Magnetic Fe 3 O 4 @ silica–xanthan gum composites for aqueous removal and recovery of Pb 2+

Magnetic ferrite nanoparticles coated with bovine serum albumin and glycine polymers for controlled release of curcumin as a model

To conquer the low water solubility and bioavailability of curcumin (CUR), to corroborate its functional qualities and to broaden its applicability in the pharmaceutical sector, numerous nanoscale methods have been widely exploited for its administration. Because of its polycystic, biodegradable, biocompatibility, non-toxicity, and non-allergenic properties, bovine serum albumin (BSA) and glycine (Gly) have been actively investigated as natural biopolymers for decades. Various BSA and Gly-based nanocarriers with unique features for CUR delivery, such as magnetic ferrite nanoparticles, are being developed (MNPs). In this work, magnesium ferrite (MgFe2O4)/BSA and nickel ferrite (NiFe2O4)/Gly nanocomposites loaded with CUR (drug model) were manufactured for the first time using a chemical co-precipitation approach to create biocompatible drug nanocarriers. It was found that the synthesized MgFe2O4/BSA and NiFe2O4/Gly nanoparticles have a uniform particle distribution and their size is much less than 100 nm. Saturation magnetization in MgFe2O4 and NiFe2O4 reaches 13.07 and 33.4 emu/g the remarkable peak of magnetization decreases to 10.99 and 32.36 emu/g after the addition of polymers. These analyses also showed the presence of chemical bonds in the structure of the nanocomposite. The curcumin diffusion process in NPs were determined using a mathematical modeling. The yielding of the product for MgFe2O4/BSA and NiFe2O4/Gly in 200 h is about 72 and 63%, respectively. Also, regressed relative diffusivities (D/R2), including effective steric hindrance, were determined as 5.75 × 10-4 and 2.72 × 10-4 h-1 for MgFe2O4/BSA and NiFe2O4/Gly, respectively. It shows that there is a significant steric barrier that significantly deviates from the molecular diffusion of the liquid. As a result, the low effective release of curcumin in the particles is more noticeable. Our study demonstrated the effective relationship between the polymer architecture and the biophysical properties of the resulting nanoparticles and shed light on new approaches for the design of efficient NP-based drug carriers.

Adsorption of Pb (II) and Cu (II) by magnetic beads loaded with xanthan gum

Green and environmentally friendly and efficient separation adsorbents have attracted much attention in the treatment of heavy metal ions wastewater. In this study, xanthan gum (XG) was supported by fly ash magnetic beads (FAMB) to prepare adsorbent XG@FAMB. The effects of XG@FAMB dosage, pH value of the solution, adsorption time, and initial Pb (II) and Cu (II) concentration on its adsorption performance for Pb (II) and Cu (II) were investigated. The results show that under the conditions of pH 6, dosage of XG@FAMB 4.0 g/L, adsorption time 120 min, and initial concentration 60 mg/L, the maximum adsorption capacity of XG@FAMB for Pb (II) and Cu (II) was 14.93 mg/g and 14.88 mg/g, respectively. The adsorption process of Pb (II) and Cu (II) by XG@FAMB could be better described by the quasi-second-order kinetic model and Langmuir isothermal adsorption model, that is, the adsorption process is monolayer adsorption controlled by chemical action. The adsorption mechanism is that Pb (II) and Cu (II) coordinate with oxygen-containing functional groups hydroxyl and carboxyl on XG@FAMB surface, accompanied by electrostatic adsorption. XG@FAMB has the advantages of environmental protection of XG and easy solid-liquid separation of FAMB, and has a good removal effect on Pb (II) and Cu (II).

Green and Superior Adsorbents Derived from Natural Plant Gums for Removal of Contaminants: A Review

The ubiquitous presence of contaminants in water poses a major threat to the safety of ecosystems and human health, and so more materials or technologies are urgently needed to eliminate pollutants. Polymer materials have shown significant advantages over most other adsorption materials in the decontamination of wastewater by virtue of their relatively high adsorption capacity and fast adsorption rate. In recent years, "green development" has become the focus of global attention, and the environmental friendliness of materials themselves has been concerned. Therefore, natural polymers-derived materials are favored in the purification of wastewater due to their unique advantages of being renewable, low cost and environmentally friendly. Among them, natural plant gums show great potential in the synthesis of environmentally friendly polymer adsorption materials due to their rich sources, diverse structures and properties, as well as their renewable, non-toxic and biocompatible advantages. Natural plant gums can be easily modified by facile derivatization or a graft polymerization reaction to enhance the inherent properties or introduce new functions, thus obtaining new adsorption materials for the efficient purification of wastewater. This paper summarized the research progress on the fabrication of various gums-based adsorbents and their application in the decontamination of different types of pollutants. The general synthesis mechanism of gums-based adsorbents, and the adsorption mechanism of the adsorbent for different types of pollutants were also discussed. This paper was aimed at providing a reference for the design and development of more cost-effective and environmentally friendly water purification materials.

Prospects of Biogenic Xanthan and Gellan in Removal of Heavy Metals from Contaminated Waters

Biosorption is considered an effective technique for the treatment of heavy-metal-bearing wastewaters. In recent years, various biogenic products, including native and functionalized biopolymers, have been successfully employed in technologies aiming for the environmentally sustainable immobilization and removal of heavy metals at contaminated sites, including two commercially available heteropolysaccharides-xanthan and gellan. As biodegradable and non-toxic fermentation products, xanthan and gellan have been successfully tested in various remediation techniques. Here, to highlight their prospects as green adsorbents for water decontamination, we have reviewed their biosynthesis machinery and chemical properties that are linked to their sorptive interactions, as well as their actual performance in the remediation of heavy metal contaminated waters. Their sorptive performance in native and modified forms is promising; thus, both xanthan and gellan are emerging as new green-based materials for the cost-effective and efficient remediation of heavy metal-contaminated waters.

Natural, low-cost adsorbents for toxic Pb(II) ion sequestration from (waste)water: A state-of-the-art review

Pb(II) ions is an inorganic pollutant that is present in the environment. Its presence affects both human health and ecosystem. Economically, amongst many wastewater treatment approaches, adsorption is both cheap and environmentally friendly for removing Pb(II) ion from contaminated water. In this state of the art review, about 227 research and review based publications on adsorption-based studies between 1989 and 2021, which have used various materials as adsorbents of Pb (II) ions, were selected and reviewed for more evaluation. A number of adsorbents which have been reported in these literatures for the adsorption of Pb(II) ion are agrobased, modified agrobased, clay minerals, modified/nanocomposite clay minerals, silica-based, zeolite-based and chitosan-based adsorbents, respectively. The adsorption potential of the adsorbents is exhibited under optimum experimental conditions. The unmodified and modified agro based adsorbents were shown to exhibit the greatest Pb(II) adsorption capacity, with great potential for further exploration, compared to the others afore-listed. The effects of operating parameters such as pH, initial metal ion concentration, adsorbent dose and reaction time are discussed. Furthermore, in order to comprehend the nature of adsorption process between the adsorbent and contaminant (Pb(II)), thermodynamic analyses of adsorption systems are intensively described. All these discussions revealed the applicability of adsorption process for toxic Pb(II) ions removal with respect to wastewater treatment techniques. The review concludes by commenting on the various adsorbents' adsorption capacity and proposes some studies that should also be considered in future works.

Heavy Metal Adsorption Using Magnetic Nanoparticles for Water Purification: A Critical Review

Research on contamination of groundwater and drinking water is of major importance. Due to the rapid and significant progress in the last decade in nanotechnology and its potential applications to water purification, such as adsorption of heavy metal ion from contaminated water, a wide number of articles have been published. An evaluating frame of the main findings of recent research on heavy metal removal using magnetic nanoparticles, with emphasis on water quality and method applicability, is presented. A large number of articles have been studied with a focus on the synthesis and characterization procedures for bare and modified magnetic nanoparticles as well as on their adsorption capacity and the corresponding desorption process of the methods are presented. The present review analysis shows that the experimental procedures demonstrate high adsorption capacity for pollutants from aquatic solutions. Moreover, reuse of the employed nanoparticles up to five times leads to an efficiency up to 90%. We must mention also that in some rare occasions, nanoparticles have been reused up to 22 times.

Magnetic Nitrogen-Doped Porous Carbon Nanocomposite for Pb(II) Adsorption from Aqueous Solution

We report in the present study the in situ formation of magnetic nanoparticles (Fe3O4 or Fe) within porous N-doped carbon (Fe3O4/N@C) via simple impregnation, polymerization, and calcination sequentially. The synthesized nanocomposite structural properties were investigated using different techniques showing its good construction. The formed nanocomposite showed a saturation magnetization (Ms) of 23.0 emu g-1 due to the implanted magnetic nanoparticles and high surface area from the porous N-doped carbon. The nanocomposite was formed as graphite-type layers. The well-synthesized nanocomposite showed a high adsorption affinity toward Pb2+ toxic ions. The nanosorbent showed a maximum adsorption capacity of 250.0 mg/g toward the Pb2+ metallic ions at pH of 5.5, initial Pb2+ concentration of 180.0 mg/L, and room temperature. Due to its superparamagnetic characteristics, an external magnet was used for the fast separation of the nanocomposite. This enabled the study of the nanocomposite reusability toward Pb2+ ions, showing good chemical stability even after six cycles. Subsequently, Fe3O4/N@C nanocomposite was shown to have excellent efficiency for the removal of toxic Pb2+ ions from water.

Synergetic adsorption and photo-Fenton degradation of methylene blue by ZnFe2O4/SiO2 magnetic double-mesoporous-shelled hollow spheres

Adsorption and Fenton technologies have been widely employed to deal with wastewater. ZnFe₂O₄/SiO₂ magnetic double-mesoporous-shelled hollow spheres (MDSHSs) were feasibly synthesized by a solvothermal method. The as-synthesized MDSHSs show excellent adsorption and selectivity for methylene blue (MB), which it took about only 1 min to reach the adsorption equilibrium. About 50% MB was removed by adsorption, and other 50% MB was degraded under further photo-Fenton process. Effects of experimental conditions on the adsorption and photo-Fenton process were investigated. The mechanisms of MDSHSs formation and photo-Fenton process were proposed. Total organic carbon (TOC) reduction reached as high as 90% with 60 mg/L of MB for 90 min. The experimental results indicated that MDSHSs exhibit a remarkable adsorption and catalytic activity for photo-Fenton process in a wide pH range of 3.3-11.0. Simultaneously, the composite shows an excellent stability and reusability.

Magnetic Nanoparticle Composites: Synergistic Effects and Applications

Composite materials are made from two or more constituent materials with distinct physical or chemical properties that, when combined, produce a material with characteristics which are at least to some degree different from its individual components. Nanocomposite materials are composed of different materials of which at least one has nanoscale dimensions. Common types of nanocomposites consist of a combination of two different elements, with a nanoparticle that is linked to, or surrounded by, another organic or inorganic material, for example in a core-shell or heterostructure configuration. A general family of nanoparticle composites concerns the coating of a nanoscale material by a polymer, SiO2 or carbon. Other materials, such as graphene or graphene oxide (GO), are used as supports forming composites when nanoscale materials are deposited onto them. In this Review we focus on magnetic nanocomposites, describing their synthetic methods, physical properties and applications. Several types of nanocomposites are presented, according to their composition, morphology or surface functionalization. Their applications are largely due to the synergistic effects that appear thanks to the co-existence of two different materials and to their interface, resulting in properties often better than those of their single-phase components. Applications discussed concern magnetically separable catalysts, water treatment, diagnostics-sensing and biomedicine.

Dimpled SiO2@γ-Fe2O3 nanocomposites - fabrication and use for arsenic adsorption in aqueous medium

We report the synthesis of nanocomposites made of silica nanoparticles whose six surface dimples are decorated with magnetic maghemite nanoparticles and their use for detection and recovery of arsenic in aqueous media. Precursor silica nanoparticles have aminated polystyrene chains at the bottom of their dimples and the maghemite nanoparticles are surface functionalized with carboxylic acid groups in two steps: amination with 3-aminopropyltrimethoxysilane, then derivatization with succinic anhydride in the presence of triethylamine. In the end, the colloidal assembly consists of the regioselective grafting of the carboxylic acid-modified iron oxide nanoparticles onto the 6-dimple silica nanoparticles. Several characterization techniques such as transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), dynamic light scattering (DLS) are employed to assess the grafting process and study the influence of the maghemite functional groups on the quality of the composites formed. The resulting magnetic nanocomposites are used for the environmentally benign detection and removal of arsenic from aqueous medium, being readily extracted through means of magnetic separation.

The process of grafting maghemite NFs onto silica dimples.

Optimal generation number in magnetic-cored dendrimers as Pb(II) and Cd(II) adsorbents

As the generation number of dendrimers increases, more organic branches and terminal groups are synthesized on the surface. However, this may not be actual situations in all generations of dendrimers. Different generations of magnetic cored dendrimer (MCD) terminalized with amine functional groups were compared as adsorbents for heavy metal ions in water. To determine the optimal generation number as adsorbent, the maximal adsorption of lead and cadmium on generation 1, 2, and 3 (G1, G2, and G3) MCDs. Higher generation MCD had more organic contents and possibly terminal groups on its structure. However, G2 MCD was the highest in adsorbing both lead and cadmium. An acid-base titration was performed to quantify the amine functional groups. The active amine sites on G2 are 4.35 times as much as that of G1 and 0.12 times as much as that of G3, which coincided with the adsorption experimental result. Incomplete dendritic structure formation due to steric hindrance caused G2 MCD to be the most efficient among the three generations of MCDs in this research.

Hybrid silica aerogel nanocomposite adsorbents designed for Cd(II) removal from aqueous solution

Hybrid silica aerogel (HSA) nanoparticles were synthesized by sol-gel method and drying at ambient pressure. Also, two magnetic nanocomposites of HSA with Fe₃ O₄ nanoparticles and chitosan (CS) were prepared including HSA-Fe₃ O₄ and HSA-Fe₃ O₄ -CS. The morphology, structure, and magnetic properties of the HSA as well as its nanocomposites were analyzed by SEM, XRD, TGA, VSM, and ATR-FTIR techniques. The saturation magnetization (M_s ) values for the Fe₃ O₄ NPs, HSA-Fe₃ O_4, and HSA-Fe₃ O₄ -CS nanocomposite film were 69.93, 19.04, and 5.77 emu/g, respectively. Furthermore, the abilities of the HSA, HSA-Fe₃ O₄ , CS, and HSA-Fe₃ O₄ -CS adsorbents were assessed for removal of cadmium(II) heavy metal ions (100 ppm) from aqueous solution. All adsorbents removed/adsorbed the maximum Cd(II) ions in 120 min when adsorbent dosage = 20 mg and pH = 8. Moreover, the highest adsorption capacities were 58.5, 69.4, 65.8, and 71.9 mg/g for the HSA, CS, HSA-Fe₃ O_4, and HSA-Fe₃ O₄ -CS, respectively. Kinetic studies using all adsorbents verified that Cd(II) adsorption obeyed the second-order model illustrating the analyte chemisorption was happened on the adsorbent surfaces. All adsorption data were well consistent with the Langmuir isotherms. The reusability experiment confirmed that all of adsorbents could preserve >95% of their initial adsorption capacities even after five series of adsorption/desorption tests. PRACTITIONER POINTS: Hybrid silica aerogel (HSA), HSA-Fe₃ O_4, and HSA-Fe₃ O₄ -CS adsorbents were produced. Nanocomposites were characterized by XRD, TGA, SEM, VSM, and ATR-FTIR analysis. Adsorption of cadmium(II) ions by adsorbents was examined in aqueous solution. The highest adsorption capacity was obtained for the HSA-Fe₃ O₄ -CS (71.9 mg/g). Cd(II) adsorption followed second-order kinetics and Langmuir isotherm model.

Functionalized magnetic particles for water treatment

In this study, we have taken the concept of water treatment by functionalized magnetic particles one step forward by integrating the technology into a complete proof of concept, which included the preparation of surface modified beads, their use as highly selective absorbents for heavy metals ions (Zinc, Nickel), and their performance in terms of magnetic separation. The separation characteristics were studied both through experiments and by simulations. The data gathered from these experimental works enabled the elaboration of various scenarios for Life Cycle Analysis (LCA). The LCA showed that the environmental impact of the system is highly dependent on the recovery rate of the magnetic particles. The absolute impact on climate change varied significantly among the scenarios studied and the recovery rates. The results support the hypothesis that chelation specificity, magnetic separation and bead recovery should be optimized to specific targets and applications.

Encapsulated green magnetic nanoparticles for the removal of toxic Pb2+ and Cd2+ from water: Development, characterization and application

Current research is based on an innovative approach of the fabrication of encapsulated sustainable, green, phytogenic magnetic nanoparticles (PMNPs), to inhibit the generation of secondary pollutants (Iron/Fe^o) during water treatment applications. These novel bio-magnetic membrane capsules (BMMCs) were prepared using two-step titration gel crosslink method, with polyvinyl alcohol and sodium alginate matrix as the model encapsulating materials to eliminate potentially toxic metals (Pb²⁺ and Cd²⁺) from water. The development of BMMCs was characterized by FTIR, XRD, XPS, SEM, VSM, TGA and EDX techniques. The effects of various operating parameters, adsorbent dose, contact time, solution pH, temperature, initial concentration of metals cations and co-existing ions were studied. The hysteresis loops have illustrated an excellent super-paramagnetic nature, demonstrating the smooth encapsulation of PMNPs without losing their magnetic properties. The maximum monolayer adsorptive capacities estimated at pH 6.5 by the Langmuir isotherm model were 548 and 610.67 mg/g for Pb²⁺ and Cd²⁺, respectively. The novel BMMCs did not only control oxidation of PMNPs but also sustained the adsorptive removal over a wide range of pH (3-8), and the electrostatic interaction and ion-exchange were the core adsorption mechanisms. The BMMCs could easily be regenerated using 25% HNO₃ as an eluent for successful usage in seven repeated cycles. Therefore, the BMMCs as a material can be used as an excellent sorbent or composite material to remove toxic metals Pb²⁺ and Cd²⁺, showing strong potential for improving water and wastewater treatment technologies.

Lead Remediation Using Smart Materials. A Review

The nanoparticles have been prepared and employed as excellent adsorbents for the sequestration of heavy metal ions and hazardous impurities from the aqueous media. The surface morphological, textural and structural properties of nanoparticles have been modified, which are capable and potentially useful for the remediation of metal ions. Several metals (oxides, doped, nanocomposites of Fe, Ti, Zn, SiO2, SiC, Mo, Co, Ni, Zr, Mn, Si, S, Al, Cu, Ce, graphene, CNTs) were reported an efficient adsorbents for the removal of lead (Pb) ions from aqueous media and polluted water. The present review focuses on different kinds of nanoparticles such as metal oxides, carbon based and host supported employed for removal of Pb ions under varying experimental conditions such as pH, temperature, contact time and concentrations. The preparation strategies, physicochemical properties and adsorption are also discussed. Based on studies, it was found that the smart materials are affective adsorbents for the purification of wastewater containing Pb ions and could possibly extended for the remediation of other heavy metal ions.

Magnetically retrievable Ce-doped Fe3O4 nanoparticles as scaffolds for the removal of azo dyes

Considering the significant impact of magnetically retrievable nanostructures, herein, Fe₃O₄ and Ce-doped Fe₃O₄ nanoparticles were employed as scaffolds for the removal of the Reactive Black 5 (RB5) azo dye. We synthesized the Ce-doped Fe₃O₄ nanoparticles via hydrothermal treatment at 120 °C for 10 h with varying cerium concentrations (1.5–3.5%) and characterized them using basic techniques such as FTIR and UV-visible spectroscopy, and XRD analysis. The retention of their magnetic behaviors even after cerium amalgamation was demonstrated and confirmed by the VSM results. FESEM and EDX were used for the morphological and purity analysis of the synthesized nanoabsorbents. XPS was carried out to determine the electronic configuration of the synthesized samples. The porosity of the magnetic nanoparticles was investigated by BET analysis, and subsequently, the most porous sample was further used in the adsorption studies for the cleanup of RB5 from wastewater. The dye adsorption studies were probed via UV-visible spectroscopy, which indicated the removal efficiency of 87%. The prepared Ce-doped Fe₃O₄ nanoabsorbent showed the high adsorption capacity of 84.58 mg g⁻¹ towards RB5 in 40 min. This is attributed to the electrostatic interactions between the nanoabsorbent and the dye molecules and high porosity of the prepared sample. The adsorption mechanism was also analyzed. The kinetic data well-fitted the pseudo-first-order model, and the adsorption capability at different equilibrium concentrations of the dye solution indicated monolayer formation and chemisorption phenomena. Furthermore, the magnetic absorbent could be rapidly separated from the wastewater using an external magnetic field after adsorption.

Considering the significant impact of magnetically retrievable nanostructures, herein, Ce-doped Fe₃O₄ nanoparticles were employed as scaffolds for the removal of the Reactive Black 5 (RB5), an azo dye.

Chelating magnetic nanocomposite for the rapid removal of Pb(ii) ions from aqueous solutions: characterization, kinetic, isotherm and thermodynamic studies

Fe₃O₄@GMA–AAm nanocomposite as a novel adsorbent with high adsorption capacity for rapid removal of Pb²⁺ from aqueous media was synthesized.

Silica-coated magnetite nanoparticles core-shell spheres (Fe3O4@SiO2) for natural organic matter removal

Background

In this work, the magnetite (Fe₃O₄) nanoparticles (MNPs) and silica-coated magnetite nanoparticles (SMNPs) were synthesized as adsorbents for removing humic acid (HA) from water resources.

Methods

The adsorption processes were performed in batch experiments with which the influence of pH, reaction time, adsorbent dosage, initial concentrations of HA and temperature were investigated. Specific techniques were applied to characterize the features of both adsorbents (i. e. TECHNIQUES) (SEM, XRD, TEM, BET, EDX and VSM).

Results

The maximum saturation magnetization for SMNPs was 30.2 emu/g, which made its separation from the solution by a magnetic field to be easier and faster. The HA adsorption process onto the both adsorbents were best described by the Freundlich isotherm and pseudo-second-order kinetic models. Highest adsorption efficiency of HA by MNPs an d SMNPs occurred at acidic conditions (pH ≈ 3). The mechanisms of adsorption process involved with a physisorption process such as (i. e. hydrogen bonding and electrostatic interaction). The predicted maximum monolayer adsorption capacities obtained by Langmuir isotherm model for MNPs and SMNPs were 96.15 and 196.07 mg/g, respectively.

Conclusion

Higher amount of HA adsorption onto the surfaces of SMNPs than MNPs surfaces was observed, reflecting that silica impregnated on MNPs enhances the efficiency of the adsorbent in removing HA.

Electronic supplementary material

The online version of this article (doi:10.1186/s40201-016-0262-y) contains supplementary material, which is available to authorized users.

Enhanced oxidative and adsorptive capability towards antimony by copper-doping into magnetite magnetic particles

Copper-doped magnetite improved particle size, enhanced adsorption capacity of antimony (Sb) and oxidation ability of Sb (III).

Removal of Cu2+ from wastewater by modified xanthan gum (XG) with ethylenediamine (EDA)

Herein, a new adsorbent was synthesized by modifying xanthan gum for the removal of Cu²⁺ from wastewater.

Magnetic solid-phase extraction based on modified ferum oxides for enrichment, preconcentration, and isolation of pesticides and selected pollutants

Recently, a simple, rapid, high-efficiency, selective, and sensitive method for isolation, preconcentration, and enrichment of analytes has been developed. This new method of sample handling is based on ferum oxides as magnetic nanoparticles (MNPs) and has been used for magnetic solid-phase extraction (MSPE) of various analytes from various matrices. This review focuses on the applications of modified ferum oxides, especially modified Fe3O4 MNPs, as MSPE adsorbent for pesticide isolation from various matrices. Further perspectives on MSPE based on modified Fe3O4 for inorganic metal ions, organic compounds, and biological species from water samples are also presented. Ferum(III) oxide MNPs (Fe2O3) are also highlighted.

Core-Shell Ferromagnetic Nanorod Based on Amine Polymer Composite (Fe3O4@DAPF) for Fast Removal of Pb(II) from Aqueous Solutions

Heavy metal ion removal from wastewater constitutes an important issue in the water treatment industry. Although a variety of nanomaterials have been developed for heavy metal removal via adsorption, the adsorption capacity, removal efficiency, and material recyclability still remain a challenge. Here, we present novel Fe3O4@DAPF core-shell ferromagnetic nanorods (CSFMNRs) for the removal of Pb(II) from aqueous solutions; they were prepared by the facile surface modification of twin-like ferromagnetic Fe3O4 nanorods using a 2,3-diaminophenol and formaldehyde (DAPF)-based polymer. The crystallinity and structure of the Fe3O4 nanorods were confirmed via X-ray diffraction (XRD). Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) revealed the core-shell morphology and composition of the materials. Pb(II) removal using the prepared Fe3O4@DAPF CSFMNRs was assessed, and comparable adsorption capacities (83.3 mg g(-1)) to the largest value were demonstrated. A thermodynamic study of the adsorption clearly indicated that the adsorption was exothermic and spontaneous. Due to the ferromagnetic properties with a high saturation magnetization value (56.1 emu g(-1)) of the nanorods, the nanorods exhibited excellent reusability with one of the fastest recovery times (25 s) among reported materials. Therefore, the Fe3O4@DAPF CSFMNRs can serve as recyclable adsorbent materials and as an alternative to commonly used sorbent materials for the rapid removal of heavy metals from aqueous solutions.

Graphene oxide-based Fe3O4 nanoparticles as a novel scaffold for the immobilization of porcine pancreatic lipase

A chloropropyl-functionalized graphene oxide decorated with Fe₃O₄ nanoparticles, CPS/GO-Fe3O4@MCM-41, was made, and porcine pancreas lipase (PPL) was immobilized onto the graphene oxide based magnetic nanoparticles via covalent bonding.