Cetyltrimethylammonium bromide-coated magnetite nanoparticles as highly efficient adsorbent for rapid removal of reactive dyes from the textile companies’ wastewaters

Preparation of stable colloidal dispersion of surface modified Fe3O4 nanoparticles for magnetic heating applications

The effect of surface modification on enhancing the magnetic heating behavior of magnetic nano fluids were investigated, for this purpose Fe3O4 nanoparticles were synthesized using co-precipitation method and surface modification was done using citric acid, ascorbic acid, tetraethyl orthosilicate (TEOS), polyvinyl alcohol (PVA) and polyethylene glycol (PEG). Experimental heating tests using AC magnetic field were done in the frequency of 100 kHz and different magnetic field (H) intensities. Theoretically the specific absorption rate (SAR) in magnetic nano fluids is independent of nanoparticles concentration but the experimental results showed different behavior. The theoretical SAR value @ H = 12kA.m-1 for Nano fluids containing bare Fe3O4 nanoparticles was 11.5 W/g but in experimental tests the obtained value was 9.72 W/g for nano fluid containing 20,000 ppm of dispersed nanoparticles. The experimental SAR calculation was repeated for sample containing 10,000 ppm of nanoparticles and the results showed increase in experimental SAR that is an evidence of nanoparticles agglomeration in higher concentrations. The surface modification has improved the dispersion ability of the nanoparticles. The Ratio of SAR, experimental, 20000ppm to SAR, experimental, 10000ppm was 0.85 for bare Fe3O4 nanoparticles dispersion but in case of surface modified nanoparticles this ratio has increased up to 0.98 that shows lower agglomeration of nanoparticles as a result of surface modification, although on the other hand the surface modification agents were magnetically passive and so it is expected that in constant concentration the SAR for bare Fe3O4 nanoparticles to be higher than this variable for surface modified nanoparticles. At lower concentrations the dispersions containing bare Fe3O4 nanoparticles showed higher SAR values but at higher concentrations the surface modified Fe3O4 nanoparticles showed better results although the active agent amount was lower at them. Finally, it should be noted that the nanoparticles that were surface modified using polymeric agents showed the highest decrease in experimental SAR amounts comparing theoretical results that was because of the large molecules of polymers comparing other implemented surface modification agents.

Pharmaceuticals removal by synergistic adsorption and S-scheme photocatalysis using nano-CeO2-coupled Fe3O4 on a CTAB matrix and investigation of the nanocomposite's antibacterial and antibiofilm activities: intrinsic degradation mechanism

S-Scheme photocatalytic mechanism of a fabricated nano-heterojunction.

Synthesis and characterizations of hybrid PEG-Fe3O4 nanoparticles for the efficient adsorptive removal of dye and antibacterial, and antibiofilm applications

PURPOSE

Dyes are highly toxic coloured compounds in nature that are largely applied in paper, food, textile and printing industries. Here, the adsorption technique was performed to remove methyl orange (MO) dye from water by polyethylene glycol (PEG) modified iron oxide nanoparticles (Fe₃O₄ NPs).

METHODS

The method used for Fe₃O₄ NPs synthesis was chemical precipitation. The particles were analyzed by transmission electron microscope, magnetometer, BET analyzer, fourier-transform infrared spectroscopy, X-ray powder diffraction, zetasizer and particle size analyzer. The influence of pH (4.0 to 10.0), NaCl concentration (0.01 mM to 2 M), adsorbent dosage (1 to 10 mg), and the role of surface charge on adsorptive removal were investigated.

RESULTS

The NPs size, zeta potential and surface area was found to be 26 ± 1.26 nm, 33.12 ± 1.01 mV and 119 m²/g respectively. The adsorption of MO on Fe₃O₄ NPs agreed best to Freundlich model (R² = 0.965) when compared with Langmuir model (R² = 0.249). By comparing pseudo-first-order kinetic model (R² = 0.937), kinetic adsorption study was better followed by pseudo-second-order kinetic model (R² = 1). The adsorption rate decreased with increasing NaCl concentration. At pH 4, maximum adsorption was noted. The particles were also exhibited excellent antibacterial and antibiofilm activities. The ROS formation, lipid peroxidation and oxidative stress were increased with increase in NPs concentration. The NPs precoated slides exhibited more than 50% growth inhibition.

CONCLUSION

The investigation denotes the versatile applications of the prepared particles for removing the dye stuffs from industrial effluents and as antibacterial and antibiofilm agent.

Preparation of a novel magnetic Pd(II) ion-imprinted polymer for the fast and selective adsorption of palladium ions from aqueous solutions

A novel magnetic ion-imprinted polymer with high accessibility to palladium ions was synthesized via co-precipitation polymerization. Accordingly, a ternary complex composed of PdCl₂ as an imprinting ion, 8-aminoquinoline (AQ) as a ligand, and 4-vinyl pyridine (4-VP) as a complexing monomer was applied to Fe₃O₄@SiO₂ as magnetic core, followed by precipitation polymerization using 2-hydroxyethyl methacrylate (2-HEMA) as a co-monomer, ethylene glycol dimethacrylate (EGDMA) as the crosslinker, and 2,2-azobisisobutyronitrile (AIBN) as an initiator in the presence of 2-methoxyethanol as a solvent. The palladium ions were leached out by a solution containing 50% (v/v) HCl. The synthesized polymer was characterized physically and morphologically using different techniques. In order to assess the conditions required for adsorption, as well as the selectivity and reusability, batch adsorption experiments were carried out. The experiments exhibited that the maximum adsorption capacity was about 65.75 mg g^-1 at 25 °C, while the pH solution and the adsorbent dose were 4 and 1 g L^-1, respectively. Kinetic studies of experimental data demonstrated that they correspond very much to the pseudo-second-order kinetic model. The development of the Langmuir and Freundlich isothermal models on the equilibrium data proved to correspond well to the Langmuir isotherm model. Interferences studies of the magnetic polymer demonstrated higher affinity and discernment for palladium ions than other co-existing ions in the solutions. Spontaneous (ΔG < 0) and exothermic (ΔH < 0) behavior of the adsorption process is confirmed by thermodynamic studies. In addition, the affinity of the spent polymer has not been dramatically reduced over at least five regeneration cycles.

Rational design, fabrication and characterization of a thiol-rich 3D-porous hypercrosslink polymer as a new engineered Hg2+ sorbent: enhanced selectivity and uptake

A new synergy between a porous matrix and active sites was developed to form a heterogeneous adsorbent for high efficiency and high selectivity mercury removal in drinking water.

Adsorption of reactive dye from aqueous solution and synthetic dye bath wastewater by Eucalyptus bark/magnetite composite

In the present study, Eucalyptus camaldulensis bark/magnetite composite (EBMC) was used for a potential application as a low-cost adsorbent for the removal of Reactive Black 5 (RB5). The adsorption experiments were performed with aqueous solution (RB5 + distilled water) and synthetic dye bath wastewater (SDBW) in order to investigate the potential application of EBMC in the textile industry. The effects of the various parameters, the initial dye concentration, the temperature, the pH, and the EBMC dosage on the adsorption were investigated. It was found that the adsorption capacity of EBMC increases by increasing the RB5 concentration and temperature and by decreasing the dosage of EBMC. 0.8 g EBMC was found to be sufficient for the removal of 250 mg/L RB5 from 150 mL SDBW with ∼85% removal efficiency. The Koble-Corrigan isotherm model described the adsorption process more effectively (R² = 0.997) than the Langmuir, Freundlich, the Dubinin-Radushkevich and the Jovanovic isotherm models. The Langmuir isotherm predicted a 370.7 mg/g maximum adsorption capacity. The thermodynamic analysis showed that the adsorption of RB5 onto the EBMC was an endothermic process. The multiple linear regression analysis was used in order to determine the cumulative effects of independent variables on the adsorption capacity.

Poly(2-aminobenzothiazole)-coated graphene oxide/magnetite nanoparticles composite as an efficient sorbent for determination of non-steroidal anti-inflammatory drugs in urine sample

In this study, for the first time, 2-aminobenzothiazole monomer was polymerized on Fe3O4 NPs, graphene oxide/Fe3O4 (GO/Fe3O4) and graphene/Fe3O4 (G/Fe3O4) nanocomposites. The synthesized magnetic nanosorbents were characterized by various techniques. The extraction ability of these nanosorbents including Fe3O4, GO/Fe3O4, G/Fe3O4, Fe3O4@poly(2-aminobenzothiazole) (Fe3O4@PABT), GO/Fe3O4@PABT and G/Fe3O4@PABT were compared for dispersive-micro-solid phase extraction of three non-steroidal anti-inflammatory drugs. The results revealed that GO/Fe3O4@PABT nanocomposite demonstrates higher extraction efficiency for naproxen, diclofenac and ibuprofen as selected model analytes. Following the sorption and elution steps, the model analytes were quantified by high performance liquid chromatography-photo diode array detection. Afterwards, a central composite design methodology combined with desirability function approach was applied to find out the optimal experimental conditions. Under the optimized conditions, the limits of detection and linear dynamic ranges were achieved in the range of 0.07-0.3 μg L(-1) and 0.25-2000 μg L(-1), respectively. The percent of extraction recovery was 87.4, 85.5 and 90.5% for naproxen, diclofenac and ibuprofen, respectively. The obtained relative standard deviation (n=5) was 7.2, 5.4 and 6.4% for naproxen, diclofenac and ibuprofen, respectively. Ultimately, this method was employed for urinary monitoring of the target analytes and satisfactory results were obtained.

Mixed hemimicelles solid-phase extraction based on sodium dodecyl sulfate (SDS)-coated nano-magnets for the spectrophotometric determination of Fingolomid in biological fluids

In this study, mixed hemimicelles solid-phase extraction (SPE) based on sodium dodecyl sulfate (SDS)-coated nano-magnets Fe3O4 was investigated as a novel method for the separation and determination of Fingolimod (FLM) in water, urine and plasma samples prior to spectrophotometeric determination. Due to the high surface area of these new sorbents and the excellent adsorption capacity after surface modification by SDS, satisfactory extraction recoveries can be produced. The main factors affecting the adsolubilization of analysts, such as pH, surfactant and adsorbent amounts, ionic strength, extraction time and desorption conditions were studied and optimized. Under the selected conditions, FLM has been quantitatively extracted. The accuracy of the method was evaluated by recovery measurements on spiked samples, and good recoveries of 96%, 95% and 88% were observed for water, urine and plasma respectively. Proper linear behaviors over the investigated concentration ranges of 2-26, 2-17 and 2-13 mg/L with good coefficients of determination, 0.998, 0.997 and 0.995 were achieved for water, urine and plasma samples, respectively. To the best of our knowledge, this is the first time that a mixed hemimicelles SPE method based on magnetic separation and nanoparticles has been used as a simple and sensitive method for monitoring of FLM in water and biological samples.

Rapid and selective separation of molybdenum ions using a novel magnetic Mo(vi) ion imprinted polymer: a study of the adsorption properties

In this work, we have developed a convenient method for the rapid and selective separation of Mo(vi) from aqueous solution by using a novel magnetic Mo(vi) ion imprinted polymer (Mo(vi)-MIIP) as the sorbent.

Boron nitride nanoplates supported zero-valent iron nanocomposites for enhanced decolorization of methyl orange with the assistance of ultrasonic irradiation

In this work, boron nitride nanoplates (BNNPs) supported nanoscale zero-valent iron (nZVI) was prepared through facile liquid-phase chemical reduction of ferric ion by borohydride under ambient conditions in the presence of BNNPs. The nZVI@BNNPs hybrids were characterized by scanning electron microscopy, X-ray diffraction and magnetic properties measurement. The hybrid material was evaluated for decolorization of a common azo dye, methyl orange (MO), with the assistance of ultrasonic irradiation. Results exhibited that a complete decolorization of 100 mg/L MO was achieved within 6 min using nZVI@BNNPs as the active material. Compared with bare nZVI and BNNPs, nZVI@BNNPs provided a faster reaction process for MO decolorization. The kinetic rate constants of MO decolorization reached 0.8175 min(-1) under ultrasound-assisted condition due to the synergistic effect of ultrasonic irradiation. Fluorescence spectrum experiment confirmed that hydroxyl radicals could be generated in the system combined nZVI with ultrasonic irradiation, and as a result, hydroxyl radicals would contribute to the decolorization process of MO.

Synthesis, modification and graft polymerization of magnetic nano particles for PAH removal in contaminated water

Magnetic nanoparticles (MNPs) were modified with 3-Mercaptopropytrimethoxysiline (MPTMS) and grafted with allyl glycidyl ether for coupling with beta naphtol as a method to form a novel nano-adsorbent to remove two poly aromatic hydrocarbons (PAHs) from contaminated water. The modified MNPs were characterized by transmission electron microscopy, infrared spectroscopy and thermogravimetric analysis. Results showed that the modified MNPs enhanced the process of adsorption. Tests were done on the adsorption capacity of the two PAHs on grafted MNPs; factors applied to the tests were temperature, contact time, pH, salinity and initial concentration of PAHs. Results revealed that adsorption equilibrium was achieved in 10 min, and the maximum adsorption capacity was determined as 4.15 mg/g at pH = 7.0 and 20°C. The equilibrium adsorption data of the two PAHs by the modified MNPs were analyzed by Langmuir, Freundlich and Temkin models. Equilibrium adsorption data was determined from the Langmuir, Freundlich and Temkin constants from tests under conditions of pH = 7 and temperature 20°C. Analysis of the adsorption-desorption process indicated that the modified MNPs had a high level of stability and good reusability. Magnetic separation in these tests was fast and this shows that the modified MNPs have great potential to be used as a new adsorbent for the two PAHs removal from contaminated water in water treatment.

Synthesis of environmentally friendly highly dispersed magnetite nanoparticles based on rosin cationic surfactants as thin film coatings of steel

This work presents a new method to prepare monodisperse magnetite nanoparticles capping with new cationic surfactants based on rosin. Core/shell type magnetite nanoparticles were synthesized using bis-N-(3-levopimaric maleic acid adduct-2-hydroxy) propyl-triethyl ammonium chloride (LPMQA) as capping agent. Fourier transform infrared spectroscopy (FTIR) was employed to characterize the nanoparticles chemical structure. Transmittance electron microscopies (TEM) and X-ray powder diffraction (XRD) were used to examine the morphology of the modified magnetite nanoparticles. The magnetite dispersed aqueous acid solution was evaluated as an effective anticorrosion behavior of a hydrophobic surface on steel. The inhibition effect of magnetite nanoparticles on steel corrosion in 1 M HCl solution was investigated using potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). Results obtained from both potentiodynamic polarisation and EIS measurements reveal that the magnetite nanoparticle is an effective inhibitor for the corrosion of steel in 1.0 M HCl solution. Polarization data show that magnetite nanoparticles behave as a mixed type inhibitor. The inhibition efficiencies obtained from potentiodynamic polarization and EIS methods are in good agreement.

Extraction and determination of trace amounts of chlorpromazine in biological fluids using magnetic solid phase extraction followed by HPLC

A simple, rapid and sensitive method termed as magnetic solid phase extraction (MSPE) combined with high-performance liquid chromatography-ultraviolet detector (HPLC-UV) has been proposed for the determination of trace amounts of chlorpromazine (CPZ) in water, urine and plasma samples. The separation and determination was performed on a C18 column under the optimal chromatographic conditions. Several factors influencing the extraction efficiency of CPZ, such as pH, surfactant and adsorbent amounts, ionic strength, extraction time, sample volume and desorption conditions, were studied and optimized. Under the optimal MSPE conditions, the extraction percentage of CPZ was 74%, 27% and 16% in water, urine and plasma samples, respectively. The limits of detection (LODs) of the proposed approach were 0.1, 5.0 and 10 ng/mL in water, urine and plasma samples, respectively. The relative standard deviations (RSDs) based on five replicate determinations at 10 ng/mL level of CPZ was 1.2%. Good linear behaviors over the investigated concentration ranges (0.25-300 ng/mL) with good coefficient of determination, R²>0.9998, were obtained. Good spike recoveries with relative errors less than 9.0% were obtained when applying the proposed method to water, urine and plasma samples.

Retracted Article: Equilibrium and kinetic studies on adsorptive removal of malachite green by the citrate-stabilized magnetite nanoparticles

Citrate-stabilized iron oxide nanoparticles can be used for the efficient removal of malachite green.

Magnetic nanoparticle-based solid-phase extraction of vitamin B12 from pharmaceutical formulations

In the present study, a novel quantitative method, namely magnetic nanoparticle-based solid-phase extraction (MSPE), was applied to extract vitamin B(12) from pharmaceutical formulations. The technique involves the use of Fe(3)O(4) nanoparticles modified by sodium dodecyl sulfate (SDS) as an efficient adsorbent for solid-phase extraction of vitamin B(12). Collection of magnetic nanoparticles (MNPs) from aqueous solution was simply achieved by applying external magnetic field. The analyte was desorbed from MNPs using alkali 1-propanol. The extracted analyte was analyzed by using flow injection inductively coupled plasma-optical emission spectrometry. Factors affecting the extraction efficiency were investigated and optimized. Under the optimum conditions, enhancement factor of 184, linear dynamic range of 2.5-500 μg L(-1) with correlation of determination (R(2) > 0.999), and limit of detection of 1.0 μg L(-1) were obtained for vitamin B(12). The percent relative standard deviation based on five-replicate determination was less than 6.2%. The method was successfully applied for extraction and determination of vitamin B(12) in different types of pharmaceutical samples such as multivitamin tablet, effervescent tablet, and injection sample. The results showed that the proposed method based on SDS-Fe(3)O(4) MSPE was a simple, accurate, and highly efficient approach for analysis of vitamin B(12).

Fast and efficient removal of mercury from water samples using magnetic iron oxide nanoparticles modified with 2-mercaptobenzothiazole

Mercury in the lowest levels of concentrations is dangerous for human health due to its bioaccumulation in body and toxicity. This investigation shows the effective removal of mercury (II) ions from contaminated surface waters by modified magnetic iron oxide nanoparticles (M-MIONPs) with 2-mercaptobenzothiazole as an efficient adsorbent. The proposed method is fast, simple, cheap, effective and safe for treatment of mercury polluted waters. Preparation of adsorbent is easy and removal time is short. Non-modified magnetic iron oxide nanoparticles (MIONPs) can adsorb up to 43.47% of 50 ngmL(-1) of Hg (II) ions from polluted water, but modified magnetic ironoxide nanoparticles (M-MIONPs) improved the efficiency up to 98.6% for the same concentration. The required time for complete removal of mercury ions was 4 min. Variation of pH and high electrolyte concentration (NaCl) of the solution do not have considerable effect on the mercury removal efficiency. Loading capacity of adsorbent for Hg ions is obtained to be 590 μgg(-1).