Recyclable Magnetic Nanoparticles Research Articles

Recyclable magnetic nanoparticles combined with TiO2 enrichment and “Off” to “On” SERS assay for sensitive detection of alkaline phosphatase

As an important enzyme in human tissues, abnormally alkaline phosphatase (ALP) is strongly associated with many diseases, particularly breast and prostate cancer. In this study, we proposed a rapid and sensitive surface-enhanced Raman scattering (SERS)-based biosensor for ALP detection. The biosensor utilized Fe3O4@Au@TiO2 nanoparticles (FAT NPs) as magnetic separation and enrichment materials to enrich grafted mediator Ag-4-mercaptophenylboronic acid (4-MPBA)-ascorbic acid 2-phosphate (AAP) NPs to form FAT-(AAP-4-MPBA-Ag) NPs, and 5,5′-dithiobis-(2-nitrobenzoic acid) (DTNB) was used as the internal standard tag molecule to prepare Au@DTNB@Ag as the signal source. The phosphate group in AAP was cleaved by ALP to form ascorbic acid (AA), which acts as a receptor for the boric acid to adsorb the 4-MPBA-Au@DTNB@Ag NPs. When the switch was “Off” to “On”, the Au@DTNB@Ag NPs were used to significantly improve the sensitivity of the proposed SERS platform, enabling detection as low as 1.17U/L of target ALP with a good linear range (R 2 = 0.991) of 2–10 U/L. Furthermore, the platform successfully detected ALP from 2 % human serum. The recoveries were 99.5–106 %. In addition, FAT-(AAP-4-MPBA-Ag) NPs could be transformed into FAT NPs to achieve recyclability by ultrasonication in acidic environments. Overall, this sensitive and fast SERS platform has promising potential for accurate and efficient identification of ALP from human serum.

CuFe2O4@SiO2-LMnCl: an efficient, highly recyclable magnetic nanoparticle for synergic catalyzing of tetrazoles

CuFe2O4@SiO2-LMnCl: an efficient, highly recyclable magnetic nanoparticle for synergic catalyzing of tetrazoles

Removal of MS-2 Viruses with Recyclable Magnetic Nanoparticles Coated with Metal Ions

Removal of MS-2 Viruses with Recyclable Magnetic Nanoparticles Coated with Metal Ions

Novel disinfection method for toxic cyanobacteria (Oscillatoria tenuis) and simultaneous removal of cyanotoxins aided by recyclable magnetic nanoparticles

An optimized disinfection method with metal ions to address cyanobacteria contamination in freshwater is presented, based on recyclable magnetic nanoparticles. In this study, the disinfection ability of individual metal ions (Ag+ and Cu2+) and combined (Ag+ + Cu2+) were evaluated with a target cyanobacteria, Oscillatoria tenuis, under various environmental conditions. The usage of combined Ag+ and Cu2+ reduces the time and concentration needed to achieve the same disinfection effectiveness compared to individual metal ions. However, the addition of Cu2+ and Ag+ stimulated production of cyanotoxin during disinfection, with an increase of 24.8% for anatoxin-a. To reduce the potential health risk, we evaluated the recovery and reuse of metal ions, and removal of cyanotoxins after disinfection, using magnetic nanoparticles with permanently confined micelle arrays (Mag-PCMA) under various environmental conditions. Recovery efficiency of Ag+, the most valuable ion, was excellent (99.8%), although it decreased to 74.5% with increasing Cl- concentration (0–10 mg/L). The regeneration and reuse of Mag-PCMA was studied for 5 cycles. Removal efficiency of Cu2+, anatoxin-a and cylindrospermopsin were minimally changed during the 5 sorption-desorption cycles, and that of Ag+ remained above 93% by the end of 5th cycle, indicating that this disinfection method may be sustainable for practical use with low energy requirements and minimized environmental impacts.

One-step selective affinity purification and immobilization of His-tagged enzyme by recyclable magnetic nanoparticles.

The NiFe2O4 magnetic nanoparticles (NF‐MNPs) were prepared for one‐step selective affinity purification and immobilization of His‐tagged recombinant glucose dehydrogenase (GluDH). The prepared nanoparticles were characterized by a Fourier‐transform infrared spectrophotometer and microscopy. The immobilization and purification of His‐tagged GluDH on NF‐MNPs were investigated. The optimal immobilization conditions were obtained that mixed cell lysis and carriers in a ratio of 0.13 in pH 8.0 Tris‐HCl buffer at 30℃ and incubated for 2 h. The highest activity recovery and protein bindings were 71.39% and 38.50 μg mg–1 support, respectively. The immobilized GluDH exhibited high thermostability, pH‐stability and it can retain more than 65% of the initial enzyme after 10 cycles for the conversion of glucose to gluconolactone. Comparing with a commercial Ni‐NTA resin, the NF‐MNPs displayed a higher specific affinity with His‐tagged recombinant GluDH.

Efficient and recyclable palladium enriched magnetic nanocatalyst for reduction of toxic environmental pollutants

In this paper, highly stable, powerful, and recyclable magnetic nanoparticles tethered N-heterocyclic carbene-palladium(II) ((CH3)3-NHC-Pd@Fe3O4) as magnetic nanocatalyst was successfully synthesized from a simplistic multistep synthesis under aerobic conditions through easily available low-cost chemicals. Newly synthesized (CH3)3-NHC-Pd@Fe3O4 magnetic nanocatalyst was characterized from various analytical tools and catalytic potential of the (CH3)3-NHC-Pd@Fe3O4 magnetic nanocatalyst was studied for the catalytic reduction of toxic 4-nitrophenol (4-NP), hexavalent chromium (Cr(VI)), Methylene Blue (MB) and Methyl Orange (MO) at room temperature in aqueous media. UV-Visible spectroscopy was employed to monitor the reduction reactions. New (CH3)3-NHC-Pd@Fe3O4 magnetic nanocatalyst exhibited excellent catalytic activity for the reduction of toxic environmental pollutants. Moreover, (CH3)3-NHC-Pd@Fe3O4 magnetic nanocatalyst could be easily and rapidly separated from the reaction mixture with the help of an external magnet and recycled minimum five times in reduction of 4-NP, MB, MO and four times in Cr(VI) without significant loss of catalytic potential and remains stable even after reuse.

Novel composite unit with one pyridinium and three N-halamine structures for enhanced synergism and superior biocidability on magnetic nanoparticles

A novel composite unit of enhanced synergism that rises from the use of a cationic pyridinium structure to attract anionic bacteria to three N-halamine structures was designed for superior biocidability on recyclable magnetic nanoparticles. Briefly, 5-(4-hydroxybenzylidene)hydantoin (HBH), containing one imide and amide NH bonds, was synthesized by Knoevenagel condensation ofp-hydroxybenzaldehyde with hydantoin. 3-Triethoxysilylpropyl succinic anhydride was ammonolyzed with 4-aminopyridine to introduce a pyridine structure and form an amide NH and a carboxylic acid group that was esterified with HBH to introduce its two NH bonds. The triethoxysilyl groups of the esterification product were hydrolyzed into silanols to condense with the counterparts of different hydrolysates and on silica modified Fe3O4nanoparticles to provide a layer of polymeric modifier. After quaternization of the pyridine and chlorination of NH bonds from each esterification product, the resultant layer is composed of units each of which contains one pyridinium and threeN-halamine sites and exerted higher biocidability against Escherichia coli and Staphylococcus aureus than comparable systems including synergistic ones with one cationic center and one N-halamine, demonstrating an enhanced synergism. The biocidal layer had promising stability under quenching-chlorinating cycles and long-term storage. The study affords a strategy for syntheses of more powerful biocidal surfaces.

Fabrication of recyclable multi-responsive magnetic nanoparticles for emulsified oil-water separation

In order to promote the convenience and environmental friendliness of recycling process for the magnetic nanoparticles (MNPs) used in emulsified oil-water separation, a series of recyclable multi-responsive MNPs were successfully fabricated via grafting triple sensitive copolymers onto the silica coated ferroferric oxide (Fe3O4@SiO2) nanoparticles. It was found that the performance of fabricated MNPs was significantly influenced by three environmental parameters, namely pH value, temperature and ionic strength (IS) of water. The synthesized MNPs tended to assemble at oil droplet surface at a temperature less than lower critical solution temperature (LCST), lower pH level or higher IS, thereby facilitating removal of emulsified oil from water phase under external magnetic field. On the contrary, these MNPs could also reversibly desorb form oil droplet surface at a temperature higher than LCST, higher pH level or lower IS. Accordingly, the spent MNPs could be easily regenerated by just regulating solution temperature, pH or IS, rather than by washing with organic solvent, thereby minimizing the risks of secondary pollution. Recycling experiment showed that the well-designed MNPs could be reused up to five cycles without showing remarkable decline in separation efficiency. It’s noteworthy that the MNPs exhibited superior separation efficiency at high IS, which is typically encountered for real saline oily water system, thereby spent MNPs could be easily recycled by merely using deionized water due to the dramatical decrease of IS during their rinsing process, suggesting its applicability for practical use. It is expected that the development of this multi-responsive and recyclable MNPs can potentially offer a promising, facile, cost-efficient and eco-friendly route for the emulsified oily wastewater treatment.

Synthesis of magnetically separable and recyclable magnetic nanoparticles decorated with β-cyclodextrin functionalized graphene oxide an excellent adsorption of As(V)/(III)

Here, we report a magnetic nanoparticles (Fe3O4NPs) decorated with β-Cyclodextrins (CDs)-functionalized graphene oxide (GO) (β-CDs-GO@Fe3O4NPs) have been synthesized via chemical reaction, this adsorbent has number of hydroxyl & carboxyl group which shows excellent water dispersibility and superior magnetic property, additionally this can be utilized as an efficient adsorbent to enhance the adsorption of As(III)/As(V). The physicochemical properties of the adsorbent prior to and after adsorption of As(III)/As(V) were characterized extensively using Powder-X-ray diffraction (Powder-XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Thermogravimetric analysis (TGA), High resolution transmission electron microscopes (HR-TEM), Superconducting quantum interference device (SQUID), Zeta potential, Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopes & elemental analysis (SEM & EDX). Batch adsorption experiments were conducted to study the various factors such as effect of pH, isotherms, kinetics, thermodynamics were studied with a view to understand the adsorption efficiency, while the data of adsorption isotherms and kinetics were better fitted by Freundlich isotherm model and the pseudo second-order kinetic model, respectively. The free energy change ΔG0 decreased with increase temperature and the positive ΔH0 and ΔS0 values indicates that endothermic nature of adsorption and increased randomness at the adsorbent-solution interface. The mechanism of adsorption has been discussed in detail and these studies provide a simple method for the preparation of smart adsorbent. Regeneration of the adsorbent was accomplished by sodium hydroxide and this adsorbent could be reused with quantitative recovery of two adsorption-desorption cycles. In addition to that, efficacy of the potential novel adsorbent has been examined in the adsorption As(V)/As(III) from aqueous solutions.

Synthesis of pH-sensitive and recyclable magnetic nanoparticles for efficient separation of emulsified oil from aqueous environments

Emulsified oil wastewaters, arisen from oil industry and oil spill accidents, cause severe environmental and ecological problems. In this study, a series of pH-sensitive magnetic nanomaterials (MNPs) were synthesized and characterized for their evaluation in separation of emulsified oil from aqueous environments. A coprecipitation method was used to produce Fe3O4 magnetic nanoparticles that were coated in a 2-step process with first silica to form a surface for anchoring an (3-aminopropyl)triethoxysilane (APTES) molecular layer. Detailed studies were conducted on effects of MNPs dosage, APTES anchoring density (DA) and pH on oil-water separation performance of the synthetic MNPs. Results showed that, under both acidic and neutral conditions, MNPs with high DA exhibited enhanced oil-water separation performance, while under alkaline condition, the oil-water separation process was minimal. Alkaline conditions allowed the MNPs to be recycled up to 9 cycles without showing any significant decrease in oil-water separation efficiency. An examination of the oil-water separation mechanism found that electrostatic interaction and interfacial activity both played important roles in oil-water separation. In conclusion, pH-sensitive MNPs can be easily synthesized and recycled, providing a promising, cost-effective and environmentally-friendly process for the efficient treatment of emulsified oil wastewater.

Oxidative dimerization of thiols to disulfide using recyclable magnetic nanoparticles

Dimerization of thiol groups to disulfide is an important transformation in chemical processes. In this study, magnetic ion exchanged Montmorillonite-k10 was synthesized and characterized using FTIR, X-ray diffraction and scanning electron microscope techniques. Then, the application of the synthesized catalyst as an efficient oxidizing agent was evaluated in oxidative dimerization of different thiols to corresponding disulfides under optimal reaction conditions. The reaction was easily performed with aromatic, aliphatic and heterocyclic thiols. The magnetic catalyst was easily recovered by applying an external magnet and, further, was reused in successive reactions.

Immobilized NNN Pd-complex on magnetic nanoparticles: efficient and reusable catalyst for Heck and Sonogashira coupling reactions

A highly efficient and easily recyclable magnetic nanoparticle supported palladium catalyst was developed and applied in the Heck and Sonogashira reactions in order to show its catalytic applicability in Pd-catalyzed C–C coupling protocols.

Surfactant-free green synthesis of Fe3O4 nanoparticles capped with 3,4-dihydroxyphenethylcarbamodithioate: stable recyclable magnetic nanoparticles for the rapid and efficient removal of Hg(II) ions from water.

Mercury is considered one of the most notorious global pollutants due to its high toxicity and widespread use in industry. Although many materials have been developed for the removal of mercury for water purification, most of these materials are difficult to reuse, which may lead to an increase in the mercury handling expense. Therefore, new sustainable materials that can be easily recycled and are highly efficient for the removal of mercury are required. Herein, we report the surfactant-free green synthesis of Fe3O4 magnetic nanoparticles (MNPs) using a watermelon (Citrullus lanatus) rind extract. The Fe3O4 MNPs were further functionalized with 3,4-dihydroxyphenethylcarbamodithioate (DHPCT) and applied to the removal of Hg(ii). Evaluation of the mercury removal efficiency and the amount adsorbed by DHPCT@Fe3O4 MNPs demonstrated a high Hg(ii) removal efficiency (98%) with a maximum Hg(ii) adsorption capacity of 52.1 mg g(-1). Systematic studies of the adsorption mechanism and selectivity suggest that the soft ligand (DHPCT) can preferentially coordinate with the soft metal ion (Hg(ii)) resulting in selective mercury removal. The developed DHPCT@Fe3O4 MNPs were readily recycled several times using an external magnet by exploiting their ferromagnetic character, without a significant decline in the Hg(ii) removal efficiency. This study provides a new insight into the preparation of a highly efficient adsorbent for Hg(ii) removal by an eco-friendly method.

Recyclable magnetic nanoparticle grafted with pH-responsive polymer for adsorption with DNA

Magnetite nanoparticles (MNPs) grafted with positively charged poly(2-(diethylamino) ethyl methacrylate (PDEAEMA) were prepared via a combination of atom transfer radical polymerization (ATRP) and “click” reaction and used as recyclable nanosupports for adsorption with DNA. Alkyne-terminated PDEAEMA was synthesized via ATRP and then “grafted to” azide-functionalized MNPs. Quaternized PDEAEMA-grafted MNPs were used as recyclable nanosupports for adsorption with negatively charged DNA via electrostatic interactions. The particles with the size of 3–8 nm in diameter were well dispersible in water. They responded to the change in their solution pH as observed by a consistent decrease in hydrodynamic size when solution pH changed from basic to acidic pH. Recycling efficiency of the MNPs was investigated by determining the percent adsorption of the particles after multiple cycles of the adsorption–separation–desorption process. Adsorption ability of the MNPs to T9 DNA tagged with fluorescein at 5′-position (FAM-dT9) retained higher than 80 % after 5-recycling process, indicating that these novel positively charged MNPs might be efficiently used as magnetic nanosupports for any negative biomolecules with good recycling efficiency.

ChemInform Abstract: New Green, Recyclable Magnetic Nanoparticles Supported Amino Acids as Simple Heterogenous Catalysts for Knoevenagel Condensation.

AbstractIron oxide supported amino acid as recoverable catalyst is applied in Knoevenagel condensation leading to different substituted coumarin derivatives.

New Green, Recyclable Magnetic Nanoparticles Supported Amino Acids as Simple Heterogeneous Catalysts for Knoevenagel Condensation

New Green, Recyclable Magnetic Nanoparticles Supported Amino Acids as Simple Heterogeneous Catalysts for Knoevenagel Condensation

A recyclable magnetic nanoparticles supported antimony catalyst for the synthesis of N-substituted pyrroles in water

A new magnetic nanoparticle-supported antimony catalyst was prepared and evaluated as a recoverable catalyst for Clauson-Kaas reaction. The reaction proceeds efficiently in aqueous medium to give the corresponding N-substituted pyrroles in high yield. The immobilized catalyst could be easily recovered by magnetic separation and recycled for six times without significant loss of its catalytic activity.

ChemInform Abstract: A Recyclable Magnetic Nanoparticles Supported Palladium Catalyst for the Hiyama Reaction of Aryltrialkoxysilanes with Aryl Halides.

AbstractA wide range of aryl iodides and bromides is applied in the reaction with phenyl trimethyloxy‐ or triethyloxysilanes to afford biaryl derivatives in high yields.

A recyclable magnetic nanoparticles supported palladium catalyst for the Hiyama reaction of aryltrialkoxysilanes with aryl halides

Download options Please wait... Supplementary files Supplementary information PDF (479K) Article information DOI https://doi.org/10.1039/C2CY20162C Article type Paper Submitted 17 Mar 2012 Accepted 24 Apr 2012 First published 25 Apr 2012 Download Citation Catal. Sci. Technol., 2012,2, 1859-1864 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions A recyclable magnetic nanoparticles supported palladium catalyst for the Hiyama reaction of aryltrialkoxysilanes with aryl halides L. Zhang, P. Li, H. Li and L. Wang, Catal. Sci. Technol., 2012, 2, 1859 DOI: 10.1039/C2CY20162C To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Social activity Tweet Share Search articles by author Lei Zhang Pinhua Li Hongji Li Lei Wang

Recoverable and recyclable magnetic nanoparticle supported aluminium isopropoxide for ring-opening polymerization of ε-caprolactone

Magnetic nanoparticle supported aluminium isopropoxide is demonstrated as a new catalyst for the ring-opening polymerization of epsilon-caprolactone. The catalyst can be easily recovered under a magnetic field and reused, yielding poly(caprolactone) with negligible metal residue.