A Critical Review on Black Phosphorus-Based Photocatalytic CO2 Reduction Application.

Energy shortages and greenhouse effects are two unavoidable problems that need to be solved. Photocatalytically converting CO2 into a series of valuable chemicals is considered to be an effective means of solving the above dilemmas. Among these photocatalysts, the utilization of black phosphorus for CO2 photocatalytic reduction deserves a lightspot not only for its excellent catalytic activity through different reaction routes, but also on account of the great preponderance of this relatively cheap catalyst. Herein, this review offers a summary of the recent advances in synthesis, structure, properties, and application for CO2 photocatalytic reduction. In detail, the review starts from the basic principle of CO2 photocatalytic reduction. In the following section, the synthesis, structure, and properties, as well as CO2 photocatalytic reduction process of black phosphorus-based photocatalyst are discussed. In addition, some possible influencing factors and reaction mechanism are also summarized. Finally, a summary and the possible future perspectives of black phosphorus-based photocatalyst for CO2 reduction are established.

Highly-sensitive and selective determination of bisphenol A in milk samples based on self-assembled graphene nanoplatelets-multiwalled carbon nanotube-chitosan nanostructure.

Graphene nanoplatelets (GNPs), multiwalled carbon nanotube (MWCNTs) and chitosan (CS) were self-assembled by a facile one-step hydrothermal reaction to obtain novel MWCNTs-CS enfolded GNPs (GNPs-MWCNTs-CS) composite. Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM), UV-visible (UV-vis) absorption spectroscopy and zeta potential analysis were employed to characterize the morphology, surface composition, interaction, surface charge and stability of the GNPs-MWCNTs-CS composite. The electrochemical behaviors of GNPs-MWCNTs-CS composite modified glassy carbon electrode (GNPs-MWCNTs-CS/GCE) were investigated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The GNPs-MWCNTs-CS/GCE was used for fast and high sensitive determination of bisphenol A (BPA) by differential pulse voltammetry (DPV). Under the optimum conditions, the calibration curve obtained is linear for the current versus the BPA concentration in the range 0.1-100 µM with a detection limit of 0.05 nM (signal-to-noise ratio of 3, S/N = 3). The between-sensor reproducibility was 1.29% (n = 6) for 0.04 mM BPA. The proposed GNPs-MWCNTs-CS/GCE based sensor showed high resistance to interference, good repeatability and excellent reproducibility. Trace BPA in milk samples could also be reliably determined.

Three-dimensional porous graphene oxide-maize amylopectin composites with controllable pore-sizes and good adsorption-desorption properties: Facile fabrication and reutilization, and the adsorption mechanism.

Three-dimensional (3D) porous graphene oxide-maize amylopectin (GO-MA) composites with controllable pore-sizes composites in the range of 6-40 nm were prepared by facile hydrothermal-assisted assembly approaches. The morphologies, pore sizes, specific surface area (SSA) and compositions of GO-MAx:y composites with and different GO-to-MA mass ratios (x:y) were characterized by scanning electron microscopy (SEM), N2 adsorption-desorption isotherms, Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). To reveal the adsorption-desorption mechanism, effects of contact time, temperature, initial adsorbate concentration, pH value of the solution on the adsorption process were studied in detail. The adsorption capacities of 3D GO-MA20:1 composite for organic contaminants including tert-butyl hydroquinone (TBHQ), p-aminophenol (PAP), p-nitrophenol (PNP), o-nitrophenol (MNP), hydroquinone (HQ), alizarin red S (ARS) and neutral red (NR) were 22.17, 116.4, 44.78, 36.96, 16.10, 39.92 and 24.23 mg g-1, respectively. The adsorption capacities of GO-MA30:1 composite for inorganic substances including Pb2+, Mn2+, Cr2O72-, Cd2+, Cu2+, Nd3+, La3+, Y3+, Yb3+ and Er3+ were 84.76, 7.92, 13.6, 17.64, 30.56, 25.52, 12.48, 16.96, 23.32 and 30.32 mg g-1, respectively. In addition, GO-MAx:y composites also exhibited high mechanical properties and good reusability. Consequently, GO-MAx:y composites could be used as reusable adsorbents for removal/enrichment inorganic/organic substances in aqueous solutions.

A novel electrochemical sensor based on self-assembled platinum nanochains - Multi-walled carbon nanotubes-graphene nanoparticles composite for simultaneous determination of dopamine and ascorbic acid.

In this study, platinum nanochains (PtNCs), multi-walled carbon nanotubes (MWCNTs) and graphene nanoparticles (GNPs) were assembled together to form a novel nanocomposite by a facile ultrasonic-assisted blending process. The PtNCs-MWCNTs-GNPs nanocomposite was characterized by high resolution transmission electron microscopy (HR-TEM), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The nanocomposite was used for the modification of glass carbon electrode (GCE) and simultaneous determination of dopamine (DA) and ascorbic acid (AA) by differential pulse voltammetry (DPV) and cycle voltammetry (CV). Under the optimum conditions, the calibration curves obtained are linear for the currents versus DA and AA concentrations over the range 2.00-50.0 µM and 100-1200 µM, respectively. And the detection limits for DA and AA are 0.500 µM and 10.0 µM, respectively. The detection and quantitative analysis of DA and AA in human serum and vitamin C tablets on PtNCs-MWCNTs-GNPs/GCE gave the recoveries of 104-110% and 101-108% with relative standard deviations (RSD) of 4.36-7.48% and 0.620-2.90%, respectively. The proposed PtNCs-MWCNTs-GNPs composite could provide a new platform for the routine analysis of DA and AA in terms of its good anti-interference ability, excellent reproducibility and repeatability, and feasibility of use.

A novel electrochemical chiral interface based on the synergistic effect of polysaccharides for the recognition of tyrosine enantiomers.

Electrochemical chiral interface based on two polysaccharides, soluble starch (SS) and chitosan (CS), was fabricated and used for chiral recognition of tyrosine (Tyr) enantiomers via square wave voltammetry (SWV). The SS-CS composite was characterized by scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) method. Under the optimized experimental conditions, the oxidation peak current ratio of L-Tyr to D-Tyr (IL/ID) and the difference between the peak potential (ΔEp = ED - EL) were observed to be 1.38 and 12 mV at the SS-CS/GCE. In addition, a good linear relationship between Tyr enantiomer concentration and peak current could be observed. The SS-CS/GCE exhibited good coefficients of determination (R2D-Tyr = 0.99631 and R2L-Tyr = 0.98333) for D-Tyr and L-Tyr in the concentration range 0.01-1.00 mM. The novel SS-CS/GCE showed an ability to predict the ratios of L- and D-Tyr in a racemic mixture and exhibited the possibility of qualitative and quantitative determination of Tyr enantiomers. The proposed SS-CS/GCE-based chiral sensor exhibited high anti-interference ability in the presence of 10-fold higher concentrations of physiological substances and various metal compounds. Meanwhile, the SS-CS/GCE possessed good repeatability and excellent reproducibility.

Novel high-gluten flour physically cross-linked graphene oxide composites: Hydrothermal fabrication and adsorption properties for rare earth ions.

Graphene oxide (GO) nanosheets were immobilized and cross-linked by high-gluten flour (HGF), and a series of biomass-GO composites with various HGF-to-GO mass ratios were fabricated through a one-step hydrothermal method. The HGF-GO composites were used as novel adsorbents to adsorb rare earth ions (REE3+: La3+, Yb3+, Y3+, Er3+ and Nd3+) from aqueous solutions, and their adsorption properties were also investigated detailly. To evaluate the physicochemical properties of HGF-GO composites and further understand the mechanisms of adsorption of REE3+ onto HGF-GO composites, the HGF-GO composites were characterized by scanning electron microscopy (SEM), thermal gravimetric analyzer (TGA), Raman spectroscopy and Fourier transform infrared (FT-IR) spectroscopy. Several important condition parameters including contact time, initial REE3+concentrations, solution pH values and temperature that might affect the adsorption process were studied in detail. The maximum adsorption capacities of HGF-GO1:1 composite toward La3+, Yb3+, Y3+, Er3+ and Nd3+ were 30.32, 36.64, 32.84, 42.36 and 48.68 mg g-1, respectively. The experimental data indicated that the adsorption of REE3+ onto HGF-GO1:1 was well fitted by the pseudo-second order kinetic model and the Langmuir isotherm model, and the adsorption process was a spontaneous and endothermic reaction. The HGF-GO1:1 composite could be well regenerated and reused after five adsorption-desorption cycles, and its removal efficiency for Yb3+ remained as a constant of 100%.

Removal of mercury by adsorption: a review.

Due to natural and production activities, mercury contamination has become one of the major environmental problems over the world. Mercury contamination is a serious threat to human health. Among the existing technologies available for mercury pollution control, the adsorption process can get excellent separation effects and has been further studied. This review is attempted to cover a wide range of adsorbents that were developed for the removal of mercury from the year 2011. Various adsorbents, including the latest adsorbents, are presented along with highlighting and discussing the key advancements on their preparation, modification technologies, and strategies. By comparing their adsorption capacities, it is evident from the literature survey that some adsorbents have shown excellent potential for the removal of mercury. However, there is still a need to develop novel, efficient adsorbents with low cost, high stability, and easy production and manufacture for practical utility.

Graphene nanosheets as novel adsorbents in adsorption, preconcentration and removal of gases, organic compounds and metal ions.

Due to their high adsorption capacities, carbon-based nanomaterials such as carbon nanotubes, activated carbons, fullerene and graphene are widely used as the currently most promising functional materials. Since its discovery in 2004, graphene has exhibited great potential in many technological fields, such as energy storage materials, supercapacitors, resonators, quantum dots, solar cells, electronics, and sensors. The large theoretical specific surface area of graphene nanosheets (2630 m(2)·g(-1)) makes them excellent candidates for adsorption technologies. Further, graphene nanosheets could be used as substrates for decorating the surfaces of nanoparticles, and the corresponding nanocomposites could be applied as novel adsorbents for the removal of low concentrated contaminants from aqueous solutions. Therefore, graphene nanosheets will challenge the current existing adsorbents, including other types of carbon-based nanomaterials.

Hemodialysis membranes for acute and chronic renal insufficiency.

As an incomplete renal replacement for the patients with either acute or chronic renal failure, membrane-based hemodialysis therapy is progressing rapidly. However, the mortality and morbidity remain unacceptably high. Much effort has been put into improving the biocompatibility of the hemodialysis membranes. To effectively remove small solutes and 'middle molecules' in compact cartridges, the hydraulic and permselective properties of the hemodialysis membranes have also been deeply investigated. An overview of recent progress of different kinds of hemodialysis membranes and their preparation technology, as well as their modification techniques, is presented. The advantages and deficiencies of many synthetic membranes, including cellulose, cellulose acetate (CA), chitosan (CS), polysulfone (PS), poly(ether sulfone) (PES), polyacrylonitrile (PAN), ethylene-vinyl alcohol copolymer (EVOH), poly (methyl methacrylate) (PMMA) and poly(vinyl alcohol) (PVA), etc. are elaborated upon.

Irradiation-mediated carbon nanotubes' use in cancer therapy.

Anticancer drugs such as biological therapeutic proteins and peptides are used for treatment of a variety of tumors. However, their wider use has been hindered by their poor bioavailability and the uncontrollable sites of action in vivo. Cancer nano-therapeutics is rapidly progressing, which is being applied for solving some limitations of conventional drug delivery systems. To improve the bio-distribution of anticancer drugs, carbon nanotubes have been used as one of the most effective drug carriers. This review discusses the carbon nanotubes-mediated methods for the delivery of anticancer drugs, with emphasis on the radiation-induced drug-targeted releasing and selective photo-thermal cancer therapy.