Magnetic Nanocomposite Hydrogels Research Articles

Magnetic, Biocompatible and Biodegradable Carboxymethyl Cellulose‐Based Hydrogel for Cationic Dye Adsorption

AbstractEnsuring the availability of water resources that are both clean and safe is crucial for the preservation of environmental health and the well‐being of humans. Here, we fabricated carboxymethyl cellulose‐based hydrogel nanocomposite using acrylic acid (AA) and 2‐acrylamido‐2‐methylpropane sulfuric acid (AMPS) monomers and Fe3O4 nanoparticles through a free radical crosslinking process for adsorption of dyes from contaminated water. The synthesized nanocomposite hydrogel was characterized using various techniques, including TEM, XRD, FTIR, SEM‐EDS, TGA, and AFM analysis. The swelling capacity of samples in an aqueous medium at multiple pH levels and the presence of different salts were investigated. The adsorption efficiency of methylene blue (MB) and crystal violet (CV), emphasizing the effect of hydrogel concentration and the medium's pH, was studied. It was concluded that the hydrogel sample containing 17 % AMPS and 51 % AA had better swelling capacity and dye removal efficiency. The dye adsorption kinetics data were fitted to pseudo‐first and second‐order kinetic models and the Langmuir and Temkin isotherm models. The maximum adsorption capacity for MB and CV was 53.97 and 53.57 mg/g, respectively. It was revealed that the pseudo‐second‐order kinetic model could best describe adsorption (qe=79.2 mg/g for MB and qe=65.8 mg/g for CV). The intra‐particle diffusion model was found to be the rate‐limiting mechanism of dye adsorption. Thermodynamic studies proposed that the adsorption of MB and CV was spontaneous and endothermic. Additionally, magnetic nanocomposite hydrogel‘s reusability up to four successive cycles further determines its probability of adsorption of dyes from wastewater.

Remote-controlled saline tolerant tough-yet-strong solar vapor evaporator based on multifunctional Fe3O4 nanoparticles reinforced gel-nacre

Solar vapor evaporators in saline hold enormous potentials in resource sustainability, seawater desalination, as well as renewable energy harvesting. Nanocomposite hydrogels with the property of photothermal conversion have emerged as candidates for solar-driven steam generation devices, but are limited by remote control and low mechanical properties in a saline environment. Here, we developed a remote-controlled, saline tolerant, and tough-yet-strong solar vapor evaporator based on multifunctional Fe3O4 nanoparticles reinforced gel-nacre. The Fe3O4 nanoparticles play triple roles of acting as nano-crosslinks, photothermal converters, and untethered manipulation, coupling gel-nacre matrix with a shrinking tendency in saline that contributes to synergistic mechanical reinforcement. Such integrated magnetic nanocomposite hydrogel exhibits tough-yet-strong mechanical properties (19.58 MPa ultimate strength, 300 % failure strain, self-recoverability under 500 %, and fatigue-resistance), addressing the challenges of remote operation system and high strength requirement for practical applications. Moreover, good photothermal conversion performances (1.26 kg m−2 h−1 evaporation rate and 92.84 % evaporation efficiency) could be achieved with remotely controlled motion or adjustable position simultaneously under an external magnetic field. The intelligent solar vapor evaporation system based on multifunctional magnetic Fe3O4@gel-nacre nanocomposite provides new opportunities for flexible energy-transducing devices with untethered manipulation in saline environment.

Multifunctional Self-Assembled Block Copolymer/Iron Oxide Nanocomposite Hydrogels Formed from Wormlike Micelles.

This article reports the preparation of multifunctional magnetic nanocomposite hydrogels formed from wormlike micelles. Specifically, iron oxide nanoparticles were incorporated into a temperature responsive block copolymer, poly(glycerol monomethacrylate)-b-poly(2-hydroxypropyl methacrylate) (PGMA-b-PHPMA), and graphene oxide (GO) dispersion at a low temperature (∼2 °C) through high-speed mixing and returning the mixture to room temperature, resulting in the formation of nanocomposite gels. The optimal concentrations of iron oxide and GO enhanced the gel strength of the nanocomposite gels, which exhibited a strong magnetic response when a magnetic field was applied. These materials retained the thermoresponsiveness of the PGMA-PHPMA wormlike micelles allowing for a solid-to-liquid transition to occur when the temperature was reduced. The mechanical and rheological properties and performance of the nanocomposite gels were demonstrated to be adjustable, making them suitable for a wide range of potential applications. These nanocomposite worm gels were demonstrated to be relatively adhesive and to act as strain and temperature sensors, with the measured electrical resistance of the nanocomposite gels changing with applied strain and temperature sweeps. The nanocomposite gels were found to recover efficiently after the application of high shear with approximately 100% healing efficiency within seconds. Additionally, these nanocomposite worm gels were injectable, and the addition of GO and iron oxide nanomaterials seemed to have no significant adverse impact on the biocompatibility of the copolymer gels, making them suitable not only for 3D printing in nanocomposite engineering but also for potential utilization in various biomedical applications as an injectable magnetic responsive hydrogel.

In vitro release dynamics of doxorubicin hydrochloride & gentamicin sulphate through nanoparticle embedded sterculia gum/gelatin self crosslinked hydrogel system

Present study synthesized stimuli-sensitive drug delivery systems for anti-cancer drug doxorubicin hydrochloride (Dox) and antibiotic drug gentamicin sulphate (GS) using sterculia gum, gelatin, and Fe3O4 nanoparticles. The approach involved oxidizing sterculia gum with NaIO4, followed by self-crosslinking with gelatin resulting a pH-responsive protein hybrid crosslinked network. Further gel matrix was reinforced with Fe3O4 nanoparticles resulted in magnetic nanocomposite hydrogel. FTIR, powdered XRD, and FESEM had been used to characterize the functionalized drug-loaded hydrogels. In vitro release behavior of Dox and GS had been studied in pH 2.2, 7.0, 7.4, simulated gastric fluid (SGF) and in simulated intestinal fluid (SIF). For both drugs, highest release had been achieved in pH 2.2 and SGF, while minimum in physiological pH 7.4. The release mechanisms adopted by Dox and GS from drug loaded OSG-cl-Gelatin and OSG-cl-Gelatin/Fe3O4 matrix have been assessed using different mathematical models viz Zero order, First order, Higuchi kinetic model and Korsmeyer Peppas model in different release mediums. Drug release mainly had occurred through Case-II diffusion mechanism. In acidic pH, Dox release followed Higuchi kinetic model while GS release occurred through Korsmeyer Peppas model. Hydrolytic degradation potential, thrombogenicity and haemocompatible behavior of functionalized gel matrix had also been screened.

Biosorptive removal of cationic dyes from ternary system using a magnetic nanocomposite hydrogel based on modified tragacanth gum

Performance of a magnetic tragacanth gum-crosslinked-poly(acrylic acid) (TG-cl-PAA/Fe3O4) nanocomposite hydrogel in removal of malachite green (MG), thioflavin T (ThT), and rhodamine B (RhB) cationic dyes from single, binary, and ternary systemes were investigated through the batch method. The adsorption parameters, including adsorbent amount, initial concentrations of dyes, pH, and contact time were optimized for all systems. Langmuir and Freundlich models were used for equilibrium adsorption isotherm investigation, and it was found that the Langmuir model is more fitted than those of the Freundlich model, which proved the linearity of the adsorption process. Maximum adsorption capacities (Qm) of TG-cl-PAA/Fe3O4 were calculated for all systems. The Qm for MG, RhB, and ThT dyes in ternary system were obtained as 642.9, 552.6, and 413.6 mgg−1, resepectively. The removal of all dyes in single, binary as well as ternary systems were well-fitted with the pseudo-second-order model that confirm the rate-limiting step might be the chemical adsorption. The developed adsorbent was regenerated through desorption process and reused for several times. It was found that the removal efficiency of adsorbent approximately remains the same for the first three cycles, and after which decreased gradually.

Magnetic nanocomposite hydrogel with ultra‐stretchable as strain sensors for monitoring human motion and the change of magnetic field

AbstractIn recent years, the smart hydrogels have gained much concern in the field of research specially related to flexible strain sensors because they exhibit many types of smart interactions that can be useful in wearable devices. However, the conventional hydrogels have poor electrical conductivity that affect the performance of the sensors, so it remains a challenge to achieve noncontact signal monitoring (e.g., for the detection of magnetic field changes). In this study, an ultra‐stretchable and magnetically responsive conductive hydrogel was fabricated by adding magnetic ferric tetroxide@polypyrrole composite nanoparticles (Fe3O4@PPy NPs) to polyacrylamide (PAm). The nanoparticles were easily agglomerated and improved the compatibility of PPy and hydrogel. The obtained PAm/Fe3O4@PPy hydrogel showed an ultra‐stretchability of (961%), a low elastic modulus of (87.8 kPa), and an excellent toughness of (1010.5 kJ m−3). Moreover, PAm/Fe3O4@PPy hydrogel also exhibited a high electrical conductivity of 0.34 S m−1, and the PAm/Fe3O4@PPy hydrogel sensor could detect human motions (such as bending of finger, bending of wrist) and muscle micromotion (such as pronouncing). In addition, it can also monitor the change in magnitude of magnetic field.

Magnetic nanocomposite through coating mannose-functionalized metal-organic framework with biopolymeric pectin hydrogel beads: A potential targeted anticancer oral delivery system

This study designed magnetic nanocomposite hydrogel beads for a potential targeted anticancer oral delivery system. To end this, nanohybrids of Fe3O4/MIL-88(Fe) (FM) were synthesized through in-situ method by the treatment of terephthalic acid (TPA) and (Fe(NO3)3·9H2O) in the presence of Fe3O4 nanoparticles. They were then modified with mannose sugar as an anticancer receptor to achieve a targeted drug delivery system. After loading methotrexate (MTX), they were coated with pH-sensitive pectin hydrogel beads in the presence of a calcium chloride crosslinker for possible transferring the nanohybrids to the intestine through the acidic environment of the digestive system. The results of different analysis techniques showed that the materials were properly synthesized, coated, and loaded. The designed magnetic nanocomposite hydrogel beads showed pH-sensitive swelling and drug release rate, protecting MTX from the acidic environment of the stomach. MTT test revealed a good cytotoxicity toward colon cancer HT29 cell lines. Remarkably, the functionalization of MTX-loaded FM nanohybrids with mannose (MTX-MFM) enhanced their anticancer properties up to about 20 %. The results recommended that the prepared novel magnetic nanocomposite hydrogel beads have a good potential to be used as a targeted anticancer oral delivery system.

A pH-sensitive magnetic hydrogel nanocomposite based on alginate for controlled release of methotrexate

Development of a carrier with controlled release manner for methotrexate (MTX), an anticancer drug with short elimination half-life of 3-10 h, is important to overcome undesired side effects of conventional systems. This study demonstrated the synthesis of a pH-sensitive magnetic hydrogel nanocomposite based on montmorillonite (MMT), magnetite (Fe3O4), and alginate (Alg) for extended release of MTX. MMT-Fe3O4 with different amounts of MMT, were prepared by growth of Fe3O4 nanoparticles on the surface of MMT. Then, the MMT-Fe3O4-MTX-Alg nanocomposite beads were prepared by coating of well dispersed MMT-Fe3O4-MTX with Alg. The characterization was investigated using FTIR, XRD, DLS, FESEM-EDX, TGA, and VSM techniques. By introducing 1 g of MMT in hydrogel beads, the encapsulation efficiency and loading content were enhanced to 99.34% and 18.71%, respectively. Pure drug exhibits a burst release of 100% within 4 h. Whereas for MMT (1)-Fe3O4-MTX-Alg, less burst release of 12.4% and 27.6% in the gastric and intestinal fluid was obtained, respectively within 4 h. This phenomenon leads to the beads remaining intact passing through the stomach, but the release rate is done at an acceptable rate at the relatively alkaline environment of the intestine. The release kinetics of MTX from the nanocomposite beads follows the Korsmeyer-Peppas model. Finally, MTT assay and RT-PCR analysis were followed on MDA-MB-231 breast cancer cells, to assess their anti-proliferative, apoptotic and antiapoptotic effects. MMT-Fe3O4-MTX-Alg significantly reduced the percentage of viable cells, with a high down-regulation in the expression level of the anti-apoptotic gene (Bcl-2), and up-regulation in the apoptotic gene (Bax).

Injectable Hydrogels Including Magnetic Nanosheets for Multidisciplinary Treatment of Hepatocellular Carcinoma via Magnetic Hyperthermia.

Relapse and unresectability have become the main obstacle for further improving hepatocellular carcinoma (HCC) treatment effect. Currently, single therapy for HCC in clinical practice is limited by postoperative recurrence, intraoperative blood loss and poor patient outcomes. Multidisciplinary therapy has been recognized as the key to improving the long-term survival rate for HCC. However, the clinical application of HCC synthetic therapy is restricted by single functional biomaterials. In this study, a magnetic nanocomposite hydrogel (CG-IM) with iron oxide nanoparticle-loaded mica nanosheets (Iron oxide nanoparticles@Mica, IM) is reported. This biocompatible magnetic hydrogel integrated high injectability, magnetocaloric property, mechanical robustness, wet adhesion, and hemostasis, leading to efficient HCC multidisciplinary therapies including postoperative tumor margin treatment and percutaneous locoregional ablation. After minimally invasive hepatectomy of HCC, the CG-IM hydrogel can facilely seal the bleeding hepatic margin, followed by magnetic hyperthermia ablation to effectively prevent recurrence. In addition, CG-IM hydrogel can inhibit unresectable HCC by magnetic hyperthermia through the percutaneous intervention under ultrasound guidance.

Preparation of pH-responsive magnetic nanocomposite hydrogels based on k-carrageenan/chitosan/silver nanoparticles: Antibacterial carrier for potential targeted anticancer drug delivery

This study reports the development of new pH-responsive drug delivery systems that are important for the treatment of cancer. The Mentha plant extract was obtained and then used for the biosynthesis of magnetic Ag bio nanoparticles (M-Ag bio-NPs). They were added in the formulation of hybrid hydrogel of k-carrageenan (k-Cr) and chitosan (CS) toward the synthesis of magnetic nanocomposite hydrogels. Their chemical structure and morphology were characterized by different analyses. Doxorubicin (DOX) was used as a model anticancer drug to study the targeted drug release behavior of the synthesized nanocomposite hydrogels (loading capacity: about 98 %). In vitro drug release studies showed that the release profile was noticeably controlled in a pH-dependent manner (higher drug release at pH 5). The antibacterial assessment confirmed the high antibacterial activity for the synthesized hydrogel against S. aureus (MIC values 39.06 μg/mL) and E. coli (MIC values > 19.53). In-vitro cytotoxicity results (MTT assay) demonstrated good biocompatibility (higher than 88 %) for the blank nanocomposite hydrogels, while DOX-loaded nanocomposite hydrogels showed high toxicity (about 22 % in the concentration of 20 μg/mL) against HeLa cells. The results showed that the present nanocomposite hydrogels can be suggested for potential application as an antibacterial and anticancer carrier.

In situ preparation of MOF-199 into the carrageenan-grafted-polyacrylamide@Fe3O4 matrix for enhanced adsorption of levofloxacin and cefixime antibiotics from water

In this research study, a novel method, an in-situ growth approach, to incorporate metal-organic framework (MOF) into carrageenan-grafted- polyacrylamide-Fe3O4 substrate was introduced. Carrageenan-grafted-polyacrylamide-Fe3O4/MOF nanocomposite (kC-g-PAAm@Fe3O4-MOF-199) was fabricated utilizing three stages. In this way, the polyacrylamide (PAAm) was grafted onto the carrageenan (kC) backbone via free radical polymerization in the presence of methylene bisacrylamide (MBA) as cross-linker and Fe3O4 magnetic nanoparticles. Next, the kC-g-PAAm@Fe3O4 was modified by MOF-199 via an in-situ solvothermal approach. Several analyses such as Fourier transform infrared spectroscopy (FT-IR), X-Ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-Dispersive X-ray Spectroscopy (EDX), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), Brunauer-Emmett-Teller (BET) demonstrated the successful synthesis of kC-g-PAAm@Fe3O4-MOF-199 magnetic hydrogel nanocomposite. The XRD pattern of magnetic hydrogel nanocomposite illustrated characteristic peaks of Fe3O4, neat kC, and MOF-199 with enhanced crystallinity in comparison with kC-g-PAAm@Fe3O4. TGA showed it has a char yield of 24 wt% at 800 °C. VSM confirmed its superparamagnetic behavior (with Ms of 8.04 emu g−1), and the BET surface area of kC-g-PAAm@Fe3O4-MOF-199 was measured at 64.864 m2 g−1, which was higher than that of kC-g-PAAm@Fe3O4 due to the highly porous MOF-199 incorporation with a BET surface area of 905.12 m2 g−1). The adsorption effectiveness of kC-g-PAAm@Fe3O4-MOF-199 for eliminating cephalosporin and quinolones antibiotics, i.e., Cefixime (CFX) and Levofloxacin (LEV) from the aquatic area was considered. Several experimental setups were used to evaluate the efficacy of adsorption, such as solution pH, amount of adsorbent, contact duration, and initial concentration. The maximum adsorption capacity (Qmax) of the prepared magnetic hydrogel nanocomposite was found to be 2000 and 1666.667 mg−1 for LEV and CFX using employing 0.0025 g of adsorbent. The Freundlich isotherm model well described the experimental adsorption data with R2CFX = 0.9986, and R2LEV = 0.9939. And the adsorption kinetic data were successfully represented by the pseudo-second-order model with R2LEV = 0.9949 and R2CFX = 0.9906. Hydrogen bonding, π-π interaction, diffusion, and entrapment in the hydrogel network all contributed to the successful adsorption of both antibiotics onto the kC-g-PAAm@Fe3O4-MOF-199 adsorbent. Other notable physicochemical properties include the three-dimensional structure and availability of the reactive adsorption sites. Moreover, the adsorption/desorption efficacy of magnetic hydrogel nanocomposites was not significantly diminished after four cycles of recovery.

Precipitation‐Based Silk Fibroin Fast Gelling, Highly Adhesive, and Magnetic Nanocomposite Hydrogel for Repair of Irregular Bone Defects

AbstractCritical‐sized bone defects, especially for irregular shapes, remain a significant challenge in orthopedics. Although various biomaterials are developed for bone regeneration, their application for repair of irregular bone defects is limited by the complicated preparation procedures involved, and their lack of shape‐adaptive capacity, physiological adhesion, and potent osteogenic bioactivity. In the present study, a simple strategy of precipitation by introducing tannic acid (TA) with abundant phenolic hydroxyl groups and Fe3O4 nanoparticles, as metal‐phenolic networks (MPN), is developed to easily prepare a fast gelling, shape‐adaptive, and highly adhesive regenerated silk fibroin (RSF)/TA/Fe3O4 hydrogel system that can respond to a static magnetic field (SMF). The RSF/TA/Fe3O4 hydrogel exhibits sufficient adhesion in biological microenvironments and good osteogenic effect in vitro and in vivo, under an external SMF, and thus, can be applied to repair critical‐sized bone defects. Moreover, bioinformatics analysis reveals that the synergistic mechanism of Fe3O4 NPs and SMF on osteogenic effects can be promotion of osteoblast differentiation via activation of the cyclic guanosine monophosphate (cGMP)/protein kinase G (PKG)/extracellular signal‐regulated kinase (ERK) signaling pathway. This study provides a promising biomaterial with potential clinical application for the future treatment of (irregular) critical‐sized bone defects.

Study of the tunable mechanical and swelling properties of magnetic sensitive calcium alginate nanocomposite hydrogels

Study of the tunable mechanical and swelling properties of magnetic sensitive calcium alginate nanocomposite hydrogels

Removal of methylene blue from aqueous solution by magnetic hydrogel nanocomposite absorbents

Currently reported adsorbents for wastewater purification generally have only limited adsorption capacity and low adsorption rate towards dye contaminants. In this work, KH570-modified magnetic hydrogel nanocomposites (KH570-mHNCs) with semi-IPNs structure were prepared based on poly (acrylamide-co-acrylic acid), polyvinyl pyrrolidone (PVP), and KH570-modified magnetic nanoparticles, and it exhibited high absorption capacity and absorption rate for methylene blue dye. KH570-mHNCs had a rough surface with many porous and gully structures, and FTIR results preliminarily confirmed the target structure of KH570-mHNCs. KH570-mHNCs could rapidly absorb methylene blue by approaching absorption equilibrium at 90 min. Dye absorption of KH570-mHNCs had maximum dye absorption capacity at pH = 8, and methylene blue adsorption capacity was 255.4 mg/g, 326.3 mg/g, and 418.5 mg/g in the condition of initial dye concentrations of 700 mg/L, 900 mg/L, and 1100 mg/L, respectively. Methylene blue adsorption isotherms and kinetics conformed to the Langmuir model and pseudo-second-order kinetic model, respectively. Methylene blue adsorption for KH570-mHNCs was a spontaneous, exothermal, and entropy reduction process. In addition, KH570-mHNCs had good magnetic response, desorption, and reusability, which made it a potential application in the field of methylene blue removal from the aqueous solution.

Adsorption behaviours of copper(II), lead(II), and cadmium(II) ions from aqueous solution by polyethylenimine -modified magnetic hydrogel nanocomposites

Adsorption behaviours of copper(II), lead(II), and cadmium(II) ions from aqueous solution by polyethylenimine -modified magnetic hydrogel nanocomposites

Enhanced adsorption of crystal violet from aqueous solution by polyethyleneimine-modified magnetic hydrogel nanocomposites

Enhanced adsorption of crystal violet from aqueous solution by polyethyleneimine-modified magnetic hydrogel nanocomposites

Efficient activation of peroxydisulfate by a novel magnetic nanocomposite lignin hydrogel for contaminant degradation: Radical and nonradical pathways

A novel magnetic nanocomposite lignin hydrogel (MNLH) was synthesized and applied for peroxydisulfate (PDS) activation in this study. Detailed characterization data indicated that the unique 3-dimensional (3D) structure of the lignin hydrogel is beneficial in dispersing magnetic nanoparticles (nZVI/Ni particles), which enhances the maximum exposure of nZVI/Ni particles. The 3D structure of the lignin hydrogel provides more attachment sites for nZVI/Ni, PDS and contaminants, accelerating the electron transfer between nZVI/Ni and PDS and promoting the degradation of contaminant. Notably, the optimized MNLH0.8 catalyst (where the number 0.8 indicates the mass ratio of [Lignin hydrogel]/[nZVI/Ni] = 0.8) exhibits excellent performance for PDS activation. Under the MNLH0.8/PDS system, 5 mg/L bisphenol A (BPA, 40 mL) can be completely degraded within 15 min with 0.05 g/L catalyst and 0.66 mM PDS. Quenching experiments and electron spin resonance (ESR) spectra reveal that both radicals (O2•−) and nonradicals (1O2) are generated in the MNLH0.8/PDS system as the dominant active species for BPA degradation. In addition, the MNLH0.8 catalyst still shows effectiveness for BPA degradation in the presence of inorganic anions and natural organic matter (NOM). UPLC-Q-TOF-MS system was used to identify the BPA degradation products and four possible pathways for BPA degradation were proposed. According to the results of toxicity prediction, BPA can eventually be transformed into nontoxic products. Additionally, the MNLH/PDS system can effectively degrade different contaminants in water, which highlights promising applications for organic wastewater treatment.

Separation and preconcentration of cerium (III) and Iron (III) on magnetic nanocomposite hydrogel

Iron is the most significant interfering metal ion during the purification of rare earth elements (REEs) from their mineral sources. Therefore, the current study aims to investigate the sorption behavior of the Ce3+ and Fe3+ ions using polyfunctional nanocomposite hydrogel (NCHG), as well as to provide foundational data for the development of the Ce3+ ions separation procedure. The adsorption capacity was tested in various aqueous media (chloride and sulfate media) to determine the optimal separation conditions for Ce3+ and Fe3+ ions. Numerous parameters, such as contact time, pH, and initial metal ion concentration, may impact the sorption process in batch mode. The results demonstrated that separation is more effective in an aqueous medium than in a chloride medium. In addition, their sorption is poor in sulfate medium, indicating that the prepared nanocomposite was selective in separating cerium from high-grade monazite (in chloride medium). With an adsorption uptake of up to 80% for Ce3+ in an aqueous medium, the synthesized nanocomposite was efficiently utilized for selective separation. The correlation coefficient (R2) of the Langmuir isotherm model was determined to be the highest and closest to 1. The experimental adsorption capacity of Ce3+ was reported at 151 mg/g. The adsorbed Ce3+ was desorbed efficiently from NCHG.

Synthesis of polyethylenimine-modified magnetic hydrogel nanocomposite absorbents for heavy metals removal

Synthesis of polyethylenimine-modified magnetic hydrogel nanocomposite absorbents for heavy metals removal

Absorption thermodynamic and kinetics of heavy metals by magnetic hydrogel nanocomposite absorbents with semi‐interpenetrating networks structure

AbstractKH570‐modified magnetic hydrogel nanocomposite absorbents (KH570‐mHNAs) with semi‐interpenetrating networks (semi‐IPNs) were synthesized by radical copolymerization based on poly(acrylamide‐co‐acrylic acid), PVP and KH570‐modified magnetic nanoparticles. KH570‐mHNAs with porous and ravine structure have the target structure confirmed by FTIR and XRD results. KH570‐mHNAs have high adsorption capacities of Cu(II) (163 mg/g), Cd(II) (150 mg/g), and Pb(II) (460.8 mg/g), approaching the absorption equilibrium at 60 min. Heavy metal absorption was highly dependent on different process variables, such as pH value, initial heavy metal ion concentration, contact time, and temperature. The endothermic, entropy increasing, and spontaneous nature of heavy metal ion adsorption was revealed from thermodynamic study. Heavy metal ions adsorption isotherms and kinetics were in agreement with the Langmuir model and pseudo‐second‐order kinetic model, respectively. Besides, KH570‐mHNAs had good magnetic responsiveness, desorption, and reusability, which made it a promising adsorbent for removing heavy metal ions from the contaminated wastewater.