Magnetic nanocomposite hydrogel prepared by ZnO-initiated photopolymerization for La (III) adsorption

Modification of graphene oxide with imidazolium-based ionic liquid for significant sorption of La(III) and Pr(III) from aqueous solutions

A straightforward ferrocyanide immobilization on the surface of graphene oxide (GO) was conducted for rapid and efficient adsorption capacity for lanthanum and praseodymium from an aqueous solution. The GO was mixed with 1-methyl imidazole in the presence of epichlorohydrin to form GO-imidazole-Cl and thereafter suspended in a potassium ferrocyanide solution to fabricate GO-imidazole-FeCN. The prepared materials were characterized with different advanced techniques confirming the preparation method. The adsorption ability of GO-imidazole-FeCN towards La(III) and Pr(III) ions was evaluated. Moreover, the adsorption isotherm showed that the sorption process was fitted with the Langmuir isotherm model with a considerable maximum adsorption capacity of 781.25 mg g−1 for La(III) and 862.07 mg g−1 for Pr(III). The thermodynamic studies showed that the adsorption of both metal ions was spontaneous and endothermic. In addition, the adsorbent showed excellent adsorption–desorption behavior over 5 times, suggesting that GO-imidazole-FeCN may be considered a potential candidate for La(III) and Pr(III) removal from different metal ions which present in fission products.

Polyaminophosphoric Acid-Modified Ion-Imprinted Chitosan Aerogel with Enhanced Antimicrobial Activity for Selective La(III) Recovery and Oil/Water Separation

In this study, polyaminophosphoric acid (PA)-functionalized ion-imprinted chitosan (CS) aerogel was fabricated for the first time, exhibiting good antibacterial property for selective La(III) recovery and oil/water separation. The as-prepared PA-CS-IIA-2 shows a remarkable adsorption capacity of 114.6 mg/g toward La(III) and high selectivity in the competitive adsorption systems, which is attributed to its abundant imprinting sites and surface functional groups. Benefiting from the amphiphilic property, the PA-CS-IIA-2 also exhibits an excellent adsorption performance for the extractant, oils, and organic solvents. Besides, the PA-CS-IIA-2 presents excellent regeneration and reusability characteristics. Moreover, compared with CS, the PA-CS-IIA-2 exhibits a significantly improved antibacterial activity originating from the PA component. Most importantly, the PA-CS-IIA-2 aerogel is capable of removing multiple pollutants all together and effectively inhibiting bacteria in the complex wastewater environments. Therefore, this study paves the way for developing high-performance rare-earth capture materials with multiple functions to meet diverse applications.

Carbon Quantum Dots-Based Fluorescent Hydrogel Hybrid Platform for Sensitive Detection of Iron Ions

In this study, we prepared novel fluorescent carbon quantum dots/hydrogel nanocomposite material (CQDsHG) with good adsorption and stable fluorescence detection of Fe3+. The materials were subsequently characterized according to their morphological features, chemical composition, adsorption, and optical properties. The carbon quantum dots (CQDs) were prepared using a microwave-assisted hydrothermal method in no more than 15 min, and the as-prepared CQDs exhibited excellent water solubility, as well as emitted strong bright blue fluorescence with an ultrahigh quantum yield of 93.60%. The CQDs were then loaded into a hydrogel (HG) using the sol-gel method to obtain a functional CQDsHG. The CQDsHG exhibited high adsorption amounts (31.94 mg/g) and a good quenching response for Fe3+, thus, it could be used as a sensor to selectively detect Fe3+ in the linear range of 0–150 μM with a detection limit of 0.24 μM. We observed minimal difference in the fluorescence lifetimes between the CQDsHG with and without a quencher (Fe3+), with values of 5.816 ns and 5.824 ns, respectively, confirming that Fe3+ was statically quenched on CQDsHG. The results indicated that the innovative combination of CQDs and HG can improve the synergistic performance of each component for the adsorption and quantitative detection of heavy metal ions in the aqueous environment.

Nanohydrogels: Advanced Polymeric Nanomaterials in the Era of Nanotechnology for Robust Functionalization and Cumulative Applications

In the era of nanotechnology, the synthesis of nanomaterials for advanced applications has grown enormously. Effective therapeutics and functionalization of effective drugs using nano-vehicles are considered highly productive and selectively necessary. Polymeric nanomaterials have shown their impact and influential role in this process. Polymeric nanomaterials in molecular science are well facilitated due to their low cytotoxic behavior, robust functionalization, and practical approach towards in vitro and in vivo therapeutics. This review highlights a brief discussion on recent techniques used in nanohydrogel designs, biomedical applications, and the applied role of nanohydrogels in the construction of advanced therapeutics. We reviewed recent studies on nanohydrogels for their wide applications in building strategies for advantageously controlled biological applications. The classification of polymers is based on their sources of origin. Nanohydrogel studies are based on their polymeric types and their endorsed utilization for reported applications. Nanotechnology has developed significantly in the past decades. The novel and active role of nano biomaterials with amplified aspects are consistently being studied to minimize the deleterious practices and side effects. Here, we put forth challenges and discuss the outlook regarding the role of nanohydrogels, with future perspectives on delivering constructive strategies and overcoming the critical objectives in nanotherapeutic systems.

Simultaneously Remove and Visually Detect Ce4+ Based on Nanocomposite of UiO-66-NH2/CPA-MA

Effective strategies to deal with rare earth pollution are urgently needed due to the overexploitation of rare earths resource. In this study, a novel nanocomposite of UiO-66-NH2/CPA-MA denoted as UA was successfully synthesized, which can simultaneously remove and detect Ce4+ in water. The hybrid consists of UiO-66-NH2 and CPA-MA. Based on the high adsorption performance of UiO-66-NH2, it can remove Ce4+ with high capacity by adsorption. Moreover, it can change its color from olive drab to light cyan depending on the adsorbed Ce4+ concentration, and the chroma is linearly related to the Ce4+ concentration. So, UA can be used to qualitatively and quantitatively detect Ce4+ by its color changing. The kinetics of adsorption course was investigated in details. The anti-inference ability of the nanocomposite in coexisting systems was carefully evaluated. The results indicate that UiO-66-NH2/CPA-MA is highly potential to deal with Ce4+ pollutions due to its bifunctionality.

A 3D porous fluorescent hydrogel based on amino-modified carbon dots with excellent sorption and sensing abilities for environmentally hazardous Cr(VI)

To effectively detect and remove environmentally hazardous Cr(VI), a novel 3D porous fluorescent hydrogel was synthesised using amino-modified carbon dots and cellulose nanofibers. The synthesised fluorescent hydrogel was characterized to determine its morphology, crystalline structure, chemical composition and optical property using scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, UV-vis absorption spectroscopy and photoluminescence spectroscopy. The sorption properties of the synthesised fluorescent hydrogel were further analyzed. The maximum sorption capacity for Cr(VI) reached 534.4 mg/g, the adsorption isotherm was well fitted using Langmuir model, and the adsorption kinetics were well fitted using a pseudo-second-order model. The sensing ability of the synthesized hydrogel for Cr(VI) was also determined. Furthermore, the mechanism of Cr(VI) sorption and sensing was determined. Accordingly, this novel 3D porous fluorescent hydrogel was identified to be a promising sorbent with advantages of excellent sorption and sensing abilities for environmentally hazardous Cr(VI).

Heterogeneous photocatalytic reversible deactivation radical polymerization

Photocatalytic reversible deactivation radical polymerization (RDRP) permits the use of sustainable solar light for spatiotemporal regulation of radical polymerization under mild conditions.

Hydrogel-clay Nanocomposites as Carriers for Controlled Release

The present review aims to summarize the research efforts undertaken in the last few years in the development and testing of hydrogel-clay nanocomposites proposed as carriers for controlled release of diverse drugs. Their advantages, disadvantages and different compositions of polymers/biopolymers with diverse types of clays, as well as their interactions are discussed. Illustrative examples of studies regarding hydrogel-clay nanocomposites are detailed in order to underline the progressive researches on hydrogel-clay-drug pharmaceutical formulations able to respond to a series of demands for the most diverse applications. Brief descriptions of the different techniques used for the characterization of the obtained complex hybrid materials such as: swelling, TGA, DSC, FTIR, XRD, mechanical, SEM, TEM and biology tests, are also included. Enlightened by the presented data, we can suppose that hydrogel-clay nanocomposites will still be a challenging subject of global assiduous researches. We can dare to dream to an efficient drug delivery platform for the treatment of multiple affection concomitantly, these being undoubtedly like "a tree of life" bearing different kinds of fruits and leaves proper for human healing.

Enhanced adsorption of Cd(II) using a composite of poly(acrylamide-co-sodium acrylate) incorporated LDH@MoS24

The Mg/Al layered double hydroxide (Mg/Al-LDH) intercalated with the [Formula: see text] (MoS₄-LDH) impregnated into poly(acrylamide-co-sodium acrylate) (PP) was synthesized as layered double hydroxides-PP (LDHS-PP), whose characterization, adsorption properties and mechanisms were investigated. The maximum adsorption capacity (q_m) for Cd(II) was ∼2789.58 mg/g by 1% LDHS-PP, while it was ∼1893.09 mg/g by PP, which indicated that the MoS₄-LDH greatly improved the Cd(II) uptake for PP in aqueous solution. In strongly acidic conditions (∼pH 3.0), there was still a good removal efficiency of about 45.65% by the 1% LDHS-PP, while that of PP was almost zero. At pH 5.0 the removal efficiency increased to 85.17% by the 1% LDHS-PP. The sorption kinetics for the 1% LDHS-PP was described well by a pseudo-second-order kinetic model. X-ray photoelectron spectrometry (XPS) and elemental distribution maps further confirmed the presence of MoS₄-LDH in the PP and most of the Cd(II) chemisorption based on the Cd-S bonding. Due to its high removal efficiency and acid resistance, LDHS-PP is a promising in-situ fixation agent for the remediation of agricultural soil polluted with Cd(II) at low pH.

Highly Tough, Biocompatible, and Magneto-Responsive Fe3O4/Laponite/PDMAAm Nanocomposite Hydrogels

Magneto-responsive hydrogels (MRHs) have attracted considerable attention in various applications owing to their smart response to an externally applied magnetic field. However, their practical uses in biomedical fields are limited by their weak mechanical properties and possible toxicity to the human body. In this study, tough, biocompatible, and magneto-responsive nanocomposite hydrogels (MR_NCHs) were developed by the in-situ free-radical polymerization of N, N-dimethylacrylamide (DMAAm) and laponite and Fe3O4 nanoparticles. The effects of the concentrations of DMAAm, water, and laponite and Fe3O4 nanoparticles in the pre-gel solutions or mixtures on the viscoelastic and mechanical properties of the corresponding hydrogels were examined by performing rheological and tensile tests, through which the mixture composition producing the best MR_NCH system was optimized. The effects were also explained by the possible network structures of the MR_NCHs. Moreover, the morphology, chemical structure, and thermal and mechanical properties of the MR_NCHs were analyzed, while comparing with those of the poly(DMAAm) (PDMAAm) hydrogels and laponite/PDMAAm NCHs. The obtained optimal MR_NCH exhibited noticeable magnetorheological (MR) behavior, excellent mechanical properties, and good biocompatibility. This study demonstrates how to optimize the best Fe3O4/laponite/PDMAAm MR_NCH system and its potential as a soft actuator for the pharmaceutical and biomedical applications.

Preparation of diglycolamide polymer modified silica and its application as adsorbent for rare earth ions

Three novel diglycolamide monomers were synthesized and polymerized on silica. The diglycolamide polymer grafted silica were used as adsorbents for rare earth ions. The effects of acid concentration, structure of monomer, initial solution concentration, contact time and coexisting ions on adsorption of rare earth ions were investigated in detail. It was shown that the adsorption capacity increased with increasing acid concentration. Three adsorbents exhibited selectivity for middle and heavy rare earth over light rare earth in different extent. The adsorbent prepared from the monomer having the largest alkyl substituent showed the lowest adsorption capacity but the highest selectivity for different rare earth elements (REEs). Adsorption data were well fitted to the Langmuir isotherm and pseudo-second-order models. The presence of high concentrations (100 fold) of coexisting metal ions, K(I), Cr(II), Cu(II) or Fe(III), does not decrease the adsorption for rare earth ions seriously.

Superior amine-rich gel adsorbent from peach gum polysaccharide for highly efficient removal of anionic dyes

Herein, we demonstrated the potential of peach gum polysaccharide-based amine-rich gel (ARG) as an efficient adsorbent for removal of anionic dyes from water. The adsorption performance of ARG was systematically studied by choosing methyl orange (MO) and amaranth (ART) as representative anionic dyes. The effects of various parameters such as pH, ionic strength, temperature, initial dye concentration and contact time on the adsorption were investigated. The ARG exhibited superior adsorption selectivity and stable adsorption behaviors against variation of pH and ionic strength for anionic dyes. Adsorption process reached equilibrium within 10 min and showed good correlation with pseudo-second-order kinetic model and Langmuir isotherm. The adsorption capacity of ARG for MO and ART can reach 1949.5 and 1082.2 mg g^-1, respectively. Based on its sustainable characteristic, low cost and excellent adsorption property, the ARG holds great promise for utilizing as an adsorbent for practical water treatment applications.

Functionalized Magnetic Silica Nanoparticles for Highly Efficient Adsorption of Sm3+ from a Dilute Aqueous Solution

Separation of Sm³⁺ from a dilute solution via conventional solvent extraction is often plagued by emulsion and third phase formation. These problems can be overcome with functionalized magnetic nanoparticles that can capture the target species and be separated from the raffinae phase rapidly and efficiently on application of a magnetic field. Magentic silica nanoparticles (Fe₂O₃/SiO₂) were synthesized by a modified Stöber method and functionalized with carboxylate (Fe₂O₃/SiO₂/RCOONa) and phosphonate (Fe₂O₃/SiO₂/R₁R₂PO₃Na) groups to achieve high adsorption capacity and fast adsorption kinetics. The adsorbents were characterized by X-ray diffraction analysis, transmission electron microscopy, BET measurements, magnetization property evaluation, Fourier infrared spectroscopy, and thermogravimetric analysis. Equilibrium adsorption of Sm³⁺ on Fe₂O₃/SiO₂/RCOONa particles was attained within 10 min and within 20 min on Fe₂O₃/SiO₂/R₁R₂PO₃Na nanoparticles. The kinetic data were correlated well with a pseudo-second-order model. Adsorption capacities of Fe₂O₃/SiO₂/RCOONa and Fe₂O₃/SiO₂/R₁R₂PO₃Na were 228 and 180 mg/g, respectively. The recovery of the adsorbed Sm³⁺ using 2 mol/L HCl as desorption agent was evaluated. The adsorption mechanism is discussed based on FTIR analysis, carboxylate group/Sm³⁺ molar ratio, phosphonate group/Sm³⁺ molar ratio, and pH. The adsorbents show significant potential for Sm³⁺ recovery in industrial applications.

Sulfonylcalix[4]arene functionalized nanofiber membranes for effective removal and selective fluorescence recognition of terbium(iii) ions

A novel sulfonylcalix[4]arene functionalized aminated polyacrylonitrile (APAN) nanofiber membrane was fabricated, exhibiting good Tb³⁺ adsorption capacity and photoluminescence performance.

Synthesis of magnetic graphene oxide grafted polymaleicamide dendrimer nanohybrids for adsorption of Pb(II) in aqueous solution

In this paper, using maleic anhydride and ethylenediamine as functional monomers, graphene oxide (GO) loaded magnetic Fe₃O₄ nanoparticles modified by (3-Aminopropyl) triethoxysilane as support, magnetic graphene oxide grafted polymaleicamide dendrimer (GO/Fe₃O₄-g-PMAAM) nanohybrids were fabricated by divergent method and magnetic separation technology. The obtained samples were characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, elementary analyzer and vibrating sample magnetometer. The effects of PMAAM generations, solution pH, Pb(II) initial concentration, temperature and contact time on the adsorption property of the samples for Pb(II) in aqueous solution were studied. The results demonstrated that nitrogen content and adsorption capacity of the as-synthesized samples with amino terminal groups were all higher than their adjacent generations PMAAM with carboxyl terminal groups. Moreover, with increasing generations of PMAAM grafted on to the GO/Fe₃O₄, the nitrogen content and the adsorption capacity of the samples with the same terminal groups gradually increased. The maximum adsorption capacity of GO/Fe₃O₄-g-G3.0 for Pb(II) was 181.4mgg^-1 at 298K. The rising of temperature was beneficial for the adsorption. The adsorption kinetics had a better agreement with pseudo-second-order equation, and equilibrium data followed the Langmuir model.

Nanostructured biogel templated synthesis of Fe3O4 nanoparticles and its application for catalytic degradation of xylenol orange

Using jellyfish mesoglea as a natural template, nanocomposite hydrogels with well-dispersed Fe₃O₄ nanoparticles are obtained.

Electrospun Poly(acrylic acid)/Silica Hydrogel Nanofibers Scaffold for Highly Efficient Adsorption of Lanthanide Ions and Its Photoluminescence Performance

Combined with the features of electrospun nanofibers and the nature of hydrogel, a novel choreographed poly(acrylic acid)-silica hydrogel nanofibers (PAA-S HNFs) scaffold with excellent rare earth elements (REEs) recovery performance was fabricated by a facile route consisting of colloid-electrospinning of PAA/SiO2 precursor solution, moderate thermal cross-linking of PAA-S nanofiber matrix, and full swelling in water. The resultant PAA-S HNFs with a loose and spongy porous network structure exhibited a remarkable adsorption capacity of lanthanide ions (Ln(3+)) triggered by the penetration of Ln(3+) from the nanofiber surface to interior through the abundant water channels, which took full advantage of the internal adsorption sites of nanofibers. The effects of initial solution pH, concentration, and contact time on adsorption of Ln(3+) have been investigated comprehensively. The maximum equilibrium adsorption capacities for La(3+), Eu(3+), and Tb(3+) were 232.6, 268.8, and 250.0 mg/g, respectively, at pH 6, and the adsorption data were well-fitted to the Langmuir isotherm and pseudo-second-order models. The resultant PAA-S HNFs scaffolds could be regenerated successfully. Furthermore, the proposed adsorption mechanism of Ln(3+) on PAA-S HNFs scaffolds was the formation of bidentate carboxylates between carboxyl groups and Ln(3+) confirmed by FT-IR and XPS analysis. The well-designed PAA-S HNFs scaffold can be used as a promising alternative for effective REEs recovery. Moreover, benefiting from the unique features of Ln(3+), the Ln-PAA-S HNFs simultaneously exhibited versatile advantages including good photoluminescent performance, tunable emission color, and excellent flexibility and processability, which also hold great potential for applications in luminescent patterning, underwater fluorescent devices, sensors, and biomaterials, among others.

New Synthesis Route of Hydrogel through A Bioinspired Supramolecular Approach: Gelation, Binding Interaction, and in Vitro Dressing

Peptide-based supramolecular hydrogels have been comprehensively investigated in biomaterial applications because of their unique bioactivity, biofunctionality, and biocompatible features. However, the presence of organic building blocks in peptide-based hydrogels often results in low mechanical stability. To expand their practical use and range of applications, it is necessary to develop the tool kit available to prepare bioinspired, peptide-based supramolecular hydrogels with improved mechanical stability. In this paper, we present an innovative electrostatic and cross-linking approach in which naphthyl-Phe-Phe-Cys (NapFFC) oligopeptides are combined with gold nanoparticles (AuNPs) and calcium ions (Ca(2+)) to produce peptide-based supramolecular hydrogels. We further investigate the interactions among NapFFC, AuNPs and Ca(2+) by microscopy. The morphology of the nanofibrous network constructions and the binding forces exhibited from the hydrogel demonstrated that the combination of two mechanisms successfully enhanced the mechanical stability through the formation of a densely entangled fibrous network of peptide multimers that is attributed to the AuNP linkage and Ca(2+)-induced agglomeration. UV-vis spectrophotometry and fluorescence analysis were also used to demonstrate the enhanced stability of the hydrogel under various conditions such as thermal, solvent erosion, pH value and sonication. All results indicate that the presence of AuNPs and Ca(2+) can strengthen the prepared hydrogel by more than doubling the diameter of NapFFC nanofibers, enabling the formation of stronger frameworks and slowing the release of components. Further experiments confirmed that HeLa cells can grow on the bioinspired NapFFC-AuNP hydrogel and exhibit high cell viability and that these cells were killed on contact with a hydrogel containing a drug. Our peptide-based supramolecular hydrogels prepared from the observed electrostatic and cross-linking mechanisn exhibited a significantly improved mechanical stability, making them well suited to use as a drug carrier in hydrogel dressings and as extracellular materials (ECMs) for tissue engineering.

Fabrication of poly(β-cyclodextrin-co-citric acid)/bentonite clay nanocomposite hydrogel: thermal and absorption properties

A β-cyclodextrin (β-CD)/bentonite clay (BNC) nanocomposite hydrogel was prepared through combining in situ intercalative polymerization and melt intercalation methods.