Magnetic Bentonite Research Articles

Induced orientation of magnetic bentonite nanoparticles to produce low-density polyethylene nanocomposites

Clay-polymer nanocomposites have considerable importance in various areas of engineering; however, the addition of hydrophilic clays into hydrophobic polymer matrices is a challenge due to the low affinity between them, causing performance problems. Thus, the aim of this work was developing a method to improve dispersion and generate a high aligned morphology in clay-polymer nanocomposites. For this, clay nanoparticles with magnetic properties were produced and incorporated (3 wt% and 5 wt%) in low-density polyethylene matrices. The effect of the alignment on the thermal and thermo-mechanical properties of polymer was evaluated. The use of an external magnetic field during the molding process led to an efficient alignment of the nanoparticles, where the magnetic clay nanoparticles lined up along the magnetic field lines. The presence of nanoparticles had a crucial impact on the thermal properties of the nanocomposites with increments up to 40 °C in the initial degradation temperature of the polymeric matrix by forming physical barriers distributed across the samples. The alignment of nanoparticles also resulted in increments of up to 43% in the storage modulus of the polymer as a result of improved adsorption of mechanical energy. The results indicated a very promising methodology with potential application in the production of new polymeric materials with high barrier properties to liquids and gases and thin films with magnetic shielding properties.

Adsorption of Ciprofloxacin and Tetracycline by Organically Modified Magnetic Bentonite

In order to endow magnetic bentonite (MB) with better magnetic separation and magnetic stability, obtain stronger adsorption of antibiotics, carboxymethylcellulose-chitosan/magnetic bentonite composite (MB/CC) was prepared by modifying previously fabricated MB with carboxymethylcellulose (CMC) and chitosan (CS). The characterization of MB/CC and the adsorption properties towards ciprofloxacin (CIP) and tetracycline (TC) was investigated. The characterization results revealed that CC improves the Fe3O4 stability and removal capability of CIP and TC for the final product. Adsorption results indicated that MB/CC exhibited superior adsorption performance for CIP (182 mg·g−1) and TC (189 mg·g−1). Adsorptive removal of CIP and TC by MB/CC was more than 90% even after 5 cycles of adsorption-desorption process. The adsorption process fitted well with the Langmuir model and the pseudo-second order kinetic model. The main steps during the successful adsorption process of MB/CC for CIP and TC includes pore diffusion, ion exchange and electrostatic interaction. MB/CC has advantages of simplified synthesis, convenient operation and high-efficiency, which could be deemed as a promising alternative adsorbent for antibiotics removal from wastewater.

Retraction: A carboxymethyl cellulose modified magnetic bentonite composite for efficient enrichment of radionuclides.

[This retracts the article DOI: 10.1039/C6RA10990J.].

Magnetic clay\zeolitic imidazole framework nanocomposite (ZIF-8@Fe3O4@BNT) for reactive orange 16 removal from liquid media

This study was performed to evaluate the removal from wastewater of reactive orange 16 (RO16) with magnetically separable zeolitic imidazole frameworks coated magnetic bentonite nanocomposites (ZIF-8@Fe 3 O 4 @BNT). Various microscopic and spectroscopic analyses were carried out to reveal the surface characteristics of the nanocomposite. Point of zero charging (pH PZC ) of ZIF-8@Fe 3 O 4 @BNT was obtained as 8.84. The dependence of RO16 removal yield on initial pH, initial dye concentration (C o ), adsorbent dose and contact time was investigated using the central composite design (CCD) included in response surface methodology (RSM). With the obtained quadratic model equation from CCD, the optimum values were determined as initial pH of 3.9, initial concentration (C o ) of 19.76 mg/L, adsorbent amount of 12 mg (480 mg/L), and contact time of 150 min. The maximum removal efficiency of 98.5% and the maximum adsorption capacity of 40.5 mg/g were reached at these optimal points. Adsorption kinetic analysis and equilibrium experiments showed that the best fit was reached with the pseudo-second-order and Langmuir isotherm models, respectively. Also, thermodynamic parameter changes for RO16 removal were calculated, and the results showed that the adsorption was favorable, spontaneous, and exothermic. With all of these, the fact that ZIF-8@Fe 3 O 4 @BNT has high recovery efficiency for RO16 removal, fast kinetics and can be separated easily and quickly with the help of a magnet before and after treatment provide significant advantages for wastewater treatment.

Dually organic modified bentonite with enhanced adsorption and desorption of tetracycline and ciprofloxacine

Tetracycline (TC) and ciprofloxacin (CIP) cause serious environmental and health issues upon their uncontrolled release to the aquatic system and hence their control required serious attention. In this study, adsorption and desorption performances of TC and CIP by sodium carboxymethylcellulose (CMC) and polyethyleneimine (PEI) modified magnetic bentonite (MBCP) were explored. It was found that active functional groups such as –COOH, –OH and –NH2 loaded on the surface of MBCP increased the selective adsorption performance of MBCP for TC and CIP. Meanwhile, MBCP had superior adsorption performance in a wide pH range, magnetic separation capability and good regeneration. Based on the adsorption kinetics, isotherm, pHPZC, FE–SEM, TEM, FT–IR, XRD, BET, XPS and VSM results, the mechanisms of MBCP adsorption and desorption were investigated which mainly involved electrostatic interaction, pores deposition, complexation and ions exchange phenomena. MBCP was realized higher adsorption capacity for TC (476 mg/g), and CIP (457 mg/g) than MB (300 and 270 mg/g, respectively). This study provides important reference information for the fabrication of MBCP as a novel and promising adsorbent for the remediation of antibiotics from wastewater on the industrial level.

Adsorption behavior of tetracycline on carboxymethyl starch grafted magnetic bentonite

Adsorption behavior of tetracycline on carboxymethyl starch grafted magnetic bentonite

Novel environment-friendly magnetic bentonite nanomaterials functionalized by carboxymethyl chitosan and 1-(2-pyridinylazo)-2-naphthaleno for adsorption of Sc(III)

For effective adsorption and separation of precious rare metal scandium (Sc) from waste water, a new bifunctional magnetic bentonite material was prepared, named bentonite/CoFe2O4@SiO2-CMC/PAN to enhance the selective extraction of scandium. Magnetic bentonite was functionalized with carboxymethyl chitosan (CMC) and 1-(2-pyridinylazo)-2-naphthaleno (PAN). The adsorbent was characterized by BET, XRD, EDS, SEM, TEM and FTIR. Factors such as pH, initial concentration, reaction time, adsorbent dosage, selectivity, and reusability were systematically investigated. The results showed that the adsorption isotherm and kinetic data were accurately described by Langmuir model and pseudo second order model, indicating that the adsorption conformed to the monolayer chemical adsorption, and the adsorption rate was controlled by multiple steps. The adsorption rate was 98%, and the maximum adsorption capacity was up to 49.05 mg·g−1. The bentonite/CoFe2O4@SiO2-CMC/PAN showed high selectivity. Additionally, the adsorbent could be magnetically separated quickly. XPS analysis results showed that scandium ion (Sc(III)) could not only carry out electrostatic and complexation with carboxyl groups and hydroxyl, but also chelate with amino, azo and pyridine groups. In general, bentonite/CoFe2O4@SiO2-CMC/PAN showed a hopeful way for the recovery and utilization of Sc.

Implementation of magnetic bentonite in food industry wastewater treatment for reuse in agricultural irrigation

Combining natural materials and pretreatment processes with nanomaterials is an alternative to be evaluated for the increase in efficiency and cost reduction of water treatment processes. This work aimed to study the combination of pretreatment processes and primary treatments with bentonite impregnated with magnetic nanoparticles (Bentonite@MNPs) to reuse wastewater from the food indust|ry. Bentonite@MNPs were obtained by green synthesis using glucose as a reducing/stabilizing agent, and the nanocomposite was characterized by SEM, EDS, FTIR, VSM, and XRD analysis. The synthesized nanocomposite was used to remove nitrates and COD from wastewater from the production of guava bars that had been pretreated with coagulation-flocculation-sedimentation processes. Batch adsorption experiments were conducted, where the influence of several parameters such as contact time, adsorbent amount, and the temperature was studied. According to the results, the wastewater treated with the coagulation-flocculation-sedimentation processes was still outside the standards for agricultural reuse. After applying the treatment with Bentonite@MNPs, a reduction of COD, nitrates, chlorides, and sulfates of 82%, 75.4%, 98.18%, and 70%, respectively, was achieved. The adsorption isotherm data were best explained by the Langmuir model for COD, and Frendluich model for Nitrates and the adsorption capacity of Bentonite@MNPs for COD and Nitrates was 34.84 and 28.11 mg/g when adsorption temperature was 318 K. The results of thermodynamic studies (ΔG°, ΔH°, and ΔS°) showed the spontaneous, endothermic and randomness in the adsorption process. Desorption studies showed excellent regenerative efficiency (up to the 10th cycle) of nanocomposites using 0.01 M NaOH, so this wastewater treatment system for the food industry is promising to implement for the sake of using wastewater as a circular economy component.

Functionalized magnetic bentonite-iron oxide nanocomposite and its application to decrease scale formation in tubing of oil/gas production

This study reports the development of 3-aminopropyltriethoxysilane (APTES) functionalized magnetic bentonite (AMB) nanocomposite by microwave assisted route to adsorb and decrease Ba(II) and Sr(II) ions, which are responsible for scale formation in the tubing of gas and oil production. Phases, function groups, morphology and magnetic properties was investigated for the prepared samples as well as porosity and surface area. Adsorption results obtained at different temperatures shows that the adsorption process of the prepared AMB is exothermic and follows Langmuir adsorption isotherm model. Kinetics of the adsorption processes at AMB surface was investigated. The process was found to follow the pseudo-second order kinetic model. pH of the system has a great influence on the adsorption of both ions. At pH 9, maximum adsorption was achieved, 124.8 mg/g and 120.0 mg/g for strontium and barium ions, respectively. While it was 107.7 mg/g and 86.7 mg/g for strontium and barium, respectively, at pH 7 similar to produced water pH. AMB showed good removal efficiency that reached 41% and 76.2% for Ba(II) and Sr(II), respectively. Based on the experimental results, AMB is a good natural low-cost material that can be used to decrease scale formation in tubing of oil/gas production.

Novel magnetic polymer/bentonite composite: Characterization and application for Re(VII) and W(VI) adsorption

A novel magnetic polymer/bentonite composite was prepared by suspension copolymerization of glycidyl methacrylate and ethylene glycol dimethacrylate in the presence of magnetic bentonite (MB-PGME) and functionalized with ethylene diamine and hexamethylene diamine (MB-PGME-ED and MB-PGME-HD). The obtained samples were characterized in terms of structure as well as thermal, magnetic and morphological properties. The sorption of rhenium (Re) and tungsten (W) from aqueous solution onto MB-PGME-ED and MB-PGME-HD was investigated considering their contact time and different initial ion concentration, giving possibility for usage of these composites as commercial sorbents. The sorption system follows the pseudo-second order and intraparticle diffusion kinetic models. The results indicated a better fit with the Freundlich isotherm model.

Adsorption Equilibrium and Thermodynamic Studies of Ciprofloxacin from Aqueous Solutions by Magnetic Bentonite Nanocomposites

Objectives: Today, due to increasing usage of antibiotics and their destructive effects on health and environment, it is necessary to remove them from receiving waters. Although there are few studies on the use of magnetic nanocomposites for removal of different antibiotics, but the effect of this adsorbent on the removal of Ciprofloxacin (CIP) has not been evaluated yet. Therefore, this study was conducted to investigate the removal of CIP by magnetic Bentonite nanocomposites (Fe3O4- BNP) as an adsorbent. Methods: Batch studies were performed to evaluate and optimize the effects of various parameters such as contact time, temperature of the solution, CIP concentrations and Fe3O4-BNP dosage. The adsorbent characteristics were determined using SEM and FT-IR spectroscopy. Also, the adsorbent surface area was measured by BET technique. Results: the optimal values for the factors affecting CIP removal were calculated. It was revealed that the maximum CIP removal was obtained at pH = 7, temperature = 55°C, CIP concentration = 10 mg/L, Fe3O4-BNP dosage = 1.25 g/L and contact time= 90 min. The maximum removal percentage was 99.25%. It was also revealed that Langmuir isotherm is the best fitted isotherm model. The thermodynamic parameters like ΔG0, ΔH0 and ΔS0 changes for the adsorption of CIP have also been computed and discussed. The heat of adsorption implied that the adsorption was exothermic in nature. Conclusion: The Fe3O4-BNP was successfully applied for the uptake of CIP from industrial wastewater and separated easily by means of magnetic separation.

Magnetic bentonite nanocomposite for removal of amoxicillin from wastewater samples using response surface methodology before determination by high performance liquid chromatography

Antibiotics and pharmaceutical products cannot remove by conventional sewage treatment. In this work, an effective adsorbent Magnetic Multiwalled Carbon nanotube (MMWCNTs) was synthesized by co-precipitation of MWCNTs with Fe3O4 and used for removal of Amoxicillin from aqueous solutions. Response surface methodology on Central Composition Design (CCD) was applied for designing of experiments and building of models. Four factors including pH, adsorbent dose, time, and temperature were studied and used for the quadratic equation model to the prediction of optimal points. By solvent the equation and considering the regression coefficient (R2 =0.99) the optimal points obtained as follows: pH =2.98; adsorbent dosage =2.16 g; time =22 min and temperature = 37.88 o C. Isotherm study of adsorption showed that the adsorption of amoxicillin onto MMWCNTs follows the Langmuir model. The maximum adsorption capacity is 215 mg g-1 obtained from Langmuir isotherm.

Three dimensional electro-Fenton oxidation of diclofenac and naproxen with magnetic bentonite as a novel particle electrode

ABSTRACT Magnetic bentonite (MBt) and Ti/TiO2 nanotube/PbO2, for the first time, were investigated as particle electrodes and anode of three dimensional electro-Fenton process (3DEF) for the degradation of diclofenac (DCF) and naproxen (NPX). The characteristics of the electrodes were determined by X-ray diffraction(XRD), scanning electron microscope(SEM) and energydispersive X-ray spectroscopy(EDS) analyses and the effects of operating parameters on degradation were studied. The results showed that adsorption and electrochemical processes have lower removal efficiency than the 3DEF process at neutral pH. This efficiency was due to the greater production of hydroxyl radical (•OH) through the anode and MBt surface. The results of the scavenging experiments confirmed an increase in the amount of production of •OH. The maximum removal efficiency of DCF and NPX was obtained at pH of 6, MBt dosage of 500 mg/L, current density of 25 mA/cm2and electrolysis time of 120 min. The electrodes reusability was confirmed by consecutive reaction cycle and the Fourier-transform infrared spectroscopy (FTIR) and SEM-mapping analysis explained their stability. The results of continuous electro-oxidation reactor showed proper removal of the chemical oxygen demand(COD) from real wastewater. The degradation by-products were identified by gas chromatography mass-spectrometry (GC-MS) analysis coupled with dispersive liquid–liquid microextraction (DLLME). Based on comparative tests and products identification, the possible mechanism and pathway of drugs degradation were suggested.

Highly selective enrichment of radioactive cesium from solution by using zinc hexacyanoferrate(III)-functionalized magnetic bentonite

Realizing highly effective and selective enrichment of radioactive Cs(I) in complex environmental systems and exploring the microscale adsorption mechanism of Cs(I) on adsorbing material is the key point for developing highly efficient materials for Cs(I) adsorption. In addition, the low cytotoxicity of materials is essential for practical applications and environmental protection. In this study, the controlled assembly of bentonite carrier with a highly selective substance of Cs(I) is prepared by in-situ synthesis method in order to construct a low-toxic functional clay material with high adsorption capacity and selectivity of Cs(I) in complex environmental systems. The efficiency of the zinc hexacyanoferrate(III)-grafted magnetic bentonite (denoted as ZHF/MB) composite was evaluated in adsorption isotherm studies, kinetics analyses, and selectivity tests by using the batch technique. The toxicity of the ZHF/MB composite was evaluated through in vitro cytotoxicity assays using human hepatic cells (HepG2 cells). The results revealed that the ZHF/MB composite had not only a higher adsorption capacity (1.638 mmol/g, 60 °C) for Cs+ ions than a number of other natural and manmade materials but also no cytotoxicity in human cells. In addition, the ZHF/MB composite showed excellent selectivity for Cs+ with a removal efficiency of over 90% from solution (m/V = 0.4 g/L, [Mn+]initial = 10 mg/L, Mn+= Cs+, Ni2+,Sr2+, Co2+). The promising safe toxicology profile, remarkable Cs+ adsorption efficiency, and excellent selectivity of the ZHF/MB composite demonstrate its great potential for using as a decorporation agent for radioactive cesium remediation. The implementation of this research will provide new adsorption materials and method for radioactive Cs(I) waste management.

Preparation of the efficient nano-bimetallic cobalt-nickel catalysts supported on the various magnetic substrates for hydrogen generation from hydrolysis of sodium borohydride in alkaline solutions

The heterogeneous catalytic hydrolysis of NaBH4 over the various bimetallic cobalt-nickel catalysts supported on the magnetic substrates was studied to understand their catalytic performances. Bentonite, zeolite (clinoptilolite), walnut based activated carbon, and Scharlau activated carbon (commercial sample) were used for the preparation of the magnetic catalysts. Despite the interest, no one to the best of our knowledge has studied the synthesize of the efficient bimetallic catalyst over the magnetic bentonite. The physico-chemical properties of the catalysts were evaluated by using XRD, FTIR, FESEM, TEM, BET, and VSM tests. The characterization of the catalysts indicated that the co-precipitation along with hydrazine is an appropriate method for the synthesis of the superparamagnetic nanoparticles over the porous substrates with sizes less than 30 nm. The highest magnetic strength was achieved to be 30.49 emu/g for the samples supported on the magnetic bentonite. The various operating conditions were also investigated including reaction temperature, NaOH, and NaBH4 content. The results illustrated that the hydrolysis of NaBH4 to hydrogen was a zero-order type reaction with respect to the NaBH4 content. The maximum hydrogen generation rate was measured to be 186 mL.min−1.gcat−1 in the presence of the bimetallic cobalt-nickel catalyst supported on the magnetic bentonite. The minimum activation energies were also calculated to be 37.62 and 44.98 kJ.mol−1 over the samples supported on the magnetic zeolite and bentonite, respectively. The reusability of the catalyst was also investigated in six cycles.

Green synthesis of reusable multifunctional γ-Fe2O3/bentonite modified by doped TiO2 hollow spherical nanocomposite for removal of BPA

Eco-friendly treatment of refractory pollutants in wastewater is still full of challenge in catalytic oxidation and adsorption. In this study, based on the concept of green chemistry, sulfur-doped titanium dioxide hollow spheres modified by surfactant loaded on magnetic bentonite (CST/γ-Fe2O3-BT) is synthesized in two steps, and bisphenol A (BPA) was chosen as the representative organic pollutant. These materials were characterized by means of XRD, FTIR, SEM, EDS, TEM, XPS, BET, and VSM techniques. The adsorption and photodegradation behavior of CST/γ-Fe2O3-BT were examined. The Langmuir isotherm exhibited a better fit with a maximum adsorption capacity of 77.36 mg/g. At pH 7, the reaction rate constant (k) of the BPA photocatalytic degradation by product was 0.00104 min−1, and the adsorption equilibrium constant (K) was 0.04034L/mg. In addition, the composite can be recovered from the reaction mixture by applying an external magnetic field due to the existence of the superparamagnetic iron oxide nanoparticles in the construct. The recovered particles retained their catalytic activity which the catalytic activity of the material still reached 91% of the first catalytic experiment after 5 repetitive experiments. Results infer that the material has excellent reusability. Thus, CST/γ-Fe2O3-BT is a significant candidate for the treatment of recalcitrant organic pollutants in wastewater.

Facile fabrication of hydroxyapatite-magnetite-bentonite composite for efficient adsorption of Pb(II), Cd(II), and crystal violet from aqueous solution

This study reports a facile fabrication route for hydroxyapatite (HAp) nanoparticles impregnated magnetic bentonite (HAp@Fe 3 O 4 @bentonite) composite, which was in turn applied for the removal of Pb(II), Cd(II) and crystal violet (CV) dye from aqueous solution. Adsorption isotherm data best fitted with Freundlich isotherm model and kinetic behavior adopted pseudo-second order adsorption mechanism attaining equilibrium in 60 min over a wide pH range (2.0–13). HAp@Fe 3 O 4 @bentonite was magnetically separable and realized higher adsorption capacity for Pb(II) (404.56 mg/g), Cd(II) (310.36 mg/g) and CV (1201.30 mg/g) than those of acid-treated bentonite (161.28, 155.7 and 740.14 mg/g, respectively). Similarly, the higher Langmuir maximum adsorption capacity exhibited by HAp@Fe 3 O 4 @bentonite for Pb(II), Cd(II) and CV (482, 309 and 1290 mg/g respectively) was attributed to –OH, NH 2 , PO 4 3− surface functionalities. Fresh and spent adsorbents were characterized by Fourier transform infra-red (FTIR) spectroscopy, X-ray diffraction (XRD), differential thermogravimetry , Brunauer–Emmett–Teller (BET) surface area analysis, scanning electron microscopy, energy dispersive X-ray analysis, X-ray photoelectron spectroscopy and vibrating-sample magnetometry techniques. HAp@Fe 3 O 4 @bentonite composite exhibited BET surface area of 73.72 m 2 /g, pore volume of 0.026 cm³/g and an average particle size of 81.39 nm. The composite remained active for five successive adsorption reuses with minimal loss in adsorption capacity as confirmed by FTIR and XRD analyses. The newly synthesized HAp@Fe 3 O 4 @bentonite composite possessing high adsorption efficiency for Pb(II), Cd(II) and CV can be envisaged as a promising solution for wastewater treatment . • Hydroxyapatite-impregnated magnetite-bentonite composite was synthesized. • Adsorption capacity for Pb(II) (482 mg/g) and Cd(II) (309 mg/g) was achieved. • Composite remained stable in pH range 2.0–13.0 and was thermally stable. • Enhanced adsorption of composite was due to -OH - , -PO 4 3- and –NH 2 surface groups.

Comparison of Cd2+ adsorption onto amphoteric, amphoteric-cationic and amphoteric-anionic modified magnetic bentonites

Organic-magnetic bentonites (OMBts), i.e., amphoteric modified MBt (BS-MBt), amphoteric-cationic modified MBt (BS-CT-MBt) and amphoteric-anionic modified MBt (BS-SDS-MBt), obtained by modifying magnetic bentonite (MBt) with amphoteric surfactant (BS), cationic surfactant (CT) and anionic surfactant (SDS) were investigated with the aim to remove cadmium (Cd2+). The modifier contents, surface charge and Cd2+ adsorption performances of OMBts were compared, and the influences of pH, temperature and ionic strength on Cd2+ removal were evaluated. Results showed that modifier contents of OMBts increased in the order: BS-CT-MBt > BS-MBt > BS-SDS-MBt. Although CEC of adsorbents increased in the order: MBt > BS-MBt > BS-SDS-MBt > BS-CT-MBt. The BS-MBt exhibited the highest Cd2+ adsorption capacity (233.19 mmol kg−1) than other adsorbents. The adsorption isotherms could be well described by Langmuir model. The Cd2+ adsorption capacities on MBt and OMBts increased with an increase in pH, temperature and with a decrease of ionic strength. According to characterizations (FT-IR and XPS) and experiments, Cd2+ adsorption on MBt and OMBts most possibly involved electrostatic interaction, ion exchange, and surface complexation. Furthermore, the adsorption of Cd2+ on BS-MBt was also attributed to the chelation. The amidocyanogen group of BS-CT-MBt inhibited adsorption of Cd2+ due to electrostatic repulsion, while Cd2+ was adsorbed on BS-SDS-MBt through electrostatic attraction induced by the sulfo group.

Enhanced removal of phenol by novel magnetic bentonite composites modified with amphoteric-cationic surfactants

Magnetic bentonite (MBent) was modified by both amphoteric surfactant (BS) and cationic surfactant (CT). The structural characteristics of BS-CT-MBent were explored along with the factors primarily influencing their effectiveness in phenol sorption. The results indicated that BS-CT-MBent showed high separation potential and good stability. The carbon contents of BS-CT-MBent increased while specific surface areas decreased with increasing the BS and CT loading level. The sorption capacities of BS-CT-MBent for phenol (198.74–205.81 mmol kg−1) were improved compared to MBent (16.34 mmol kg−1). The phenol sorption capacities on BS-CT-MBent increased with an increase of BS or CT loading level, while the phenol sorption efficiency decreased at high BS and CT loading level. The phenol sorption capacities decreased with an increase of pH, temperature and with a decrease of background electrolyte concentration. Hydrophobic phases formed by surfactants were the main phenol sorption domains and the hydrophobic partition was the key mechanism.

Synthesis of amino-functionalized bentonite/CoFe2O4@MnO2 magnetic recoverable nanoparticles for aqueous Cd2+ removal

Magnetic nano-composite materials have been attracting considerable attention due to their unique properties and versatile applications. In this study, a novel magnetic amino-functionalized conjugate adsorbent, named as bentonite/CoFe2O4@MnO2-NH2 (BCFMNs), was synthesized by combining APTES and MnO2 with magnetic bentonite. XRD, FT-IR, SEM, EDS, TEM, and VSM techniques were used to characterize its structure and magnetic properties. Results were in indicative of productive synthesis, well-defined architecture and satisfactory magnetism. BET examinations illustrated 84.97m2/g of specific surface area, 0.15cm3/g of pore volume and 7.02nm average pore size. The effect parameters such as adsorbent dosage, contact time, initial concentration and ion selectivity and recycling were evaluated and optimized systematically. Also, the metal concentrations were measured by ICP-MS spectrometer. The feasibility of the BCFMNs for removal of Cd2+ from aqueous solution was also evaluated by adsorption experiments with the maximal adsorption efficiency for Cd2+ up to 98.88%. Cd2+ adsorption could be interpreted by the Langmuir adsorption isotherm and the maximum adsorption capacity was 115.79mg/g. The results revealed that the adsorbent still had higher selectivity of Cd2+ removal even in the presence of high concentration coexisting cations. The as-prepared magnetic conjugate adsorbent could be recycled by taking advantage of its magnetic properties. The distinctive structure of BCFMNs and its excellent adsorption performance of cadmium reflects its prospective application in water treatment.