Acid Functionalized Graphene Oxide Research Articles

Acrylic acid functionalized graphene oxide: High-efficient removal of cationic dyes from wastewater and exploration on adsorption mechanism

A novel p(AA)-g-GO material was prepared by grafting polymerization of acrylic acid (AA) onto graphene oxide (GO) skeleton, presenting efficient removal of dyes from wastewater, because the layer spacing of GO is expanded and successfully introduced numerous polar carboxyl groups. The study revealed a rapid adsorption kinetic process and the adsorption capacity for methylene blue (MB) increases with pH, contact time, initial dye concentration and temperature. The maximum adsorption capacity is about 1448.2 mg/g at 25 °C for MB according to the Langmuir isotherm. More importantly, the adsorbent maintains excellent adsorption capacity after five cycles of adsorption-desorption and has remarkable selective separability for methylene blue/methyl orange mixed solution at pH = 10. Furthermore, the equilibrium adsorption capacities for other cationic dyes as malachite green (MG), basic fuchsin (BF) and rhodamine B (RhB) reached 582.1, 571.7 and 437.1 mg/g, respectively. Additionally, the mechanism analysis indicated that electrostatic interactions, π-π conjugation and hydrogen bonding are the predominant forces for adsorbing cationic dyes. Therefore, p(AA)-g-GO is an outstanding adsorbent and has a potential application prospect in the treatment of dye wastewater.

Mixed matrix membranes containing aspartic acid functionalized graphene oxide for enhanced oil-water emulsion separation

Polysulfone (PS) mixed matrix membranes (MMMs) containing aspartic acid (AA) functionalized graphene oxide (fGO) with improved flux, oil rejection, and resistance to fouling were fabricated via phase inversion. The membranes hydrophilicity, morphology, porosity, and mechanical properties were analyzed and the impact of fGO loading on them was investigated using contact angle measurements, SEM, AFM, and dynamic mechanical analysis. The results revealed an increase in the membrane’s hydrophilicity, water permeability and oil rejection at very low fGO loadings, i.e., 0.05 – 0.2 wt.%, but no further enhancement was obtained at higher loadings, i.e., 0.4−0.8 wt.%. Water permeability increased by 97 % at 0.2 wt.% fGO membrane compared to pristine membrane and oil rejection reached 97.9 % upon filtration of 200 mL oil emulsion. Moreover, the MMM containing 0.2 wt.% fGO exhibited enhanced fouling resistances as demonstrated by slow flux decline and 90 % flux recovery after two cycles of fouling with bovine serum albumin (BSA).The results indicated that the carboxylic and amino groups introduced by AA functionalization were responsible for the enhanced hydrophilicity and fouling resistance. PS/fGO MMMs provided significant enhancement in performance, mechanical properties and fouling resistance at very low fGO concentration that does not affect the rheology of PS-fGO formulation and therefore requires no alteration to the commercial phase inversion process.

Metal-polyphenol dual crosslinked graphene oxide membrane for desalination of textile wastewater

With the fast development of textile industry, the increasing discharge of textile wastewater is posing a grand challenge to the environmental safety. Graphene oxide (GO) nanosheet with excellent physicochemical properties and lamellar structure, is regarded as an ideal membrane material for the rejection of dyes. However, the selectivity and long-term course of GO-based membranes are largely limited due to the narrow interlayer distance as well as poor aqueous solution stability. To address such situations, a series of GO-based membranes (Fe/GO-TAx) were prepared using coordinated tannic acid-functionalized GO (GO-TA) nanosheets with FeIII ions in this study. The results indicated that Fe/GO-TAx membranes exhibited greater interlayer distance and higher hydrophilicity, as well as a decreasing trend of negative surface charge. Furthermore, the Fe/GO-TA20 conferred a superior dye/salt selective sieving mechanism with a high separation factor and a permeability of 61.2 L m−2 h−1 bar−1 (approximately 6-times higher than the pristine GO membrane). Importantly, the fabricated Fe/GO-TA20 membrane exhibited inherent removals for organic dyes, and more than 99% removals were achieved in the test. These findings were expected to provide some simple but practical strategies for the fast fabrication of two-dimensional laminar structure GO separation membranes to achieve excellent sieving of high-salinity textile wastewater.

Sonochemical preparation of carbon nanosheets supporting cuprous oxide architecture for high-performance and non-enzymatic electrochemical sensor in biological samples.

Copper (Cu) based metal oxides have high electrocatalytic ability. In this work, we are synthesized stone-like cuprous oxide particles (Cu2O SNPs) covered on acid functionalized graphene oxide (GOS) sheets using ultrasonic process (50kHz and 100W). Besides, the chemical structural and crystalline analyses of Cu2O SNPs@GOS composites were characterized by transmission electron microscopy, X-ray crystallography and energy-dispersive X-ray spectroscopy. The Cu2O SNPs@GOS nanomaterials were tested towards detection of 8-hydroxydeoxyguanosine (8-OHdG) in biological samples. As expected Cu2O SNPs@GOS catalyst modified electrodes performed an outstanding catalytic ability on 8-hydroxydeoxyguanosine oxidation. 8-OHdG is oxidative stress biomarker. Further, it is noted that the detection performance of Cu2O SNPs@GOS coated electrodes and it's highly enhanced due to the synergistic effect of Cu2O SNPs and GOS. Besides, the modified materials provide more electro-active faces and as well as rapid electron transport pathway and shorten diffusion. Moreover, oxidation of 8-OHdG sensor is exploring a long linear or working range of 0.02-1465µM and high sensitivity (8.75nM). The viability of the Cu2O SNPs@GOS proposed electrochemical methods have tested, to find out 8-OHdG concentrations in biological fluids (blood serum and urine) with a satisfying recovery ranges.

Molecular imprinted polymer-wrapped AgNPs-decorated acid-functionalized graphene oxide as a potent electrochemical sensor for ibuprofen

A new molecular imprinted polymer (MIP)-based electrochemical sensor is fabricated on silver nanoparticle (AgNPs)-decorated acid-functionalized graphene oxide (Af-GO). The synthesis of AgNPs is achieved using Caesalpinia sappan leaf extract. The fabricated AgNPs are effectively decorated on Af-GO on which MIP is grafted. All the functional modification and surface morphology of graphene and fabricated molecular imprinted polymer on AgNPs-decorated graphene oxide (AgNPs@Af-GO-MIP) are characterized by Fourier-transform infrared spectroscopy, UV–Vis spectroscopy, powder X-ray diffraction analysis, transmission electron microscopy and scanning electron microscopy techniques. The synthesized AgNPs@Af-GO-MIP is developed as a sensor for S-Ibuprofen (IBUP) determination. The experimental result demonstrates that AgNPs@Af-GO-MIP has fine selectivity and sensing ability toward IBUP. The sensing ability of AgNPs@Af-GO-MIP is found to be directly proportional to IBUP concentration with a detection limit of 8.7 × 10−9 mol L−1 (S/N = 3). The quantitative result of imprinting factor shows that the developed AgNPs@Af-GO-MIP sensor has an excellent selectivity toward IBUP from interfering compounds like ascorbic acid, caffeine, dopamine, glucose and uric acid. Most promisingly, the sensing capability of developed AgNPs@Af-GO-MIP is fruitfully demonstrated in pharmaceutical and human urine samples, which is a brief glimpse of the real-time applicability of the sensor.

Folic acid-functionalized graphene oxide nanosheets via plasma etching as a platform to combine NIR anticancer phototherapy and targeted drug delivery.

PEGylated graphene oxide (GO) has shown potential as NIR converting agent to produce local heat useful in breast cancer therapy, since its suitable photothermal conversion, high stability in physiological fluids, biocompatibility and huge specific surface. GO is an appealing nanomaterial for potential clinical applications combining drug delivery and photothermal therapy in a single nano-device capable of specifically targeting breast cancer cells. However, native GO sheets have large dimensions (0.5-5 μm) such that tumor accumulation after a systemic administration is usually precluded. Herein, we report a step-by-step synthesis of folic acid-functionalized PEGylated GO, henceforth named GO-PEG-Fol, with small size and narrow size distribution (∼30 ± 5 nm), and the ability of efficiently converting NIR light into heat. GO-PEG-Fol consists of a nano-GO sheet, obtained by fragmentation of GO by means of non-equilibrium plasma etching, fully functionalized with folic acid-terminated PEG2000 chains through amidic coupling and azide-alkyne click cycloaddition, which we showed as active targeting agents to selectively recognize breast cancer cells such as MCF7 and MDA-MB-231. The GO-PEG-Fol incorporated a high amount of doxorubicin hydrochloride (Doxo) (>33%) and behaves as NIR-light-activated heater capable of triggering sudden Doxo delivery inside cancer cells and localized hyperthermia, thus provoking efficient breast cancer death. The cytotoxic effect was found to be selective for breast cancer cells, being the IC50 up to 12 times lower than that observed for healthy fibroblasts. This work established plasma etching as a cost-effective strategy to get functionalized nano-GO with a smart combination of properties such as small size, good photothermal efficiency and targeted cytotoxic effect, which make it a promising candidate as photothermal agent for the treatment of breast cancer.

Efficient and stable planar perovskite solar cells with a PEDOT:PSS/SrGO hole interfacial layer

An efficient planar perovskite solar cell (PSC) was fabricated with a bi-layer consisting of the poly (3,4-ethylenedioxythiophne):poly (styrene sulfonate) (PEDOT:PSS) and sulfonic acid functionalized graphene oxide (SrGO) as a hole interfacial layer. The low temperature and solution processed PEDOT:PSS/SrGO interlayer produced better power conversion efficiency (PCE) of 16.01% than other single layers. Comprehensive investigations reveal that the increased PCE is mostly due to the decreased recombination and the increased built in potential for better charge transport and extraction. In addition, the device with PEDOT:PSS/SrGO showed excellent long-term stability in ambient air conditions. Consequently, these results support that the introduction of graphene materials into interlayers can be a promising approach for high performance and cost-efficient solar devices.

Polyacrylic acid-functionalized graphene oxide for high-performance adsorption of gallium from aqueous solution

Graphene oxide (GO) has great potential in metal recovery and water purification owing to their high surface area, abundant hydroxyl (OH) and carboxyl (COOH) groups. To fully understand the influence of the dispersity of GO on the adsorption capacity of metal ions, a series of polyacrylic acid (PAA) functionalized GO (PAA/GO) composites with different dispersity were prepared. The charge density of the PAA/GO composites were much higher than that of the untreated GO in acidic conditions, demonstrating a significant improvement of dispersibility by introducing PAA on the surfaces. Moreover, recovery of gallium by employing the PAA/GO composites as adsorbent were studied. The maximum adsorption capacity towards gallium ions of the adsorbent can reach 196.84 mg·g−1, much higher than that of other commercially available resins (CL-P204, P507). This superiority could be attributed to the abundant COOH groups on the surfaces and the good dispersity of the PAA/GO composites. These results revealed that the PAA/GO composites could be promising adsorbents for selective adsorption and efficient recovery of Ga(III).

Microcapsules responsive to pH and temperature: synthesis, encapsulation and release study

In this present article, we report preparation of dual responsive microcapsules by using poly(N-isopropyl acrylamide-co-methacrylic acid) [poly(NIPAM-co-MAA)] and acid functionalized graphene oxide (GO). While the methacrylic acid part is responsible for the responsiveness towards the change in pH, N-isopropylacrylamide part is responsible for the responsiveness towards change in temperatures. Functionalized GO forms the core of the microcapsules and its interaction with the polymer controls the movement of the encapsulated materials in response to change in neighboring environment. Surface morphology and interconnectivity of the microcapsules was observed by optical polarized microscopy and the presence of the GO sheets on the wall was observed in High Resolution Transmission Electron Microscopy images. The pH and temperature responsive nature of the microcapsules were studied by loading vitamin B2 or anticancer drug cisplatin. It was found that both pH and temperature influences releasing pattern of the either drug from microcapsule.

Tin-Decorated Reduced Graphene Oxide and NaLi0.2Ni0.25Mn0.75O as Electrode Materials for Sodium-Ion Batteries.

A tin-decorated reduced graphene oxide, originally developed for lithium-ion batteries, has been investigated as an anode in sodium-ion batteries. The composite has been synthetized through microwave reduction of poly acrylic acid functionalized graphene oxide and a tin oxide organic precursor. The final product morphology reveals a composite in which Sn and SnO2 nanoparticles are homogenously distributed into the reduced graphene oxide matrix. The XRD confirms the initial simultaneous presence of Sn and SnO2 particles. SnRGO electrodes, prepared using Super-P carbon as conducting additive and Pattex PL50 as aqueous binder, were investigated in a sodium metal cell. The Sn-RGO showed a high irreversible first cycle capacity: only 52% of the first cycle discharge capacity was recovered in the following charge cycle. After three cycles, a stable SEI layer was developed and the cell began to work reversibly: the practical reversible capability of the material was 170 mA·h·g−1. Subsequently, a material of formula NaLi0.2Ni0.25Mn0.75Oδ was synthesized by solid-state chemistry. It was found that the cathode showed a high degree of crystallization with hexagonal P2-structure, space group P63/mmc. The material was electrochemically characterized in sodium cell: the discharge-specific capacity increased with cycling, reaching at the end of the fifth cycle a capacity of 82 mA·h·g−1. After testing as a secondary cathode in a sodium metal cell, NaLi0.2Ni0.25Mn0.75Oδ was coupled with SnRGO anode to form a sodium-ion cell. The electrochemical characterization allowed confirmation that the battery was able to reversibly cycle sodium ions. The cell’s power response was evaluated by discharging the SIB at different rates. At the lower discharge rate, the anode capacity approached the rated value (170 mA·h·g−1). By increasing the discharge current, the capacity decreased but the decline was not so pronounced: the anode discharged about 80% of the rated capacity at 1 C rate and more than 50% at 5 C rate.

Magnetic Fe3O4-supported sulfonic acid-functionalized graphene oxide (Fe3O4@GO-naphthalene-SO3H): a novel and recyclable nanocatalyst for green one-pot synthesis of 5-oxo-dihydropyrano[3,2-c]chromenes and 2-amino-3-cyano-1,4,5,6-tetrahydropyrano[3,2-c]quinolin-5-ones

Synthesis of a novel magnetic 1-naphthalenesulfonic acid-grafted graphene oxide (Fe3O4-GO-naphthalene-SO3H) via a three-step procedure has been described. The structure of this newly synthesized nanographene oxide was fully characterized by X-ray diffraction, energy dispersive X‐ray, vibrating sample magnetometer, scanning electron microscopy, Fourier-transform infrared, Raman spectroscopy, and thermo-gravimetric analytical techniques. The catalytic efficiency of these nanoparticles as recyclable nanocatalyst was explored in one-pot three-component reaction between aldehydes, malononitrile, and 4-hydroxyquinolin-2(1H)-one or 4-hydroxycoumarin under green conditions in water for the synthesis of 2-amino-3-cyano-1,4,5,6-tetrahydropyrano[3,2-c]quinolin-5-ones and 5-oxo-dihydropyrano[3,2-c]chromenes (coumarins) respectively. High yields of the products, low reaction times, easy preparation of the catalyst, and use of water as green solvent are the main advantages of this protocol. In addition, the catalyst can be easily separated simply by using a magnet and reused for six fresh runs without significant loss of activity.

Fabrication of PEI-Fc/SGO multilayer films modified electrode through LBL assembly technique for the detection of dopamine

In this work, a sensor for the detection of dopamine (DA) based on electroactive polymer (PEI-Fc)/sulfonic acid-functionalized graphene oxide (SGO) multilayer film-modified glassy carbon electrode (GCE) through layer-by-layer (LBL) method was fabricated. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy revealed the successful functionalization of GO into SGO with negatively charged sulfonic groups. The obtained PEI-Fc/SGO multilayer films were characterized using scanning electron microscopy (SEM) and ultravioletvisible spectrometer (UV-Vis). Cyclic voltammetric studies demonstrated that the modified electrode presented enhanced electrocatalytic performance towards DA in terms of peak currents compared with bare GCE. The choronoamperometric results indicated that the modified electrode exhibited a wide linear range from 1 to 695 μM with a low detection limit of 0.255 μM towards the detection of DA. Besides, the modified electrode exhibited good selectivity, excellent reproducibility, and high stability of at least 1 month.

Redox-responsive hyaluronic acid-functionalized graphene oxide nanosheets for targeted delivery of water-insoluble cancer drugs.

BackgroundGefitinib (Gef), an important epidermal growth factor receptor (EGFR), is used to treat lung cancer, but low water solubility and poor bioavailability severely limit its application in cancer therapy.MethodsIn this study, nanographene oxide (NGO) was decorated with hyaluronic acid (HA) by a linker cystamine dihydrochloride containing disulfide bonds (-SS-), followed by the incorporation of gefitinib, thus, constructing a HA-functionalized GO-based gefitinib delivery system (NGO-SS-HA-Gef). Subsequently, studies of biological experiments in vitro and in vivo were performed to investigate the therapeutic effect of the system in lung cancer.ResultsThe HA-grafted GO nanosheets possessed enhanced physiological stability, admirable biocompatibility, and no obvious side effects in mice and could act as a nanocarrier for the delivery of gefitinib to tumor. Cellular uptake and intracellular cargo release assays showed that the uptake of NGO-SS-HA by A549 cells was facilitated via CD44 receptor-mediated endocytosis, and that more drug was released from NGO-SS-HA in the presence of GSH than in the absence of GSH. The target-specific binding of NGO-SS-HA to cancer cells with redox-responsive cargo release significantly enhanced the abilities of gefitinib-loaded GO nanosheets to induce cell apoptosis, suppress cell proliferation, and inhibit tumor growth in lung cancer cell-bearing mice.ConclusionThe results demonstrated the potential utility of NGO-SS-HA-Gef for therapeutic applications in the treatment of lung cancer.

Enhanced immobilization of mercury (II) from desulphurization wastewater by EDTA functionalized graphene oxide nanoparticles

ABSTRACTGraphene oxide (GO) is a new promising nanometer material in a superconductor and wastewater heavy metal ions removal for its functionalized groups. Ethylenediaminetetraacetic acid functionalized graphene oxide complexes (EDTA-GO) was produced by a realizable silanization chemical reaction. Characteristics of Hg(II) removal in desulphurization wastewater was also under investigation. The chemical composition and microstructures of the EDTA-GO adsorbents were characterized by X-ray photoelectron spectroscopy (XPS), Transmission electron microscope (TEM), Scanning Electron Microscopy (SEM) analyses. To investigate the performance of EDTA-GO adsorbents on adsorption of Hg(II) in wastewater of wet flue gas desulphurization (WFGD), experiments were performed to optimize the main influence factors such as reaction temperatures (35–70°C), pH values(2–13), contact time (0–120 min), initial Hg(II) concentrations(800 ug/L) and adsorbent doses (20–50 mg/L). The maximum uptake removal efficiency (97.14%) was achieved under the optimal conditions at the pH of 7, the temperature of 70°C, the Hg(II) concentration of 1200 μg/L and the EDTA-GO dose of 40 mg/L. The kinetic data fitting results were well consistent with the pseudo-second-order model (R2 = 0.99997) and a spontaneous and endothermic adsorption reaction was elaborated by thermodynamics studies (ΔG < 0, ΔH > 0, ΔS > 0). The experiments of recycled adsorbents by HCl generation were carried out to obtain the performance of the reused EDTA-GO adsorbent, the fourth regenerative adsorption efficiency still maintained 80.4%, which indicated that excellent potential application in desulphurization wastewater treatment.

Disposable amperometric immunosensor for Saccharomyces cerevisiae based on carboxylated graphene oxide-modified electrodes.

A sensitive and disposable amperometric immunosensor for Saccharomyces cerevisiae was constructed by using carbon screen-printed electrodes modified with propionic acid-functionalized graphene oxide as transduction element. The affinity-based biosensing interface was assembled by covalent immobilization of a specific polyclonal antibody on the carboxylate-enriched electrode surface via a water-soluble carbodiimide/N-hydroxysuccinimide coupling approach. A concanavalin A-peroxidase conjugate was further used as signaling element. The immunosensor allowed the amperometric detection of the yeast in buffer solution and white wine samples in the range of 10-107CFU/mL. This electroanalytical device also exhibited low detection limit and high selectivity, reproducibility, and storage stability. The immunosensor was successfully validated in spiked white wine samples.

Immobilization of l-asparaginase on aspartic acid functionalized graphene oxide nanosheet: Enzyme kinetics and stability studies

There is an increasing interest in using l-asparaginase in medical fields and food processing industries. Enzyme immobilization is an attractive field to improve l-asparaginase activity and stability. Graphene oxide (GO) is a promising candidate for enzyme immobilization due to its large specific surface area. In this study, GO was first functionalized with l-aspartic acid (GO-Asp), and then l-asparaginase was immobilized on the GO-Asp either physically or through chemical conjugation. A significant enzyme loading was achieved through covalent immobilization (100% immobilization efficiency). Stability of free and the immobilized l-asparaginase was examined at various temperatures (20–60 °C) and pH (5–9). The covalently immobilized l-asparaginase showed higher enzyme activity than free enzyme at pH 8 with the maximum recovered activity of 100%, 90.5% and 40.6% after 24 h of incubation at 20 °C, 40 °C and 60 °C, respectively. In addition, the covalently immobilized l-asparaginase on GO-Asp showed 42% recovered activity after eight continuous reaction cycles at 60 °C. The kinetic parameters of the immobilized and free enzyme were also calculated, indicating no significant changes in the enzyme affinity through covalent conjugation. The results clearly reflect the suitability of GO-Asp as a nanosheet support for l-asparaginase loading as well as its usage in future industrial applications.

Preparation of a novel two-dimensional carbon material and enhancing Cu(II) ions removal by phytic acid

A novel two-dimensional carbon material using phytic acid-functionalized graphene oxide was successfully synthesized by a simple hydrothermal method. Properties of the material were characterized by SEM, FT-IR, FITR-Rama and BET. Some factors like contact time, pH, and temperature were studied to investigate the adsorption characteristics on Cu(II) ions of the material. Experiment results showed that the material can reach equilibrium adsorption in 20 min and get maximum adsorption capacity (316.586 mg g) under the condition of pH 4.0, 304 K. The adsorption of Cu(II) ions was an exothermic and spontaneous process, and could be better simulated by the pseudo-second-order kinetics and Freundlich isotherm model.

Selective removal of mercury(II) from water using a 2,2-dithiodisalicylic acid-functionalized graphene oxide nanocomposite: Kinetic, thermodynamic, and reusability studies

2,2-Dithiodisalicylic acid-functionalized magnetic graphene oxide (Fe3O4@DTSA_GO) was used for the selective removal of Hg(II) from aqueous solution. The equilibrium was reached after 10 min and the maximum Hg(II) adsorption capacity of the Fe3O4@DTSA_GO nanocomposite was 283.5 mg g−1. The Hg(II) adsorption ability increased with the pH value of the aqueous solution. Isotherm and kinetic studies revealed the Sips isotherm model and pseudo-second kinetic model to provide the best fit to the experimental results. The positive value of ΔH° indicated endothermic interactions between Hg(II) and Fe3O4@DTSA_GO, while the negative ΔG° revealed a spontaneous reaction and the positive ΔS° an increase of the randomness at the solid–solute interface during the adsorption process. The selective removal of Hg(II) by the nanocomposite confirmed the presence of higher-affinity binding sites for Hg(II) than for Cd(II), Co(II), Zn(II), and Ni(II) ions. Furthermore, the Fe3O4@DTSA_GO nanocomposite exhibited excellent preferential adsorption for Hg(II) spiked in drinking water samples. EDTA 0.01 N was found to be an efficient elution agent for nanocomposite regeneration, with which over 84% of the adsorbed Hg(II) was recovered after five adsorption/desorption cycles.

Sulfonated graphene oxide as an adsorbent for removal of Pb2+ and methylene blue

One of the major challenges encountered in some conventional nano-structured adsorbents such as graphene oxide (GO) and graphene is the structural limits including serious aggregation and hydrophilic surface in water. And the sulfanilic acid functionalized graphene oxide (SGO) can powerfully attract positively charged pollutants. Therefore, the SGO served as an adsorbent to remove dyes and toxic metal ions from aqueous solution were intensively investigated. At the same time the reduced sulfonated graphene oxide (rSGO), reduced graphene oxide (rGO), and graphene oxide (GO) were performed as the comparative samples. The results showed that the maximum adsorption capacities of SGO were 2530 mg/g for methylene blue and 415 mg/g for Pb2+, which was much higher than that of the contrast samples and adsorbents reported in literatures. The adsorption of SGO was investigated systematically including the saturated adsorption capacities, isotherm, and kinetic adsorption process. The SGO displayed high adsorption efficiency and superior adsorption capacity toward metal ions and dyes, which is mainly attribute to the good dispersibility and the multiple adsorption sites of SGO. These results are promising not only providing effective adsorbing heavy metal ions and organic dyes, but also gaining insights into adsorption mechanism of graphene materials.

Achieving high-performance poly (styrene-b-ethylene-ranbutylene-b-styrene) nanocomposites with tannic acid functionalized graphene oxide

In this paper, graphene oxide (GO) was functionalized with tannic acid (TA), an easy-available and low-cost plant, on the GO surface through simple ultrasound-/shearing-assisted solution blending. The TA endows GO a stronger interfacial interaction with poly (styrene-b-ethylene-ran-butylene-b-styrene) (SEBS) and greatly improves the dispersion of GO in the SEBS, resulting in a much high efficiency of GO on improving the performance of the matrix. By adding 10 wt % of TA-GO (weight ratio of TA and GO = 2:1), the dielectric constant of SEBS matrix at 100 Hz reached up to 58.7, about 27-fold and 7-fold increment compared with that of neat SEBS and SEBS/GO nanocomposites, respectively. Moreover, compared with neat SEBS, the tensile strength, modulus and fracture toughness of SEBS/TA-GO nanocomposites with the addition of 0.5 wt% of TA-GO were enhanced by 122%, 91% and 107%, respectively. GO-induced firbous SEBS and microcrack formed around GO were found and proposed as the toughening and reinforcing mechanism of TA-GO in SEBS. This study not only provides a strategy to prepare high-performance SEBS nanocomposites, but also puts forward a facile, easy, low-cost and effective strategy to enhance the graphene-polymer interfacial interaction and improve the dispersion of graphene in the polymers.