Search

Tetraphenyldithiodiphosphonate is synthesized by polymerization precipitation. The P = S bond of the material has strong polarity, which is conducive to improving the electron mobility of the complex and inhibiting the accumulation between molecules. The synthesized tetraphenyldithiodiphosphonate is characterized by FT-IR, SEM, XPS and XRD. In addition, the pseudo-second-order kinetic model is used to simulate the experimental data well, and the adsorption process conforms to the Langmuir isotherm model. Thermodynamic studies of adsorption have shown that the adsorption process is essentially a spontaneous endothermic process. At room temperature, tetraphenyldithiodiphosphonate demonstrates a maximum adsorption capacity for uranium(VI) reaching 398.8 mg g−1. [ABSTRACT FROM AUTHOR]

In this study, amino modified mesoporous silica (HMS-TEEPA-TEA) was used for the first time to remove uranium (VI) from aqueous solution. The synthesized HMS-TEEPA-TEA was characterized by SEM, EDS, FTIR, BET and XPS techniques. The present work attempted to optimize and compare the adsorption process parameters like pH, adsorbate concentration, and adsorbent dose using Box-Behnken designs of response surface methodology. The adsorption amount and removal rate reached 337.26 mg/g and 99.57%, respectively. Model P> F < 0.0001 in this experiment (generally P > F < 0.05 is considered significant), indicating that the model is extremely significant and can be considered as highly referable for its predicted response values. The fit of the data to the Langmuir isotherm and the proposed secondary kinetics indicates that the adsorption process is monolayer and chemical in nature. The effect of copper on HMS-TEEPA-TEA adsorption is more complex than other background ions. The removal of uranium (VI) by HMS-TEEPA-TEA remained above 80% for four consecutive experiments with repeated adsorbent use. The results indicate that HMS-TEEPA-TEA is an effective adsorbent for the removal of uranium (VI) from aqueous solutions with the advantages of low cost, high availability and easy production. [ABSTRACT FROM AUTHOR]

The phosphinimide materials described in this paper were synthesized by polymerization precipitation. The properties of complexes coordinated with metal ions can be used as adsorbents for the adsorption of radioactive elements by using ligands such as imide and phosphorus groups. Then, the synthetic phosphinimide was characterized in detail by FT-IR, SEM, EDS and XPS, and its morphology and structural changes were studied. In addition, the effects of the material on the removal of uranium(VI) from aqueous solutions at different pH, sorbent doses, contact times, initial concentrations, and temperatures were studied. The experimental data shows that the adsorption process can fit the pseudo-second-order kinetic model well, which is in line with the Langmuir isotherm model. The thermodynamic study of adsorption shows that the adsorption process is a spontaneous endothermic process. In addition, at a temperature of 303.15 K and pH = 6, the maximum adsorption of uranium(VI) by phosphinimide in 25 min can reach 234.6 mg g−1, and a removal rate of 97.75%. [ABSTRACT FROM AUTHOR]

Bis(diphenyl phosphate) imine(Htpop) was synthesized as an adsorbent for the effective removal of U(VI) from aqueous solutions using triphenyl phosphate(TPP) as the starting material. Htpop possesses notable polarity, characterized by the presence of -P O(phosphoryl) and -N-H(imino) functional groups, along with other bulky substituents. It has the capability to form chelates with metal ions, thus enabling the removal of radionuclide U(VI) from aqueous solution. The overall adsorption experiment shows that both phosphoryl and imino groups interact with uranyl ions, and the removal rate reaches 99.53 % at pH 6.0. The adsorption process conforms to the Pseudo-second-order kinetic model and Langmuir isotherm model. [ABSTRACT FROM AUTHOR]

Poly(cyclotriphosphazene-co-polyethyleneimine) microspheres with the solid structure were synthesized by precipitation polymerization method for the separation of highly toxic uranium(VI). The structure and morphology of the prepared microspheres were analyzed via FTIR, SEM–EDS, TEM and BET. The optimal adsorption conditions were also investigated, and the maximum adsorption capacity was 274.2 mg g−1. The experimental results showed that the adsorption kinetics conformed to the pseudo-second-order kinetics and was in good agreement with the Langmuir adsorption isotherm model. Removal of uranium(VI) ions was achieved by the complexation between the amino groups on the adsorbent and uranyl ions. [ABSTRACT FROM AUTHOR]

Highly crosslinked organic–inorganic hybrid polymer poly(cyclotriphosphazene-co-melamine) microspheres (PZM) were synthesized by a simple method. The microspheres was characterized by FTIR, SEM and EDX. It was applied to eliminate thorium(IV) from aqueous solution under various conditions, i.e., pH, initial concentration, dosage and contact time. The experimental data were well-imitated via the pseudo-second-order kinetic model and its adsorption processes comply with the Langmuir isotherm model. Adsorption thermodynamic studies demonstrated that the adsorption process, in essence, was spontaneous and endothermic. Furthermore, the maximum experimental adsorption capacity was 98.6 mg g−1 for initial thorium(IV) concentration 50 mg L−1. When pH = 0.0, the thorium(IV) removal efficiency reached at 76.9%, which indicates that the adsorbent can also was used in a peracid environment. Adsorption behavior of thorium(IV) onto the microspheres were weakly affected via temperature, implying that adsorption would be done at room temperature. [ABSTRACT FROM AUTHOR]

Poly(cyclotriphosphazene-co-4,4′-diaminodiphenyl ether) crosslinked microspheres with active amino groups on the surface were prepared by one-step precipitation polymerization method. The as-prepared material were characterized by means of FTIR, XPS, XRD, EDS and SEM. The effects of pH, time of contact, dosage, initial concentration and temperature on the adsorption of uranium(VI) by the crosslinked microspheres were studied, and the adsorption mechanism was elucidated. Under the optimized adsorption conditions, the adsorption removal efficiency reached 97.03%. The experimental results fit the Langmuir isotherm model and adsorption processes comply with the pseudo-second-order kinetic model. Thermodynamic data revealed that the adsorption behavior of uranium(VI) on the microspheres was spontaneous and exothermic. [ABSTRACT FROM AUTHOR]

Poly(cyclotriphosphazene-co-phloroglucinol) (PCPP) microspheres, a new solid phase extraction for extracting uranium(VI), synthesized via one-pot precipitation copolymerization. The PCPP microspheres were characterized by FT-IR, SEM/EDS, zeta potential and N2 adsorption/desorption isotherms. Through the extraction experiment to evaluate the extraction behavior of the PCPP microspheres for uranium(VI). The extractant can achieve the optimal effect under the conditions of contact time with 60 min, pH = 3.5, initial concentration 100 mg L−1 and extractant dosage 0.70 g L−1. The extraction behavior obeyed with the pseudo second-order model and Langmuir isotherm model. [ABSTRACT FROM AUTHOR]

The specialized poly(cyclotriphosphazene-co-4,4′-sulfonyldiphenol) (PZS) microspheres were prepared via a reliable and simple precipitation polymerization method and used adsorbent for the removal of thorium (Th) from aqueous solution. The PZS microspheres were characterized by FT-IR, XPS and SEM. The variables influencing the adsorption capacity were investigated. Adsorption experimental data showed thorium adsorption was equilibrium at time 60 min, pH 3.5, adsorbent dosage 1.0 g L and initial concentration 25 mg L, and the adsorption capacity reached to 17.30 mg g. The experimental data followed the pseudo-second-order kinetic model and equilibrium data fit the Langmuir isotherm model very well. [ABSTRACT FROM AUTHOR]

A new synthetic method was designed to prepare poly (trimesoyl chloride-co-polyethyleneimine) (PEI-TMC). Characterization of PEI-TMC was investigated by FTIR, SEM, EDS, XPS, TGA, and BET. TGA test revealed that the PEI-TMC had excellent thermal stability. The BET specific surface area (4.74 ​m2 ​g−1) and pore diameter of about 9.44 ​nm indicated that PEI-TMC possessed a mesoporous structure. The adsorption behavior of U(VI) on the PEI-TMC was investigated. The thermodynamic analysis showed that the process of PEI-TMC adsorption of U(VI) was endothermic and spontaneous, and the adsorption efficiency was better at higher temperatures. The U(VI) sorption on PEI-TMC was conformed to the Langmuir adsorption isotherm and pseudo-second-order kinetic models. The adsorption mechanism of U(VI) with PEI-TMC was systematically elucidated by XPS and FTIR. Under the best condition, the maximum adsorption capacity of PEI-TMC could reach 212.8 ​mg ​g−1 ​by calculating the Langmuir isothermal model. It indicated that PEI-TMC was a potential adsorbent for the treatment of U(VI)-containing wastewater. Diagram of PEI synthesis and its adsorption mechanism for U(VI). Image 1 • A new and facile method is used to prepare PEI-TMC. • The application field of PEI-TMC was expanded for the separation of U(VI). • Excellent adsorption performance was demonstrated. [ABSTRACT FROM AUTHOR]

Poly(cyclotriphosphazene-co-4,4′-diaminodiphenyl ether) microspheres (PZA) was based on hexachlorocyclotriphosphazene (HCCP) and 4,4′-diaminodiphenyl ether (ODA). It was synthesized via one-step precipitation method. The PZA microspheres were characterized by FT-IR, XPS, zeta potential and SEM/EDS. Through experimental research, PZA microspheres had the optimal adsorption performance with pH value 3.5, contact time of 60 min, thorium(IV) ions concentration of 30 mg L−1, and PZA microspheres of 10 mg. The maximum adsorption capacity of PZA microspheres for thorium(IV) was 29.04 mg g−1. The adsorption process could be described by the quasi-second order kinetic model and simulated by the Langmuir isotherm equation. [ABSTRACT FROM AUTHOR]