Magnetic Nanoparticle Adsorbents Research Articles

Removal of anionic azo dye from wastewater using Fe3O4 magnetic nanoparticles adsorbents in a batch system

This work investigates removing the anionic azo dye from wastewater using Fe3O4 magnetic nanoparticle adsorbents in a batch system. The effects of adsorbent dosage (0.1–0.5 g/L), pH (2−10), dye concentration (5–45 mg/L), contact duration (0–140 min), and shaking speed (100–180 rpm) on the removal (adsorption) efficiency at 23 °C were investigated. Besides the kinetic and isothermal studies were applied as well to improve commercial adsorbents’ performance in removing anionic dyes. Fe3O4 magnetic nanoparticles achieve a maximum azo dye removal (adsorption) efficiency of 99.99% at the optimum values of the investigated parameters: 3 g/L of adsorbent dose, 5 mg/L dye concentration, pH 2, and 180 rpm in 120 min at 23 °C. Langmuir adsorption isotherm has the highest correlation coefficient (R2 = 0.977) compared to Freundlich, and Temkin isotherms; the maximum absorption of azo dye is estimated to be 0.4158 mg/g. The values of the equilibrium parameter (RL) in the Langmuir isotherm model are between 0 and 1, indicating the Langmuir isotherm's favorability. The Fe3O4 magnetic nanoparticle adsorption rates follow pseudo-first-order adsorption kinetics, with R2 = 0.973.

Efficient removal of cationic and anionic dyes by surfactant modified Fe3O4 nanoparticles

Magnetic nanoparticle adsorbents overcome the difficulty of solid-liquid separation in adsorption technology systems. However, their extremely large specific surface energy results in high levels of nanoparticle agglomeration and reduces their adsorption efficiency. To solve this problem, this study modified Fe3O4 particles with sodium dodecyl sulfate (SDS) and Cetyl Pyridine Chloride (CPC). Compared with pure Fe3O4 particles, the size distributions of SDS@Fe3O4 and CPC@Fe3O4 were more uniform, with a high level of magnetism and the capacity to achieve rapid separation (56.49 emu/g for SDS@Fe3O4 and 55.89 emu/g for CPC@Fe3O4). The results of dye adsorption tests showed that the adsorption effect was improved after modification, resulting in adsorption capacities of 62.43 mg/g for methylene blue (MB) by SDS@Fe3O4 and 176.98 mg/g for Congo red (CR) by CPC@Fe3O4. XRD results showed that the structure did not change, while FTIR results showed that no new functional groups were formed after adsorption. Adsorption followed pseudo-second-order reaction models, indicating that adsorption occurs via chemical adsorption processes. The adsorption process occurred mostly in accordance with the Langmuir model, which illustrates that monolayer adsorption was the dominant process. Thermodynamic data indicates that the adsorption process was endothermic and spontaneous. The adsorption mechanism for MB by SDS@Fe3O4 may be electrostatic adsorption and hydrophobic interaction, while for CR by CPC@Fe3O4 the mechanism may be electrostatic adsorption and hydrogen bonding. In addition, after five cycles of regeneration, the removal rate of MB was >77.0% and the removal rate of CR was >91.9%, confirming the excellent regeneration performance of Fe3O4. The simple and environmentally friendly manufacturing method, efficient adsorption process, rapid magnetic separation, indicate that surfactant modification of magnetic nanoparticles is an effective method for dye adsorption and removal.

Development of ion imprinted based magnetic nanoparticles for selective removal of arsenic (III) and arsenic (V) from wastewater

ABSTRACT In this study, we fabricated magnetic ion-imprinted polymers (IIP) for arsenic removal. Ion-imprinted method was developed by complexing N-methacryloyl-l-cysteine (MAC) monomer and As(III) and As(V) as template molecules. The utilization of the MAC-As complex was chosen to provide a rebinding of As(III) and As(V) on IIP. The template molecules were removed by using 0.01 M HNO3 containing 0.05% thiourea solution as a desorption agent. The adsorption of As(III) and As(V) was ideal in buffer solution pH 5.0 for 120 min with removal capacity. The ion-imprinted-based magnetic nanoparticles were selective for arsenic toward other analogs (NO3 −, PO4 3-, SO4 2- as an anion, and AsO2 −, HAsO4 − as an oxi-anion). The adsorption isotherm model fitted the Langmuir model with an R2 value of 0.9935–0.9118 and the Qmax values of 91.7 mg/g for As(III)-IIP magnetic nanoparticles and 99.0 mg/g As(V)-IIP nanoparticles, respectively. Finally, IIP-based magnetic nanoparticle adsorbents have been utilized successfully for effective arsenic removal from wastewater samples.

Application of solid-phase extraction based on magnetic nanoparticle adsorbents for the analysis of selected persistent organic pollutants in environmental water: A review of recent advances

Sample preconcentration is a critical step in the analysis of trace organic pollutants in environmental water. In recent years, solid-phase extraction based on functionalized magnetic nanoparticle (MNP) adsorbents has attracted wide attention because of its advantages in time, reagent, and labor savings, as well as its high extraction efficiency. To improve the selectivity, dispersibility, stability, and reusability of MNP adsorbents, various functional materials have been applied, including inorganic materials, carbonaceous materials, organic compounds, metal–organic frameworks, and bio-sorbents and their hybrid forms. Here, the application of solid-phase extraction based on MNP adsorbents for trace persistent organic pollutant (POP) detection in environment water from 2015 to 2019 is reviewed. In addition, the synthetic routes, characteristics of modification materials, selective sorption mechanisms, and analytical performance of these adsorbents are also discussed. The properties of environmental water samples have complicated effects on the extraction efficiency of POPs, and improvements in magnetic solid-phase extraction (MSPE) for POP analysis should be carried out with regard to the following four aspects: (1) development of novel applicable functionalized MNP adsorbents; (2) choice of suitable detection techniques; (3) combination of other extraction techniques; and (4) automation of MSPE.

Magnetic adsorbents for selective removal of selenite from contaminated water

ABSTRACTNovel meso- and microporous tire-derived carbon framework as a support for magnetic iron oxide nanoparticle adsorbents (MNA) that selectively adsorb selenite (Se(IV)) ions from contaminated water has been developed. Carbon-supported magnetic nanoparticle adsorbents (C-MNA) displayed higher adsorption values compared to MNA from 5 to 50 ppm selenite concentrations, maximizing at 48 ± 5 mg/g capacity with >99% Se removal at pH 3 and 5, and outperforms MNA at pH 7. These improvements will expand the range of water sources that can be treated, as well as easing adsorbent collection through magnetic separation.

Preparation of Modified Magnetic Cobalt Nanoparticles as a New Magnetic Sorbent for the Preconcentration and Determination of Trace Amounts of Lead Ions in Environmental Water and Soil (Air-Dust) Samples

ABSTRACTIn this study, cobalt magnetic nanoparticles (MNPs) were synthesized and then modified by sodium dodecyl sulfate (SDS) and 2-(5-bromo-2-pyridylazo)-5-diethyl aminophenol ligand (5-Br-PADAP), through a chemical precipitation method. Characterization of the prepared MNP adsorbents was performed by Fourier transform infrared and transmission electron microscopy. Cobalt nanoparticles (NPs) surface modified with SDS and 5-Br-PADAP was evaluated as a nanoparticulate solid-phase extraction (SPE) absorbent for lead ions Pb(II) from water and standard samples, prior to its flame atomic absorption spectrometry determination. Effects of pH, amount of sorbent, desorption solvent, adsorption time, desorption time, and interfering ion concentration on extraction efficiency were investigated. Under optimal conditions, the calibration curve was linear in the range of 1.0–500 ng mL−1of Pb(II) with R2 = 0.998. Detection limit was 1.6 ng mL−1 in the original solution (3Sb/m), and the relative standard deviation for replicate determination of 0.5 μg mL−1 Pb(II) was ±2.7%.

Removal of cadmium and lead ions from water by sulfonated magnetic nanoparticle adsorbents

A new adsorbent, Fe3O4 sulfonated magnetic nanoparticle (Fe3O4-SO3H MNP), was developed for heavy metal ions removal from water, which could be effectively separated from the solution owing to the superparamagnetic property. The nanoparticles can be used to remove heavy metal ions due to the additional active site, “sulfo-group”, introduced by the AMPS branches grafted onto the iron oxide. The as-synthesized materials were characterized by SEM, TEM, FT-IR and BET. The FTIR, XPS and Zeta potential were used to describe the adsorption mechanism. The Fe3O4-SO3H MNPs showed rapid removal for Pb2+ and Cd2+ with maximum of adsorption capacity of 108. 93 and 80.9mg/g at 25°C, respectively. The adsorption isotherms for Pb2+ and Cd2+ fitted better with Langmuir than Freundlich models, indicated that the processes of the removal of Pb2+ and Cd2+ could follow a kind of similar adsorption manner. The adsorption kinetic was consistent with pseudo-second-order model. Furthermore, the reuse experiments results showed the adsorbent might have potential in treating heavy metal ions pollution in water.

Enhanced Aqueous Arsenic Absorbing Substituted Spinel Nickel Ferrite (NiFe2O4) Nano-Particles

Arsenic is noxious metal exist in water in form of organic dimethyl arsenic acid (C2H7AsO2) and monomethylarsonic acid (CH5AsO3) while in inorganic arsenic trioxide (As2O3) and sodium arsenate (NaH2AsO4). Its trivalent and pentavalent forms are abundant in natural water. Its trivalent form is 60 times more hazardous than pentavalent form. Reports proved that arsenic contamination in water is the basic reason behind many chronic health problems and its removal was the major concern issue. Versatile soft synthesized ferrite material was used as an efficient adsorbent to adsorb arsenic from drinking water in recent times. In these contribution, magnetic nanoparticles adsorbents (NiFe2O4) have been synthesized by co-precipitation route using stable nickel salts and ferric with potassium hydroxide as the precipitating agent. Synthesized NiFe2O4 exhibits tetrahedral and octahedral sites having typical ferromagnetic and technologically properties and used as adsorbent. Nickel ferrite was well characterized by thermo gravimetric analysis (TGA), powder X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and field emission scanning electron microscope (FESEM). Adsorption of as using NiFe2O4 correlated well (R2>0.90) with the Freundlich isotherm. The analysis revealed that 98% arsenic has been removed from water by nickel ferrite which is much higher than other adsorbents.

Simultaneous removal of PAHs and metal contaminants from water using magnetic nanoparticle adsorbents

Many industrial wastewaters are contaminated with both heavy metal ions and organic compounds, posing a major threat to public health and the environment. In this study, magnetic nanoparticle adsorbents, namely Mag-PCMA-T, which contain a maghemite core and a silica mesoporous layer that permanently confines surfactant micelles within the mesopores, were synthesized to achieve simultaneous removal of polycyclic aromatic hydrocarbons (PAHs) (1mg/L) and metal contaminants (1mg/L). The individual removal efficiency of Cd2+ and acenaphthene using Mag-PCMA-T was evaluated under a range of initial ion concentrations and adsorbent dosages, as well as the competitive adsorption with Cd2+ and acenaphthene simultaneously present. The isotherms and kinetics of Cd2+ and acenaphthene sorption onto Mag-PCMA-T were determined. Mag-PCMA-T removed >85% of the acenaphthene in <30min, with relatively high sorption capacity (up to 1060mg/kg). Mag-PCMA-T also exhibited high sorption capacity for Cd2+ (up to 2250mg/kg). The simultaneous sorption performance was stable across a wide pH range (4–9) as well as in the presence of competitive metal ions (Ca2+ and Mg2+) or natural organic matters. The Mag-PCMA-T can be regenerated and reused, providing a sustainable, fast, convenient, and efficient approach for water treatment.

Surface modified magnetic nanoparticles as efficient and green sorbents: Synthesis, characterization, and application for the removal of anionic dye

The object of this study was to evaluate the removal efficiency of sunset yellow (SY) anionic dye from aqueous solutions by using new surface modified iron oxide magnetic nanoparticles (MNPs). Pure Fe3O4 MNPs were synthesized and then functionalized by aminopropyltriethoxysilane (APTES), through a chemical precipitation method. Characterization of the prepared MNP adsorbents was performed by furrier transform infrared (FT-IR), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), and transmission electron microscopy (TEM). According to XRD and TEM results, average size of the magnetic Fe3O4/APTES NPs was estimated to be around 12nm. The prepared magnetic adsorbent can be well dispersed in the water and easily separated magnetically from the medium after loaded with adsorbate. In the adsorption process, the effect of main experimental parameters such as pH of dye solution, initial concentration of SY dye, reaction time, and amount of MNP adsorbent on the removal of SY were studied and optimized. The small amount of this adsorbent (10mg) is applicable for the removal of high concentrations of SY dye in reasonable time (17min), at pH 3.1. Additionally, the adsorption studies show that the Langmuir model is a suitable model to explain the experimental data with high correlation coefficient.

A simple and fast Fe3O4 magnetic nanoparticles-based dispersion solid phase extraction of Sudan dyes from food and water samples coupled with high-performance liquid chromatography

In recent years, nanoparticles, particularly magnetic nanoparticles (MNPs), have been emerging as a new type of important functional solid phase extraction (SPE) material. However, there has been no report on the direct application of Fe3O4 MNPs for the extraction of trace Sudan dyes as a SPE material in food and environmental analysis. In this work, Fe3O4 MNPs from a one-pot chemical coprecipitation route were prepared under ultrasound irradiation. The as-obtained Fe3O4 MNPs showed good adsorbability to the four Sudan dyes and were successfully applied as a SPE material coupled with high-performance liquid chromatography (HPLC) for the simultaneous isolation and determination of four Sudan dyes from foodstuff and water samples. Compared to the traditional SPE adsorbents, such as neutral alumina and C18, the Fe3O4 MNPs adsorbents provided simple, fast and easy operation with an effective purification effect. The results on the water matrix suggest that such purification can be considered a practicable solution for sample preparation in the routine analysis of Sudan dyes in environmental samples with good anti-interference ability to natural organic matter, and can detect Sudan dyes down to 0.02 μg L−1 when sample volumes of 750 mL and 500 mg Fe3O4 MNPs adsorbents were adopted. Also, the proposed method could be potentially applied to the rapid isolation and determination of Sudan dyes in complicated matrices, such as food samples, and can detect Sudan dyes down to 10 μg kg−1 when 1 g foodstuff and 500 mg Fe3O4 MNPs adsorbents were used. The as-obtained Fe3O4 MNPs showed operational stability and retained excellent adsorption and magnetic properties, even after an eight-cycle run for the adsorption and desorption of Sudan dyes.