Chitosan-coated Magnetic Nanoparticles Research Articles

Preparation and characterization of AChE immobilized magnetic bio-nanocomposites (Fe3O4@Cht/Au) for pesticide detection

Free enzymes cause difficulties in many applications due to their insufficient stability, loss of activity in a short time, and most importantly, although they are costly, they are used only once in reactions, lose their effect and cannot be recovered from the environment. Magnetic nanoparticles coated with biocompatible polymeric material are potential candidates for promising enzyme carriers due to their multifunctional pore surfaces, easy removal from the environment provided by the magnetization, ability to main stability under various harsh conditions. This study prepared a biosensor candidate based on the inhibiting acetylcholinesterase enzyme by organophosphate pesticides from chitosan-coated magnetic nanoparticles doped with gold. Transmission electron microscopy, scanning electron microscopy, X-ray diffraction diffractometry, and Fourier transform infrared spectroscopy analysis confirmed the structure of synthesized nanocomposites. Magnetic characteristics of the nanocomposites were assessed using VSM. Bio-nanocomposite (Fe3O4@Cht/Au/AChE) was used to determine environmental pollutants qualitatively. Remediation of organophosphate-containing wastewater is an essential issue for environmental sustainability. In this work, Dichlorvos and Chlorpyrifos were selected as organic pollutants to assess the enzymatic activity of immobilized Fe3O4@Cht/Au/AChE. Optimum conditions for AChE enzyme were immobilized nanostructures (Fe3O4@Cht/Au/AChE) were determined. The optimum pH for the immobilized enzyme was found to be 8, and the optimum temperature was found to be 60 °C. Retained immobilized enzyme activity is found to be around 50% for the 20th reuse. In the presence of 150 µL pesticide, retained immobilized enzyme activity is found to be around 25%. Method validation was performed for pesticides. When using immobilized AChE, the LOD (limit of detection)-LOQ (limit of quantitation) values for Dichlorovos and Chlorpyrifos was obtained in the range of 0.0087–0.029 nM and 0.0014–0.0046 nM, respectively. The relative standard deviation (RSD%) values, which are indicators of precision, were found to be below 2%.

Targeted Thrombolysis with Magnetic Nanotherapeutics: A Translational Assessment.

Plasminogen activators, such as recombinant tissue-type plasminogen activators (rtPAs), while effective in treating thromboembolic diseases, often induce hemorrhagic complications due to non-specific enzyme activities in the systemic circulation. This study evaluated the targeting efficiency, efficacy, biodistribution, and potential toxicity of a rtPA covalently attached to chitosan-coated magnetic nanoparticles (chitosan-MNP-rtPA). The thrombolytic activity of a chitosan-MNP-rtPA was preserved by protection from an endogenous plasminogen activator inhibitor-1 (PAI-1) in whole blood and after circulation in vivo, as examined by thromboelastometry. Single-photon emission computed tomography (SPECT) demonstrated real-time retention of a 99mTc-MNP-rtPA induced by magnet application in a rat embolic model; an 80% reduction in rtPA dosage for a chitosan-MNP-rtPA with magnetic guidance was shown to restore blood flow. After treatment, iron deposition was observed in the reticuloendothelial systems, with portal edema and neutrophil infiltration in the liver at a ten-fold higher dose but not the regular dose. Nevertheless, no liver or renal toxicity was observed at this higher dose. In conclusion, the liver may still be the major deposit site of rtPA nanocomposites after targeted delivery; chitosan-coated MNPs are potentially amenable to target therapeutics with parenteral administration.

Preparation of berberine magnetic nanoparticles and their inhibition of human gastric cancer BGC-823 cells

A new drug delivery system loaded with the drug berberine on carboxymethyl chitosan-coated magnetic nanoparticles (Fe3O4@CMCS-BBR) was prepared and characterized through x-ray diffraction, Fourier transform-infrared spectroscopy, a vibrating sample magnetometer, and transmission electron microscopy. By comparing the size of the uncoated nanoparticles (39.26 nm) and the size of the coated magnetite nanoparticles (73.75 nm), it was found that with the CMCS coating on the magnetite nanoparticles, the dispersion of the nanoparticle improved. The optimum pH testing showed a higher drug encapsulation of 51.23% and drug loading of 17.10% at a pH of 5.5 because of the better interaction of the NH3+ group with the negative functional groups of the CMCS. Furthermore, 85.89% of the drug was released within 72 h. The CCK-8 test results showed that Fe3O4@CMCS-BBR magnetic nanocomposites had good biocompatibility with gastric cancer BGC-823 cells and that Fe3O4@CMCS-BBR effectively inhibited the proliferation of cancer cells. The magnetic experimental results showed that Fe3O4@CMCS-BBR had good responsiveness to external magnetic fields and aggregated in the presence of a magnetic field. The results of targeting experiments showed that fluorescein isothiocyanate emitted a strong yellowish fluorescence in cells, which became stronger over time, and the killing effect on cancer cells became greater. The apoptosis results showed that the apoptosis rate induced by the magnetic nanodrug was 54.90%, indicating that the drug had a promoting effect on the apoptosis of BGC-823 cells.

Immobilization of fungal α-galactosidase on magnetic nanoparticles and hydrolysis of raffinose family oligosaccharides (RFO) in soymilk

Immobilization of enzymes is a very attractive technique to develop efficient and cost-effective bioprocesses. In present investigation, immobilization of partially purified α-galactosidase from Penicillium aculeatum APS1 (APS1αgal) was carried out on chitosan coated magnetic nanoparticles, Fe3O4. Immobilization conditions such as enzyme concentration, amount of chitosan coated magnetic nanoparticles (CMNP), pH and time for immobilization were optimised and maximum immobilization yield of 45 ± 2% and activity yield of 47 ± 3% were achieved. Immobilized particles were characterised by thermal analysis and Fourier transform infrared spectroscopy (FT-IR). The surface morphology of particles was studied by scanning electron microscopy (SEM). Moreover, biochemical properties of free and immobilized enzymes were compared. Thermostability and storage stability of APS1αgal were found to be improved after immobilization. Reusability of immobilized APS1αgal was assessed and it was found to retain 65% activity after 12 consecutive cycles. Further experiments were conducted to assess the ability of immobilized APS1αgal for removal of raffinose family oligosaccharides (RFO) in soymilk. During batch hydrolysis, about 80% removal of RFO was achieved. Hydrolysis of RFO was confirmed by TLC analysis. Immobilized APS1αgal was able to carry out hydrolysis of RFO up to 45% even after 7 cycles. Overall, results of this study show the potential of immobilized APS1αgal for efficient removal of non-digestible RFO in soymilk.

The Relationship Between the Cross-Linker on Chitosan-Coated Magnetic Nanoparticles and the Properties of Immobilized Papain.

The immobilized enzymes' properties can be affected by cross-linkers on the surface of supports. To study how cross-linkers alter enzymes function, chitosan-coated magnetic nanoparticles (CMNPs) with immobilized papain were prepared using glutaraldehyde and or genipin, and then, the properties of the nanoparticles and the immobilized enzymes were assessed. The Scanning Electron Microscope (SEM), Fourier Transform Infrared (FTIR), and X-Ray Diffraction (XRD) results showed that the CMNPs were prepared and papain molecules were immobilized on CMNPs by glutaraldehyde (CMNP-Glu-Papain) or by genipin (CMNP-Gen-Papain). Also, the results associated with enzymes activity indicated that the immobilization by glutaraldehyde and genipin increased the pH optimum of papain from 7 to 7.5 and 9, respectively. The kinetic results indicated that the immobilization by genipin slightly affects the enzyme affinity to the substrate. The stability results showed that CMNP-Gen-Papain has more thermal stability than CMNP-Glu-Papain and papain immobilization on CMNPs by genipin leads to stabilization of the enzyme in the presence of polar solvents, probably due to the more hydroxyl groups on CMNPs activated by genipin. In conclusion, this study suggests that there is a relationship between the types of cross-linker on the surface of supports, and the mechanism of action, kinetic parameters, and the stability of immobilized papain.

Immobilization of laccase on carboxyl-functionalized chitosan-coated magnetic nanoparticles with improved stability and reusability

Immobilization of laccase on carboxyl-functionalized chitosan-coated magnetic nanoparticles with improved stability and reusability

Electrochemical detection of gram-negative bacteria through mastoparan-capped magnetic nanoparticle

The increasing number of multidrug resistance microorganisms is an alarming threat, and their rapid detection is essential to prevent nosocomial, foodborne, or waterborne infections. Many peptides derived from the venom of wasp Synoeca surinama have antimicrobial activity against Gram-positive and Gram-negative bacteria. Synoeca-MP, an antimicrobial peptide (AMP) from mastoparan family, seems to increase bacterial membrane permeability, promoting cytotoxicity and membrane disruption. Here Synoeca-MP was evaluated as biorecognition element tethered over chitosan-coated magnetic nanoparticles (Fe3O4-Chit). The transducing layer of the biosensor was developed from the self-assembling of 4-mercaptobenzoic acid (4-MBA) monolayer onto gold substrate. Atomic force microscopy (AFM) analyses confirmed the biointeraction between AMP and different pathogens membranes. The fabrication and performance of the biosensing assembly were characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Detection of Enterococcus faecalis (G+), Klebsiella pneumoniae (G-), Pseudomonas aeruginosa (G-), and Candida tropicalis was assessed in a recognition range from 101 to 105 CFU.mL−1. An instrumental limit of detection of 10 CFU.mL−1 was obtained for each specimen. However, the device presented a preferential selectivity towards Gram-negative bacteria. The proposed biosensor is a sensitive, fast, and straightforward platform for microbial detection in aqueous samples, envisaged for environmental monitoring applications.

Anion-synergistic adsorption enhances the selective removal of silver ions from complex wastewater by chitosan-coated magnetic silica core-shell nanoparticles

The selective separation and recovery of valuable metals from complex polluted wastewater is of great significance to the protection of water resources and the realization of resource recycling. Herein, the chitosan-coated magnetic silica core-shell nanoparticles (FO@SD@CS) were fabricated and applied as adsorbents for highly selective removal of precious metals silver ions (Ag(I)) from complex wastewater. In multi-ion compound polluted solutions, FO@SD@CS showed excellent selective adsorption of Ag(I) in a wide pH range, and an enhancement of the highly selective adsorption capacity of Ag(I), which was increased from 85.86 to 126.74 mg g−1 when the concentrations of methyl blue (MB) coexisted in the solution from 0 to 40 mg L−1 at pH 6.0. The results of Ag(I) single system batch adsorption experiments illustrated that the adsorption behavior of FO@SD@CS to Ag(I) shows obvious pH responsiveness, the adsorption capacity of Ag(I) increases with the increasing of pH value. The results of the adsorption isotherm and kinetics demonstrated that Langmuir and pseudo-second-order kinetics can better describe the adsorption behavior of Ag(I) on FO@SD@CS, indicating that the adsorption process was controlled by chemisorption and the maximum monolayer adsorption capacity reached 116.28 mg g−1 at room temperature. Additionally, in the dye-metal binary system, the coexisting MB promoted the adsorption capacity of FO@SD@CS to Ag(I) from 116.28 to 156.25 mg g−1, showing a synergistic adsorption effect. This study shows that the enhanced selective separation and recovery of metal ions from wastewater based on anion-synergistic not only provides new ideas for wastewater treatment, but also has important significance for water resources reuse.

Green synthesis of chitosan-coated magnetic nanoparticles for drug delivery of oxaliplatin and irinotecan against colorectal cancer cells

Green synthesis of chitosan-coated magnetic nanoparticles for drug delivery of oxaliplatin and irinotecan against colorectal cancer cells

A Bi-enzymatic Immobilized Nanobiocatalyst for the Biotransformation of Oleuropein to Hydroxytyrosol.

Multi-enzymatic assemblies offer the opportunity of bringing in proximity several enzymes that are enabled to work together for the catalysis of multi-step reactions. Especially, the development of robust nanobiocatalytic systems comprising of several enzymes has gained considerable attention over the last few years for the catalysis of complex reactions and the production of high added-value products. In the present chapter, we describe the methodology for the development of a bi-enzymatic nanobiocatalyst consisting of the enzymes β-glucosidase from Thermotoga maritima and lipase A from Candida antarctica (CalA) co-immobilized on chitosan-coated magnetic nanoparticles. This nanobiocatalyst can be efficiently applied for the biotransformation of oleuropein to hydroxytyrosol, a reaction of increased biotechnological interest. Several techniques, as well as methodologies that are required for the characterization of the structure and the activity of such systems are also comprehensively described.

Beyond processing waste: Extraction of oil from Atlantic salmon (Salmo salar) by-products using immobilized Alcalase on chitosan-coated magnetic nanoparticles

Atlantic salmon (Salmon salar) aquaculture has been fully developed on a large scale worldwide. Currently in the Atlantic salmon processing industry, 40–50% of the fish body ends up as by-products, which contain a variety of nutrients and are mainly processed into functional ingredients for premium pet food and animal feed. With the global increase of interest in nutritional diets and supplements, more research has been performed for the valorization of salmon by-products into value-added food products for human consumption. In the present study, an immobilized protease was used for hydrolysis of Atlantic salmon by-products to extract salmon oil. Alcalase was immobilized on chitosan-coated iron (II, III) oxide nanoparticles via glutaraldehyde crosslinking. The immobilized Alcalase was characterized using Fourier transform infrared spectroscopy and transmission electron microscope. The optimum pH and temperature range for the immobilized Alcalase were determined as 8 and 55–65 °C, respectively. The salmon oil extraction process using the immobilized Alcalase was optimized through a factorial design, and the highest oil yield of 20.55% (88.30% recovery) was obtained from 1 h of hydrolysis at 65 °C. The oil recovery using the immobilized Alcalase was comparable to the use of free Alcalase. The low levels of oxidation and hydrolysis indicated the high quality of the extracted oil, which is promising to be processed into high-value products such as nutraceuticals and pharmaceuticals. The immobilized Alcalase was collected using a magnet and reused at least three batches without a significant decrease in oil yield, indicating its potential for effective and consecutive oil extraction from salmon by-products. The present study would promote the production of value chain products from unutilized Atlantic salmon resources and achieve sustainable development of the blue economy.

Iron Oxide Nanoparticles Carrying 5-Fluorouracil in Combination with Magnetic Hyperthermia Induce Thrombogenic Collagen Fibers, Cellular Stress, and Immune Responses in Heterotopic Human Colon Cancer in Mice.

In this study we looked for the main protein pathway regulators which were responsible for the therapeutic impact on colon cancers when combining magnetic hyperthermia with the chemotherapeutic agent 5-fluorouracil (5FU). To this end, chitosan-coated magnetic nanoparticles (MNP) functionalized with 5FU were intratumorally injected into subcutaneous human colon cancer xenografts (HT-29) in mice and exposed to an alternating magnetic field. A decreased tumor growth was found particularly for the combined thermo-chemotherapy vs. the corresponding monotherapies. By using computational analysis of the tumor proteome, we found upregulated functional pathway categories termed “cellular stress and injury”, “intracellular second messenger and nuclear receptor signaling”, “immune responses”, and “growth proliferation and development”. We predict TGF-beta, and other mediators, as important upstream regulators. In conclusion, our findings show that the combined thermo-chemotherapy induces thrombogenic collagen fibers which are able to impair tumor nutrient supply. Further on, we associate several responses to the recognition of damage associated molecular patterns (DAMPs) by phagocytic cells, which immigrate into the tumor area. The activation of some pathways associated with cell survival implies the necessity to conduct multiple therapy sessions in connection with a corresponding monitoring, which could possibly be performed on the base of the identified protein regulators.

Enhanced selective adsorption of lead(II) from complex wastewater by DTPA functionalized chitosan-coated magnetic silica nanoparticles based on anion-synergism

Simultaneously removing heavy metal and dye from complex wastewater is of great significance to industrial wastewater treatment. Herein, a novel magnetic adsorbent, DTPA-modified chitosan-coated magnetic silica nanoparticle (FFO@Sil@Chi-DTPA), was successfully prepared and used to enhance the Pb(II) selective adsorption from multi-metal wastewater based on anion-synergism. In the competitive experiment conducted in a multi-ion solution, the type of selective adsorption of metals was changed by the adsorbents before and after amidation, in which FFO@Sil@Chi-DTPA exhibited an excellent selectively for capturing Pb(II), while FFO@Sil@Chi demonstrated highly selective adsorption of silver. More importantly, the selective adsorption of Pb(II)S by FFO@Sil@Chi-DTPA was enhanced from 111.71 to 268.01 mg g−1 when the coexisting MB concentrations ranged from 0 to 100 mg L−1 at pH 6.0. In the Pb(II)-MB binary system, Pb(II) and MB exhibited a synergistic effect, in which the presence of MB strengthened the adsorption effect of Pb(II) due to the sulfonic acid groups in MB molecules that create new specific sites for Pb(II) adsorption, while MB adsorption was also enhanced by the presence of Pb(II). This work provides a new strategy for exploring novel adsorbents that can enhance the selective removal of heavy metal in complex wastewater based on anion-synergism.

Breast cancer drug delivery by novel drug-loaded chitosan-coated magnetic nanoparticles

BackgroundBreast cancer is one of the most challenging cancers among women which is considered one of the most lethal cancers to this date. From the time that cancer has been discovered, finding the best therapeutic method is still an ongoing process. As a novel therapeutic method, nanomedicine has brought a vast number of materials that could versatilely be used as a drug carrier. The purpose of this study is to develop a novel black pomegranate peel extract loaded with chitosan-coated magnetic nanoparticles to treat breast cancer cells.ResultsThe morphology and size distribution of the nanoparticles studied by dynamic light scattering, atomic force microscopy, scanning, and transitional electron microscopy showed the spherical shape of the nanoparticles and their promising size range. Studies by Fourier transform infrared spectroscopy, X-ray diffraction, vibrating sample magnetometer, and zeta sizer confirmed the synthesis, substantial crystallinity, magnetic potential of the nanoparticles, and their satisfactory stability. The DPPH assay revealed that the obtained black pomegranate peel extract has 60% free radical scavenging activity. The cytotoxicity studies by MTT and LDH assay carried out on NIH/3T3, MBA-MB-231, and 4T1 cells confirmed that the magnetic nanoparticles had no significant cytotoxicity on the cells. However, the drug-loaded nanoparticles could significantly eradicate cancerous cells which had more efficiency comparing to free drug. Furthermore, free drug and drug-loaded nanoparticles had no toxic effect on normal cells.ConclusionOwing to the results achieved from this study, the novel drug-loaded nanoparticles are compatible to be used for breast cancer treatment and could potentially be used for further in vivo studies.

Ginsenoside CK production by commercial snailase immobilized onto carboxylated chitosan-coated magnetic nanoparticles

Immobilization of glycosidases for ginsenoside CK production is a promising method to improve industrial production. Magnetite (Fe3O4) nanoparticles encapsulated with carboxylated chitosan (CYCTS) (Fe3O4@CYCTS) provide a large specific surface area for snailase immobilization. According to the morphology, structure, and magnetic properties determined by TEM, SEM, XRD, FTIR, and VSM, the spherical, 50-nm Fe3O4@CYCTS nanoparticles were synthesized and applied for the first time in snailase immobilization. The immobilized enzyme (Fe3O4@(CYCTS+Snailase)) could be easily separated from the reaction mixture using a simple magnet. Under optimum immobilization conditions (37 ℃, pH 5.5, 5 h), the protein adsorption on the surface of Fe3O4@CYCTS was mainly driven by electrostatic interactions and exhibited a maximum value of 67.67 mg enzyme/g of support. The storage stability of immobilized enzyme and the stability against thermal, pH, or chemical denaturants were improved. The immobilized snailase shows a higher affinity toward substrates as indicated by lower Km values. At optimum reaction conditions (55 ℃, pH 5.5, 48 h), the immobilized snailase retained approximately 56% of its initial catalytic activity over 9 successive cycles. Our results revealed the potential applicability of Fe3O4@(CYCTS+Snailase) in ginsenoside transformation.

Development of a Novel Bi-Enzymatic Nanobiocatalyst for the Efficient Bioconversion of Oleuropein to Hydroxytyrosol

Lipase A from Candida antarctica (CalA) and β-glucosidase from Thermotoga maritima (bgl) were covalently co-immobilized onto the surface of chitosan-coated magnetic nanoparticles (CS-MNPs). Several parameters regarding the co-immobilization procedure (glutaraldehyde concentration, incubation time, CS-MNPs to enzyme mass ratio and bgl to CalA mass ratio) were evaluated and optimized. The developed nanobiocatalyst was characterized by various spectroscopic techniques. Biochemical parameters such as kinetic constants and thermal stability were also evaluated. The nanobiocatalytic system revealed an increase in the Km constant followed by a decrease in Vmax value compared with the native enzymes, while a significant increase (>5-fold higher) of the thermal stability of the immobilized CalA, both in individual and in co-immobilized form, was observed after 24 h incubation at 60 °C. Finally, the nanobiocatalyst was efficiently applied for the bioconversion of oleuropein to hydroxytyrosol, one of the most powerful naturally derived antioxidants, and it could be recycled for up to 10 reaction cycles (240 h of constant operation) at 60 °C, retaining more than 50% of its initial activity.

Microfluidic platform for synthesis and optimization of chitosan-coated magnetic nanoparticles in cisplatin delivery

In this study, magnetic core/chitosan shell Nanoparticles (NPs) containing cisplatin were synthesized via cisplatin complexation with tripolyphosphate as the chitosan crosslinker using two different procedures: a conventional batch flow method and a microfluidic approach. An integrated microfluidic device composed of three stages was developed to provide precise and highly controllable mixing. The comparison of the results revealed that NPs synthesized in microchannels were monodisperse 104 ± 14.59 nm (n = 3) in size with optimal morphological characteristics, whereas polydisperse 423 ± 53.33 nm (n = 3) nanoparticles were obtained by the conventional method. Furthermore, cisplatin was loaded in NPs without becoming inactivated, and the microfluidic technique demonstrated higher encapsulation efficiency, controlled release, and consequently lower IC50 values during exposure to the A2780 cell line proving that microfluidic synthesized NPs were able to enter the cells and release the drug more efficiently. The developed microfluidic platform presents valuable features that could potentially provide the clinical translation of NPs in drug delivery.

Chitosan-coated magnetic nanoparticles used as substrate immobilization carrier for α-arbutin biosynthesis process

Chitosan-coated magnetic nanoparticles (MNPs@CTS) which used as substrate immobilization carrier of glucosyl acceptor for α-arbutin production is introduced in this study. Fe3O4@CTS microspheres were prepared via an oxidation hydrothermal method, and further modified with chitosan. Substrate hydroquinone (HQ) was immobilized on the Fe3O4@CTS. When 1.0 g/L Fe3O4@CTS was shaken in HQ solution (7.0 g/L) at 28 °C with 120 rpm for 12 h, the maximum amount of HQ immobilization on the Fe3O4@CTS could reach 312 mg HQ per gram Fe3O4@CTS. The optimal reaction conditions for α-arbutin synthesis were also investigated. When 25 g/L Fe3O4@CTS@HQ (70.9 mM HQ) was shaken in fermentation broth at 30 °C with 180 rpm for 40 h, the final yield of α-arbutin reached 7.85 g/L. This work is useful for the industrial-scale production of α-arbutin.

Extraction of carboxin and bensulfuron-methyl using cysteine-functionalized chitosan-coated magnetic nanoparticles and response surface methodology

ABSTRACT In the proposed method cysteine-functionalized chitosan-coated magnetic nanoparticles were synthesized and used as an effective adsorbent for the extraction of carboxin and bensulfuron-methyl. The experiments were performed according to an orthogonal rotatable Box-Behnken design. The results showed that the limits of detection, quantification values, and linear ranges were 0.6, 2.0 µg.L−1, and 2–1000 µgL−1 for carboxin, and 0.3, 1.0 µgL−1, and 1–1000 µgL−1 for bensulfuron-methyl. The proposed method was applied to spiked real samples. The percentage of recovery values (91.53%-98.46%) with low relative standard deviation (≤4.6%) demonstrated excellent repeatability and applicability of this adsorbent to water samples. Abbreviations: Aminopropyl triethoxysilane, APTES; Box-Behnken design, BBD; Central composite design, CCD; Chitosan, CS; Double-distilled deionized water, DDW; Extraction recovery, ER; Fourier transform infrared, FT-IR; Liquid-Liquid extraction, LLE; Liquid-Solid extraction, LSE; Maximum residue limits, MRL; Magnetic dispersive-solid-phase extraction, MD-SPE; Magnetic nanoparticles, MNPs; Multiple linear regression, MLR; Response surface methodology, RSM; Solid-phase extraction, SPE; Thermal gravimetric analyses, TGA; Tetraethyl orthosilicate, TEOS; X-ray diffraction, XRD.

Magnetic phosphorylated chitosan composite as a novel adsorbent for highly effective and selective capture of lead from aqueous solution

Separating and recovering lead from heavy metal contaminated wastewater is crucial for the environment remediation and reutilization of lead resources. Herein, a novel adsorbent, the phosphorylated chitosan-coated magnetic silica nanoparticles (Fe3O4@SiO2@CS-P), was successfully fabricated and applied to highly selective adsorption of lead. Competitive experiments were conducted in a multi-ion solution (7 metal ions coexist) at pH 6.0, Fe3O4@SiO2@CS-P exhibited an excellent selectively for capturing lead with the distribution coefficient (0.75 L g−1) more ten times than other metal, while Fe3O4@SiO2@CS demonstrated a highly selective adsorption of silver. These implied that phosphorylation of adsorbent not only improves the sorption performance of lead, but also changes the selective adsorption of metal types. Acidity experiments can draw conclusions that Fe3O4@SiO2@CS-P exhibited better acid resistance (with barely any iron leaching) than silica-uncoated adsorbent (Fe3O4@CS-P) at pH 1.0. Furthermore, the FTIR and XPS spectra after adsorption suggested that the high adsorption performance and selective capture lead were predominantly controlled by the coordination of the phosphate groups on the surface of the adsorbent. This work shows a broad prospect of developing a series of novel, acid-resistant, good reusable and rapidly separable magnetic materials that can be used to efficiently and selectively capture lead from aqueous solutions.