Synthesis of PAMAM dendron functionalized superparamagnetic polymer microspheres for highly efficient sorption of uranium(VI)

Determination of copper and cobalt in different tea samples at trace levels by FAAS after preconcentration with a novel iron PAMAM-OH-encapsulated magnetic nanoparticle as SPE sorbent

Environmental contamination caused by heavy metals is a significant global concern. The presented study investigated the efficiency of iron PAMAM-OH encapsulated magnetic nanoparticles (Fe-MNP-G2-OH) as sorbent for the preconcentration of copper and cobalt from tea samples. High metal-chelating ethylenediamine core polyamidoethanol generation-2 (PAMAM-G2-OH) was encapsulated with iron oxide (Fe3O4) to synthesize the sorbent. Limit of detection (LOD) values for copper and cobalt extracted and detected by the developed Fe-MNP-G2-OH -SPE-FAAS method were 0.52 and 1.1 μg L-1, respectively. There were 230- and 101-fold improvement in detection limits for copper and cobalt, respectively, when compared to direct FAAS measurement. The percent recovery results for the analytes in green and black tea samples ranged from 93 to 107%, with low relative standard deviation (%RSD) values. The synthesis of nanoparticle was carried out through a unique method, which was characterized by thermogravimetric analysis (TGA), scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR) methods. The analytical results demonstrated the applicability and effectiveness of Fe-MNP-G2-OH nanoparticles on the preconcentration of copper and cobalt from tea samples and the developed method is suitable for the trace detection of heavy metals by FAAS method. To the best our knowledge, this is the first study where copper and cobalt in green and black tea samples were extracted by Fe-MNP-G2-OH adsorbent and precipitation of the adsorbent during its synthesis was carried out in acetone medium rather than aqueous one.

Highly Efficient Removal of Uranium from an Aqueous Solution by a Novel Phosphonic Acid-Functionalized Magnetic Microsphere Adsorbent

The development of adsorption materials which can efficiently isolate and enrich uranium is of great scientific significance to sustainable development and environmental protection. In this work, a novel phosphonic acid-functionalized magnetic microsphere adsorbent Fe₃O₄/P (GMA-MBA)-PO₄ was developed by functionalized Fe₃O₄/P (GMA-MBA) prepared by distill-precipitation polymerization with O-phosphoethanolamine. The adsorption process was endothermic, spontaneous and kinetically followed the pseudo second-order model. The maximum uranium adsorption capacity obtained from the Langmuir model was 333.33 mg g^-1 at 298 K. In addition, the adsorbent also had good acid resistance and superparamagnetic properties, which could be quickly separated by a magnetic field. XPS analysis showed that the adsorption of adsorbent mainly depended on the complexation of phosphonic acid group with uranium. This work offers a promising candidate for the application of magnetic adsorbents in the field of uranium separation and enrichment.

A Review: Adsorption and Removal of Heavy Metals Based on Polyamide-amines Composites

In recent years, the problem of heavy metal pollution has become increasingly prominent, so it is urgent to develop new heavy metal adsorption materials. Compared with many adsorbents, the polyamide-amine dendrimers (PAMAMs) have attracted extensive attention of researchers due to its advantages of macro-molecular cavity, abundant surface functional groups, non-toxicity, high efficiency and easy modification. But in fact, it is not very suitable as an adsorbent because of its solubility and difficulty in separation, which also limits its application in environmental remediation. Therefore, in order to make up for the shortcomings of this material to a certain extent, the synthesis and development of polymer composite materials based on PAMAMs are increasingly prominent in the direction of solving heavy metal pollution. In this paper, the application of composites based on PAMAMs and inorganic or organic components in the adsorption of heavy metal ions is reviewed. Finally, the prospects and challenges of PAMAMs composites for removal of heavy metal ions in water environment are discussed.

Fabrication of Fe3O4@poly(methyl methacrylate-co-glycidyl methacrylate) microspheres via miniemulsion polymerization using porous microspheres as templates for removal of cationic dyes

A novel and simple method was proposed to prepare monodisperse magnetic microspheres with controllable particle sizes and different functionalities.

An imidazole functionalized porous organic polymer for the highly efficient extraction of uranium from aqueous solutions

Solvothermal polymerization of a porous polymer functionalized with a high concentration of imidazole groups and its application in the efficient extraction of uranium from water.

Unexpected ultrafast and highly efficient removal of uranium from aqueous solutions by a phosphonic acid and amine functionalized polymer adsorbent

P(DMAA–B2MP) was prepared by solvothermal polymerization and exhibits fast and efficient sorption of uranium(vi) from aqueous solutions.

N, P and S co-doped carbon materials derived from polyphosphazene for enhanced selective U(VI) adsorption

Herein, the precursor polyphosphazene was synthesized by the polymerization of hexachlorocyclotriphosphazene (HCCP) and bis(4-hydroxyphenyl) sulfone (BPS). The adsorbent which was codoped with N, P and S (amidate-CS) was developed from the precursor by using the carbonization method. The images of Scanning electron microscope (SEM) and Transmission electron microscope (TEM) indicate that the amidate-CS possessed porous graphene-like carbon lamellar structure. The excellent behaviors with respect to kinetics (120 min for equilibrium) and thermodynamics (maximum removal of 290 mg/g when pH was at 6.0) revealed the outstanding performance of amidate-CS in removing U(VI), which is due to the functional groups and strong covalent bonds between heteroatoms and uranyl ions. The adsorption of amidate-CS followed the pseudo-second-order kinetic and Langmuir adsorption model. The thermodynamic parameters indicate that the process was spontaneous and endothermic. The adsorption and desorption efficiency of amidate-CS had a slight decrease after five cycles, indicating excellent regeneration performance. Overall, the amidate-CS is a prospective candidate for highly selective U(VI) removing.

Magnetite-based adsorbents for sequestration of radionuclides: a review

As a result of extensive research efforts by several research groups, magnetite-based materials have gained enormous attention in diverse fields including biomedicine, catalysis, energy and data storage devices, magnetic resonance imaging, and environmental remediation. Owing to their low production cost, ease of modification, biocompatibility, and superparamagnetism, the use of these materials for the abatement of environmental toxicants has been increasing continuously. Here we focus on the recent advances in the use of magnetite-based adsorbents for removal of radionuclides (such as 137Cs(i), 155Eu(iii), 90Sr(ii), 238U(vi), etc.) from diverse aqueous phases. This review summarizes the preparation and surface modification of magnetite-based adsorbents, their physicochemical properties, adsorption behavior and mechanism, and diverse conventional and recent environmental technological options for the treatment of water contaminated with radionuclides. In addition, case studies for the removal of radionuclides from actual contaminated sites are discussed, and finally the optimization of magnetite-based remedial solutions is presented for practical application.