Amino-functionalized Magnetic Nanoparticles Research Articles

Amino-functionalized magnetic humic acid nanoparticles for enhanced Pb(II) adsorption: Mechanism analysis and machine learning prediction

It is an effective removal method to adsorb heavy metals by adsorption materials, so as to realize their separation from environmental media. Optimizing the structure of the materials and adsorption conditions are essential for improving the adsorption performance. Amino-functionalized magnetic humic acid nanoparticles (AF-MHA) was synthesized using a co-precipitation method. And the adsorbing material showed remarkable lead (Pb(II)) adsorption capacity under neutral pH conditions and a maximum adsorption capacity of 119 mg/g. The adsorption process was attributed to complexation with functional groups like amine, carboxyl, and phenol hydroxyl. In order to enhance the optimization of adsorption parameters, machine learning (ML) models including Artificial Neural Network (ANN), Random Forest (RF), Support Vector Regression (SVR), and CatBoost were employed. After comparative study we find the CatBoost model was found to be the most accurate predictor with a correlation coefficient of R2=0.95. ML also facilitated the identification of key factors influencing adsorption capability by assessing the importance of input features. With ML-assisted optimization parameters offering a strategic advantage in optimizing adsorption conditions and enhancing performance, AF-MHA is a promising adsorbent for treating divalent metal-contaminated water.

Construction of magnetic recoverable porous electron-rich organic frameworks for efficiently enrichment of phenylurea herbicides from water and milk samples prior to HPLC detection

Porous electron-rich organic frameworks have attracted an increased attention in the adsorption and removal of pollutants due to their abundant electron-rich nitrogen atoms, which can effectively interact with positively charged substance. In this study, a porous electron-rich organic framework (Car-POF) and positively charged amino-functionalized magnetic nanoparticles (Fe3O4-NH2) were used to construct a magnetic electron-rich Fe3O4-NH2@Car-POF for the enrichment of some phenylurea herbicides from water and milk samples prior to high performance liquid chromatographic detection. The adsorption capacity of Fe3O4-NH2@Car-POF for the phenylureas ranged from 14.93 to 28.83 mg g−1. The LODs were observed in the range of 0.05–0.20 ng mL−1 and 0.5–1.5 ng mL−1, and LOQs in the range of 0.17–0.66 ng mL−1 and 1.7–5.0 ng mL−1 for water and milk samples with RSD less than 9.0. The adsorption studies with cationic and anionic dyes revealed that Fe3O4-NH2@Car-POF is favorable for the adsorption of positively charged compounds.

Nickel (II) complex supported on amino-functionalized magnetic nanoparticles: A active magnetically recoverable catalyst for the synthesis of esters and thioesters

Esters and thioesters are of great interest to chemists from a biological and medicinal point of view, that's why the synthesis of these compounds is always a popular research field in organic chemistry. In this method, we first synthesized Fe3O4@BA/Pyrim-Carboxamide-NiCl2 nanocatalyst, then studied its catalytic application in the preparation of esters and thioesters through carbonylation and thiocarbonylation of aryl iodides. The results of these experiments showed that the Fe3O4@BA/Pyrim-Carboxamide-NiCl2 catalyst in the presence of KOAc in ChCl-Urea solvent can easily conducted a wide range of reactions and the desired ester and thioester products were synthesized with very good yields. The structure of the Fe3O4@BA/Pyrim-Carboxamide-NiCl2 catalyst before use and after recovery was well confirmed by a series of techniques. Among the features of this method, the following can be mentioned: the synthesis of esters and thioesters with very good yields, using mild conditions, simple separation of the catalyst, high reusability of the catalyst, providing NMR analysis for all the obtained products.

Aspergillus oryzae β-D-galactosidase immobilization on glutaraldehyde pre-activated amino-functionalized magnetic mesoporous silica: Performance, characteristics, and application in the preparation of sesaminol

Aspergillus oryzae β-D-galactosidase (β-Gal) efficiently hydrolyzes sesaminol triglucoside into sesaminol, which has higher biological activity. However, β-Gal is difficult to be separate from the reaction mixture and limited by stability. To resolve these problems, β-Gal was immobilized on amino-functionalized magnetic nanoparticles mesoporous silica pre-activated with glutaraldehyde (Fe3O4@mSiO2-β-Gal), which was used for the first time to prepare sesaminol. Under the optimal conditions, the immobilization yield and recovered activity of β-Gal were 57.9 ± 0.3 % and 46.5 ± 0.9 %, and the enzymatic loading was 843 ± 21 Uenzyme/gsupport. The construction of Fe3O4@mSiO2-β-Gal was confirmed by various characterization methods, and the results indicated it was suitable for heterogeneous enzyme-catalyzed reactions. Fe3O4@mSiO2-β-Gal was readily separable under magnetic action and displayed improved activity in extreme pH and temperature conditions. After 45 days of storage at 4 °C, the activity of Fe3O4@mSiO2-β-Gal remained at 92.3 ± 2.8 %, which was 1.29 times than that of free enzyme, and its activity remained above 85 % after 10 cycles. Fe3O4@mSiO2-β-Gal displayed higher affinity and catalytic efficiency. The half-life was 1.41 longer than free enzymes at 55.0 °C. Fe3O4@mSiO2-β-Gal was employed as a catalyst to prepare sesaminol, achieving a 96.7 % conversion yield of sesaminol. The excellent stability and catalytic efficiency provide broad benefits and potential for biocatalytic industry applications.

A facile electrochemical sensor based on amino-functionalized magnetic nanoparticles for simultaneous detection of lead and mercuric ions

The development of a facile analytical way for detecting toxic heavy metal ions is highly desirable due to their serious toxicity to human health. In this work, amino-functionalized magnetic nanoparticles (Fe3O4@SiO2-NH2) were prepared by hydrothermal and sol-gel method for electrochemical detection of lead ions (Pb2+) and mercuric ions (Hg2+). All prepared materials were characterized by four kinds of technologies. The proposed sensor was fabricated by the compound of Fe3O4@SiO2-NH2 with metal ions added to the working electrode surface. Pb2+ and Hg2+ could be easily absorbed by Fe3O4@SiO2-NH2 through coordination, and differential pulse stripping voltammetry was applied to detect Pb2+ and Hg2+ directly. Several parameters, such as deposition potential, deposition time, volume, and incubation time, were optimized to obtain better sensitivity for the electrochemical determination of Pb2+ and Hg2+. Under optimal conditions, Pb2+ and Hg2+ were detected simultaneously by the developed electrochemical sensor with detection limits of 6.06 and 9.09 nmol/L, respectively. The recoveries of Pb2+ and Hg2+ in milk ranged from 95.1% to 114%. Hence, the developed electrochemical sensor presented great potential for detecting Pb2+ and Hg2+ in milk.

Removal of Pb2+, CrT, and Hg2+ Ions from Aqueous Solutions Using Amino-Functionalized Magnetic Nanoparticles.

In this paper, a circular economy approach with the adsorption and desorption of heavy metal (HM) ions-i.e., lead (Pb2+), chromium (CrT), and mercury (Hg2+)-from aqueous solutions was studied. Specific and selective binding of HM ions was performed on stabilized and amino-functionalized iron oxide magnetic nanoparticles (γ-Fe2O3@NH2 NPs) from an aqueous solution at pH 4 and 7. For this purpose, γ-Fe2O3@NH2 NPs were characterized by thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), specific surface area (BET), transmission electron microscopy (TEM), EDXS, and zeta potential measurements (ζ). The effects of different adsorbent amounts (mads = 20/45/90 mg) and the type of anions (NO3-, Cl-, SO42-) on adsorption efficiency were also tested. The desorption was performed with 0.1 M HNO3. The results showed improvement of adsorption efficiency for CrT, Pb2+, and Hg2+ ions at pH 7 by 45 mg of g-Fe2O3@NH2 NPs, and the sequence was as follows: CrT > Hg2+ > Pb2+, with adsorption capacities of 90.4 mg/g, 85.6 mg/g, and 83.6 mg/g, respectively. The desorption results showed the possibility for the reuse of γ-Fe2O3@NH2 NPs with HNO3, as the desorption efficiency was 100% for Hg2+ ions, 96.7% for CrT, and 91.3% for Pb2+.

Bio-imprinted magnetic cross-linked polyphenol oxidase aggregates for enhanced synthesis of L-dopa, a neurodegenerative therapeutic drug

Bio-imprinted magnetic cross-linked enzyme aggregates (i-m-CLEAs) of polyphenol oxidase (PPO) obtained from potato peels were prepared using amino-functionalized magnetic nanoparticles. Bio-imprinting is being used to improve the catalytic efficiency and conformational stability of enzymes. For bio-imprinting, PPO was incubated with different imprint/template molecules (catechol, 4-methyl catechol and l-3,4-dihydroxy phenylalanine) before cross-linking with glutaraldehyde. CLEAs imprinted with 4-methyl catechol showed maximum activity as compared with non-bio-imprinted magnetic CLEAs (m-CLEAs). They were further characterized by scanning electron microscopy and confocal microscopy. In bio-imprinted m-CLEAs, half-life (t1/2) of PPO significantly improved (364.74 min) as compared to free PPO (43.58 min) and non-bio-imprinted m-CLEAs (266.54 min). Bio-imprinted m-CLEAs showed excellent thermal and storage stability as well as reusability. The CLEAs preparation were used for the synthesis of l-3,4-dihydroxyphenylalanine (L-dopa, a therapeutic drug to treat neurodegenerative disorder) and a remarkable increase in L-dopa yield (23.5-fold) was obtained as compared to free enzyme. A cost effective and reusable method has been described for the production of L-dopa.

Design of bionic amphoteric adsorbent based on reed root loaded with amino-functionalized magnetic nanoparticles for heavy metal ions removal

Renewable and cheap reed roots are rich in polysaccharide and lignin and naturally possesses wastewater purification ability. However, if applied as industrial adsorbent, the active sites of reed roots need further enhancement to fit realistic amphoteric ion adsorption requirement and its recovery also request for optimization to avert secondary pollution caused by adsorbent residues. Under this background, a novel adsorbent based on reed root loaded with magnetic amino-functionalized nanoparticles (RrH@Fe3O4 @SiO2-NH2) with a bionic dendritic structure and a pleated surface was designed. The reed roots were firstly pretreated with hydrogen peroxide solution with strong oxidizing properties under UV light irradiation to expose more oxygen-containing functional groups, which then condensed with the amino groups on the surface of Fe3O4 @SiO2-NH2 nanoparticles, leading to the formation of the final adsorbent. The carboxyl, hydroxyl and methoxy and amino groups on the surface of the adsorbent synergistically contribute to the adsorption of both anions and cations. The maximum adsorption capacity for Pb (II) and Cr (VI) ions per unit mass of reed root in RrH@Fe3O4 @SiO2-NH2 reached 99.1 and 106.5 mg g− 1, much higher than those obtained with raw reed roots (24.8 and 30.6 mg g−1). The superior adsorption performance was ascribed to its physicochemical properties as characterized by a series of characterization methods. The adsorption process followed pseudo-second-order kinetic and Freundlich isotherm model, indicating a chemical multi-layer endothermic adsorption process. The addition of magnetic Fe3O4 endows the easy recovery of the adsorbent by applying a magnetic field, and after five cycles, the adsorption capacity can still reach 82% of that of the first time. In summary, the desirable adsorption performance, easy recovery, and low cost make the bionic RrH@Fe3O4 @SiO2-NH2 a promising amphoteric adsorbent for eliminating heavy metal ions from wastewater.

Magnetic solid phase extraction coupled with high-performance liquid chromatography-diode array detection based on assembled magnetic covalent organic frameworks for selective extraction and detection of microcystins in aquatic foods

It is crucially important to develop simple, selective, and rapid extraction pretreatments and analytical methods to detect microcystins (MCs) in food samples with complex matrices. In this study, a magnetic self-assembled covalent organic framework (COF) adsorbent was synthesized via a facile approach by using a one-pot reaction of 1,6-bis(4-formylphenyl)-3,8-bis(4-aminophenyl)pyrene (BFBAPy) as precursors to assemble amino-functionalized magnetic Fe3O4-NH2 nanoparticles (Fe3O4@Py-COF, simplified as mCOF). The superparamagnetic mCOF is found to exhibit a high specific surface area, abundant nanopores and good stability. In particular, adsorption experiments demonstrate that mCOF exhibits a good adsorption capability, efficiency and some specificity to MCs. The mCOF was applied for magnetic solid phase extraction (MSPE) of two kinds of MCs (MC-LR and MC-RR) from aquatic samples followed by high-performance liquid chromatography-diode array detection (HPLC-DAD). Under the optimized conditions, good linearity is obtained in the range of 10-1000 µg/kg (R2≥0.9989), the limits of detection are 3.0-4.5 µg/kg, and the relative standard deviations (RSDs) are lower than 4.9% (n=5). The extraction recoveries are also satisfactory (84.2%-105%). These results demonstrate that the developed method can be used as a good alternative method for the selective determination of MCs in complex aquatic foods.

Tribromide Immobilized on Amino-Functionalized Magnetic Nanoparticles: A Active Magnetically Recoverable Catalyst for the Synthesis of Heterocycles

A novel tribromide nanocatalyst was successfully fabricated via the heterogenization of tribromide ion on the surface of silica-coated magnetic nanoparticles modified with N2,N4,N6-tris(aminomethyl)-1,3,5-triazine-2,4,6-triamin [Fe3O4@SiO2-tris(triazine-triamine)-Br3] and was well characterized by Fourier-transform infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Energy Dispersive X-Ray Analysis (EDX), vibrating-sample magnetometer (VSM), X-ray diffraction analysis (XRD) and Thermogravimetric analysis (TGA) spectroscopic techniques. TEM and SEM analysis confirmed that the typical silica shell thickness was assessed to be around 20 nm. The as-fabricated Fe3O4@SiO2-tris(triazine-triamine)-Br3 nanomaterial was shown high catalytic activity in the multicomponent synthesis of highly substituted piperidines and polyhydroquinolines. Recycling experiments revealed that the Fe3O4@SiO2-tris(triazine-triamine)-Br3 could be easily recovered by a simple magnetic separation and recycled at least 7 times without deterioration in catalytic activity.

Evaluation of Cytotoxicity of Pb2+ Ion-Adsorbed Amino-Functionalized Magnetic Mesoporous Silica Nanoparticles: An In Vitro Study

Application of amino-functionalized mesoporous silica-coated core-shell magnetic nanoparticles (Fe3O4@mSiO2-NH2 NPs) for adsorbing heavy metal ions has attracted intensive interest in recent years. Despite the cytotoxicity triggered by the co-exposure of nanoparticles (NPs) and metal ions in relatively high dosages being reported, the effect of the adsorbed heavy metal ions on the cytotoxicity to human cells remains unexplored. Herein, we demonstrated the effect of amino-functionalized Fe3O4@mSiO2 core-shell magnetic nanoparticles before and after adsorbing Pb2+ ions on the cytotoxicity of human kidney cells (HEK293). The surface morphology, viability, and oxidative stress (OS) induction of HEK293 cells incubated with Fe3O4@mSiO2-NH2 NPs and Pb2+ ion-adsorbed Fe3O4@mSiO2-NH2 NPs were assessed, respectively. Transmission electron microscopic (TEM) images of cell sections depicted that Fe3O4@mSiO2-NH2 NPs were internalized by HEK293 cells and gathered mainly in the cytoplasm. Cell viability (MTT) assays revealed the Fe3O4@mSiO2-NH2 NPs could enhance the cell viability to 119.9% and 108.2% compared to the control group, respectively. On contrast, the Pb2+ ion-adsorbed Fe3O4@mSiO2-NH2 NPs were toxic to the cell because when the Pb2+ ion contents were 5.0 and 7.5 μg mL−1, the viabilities of the samples decreased to 97.1% and 84.7%, respectively. Oxidative stress data proved that OS was negatively affected by both dissociative Pb2+ ions and the Pb2+ ion-adsorbed Fe3O4@mSiO2-NH2 NPs. Cytotoxicity may be attributed to the OS induced by Pb2+ ions leaked from the adsorbent. Under the same Pb2+ ion concentration, the cytotoxicity of the adsorbed Pb2+ ions was lower than that of the dissociative Pb2+ ions, indicating that the adsorption by NPs inhibited the cytotoxicity of Pb2+ ions. This work will provide new references for assessing the cytotoxicity of Pb2+-adsorbed nanoparticles.

One-Step mechanochemical preparation of magnetic covalent organic framework for the degradation of organic pollutants by heterogeneous and homogeneous Fenton-like synergistic reaction

The practical application of covalent organic frameworks (COFs) is limited because of the difficulties in rapid separation. This issue is expected to be solved with the emergence of magnetic nanoparticles. However, it remains challenging to quickly prepare magnetic COFs with high catalytic activity. In this study, a magnetic COF material (Fe3O4@TpMA) was prepared using a ball milling method based on grinding amino-functionalized magnetic nanoparticles (Fe3O4-NH2) and COFs (TpMA). The -C = N bond were as a bridge between Fe3O4 and COFs. Transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) characterizations showed that the doping of Fe3O4 nanoparticles did not destroy the structure of the COFs. In addition, Fe3O4@TpMA exhibited excellent superparamagnetic properties that were conducive to the magnetic separation of pollutants and catalysts. In the Fe3O4@TpMA + H2O2 system, 88.1% of methyl orange (MO) was degraded within 40 min. The degradation rate of MO in the Fe3O4@TpMA + H2O2 system was 4.2, 8.0, and 11.8 times that in the Fe3O4-NH2 + H2O2, TpMA + H2O2, and mixed material (Fe3O4-NH2/TpMA) + H2O2 systems, respectively. Furthermore, experimental parameters such as pollutant concentration, and catalyst dosage played an important role in the degradation of MO. The Fe3O4@TpMA catalyst also achieved highly efficient degradation of MO under weakly acidic conditions (pH = 6.38). The degradation mechanism is complex, involving the heterogeneous Fenton mechanism as the main step, and the homogeneous Fenton mechanism as the auxiliary step. This study aims to provide a new strategy for the preparation of magnetic COFs via mechanical grinding.

Amino-functionalized Magnetic Iron Nanoparticles As a Carrier for Laccase Enzyme and Its Potential to Degrade Chlorpyrifos in Contaminated Soil: Fate and Kinetics

Amino-functionalized Magnetic Iron Nanoparticles As a Carrier for Laccase Enzyme and Its Potential to Degrade Chlorpyrifos in Contaminated Soil: Fate and Kinetics

Mechanistic Insights into the Thermal Decomposition of Ammonium Perchlorate: The Role of Amino-Functionalized Magnetic Nanoparticles.

This work reports the characterization and application of two promising nanocatalysts for the thermal decomposition of ammonium perchlorate (AP). To obtain these composite materials, magnetite nanoparticles (Fe3O4 NPs) were functionalized with two different amine derivative groups, tertiary amine (Fe3O4 NPs-A1) and quaternary amine. X-ray photoelectron spectroscopy and differential scanning calorimetry provided mechanistic insights into the thermal decomposition of AP. Furthermore, tertiary and quaternary amine groups play a critical role, where the presence of an extra proton could favor an electron-proton transfer as the rate-determining step. Moreover, Fe3O4 NPs-A1 causes a diminution of the high-temperature decomposition of AP positively to 335 °C, increasing the energy release by 278 J g-1 and consequently affording the lowest activation energy (102 kJ mol-1), indicating a low degree of thermal stability, and accelerating the thermal decomposition of AP.

Structure Design of Bionic Amphoteric Adsorbent Based on Reed Root Loaded with Amino-Functionalized Magnetic Nanoparticles for Aqueous Heavy Metal Ions Removal

Structure Design of Bionic Amphoteric Adsorbent Based on Reed Root Loaded with Amino-Functionalized Magnetic Nanoparticles for Aqueous Heavy Metal Ions Removal

A combination approach using two functionalized magnetic nanoparticles for speciation analysis of inorganic arsenic

Mercapto- and amino-functionalized magnetic nanoparticles, Fe3O4@SiO2@MPTMS (SMNPs-MPTMS) and Fe3O4@SiO2@APTES (SMNPs-APTES), have been applied as magnetic solid-phase extraction (MSPE) sorbents to directly extract arsenite (As(III)) and arsenate (As(V)) respectively, followed by inductively coupled plasma-mass spectrometry (ICP-MS) detection. Various MSPE parameters were optimized including dose of magnetic adsorbent, pH of sample solution, loading and elution conditions of analytes, adsorption capacity and reusability of SMNPs-MPTMS and SMNPs-APTES for As(III) and As(V) respectively. Under the optimized MSPE conditions, this combined scheme possesses excellent selectivity and strong anti-interference ability without any oxidation or reduction prior to capture of these two species. It is found that with a 25-fold enrichment factor, the limits of detection of As(III) and As(V) were 23.5 and 10.5 ng L−1, respectively. To verify the reliability of the proposed protocol, a certified reference material of environmental water was analyzed, and the results for inorganic arsenic species were in close agreement with the certified values. The applicability of the combination strategy for speciation analysis of inorganic arsenic was evaluated in spiked tap, river, lake and rain water samples. Good recoveries of 89%–96% and 90%–102% were achieved for As(III) and As(V), respectively, with the relative standard deviation ranges of 3.2%–8.0% and 2.5%–7.6%. Through the characterization of functionalized magnetic nanoparticles and the optimization of MSPE experiment, it is confirmed that the existence of mercapto and amino groups on SMNPs-MPTMS and SMNPs-APTES sorbents are responsible for the extraction of As(III) and As(V), respectively, via coordination and electrostatic interactions.

Amino-functionalized magnetic nanoparticles for CO2 capture

ABSTRACT CO2 accumulation is inducing an effect of global warming. Adsorption using solid sorbents is proving as an effective strategy for CO2 capture and reuse. The aim of this study was to develop amino-functionalized magnetic nanoparticles by depositing various amines through co-precipitation or impregnation-sonication. Structural characteristics were studied through SEM, BET and XRD analyses, evidencing coarse particles with low crystallinity and surface areas of 100–150 m2 g−1, while FT-IR confirmed CO2 interacting with substrate. The load of functional group, particles stability, and CO2 sorption capacity were assessed through elemental and thermogravimetric analysis. It was found that loads of functional groups ranging from 1.6 to 6.1 wt.%. were deposited, and most samples showed sound stability up to 100°C. Sorption capacities were in the range 0.2–1.5 g gNH2 −1, the highest being 1.46 g gNH2 −1 for ɛ-aminocaproic acid. Such sample also exhibited good recyclability, with a performance drop of 11% after many cycles. CO2 uptake decreased with increasing temperature in the range 25–45°C, suggesting a chemical bond between CO2 and amines. Amino functionalized particles could thus be an interesting solution for CO2 capture and utilization thanks to fast kinetics, recyclability, and ease of separation.

Robust and recyclable magnetic nanobiocatalysts for extraction of anthocyanin from black rice

Anthocyanins, which are natural pigments and nutraceuticals, can be extracted from plant materials using enzyme-assisted methods. However, the enzymes used are often expensive, fragile, and hard to recover/reuse. In this study, cellulase and α-amylase were immobilized on amino-functionalized magnetic nanoparticles to prepare a magnetic nanobiocatalyst. The enzymes in this nanobiocatalyst exhibited higher stability and greater catalytic activity than free enzymes, including good thermal stability (50 to 70℃) and pH stability (pH 4.5–7.5). Nanobiocatalyst efficacy was demonstrated by extracting anthocyanins from black rice, with a maximum yield of 266 mg anthocyanin/100 g black rice obtained. After six reuse cycles, cellulase and α-amylase retained around 70% and 64% of their activity, respectively. Immobilization also increased their reusability. In summary, a novel magnetic nanobiocatalyst was developed for extracting anthocyanins from black rice, which may also have other applications within the food industry.

A review of amino-functionalized magnetic nanoparticles for water treatment: Features and prospects

Magnetic nanoparticles have attracted significant attention due to their exceptional features and versatile applications, including water and/or wastewater treatment. Discharge of heavy metals and other contaminants into water resources is a concern due to the detrimental effects on humans and the environment. Grafting magnetic nanoparticles with amino functional groups yields aminated or amino-functionalized magnetic nanoparticles, which show better results than bare magnetic nanoparticles in water treatment applications. Their magnetic nature is crucial for cost-effective and greener pollutant removal from water since they are magnetically separated and reused without a major change in structure and efficiency. In this review, the synthesis, separation and adsorption processes, and future perspectives for amino-functionalized magnetic nanoparticles are discussed in addition to their applicability in water treatment. Several important works have also been discussed for the removal of metals, radionuclides, organic contaminants, dyes and pathogens from water. The influence of parameters, such as magnetic nanoparticle dosage, pH, contact time, ion selectivity, and recyclability are also presented.

Removal of bisphenol A in aqueous solution using magnetic cross-linked laccase aggregates from Trametes hirsuta

Enzymatic removal of Bisphenol A (BPA), acknowledged as an environmentally friendly approach, is a promising method to deal with hard degradable contaminants. However, the application of “enzymatic treatment” has been limited due to lower operational stability and practical difficulties associated with recovery and recycling. Enzyme immobilization is an innovative approach which circumvents these drawbacks. In this study, laccase from Trametes hirsuta was used for BPA removal. Amino-functionalized magnetic Fe3O4 nanoparticles were synthesized via the co-precipitation method followed by surface modification with (3-aminopropyl)trimethoxysilane (APTMS). The as-prepared nanoparticles were utilized for the immobilization of laccase with the magnetic cross-linked enzyme aggregates method (MCLEAs). Activity recovery of 27% was achieved, while no immobilized laccase was observed in the cross-linked enzyme aggregates method. The performance of immobilized laccase was measured by analyzing the degradation of BPA pollutant. The maximum removal efficiency of 87.3% was attained with an initial concentration of 60 ppm throughout 11 h.