated poly (γ-methyl L-glutamate) spheres

Summary A method is described for the selective removal of endotoxins from various protein solutions using columns packed with aminated poly (-methyl L-glutamate) (PMLG-NH₂) spheres. The PMLG-NH₂ adsorbents showed a high adsorbing activity for endotoxins which had an ionic strength of =0.05–1.0 and pH 5.0–9.0. The endotoxin-adsorbing capacity per millitre of the wet adsorbent increased from 0.40 to 1.35 mg (E. coli O111: B4 LPS) at =0.2 and pH 7.0 while the aminogroup content of the adsorbent increased from 0.8 to 3.5 meq g^–1. The PMLG-NH₂-3.5 has an amino-group content of 3.5 meq g^–1. This column packing selectively adsorbed endotoxins, without loss of the protein, from a -globulin or cytochromec solution which contained endotoxins at =0.05 and pH 7.0. On the other hand, when bovine serum albumin (BSA) was present in solution with endotoxins, both the endotoxins and the BSA were adsorbed by the column. The BSA-adsorbing activity increased with increasing amino-group content of the adsorbent. However, this undesirable adsorption was suppressed with increasing ionic strength of the buffer. As a result, when the packing which had an amino-group content of 1.5 meg g^–1 was used in conditions of =0.2 and pH 7.0, the endotoxins were removed from a BSA-containing solution without affecting the recovery of the BSA.