Magnetite Graphene Oxide Research Articles

Alginate-based bio-nanocomposite reinforced with poly(2-hydroxypropyl methacrylamide) and magnetite graphene oxide for delivery of etoposide and photothermal therapy

Recently, bio-nanocomposite nanogels/hydrogels composed of natural polymers and carbon-based nanomaterials are attracting increasing attention in the fields of nanomedicine and bioengineering due to their unique properties. In this study, we propose the creation of an innovative multifunctional bio-nanocomposite based on alginate graft copolymer with poly(2-hydroxypropyl methacrylamide) (SA-g-PHPM) and magnetite graphene oxide (mGO) loaded with etoposide (EPS) for drug delivery and photothermal therapy (PTT). The SA-g-PHPM/mGO bio-nanocomposite was synthesized using an emulsion method and exhibited favorable physicochemical properties. The structural functionalities and surface morphology of the SA-g-PHPM/mGO bio-nanocomposite were comprehensively characterized using spectroscopic techniques, including FT-IR, XRD, UV, DLS, TEM/FE-SEM, and AFM analyses. Under near-infrared (NIR) irradiation (808 nm, 1 Wcm−2, 10 min), the SA-g-PHPM/mGO bio-nanocomposite demonstrated the ability to effectively induce a temperature increase exceeding 29 °C. Additionally, exposure to NIR light and magnetic field led to an increased release of EPS whereas an increment in percentage of mGO caused a decreased EPS release. Notably, the synergistic effects of chemotherapy, light-triggered drug release, and PTT collectively contributed to a significant enhancement in lung cancer (H1299) cell death. In conclusion, our findings suggest that the developed SA-g-PHPM/mGO/EPS bio-nanocomposite serves as an efficient vehicle for multimodal therapy in lung cancer.

Magnetic Magnetite-Graphene Oxide (Fe3O4-GO) Nanocomposites for Removal of Dyes from Aqueous Solution

Magnetic magnetite-graphene oxide (Fe3O4-GO) was synthesized using an in-situ precipitation technique and applied in the adsorption of cationic rhodamine B (RhB) and anionic methyl orange (MO) dyes from aqueous solution. The nanocomposite was characterized by different techniques including FTIR, XRD, Raman, XPS, PPMS, BET, SEM and TEM techniques. Batch adsorption studies were conducted to investigate the effect of solution pH, initial metal ion concentration, adsorbent dosage and contact time. The synthesized Fe3O4-GO exhibited characteristic magnetic properties (saturation magnetization of 34 emu/g) and it separated from aqueous solution with ease through the application of an external magnetic field. The adsorption equilibrium time on the adsorption of RhB and MO onto Fe3O4-GO showed best removal of 99.12% for RhB after 60 min, while MO was removed efficiently after 120 min with a removal efficiency of 97.60%. The adsorption of the azo dyes followed the pseudo-second-order kinetics model with high correlation coefficients (0.99995) for RhB and (0.99925) for MO. Maximum removal of the dye pollutants by occurred at pH 8 for RhB and pH 4 for MO, while the optimal adsorbent dosage was 30 mg. The results showed that adsorption equilibrium data were fitted to Langmuir isotherm model and maximum monolayer adsorption capacities for RhB and MO at 70.64 and 15.94 mgg−1, respectively. The magnetic adsorbents were reused for a maximum of 7 cycles and showed reasonable stability and reproducibility. Furthermore, the results showed that Fe3O4-GO nanocomposite can be used as an effective material in the removal of dyes from wastewater.

Magnetic graphene oxide functionalized dimercaptosuccinic acid/putrescine as a selective and stable solid-phase extraction adsorbent for preconcentration and speciation of arsenic (III) in water samples

ABSTRACT It is challenging for environmental scientists to identify the trace value of arsenite (As(III)) as an essential hazardous material in the presence of arsenate (As(V)) and other metal ions. This paper proposes a method of magnetic solid-phase extraction (MSPE) for the trace analysis of As(III) using magnetite graphene oxide (MGO) covalently functionalised with dimercaptosuccinic acid (DMSA) and putrescine (PUT). The hydrothermally synthesised MGO/DMSA-PUT adsorbent was carefully characterised by using energy-dispersive X-ray spectroscopy analysis, Fourier transform infrared, dynamic light scattering, scanning electron microscopy, zeta potential analyser, X-ray diffraction, and vibrating sample magnetometer techniques in detail. Maximum adsorption capacity of MGO/DMSA-PUT for As(III) was determined 144 mg g−1 which considerably improved vs. graphene oxide with the adsorption capacity of 54.8 mg g−1. Sample pH of 6 with a volume of 50 mL, contact time of 5 minutes, initial concentration of 50 μg L−1, adsorbent dosage of 0.1 g and volume of eluent 3 mL were obtained as the optimised parameters for the developed MSPE procedure. According to experimental data obtained with hydride generation atomic absorption spectroscopy, the linear range and detection limit of the proposed method for As(III) measurement was found to be 0.4–5000 µg L−1 and 9.914 ng L−1, respectively. According to experimental results, a preconcentration limit (PL) of 1.72 µg L−1 was achieved for As(III), corresponding to a preconcentration factor of 965. Statistical analysis of standard reference materials confirmed the accuracy of the method against systematic and constant errors (>95% recovery with <5% RSD). Because of the selectivity of MGO/DMSA-PUT towards the As(III), the developed MSPE procedure is capable for successful speciation and determination of As(III) in water samples with satisfactory analytical results.

Removal of fluorouracil from aqueous environment using magnetite graphene oxide modified with γ-cyclodextrin.

Fluorouracil (FU) is a widely utilized antineoplastic medication in the pharmaceutical industry for combating gastrointestinal cancers. However, its presence in wastewater originating from pharmaceutical facilities and hospital effluents has a potential effect on DNA, and cannot be efficiently eliminated through conventional treatment methods. Consequently, the adoption of advanced technologies becomes crucial for effectively treating such wastewater. Accordingly, this study investigated the efficiency of magnetite graphene oxide nanocomposite functionalized with γ-cyclodextrin for removing fluorouracil from aqueous solutions. The magnetite graphene oxide nanocomposite functionalized with γ-cyclodextrin was synthesized via the hydrothermal method. Next, the effect of pH, temperature, adsorbent content, and contact time on the fluorouracil removal efficiency was explored. Ultimately, the experimental data were matched against Langmuir, Freundlich, and Temkin isotherms and Kinetic models. Accordingly, the efficiency of the absorbent used was dependent on the pH, contact time, temperature, and initial concentration of the adsorbent. The results indicated that the maximum removal efficiency for fluorouracil was achieved within the contact time of 45 min and adsorbent content of 0.020 g. In addition, the optimal pH for removing the medicine was 7. The conditions of the adsorption process followed Langmuir isotherm with correlation coefficients of 0.992 and a quasi-second kinetic model with a correlation coefficient of 0.999, with the maximum adsorption capacity of the adsorbent synthesized for the evaluated medicine estimated as 190.9 mg/g. The results showed that the magnetite graphene oxide nanocomposite functionalized with γ-cyclodextrin could be used as an effective and available adsorbent for removing fluorouracil from pharmaceutical wastewater.

Multifunctional and self-healable conductive IPN hydrogels functionalized with reduced magnetite graphene oxide for an advanced flexible all in one solid-state supercapacitor

The all in one solid-state (AIOS) stretchable and flexible hydrogel electronic devices play a pivotal role in the development of elastic supercapacitors for energy storage and fast charging–discharging rates.

Green and facile synthesis of novel nanocomposites: Insights of interfacial studies in the removal of diclofenac sodium and Rhodamine B

The persistent water contaminants, especially the diclofenac sodium and Rhodamine B, severely concern human and marine life. Advanced and indigenous materials received greater attention in advanced remediation technologies. The study aims to synthesize a novel mesoporous nanocomposite (MSoGO@Bn) material using a facile and greener approach using Saccharum officinarum as a precursor of graphene oxide. Further, the bentonite-supported magnetite graphene oxide nanocomposite is utilized for efficiently remedying an aqueous solution contaminated with diclofenac sodium (DCF) and Rhodamine B (RhB). Advanced analytical techniques adequately characterize the nanocomposite material. The parametric studies viz pH, sorptive concentration, adsorption isotherm, and kinetics are extensively conducted and pointed the efficiency of MSoGO@Bn towards the DCF and RhB removal with the adsorption capacity of 55.02 and 12.68 mg/g, respectively. The organophilic interaction with π-π interaction bounds the DCF and RhB at the solid surface of MSoGO@Bn. Recovery and reusability revealed the stability of solid MSoGO@Bn. Additionally, the real matrix implication of solids indicated the more excellent selectivity of solids in removing these pollutants in the aqueous medium.

Performance Assessment: Influence of Sorbate-Sorbent Interphase Using Magnetite Modified Graphene Oxide to Improve Wastewater Treatment

The adsorption of brilliant green onto magnetite-graphene oxide nanoparticles (MGONPs) from an aqueous solution was explored via batch experiments. The adsorption properties of MGONPs were carried out under various experimental conditions related to pH, contact time, adsorbent dose, temperature, and initial adsorbate concentration. The adsorption capacity of MGONPs and optimum pH were 54.57 mg g−1 and 6, respectively. Equilibrium was attained after 30 min, and the adsorption kinetics data best fitted the pseudo-second-order. The Freundlich isotherm best fits the equilibrium. Acetone was able to desorb the dye from the loaded adsorbent. Additionally, the newly developed adsorption attributes effective surface area (eSBET) and dimensionless preferential adsorption (qp) were more accurate than the conventional specific surface area (SBET). The adsorption capacity provides information about the sorbate-sorbent interface (q). The relevance and accuracy of the new parameters for future adsorption system design by correlation analysis were validated. This study confirms the successful modification of MGONPs for the sorption of the cationic dye brilliant green.

Unexpectedly efficient ion desorption of graphene-based materials

Ion desorption is extremely challenging for adsorbents with superior performance, and widely used conventional desorption methods involve high acid or base concentrations and large consumption of reagents. Here, we experimentally demonstrate the rapid and efficient desorption of ions on magnetite-graphene oxide (M-GO) by adding low amounts of Al3+. The corresponding concentration of Al3+ used is reduced by at least a factor 250 compared to conventional desorption method. The desorption rate reaches ~97.0% for the typical radioactive and bivalent ions Co2+, Mn2+, and Sr2+ within ~1 min. We achieve effective enrichment of radioactive 60Co and reduce the volume of concentrated 60Co solution by approximately 10 times compared to the initial solution. The M-GO can be recycled and reused easily without compromising its adsorption efficiency and magnetic performance, based on the unique hydration anionic species of Al3+ under alkaline conditions. Density functional theory calculations show that the interaction of graphene with Al3+ is stronger than with divalent ions, and that the adsorption probability of Al3+ is superior than that of Co2+, Mn2+, and Sr2+ ions. This suggests that the proposed method could be used to enrich a wider range of ions in the fields of energy, biology, environmental technology, and materials science.

On As(III) Adsorption Characteristics of Innovative Magnetite Graphene Oxide Chitosan Microsphere.

A magnetite graphene oxide chitosan (MGOCS) composite microsphere was specifically prepared to efficiently adsorb As(III) from aqueous solutions. The characterization analysis of BET, XRD, VSM, TG, FTIR, XPS, and SEM-EDS was used to identify the characteristics and adsorption mechanism. Batch experiments were carried out to determine the effects of the operational parameters and to evaluate the adsorption kinetic and equilibrium isotherm. The results show that the MGOCS composite microsphere with a particle size of about 1.5 mm can be prepared by a straightforward method of dropping FeCl2, graphene oxide (GO), and chitosan (CS) mixtures into NaOH solutions and then drying the mixed solutions at 45 °C. The produced MGOCS had a strong thermal stability with a mass loss of <30% below 620 °C. The specific surface area and saturation magnetization of the produced MGOCS was 66.85 m2/g and 24.35 emu/g, respectively. The As(III) adsorption capacity (Qe) and removal efficiency (Re) was only 0.25 mg/g and 5.81% for GOCS, respectively. After 0.08 mol of Fe3O4 modification, more than 53% of As(III) was efficiently removed by the formed MGOCS from aqueous solutions over a wide pH range of 5–10, and this was almost unaffected by temperature. The coexisting ion of PO43− decreased Qe from 3.81 mg/g to 1.32 mg/g, but Mn2+ increased Qe from 3.50 mg/g to 4.19 mg/g. The As(III) adsorption fitted the best to the pseudo-second-order kinetic model, and the maximum Qe was 20.72 mg/g as fitted by the Sips model. After four times regeneration, the Re value of As(III) slightly decreased from 76.2% to 73.8%, and no secondary pollution of Fe happened. Chemisorption is the major mechanism for As(III) adsorption, and As(III) was adsorbed on the surface and interior of the MGOCS, while the adsorbed As(III) was partially oxidized to As(V) accompanied by the reduction of Fe(III) to Fe(II). The produced As(V) was further adsorbed through ligand exchange (by forming Fe–O–As complexes) and electrostatic attraction, enhancing the As(III) removal. As an easily prepared and environmental-friendly composite, MGOCS not only greatly adsorbs As(III) but also effectively removes Cr(VI) and As(V) (Re > 60%) and other metals, showing a great advantage in the treatment of heavy metal-contaminated water.

Hydroxypropyl cellulose functionalized magnetite graphene oxide nanobiocomposite for chemo/photothermal therapy

In this work, graphene oxide nanosheets (GO) are dual functionalized with Fe3O4 nanoparticles and hydroxypropyl cellulose (CLS) for chemo/phototherapy. The TEM, XRD, FTIR, Raman, UV, TG, DLS, and VSM analyses were used to confirm the CLS and Fe3O4 incorporated GO (CLS@mGO) nanobiocomposite structure. Functionalization of magnetite graphene oxide surface by CLS not only improved biocompatibility, colloidal stability, and entrapment efficiency for paclitaxel (PTX) but also accelerated PTX release. Under 808 nm laser light, the CLS@mGO-PTX nanobiocomposite displayed good photothermal features. The CLS@mGO-PTX nanobiocomposite exhibited high photothermal conversion efficiency (47.85%) and photo stability. The notable synergistic chemo/photothermal impacts have also been determined by the in vitro experiments in killing MCF-7 cancer cells. The results of these experiments exhibited that compared to single phototherapy and chemotherapy, chemo/phototherapy could more effectively kill cancer cells by synergetic anticancer impact. Therefore, the CLS@mGO-PTX nanobiocomposite has great potential for chemo/phototherapy.

Comparative of alginate/graphene oxide and alginate/magnetite graphene oxide aerogel as adsorbents

Magnetite graphene oxide (MGO) has gained attention as a potential adsorbent in wastewater treatment. In this study, incorporation of MGO into biopolymer matrix and dried by supercritical CO2 to improve the adsorption efficiency is presented. Alginate/MGO aerogel was prepared by blending the MGO with alginate and formed hydrogel by ionic crosslinking through external gelation. The blend ratio of MGO and alginate studied are comprised of 2 and 3 wt%, respectively. The hydrogel was dried by supercritical CO2 at 110 ± 5 bar and 40 °C in 4h. The physical-chemical properties of alginate/MGO adsorbent and its adsorption efficiency via removal of methylene blue (MB) are studied. The sharp curve for 30% weight loss for both types of adsorbents has been shown around 200 °C in TGA correspond to the exothermic peak form in DSC analysis. Alginate/GO and alginate/MGO are stable over temperatures of 300 and 700 °C, respectively. Alginate/GO successfully adsorbed 90% of MB concentration meanwhile the alginate/MGO had removed up to 84% of MB. Another highlighted technique is supercritical CO2 drying which considered as one of the most promising techniques to preserve the structure of aerogel with minimal shrinkage as low as 15% in comparison to ambient drying (50%).

Integrated ultrasound-assisted magnetic solid-phase extraction for efficient determination and pre-concentration of polycyclic aromatic hydrocarbons from high-consumption soft drinks and non-alcoholic beers in Iran.

In the present research, an ultrasound-assisted magnetic solid-phase extraction coupled with a gas chromatography-mass spectrometry hybrid system was developed for the extraction/determination of trace amounts of polycyclic aromatic hydrocarbons in high-consumption soft drinks and non-alcoholic beers in Iran using magnetite graphene oxide adsorbent. The magnetite graphene oxide was characterized by scanning electron microscope, transmission electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, and vibrating-sample magnetometer techniques. The highest extraction recovery (73.05%-95.56%) and enrichment factor (90.65-106.38) were obtained at adsorbent mass: 10mg, adsorption time: 30min, salt addition: sodium chloride 10% w/v, desorption time: 20min, eluent type: hexane: acetone (1:1, v/v), and desorption solvent volumes: 200 μl. Under optimum conditions, the linearity range for polycyclic aromatic hydrocarbons determination was 0.2-200ng/mlwith a coefficient of determination>0.993, the limit of detection=0.09-0.21ng/ml, the limit of quantitation=0.3-0.7ng/ml, and relative standard deviation<8.1%, respectively. Relative recoveries in spiked real samples ranged from 94.67 to 109.45% with a standard deviation<6.05%. The proposed method is effective, sensitive, and reusable and it is promising for the analysis of polycyclic aromatic hydrocarbons residues in environmental samples.

Enhanced sunlight-driven photocatalytic, supercapacitor and antibacterial applications based on graphene oxide and magnetite-graphene oxide nanocomposites

Herein, we report an enhanced sunlight-driven photocatalytic, supercapacitor and antibacterial applications based on graphene oxide (GO) and magnetite -graphene oxide (Fe3O4-GO) nanocomposites. The materials were synthesized by the facile chemical precipitation method and examined in detail by various techniques including field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), UV–Visible (UV–Vis.) spectroscopy, Fourier transform infrared (FTIR) spectroscopy and vibrating sample magnetometer (VSM). The effective production of GO and Fe3O4-GO nanocomposite was validated by XRD, while UV–Vis. measurements demonstrated a smaller bandgap for the nanocomposites. The uniform distribution of Fe3O4 nanoparticles over GO nanosheets were observed through FESEM and TEM studies. The prepared materials were further utilized as sun-light driven photocatalyst for the degradation of methylene blue (MB) dye, working electrode for the supercapacitor application and efficient biomaterial to examine the antibacterial characteristics against Gram-positive (S. aureus) and Gram-negative (E. Coli) bacterial strains. As an efficient photocatalyst, the Fe3O4-GO nanocomposites exhibited a rapid degradation (91% in 30 min) for methylene blue dye under direct sunlight irradiation. The synthesized nanocomposite exhibited a maximum specific capacitance of 775 Fg-1 at a current density of 1 Ag-1 and exceptional chemical stability as an electrode material. Antibacterial activities of the synthesized materials were also exhibited against Gram-positive (S. aureus) and Gram-negative (E. coli) bacterial strains.

Deep Eutectic Solvent Functionalized Graphene Oxide Based Ferrofluid for the Liquid Phase Microextraction of Fluoroquinolones from Water Samples

The development of smart materials have a significant impact on sample preparation and preconcentration methods. Ferrofluid or magnetic fluids (FF) are smart colloidal suspensions of single domain magnetic nanoparticles in a polar or non-polar liquid carrier. In this study, graphene oxide magnetite (GO@Fe3O4) and deep eutectic solvent-based choline chloride and ethylene glycol as a carrier liquid were utilized to form GO@Fe3O4-DES FF. The synthesised GO@Fe3O4-DES FF was characterized using FTIR, SEM, TEM and vibrating sample magnetometer (VSM). GO@Fe3O4-DES FF was further developed for the application of GO@Fe3O4-DES FF-liquid phase microextraction (LPME) for enrofloxacin as test compound. Several parameters such as type of FF composition and volume, extraction time, desorption solvent volume, desorption time and solution pH were optimised and analysed using HPLC-UV. Under optimum conditions, the developed GO@Fe3O4-DES FF-LPME method showed good linearity, R2 ≥ 0.9921, repeatability, RSD 0.57 – 9.40 %. The developed GO@Fe3O4-DES FF-LPME method was applied for the determination of enrofloxacin in water samples from Langat River Basin, Selangor and the recovery of 71.6 – 112.3% was obtained. In conclusion, the developed GO@Fe3O4-DES FF-LPME method for the determination of enrofloxacin showed excellent sensitivity and precision and may be an excellent alternative method for the extraction on water samples.

Multifunctional aptamer-conjugated magnetite graphene oxide/chlorin e6 nanocomposite for combined chemo-phototherapy

Herein, aptamer-functionalized magnetite Fe3O4@graphene oxide/photosensitizer nanocomposite was designed and prepared for chemo-photothermal/photodynamic therapies. Chlorin e6 (Ce6, as a photosensitizer) is used to conjugate with magnetite graphene oxide (Fe3O4@GO). The structure of Fe3O4@GO@Ce6 nanocomposite was characterized by using FTIR, UV, TGA, XRD, VSM and TEM methods. An antineoplastic drug, paclitaxel (Pac), was loaded onto Fe3O4@GO@Ce6 nanocomposite, forming a Fe3O4@GO@Ce6@Pac nanocomplex. The Fe3O4@GO@Ce6 nanocomposite was functionalized with aptamer (Apt) for selective killing of MCF-7 tumor cells. Fe3O4@GO@Ce6@Pac nanocomposite offers a notably enhanced tumor cell photodynamic destruction impact compared to free Ce6. It is displayed that the photothermal impact of magnetite Fe3O4@GO@Ce6 nanocomposite can be used to promote the Ce6 release when irradiated to a near-infrared laser at a low power density, further improving the photodynamic therapy efficiency on tumor cells. It is observed that the Fe3O4@GO@Ce6 nanocomposite possessed good colloidal/photo stability, biocompatibility, and high loading capacity for Pac. Furthermore, compared to the free Ce6, the Fe3O4@GO@Ce6@Apt-Pac nanocomposite display significantly enhanced photodynamic efficacy. Due to its intrinsic optical features, ultrahigh specific surface area, targeting ability, and unique physical interactions with aromatic active agents, Fe3O4@GO@Ce6@Apt-Pac is a promising new nanomaterial for medical and biological applications.

Determination of Propranolol at a Carbon Paste Electrode Modified with Magnetite–Graphene Oxide in Combination with Presence of Sodium Dodecyl Sulfate

Determination of Propranolol at a Carbon Paste Electrode Modified with Magnetite–Graphene Oxide in Combination with Presence of Sodium Dodecyl Sulfate

Magnetite graphene oxide modified with β-cyclodextrin as an effective adsorbent for the removal of methotrexate and doxorubicin hydrochloride from water

The purpose of this investigation was to analyze the performance of magnetite graphene oxide modified with β-cyclodextrin (GO@Fe3O4@β-CD) for adsorption of methotrexate (MTX) and doxorubicin (DOX) from aqueous solutions. Characterization of GO@Fe3O4@β-CD was carried out using some methods. The perfect conditions for the adsorption of MTX and DOX were 7.0, 45min, 20mg, and 25°C for solution pH, contact time, adsorbent dose, and temperature, respectively, with removal efficiency values of 97.8% and 98.5% for MTX and DOX, respectively. The adsorption kinetic of MTX and DOX via GO@Fe3O4@β-CD followed pseudo second-order (PSO) model, while the adsorption isotherm obeyed Langmuir model by monolayer adsorption with maximum adsorption capacities of 198.5 and 204.5mgg-1 for MTX and DOX, respectively. Therefore, it could be argued that HCl and 0.1mol L-1 NaOH would reflect adequate elution properties for GO@Fe3O4@β-CD recovery.

Development of Magnetite/Graphene Oxide Hydrogels from Agricultural Wastes for Water Treatment

A novel magnetic hydrogel loaded with graphene oxide (GO) was developed in this study. Firstly, GO was prepared from bagasse through a single step via oxidation in the presence of ferrocene under muffled atmospheric conditions, followed by the loading of different amounts of magnetite onto GO via co-precipitation reaction of iron onto GO sheets. Finally, the 2-acrylamido-2-methyl-1-propane sulfonic acid was grafted onto carboxymethyl cellulose in the presence of magnetite GO and N, N′-methylenebisacrylamide as crosslinker yielded hydrogel. The structure, morphological, and thermal behavior of the prepared hydrogels were investigated. In addition, the adsorption performance of Ni(II) ions from aqueous media by the prepared hydrogels was investigated as a function of temperature, time, and concentration of adsorbate in a batch system. The results demonstrated a remarkable enhancement in the adsorption process of Ni(II) (Removal efficiency = 98.82%). All isotherms were found to fit the Langmuir model best. The adsorption properties of both magnetic GO and magnetic hydrogel showed promising properties as green and cheap adsorbents.

Falkner–Skan flow of aqueous magnetite–graphene oxide nanoliquid driven by a wedge

Flow of liquid over moving wedge is a crucial process in engineering applications because both the velocities of liquid and plate are proportional to each other in this process. Hence, it is very useful in preparation of paper, polymeric sheets and drawing of plastic films. We developed a mathematical model to report the hybrid nanoliquid flow past a wedge by incorporating the induced magnetic effect. Hybrid nanoliquid is taken by the mixture of magnetite–graphene oxide with water based nanoparticles. To obtain the nonlinear ordinary differential equations, preferable transformations are used and quantitative results are obtained using the Runge-Kutta-Fehlberg (RKF) fourth and fifth order schemes. Impact of controlling parameters in the problem statement is discussed through graphs and tables. Examination revealed that the higher magnetic parameter reduces the hybrid nanoliquid velocity, induced magnetic field, but the temperature field enhances. Also, when the wedge parameter value is negative, the Nusselt number and skin-friction values are higher compared to positive wedge values.

Hydrophilic role of deep eutectic solvents for clean synthesis of biphenyls over a magnetically separable Pd-catalyzed Suzuki-Miyaura coupling reaction

The development of an efficient and sustainable catalytic system for the preparation of biphenyls through the Suzuki-Miyaura coupling reaction is still a great challenge to green chemistry. Encouraging the prevailing challenge, in the present work, a heterogeneous Pd catalyst was synthesized through a green method and used for the production of biphenyls in deep eutectic solvents (DESs) as green reaction media. In order to prepare the catalyst, magnetite-graphene oxide nanocomposite was modified with cellulose via the click reaction and applied as support for Pd nanoparticles. Cellulose acted as both reducing and stabilizing agent for Pd nanoparticles and eliminated the requirement of a reducing agent. The prepared catalyst was characterized by different methods such as FT-IR, EDX, EDX-mapping, XPS, SEM, TEM, XRD, VSM, and ICP-OES analyses. Catalytic properties of the obtained catalyst was explored in the coupling reaction of aryl halides with aryl boronic acids in different hydrophilic and hydrophobic DESs. The presence of cellulose with hydrophilic character on the structure of catalyst offered well dispersion of the catalyst in hydrophilic DESs, which led to enhancement of its catalytic activity. Among various hydrophilic DESs, the DES composed of dimethylammonium chloride and glycerol was verified as the most effective solvent for the preparation of biphenyls. The catalyst was compatible with a variety of substrates, with which all the Suzuki coupling products were achieved in high to excellent yields. Thanks to the low solubility of catalyst and DES in organic solvents, the separated aqueous phase containing both of the catalyst and DES could be readily recovered by evaporating water and reused up to five successive runs with a stable activity. This simple and new separation strategy provided a clean and highly efficient synthetic methodology for the synthesis of various biphenyls. Moreover, hot filtration test efficiently confirmed that the catalyst is heterogeneous and completely stable under reaction conditions.