Multiwall carbon nanotubes (MWCNTs) have been hydrothermally prepared using polyethylene glycol as the carbon source. Herein, new MWCNTs composites with high adsorption capacity were prepared and applied as efficient adsorbents for adsorption of maxilon blue dye (GRL) from aqueous solution. The morphologies of the MWCNTs were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform-infrared (FT-IR) spectroscopy. The adsorption property of maxilon blue (GRL) from aqueous solution onto MWCNTs was studied as a function of mass dosage, pH of solution, initial dye concentration and temperature. The adsorption of GRL depends on the initial pH of the solution with maximum uptake occurring at about pH 10. The maximum adsorption capacity of prepared MWCNTs was 260.7 mg/g. Langmuir, Freundlich and Temkin isotherms were applied to fit the experimental data. The Freundlich equilibrium isotherm fitted well the experimental data indicating the homogeneity of the adsorbent surface sites. Thermodynamics parameters were studied the changes in free energy (ΔG 0 ), enthalpy (ΔH 0 ) and entropy (ΔS 0 ) during adsorption. It is noticeable that the adsorption of GRL dye onto MWCNTs was a spontaneous and endothermic process and indicates that the adsorption is favored at high temperature.

No abstract

In the present work, z-scan technique was used to study the nonlinear properties, represented by nonlinear refractive index and nonlinear absorption coefficient for Coumarin 450 (C₄₅₀) doped PMMA as a function of concentration for two different solvents. The results show change of the effect from self-focusing to self-defocusing in closed aperture z-can (or change of the effect from two photon absorption to saturable absorption in open aperture z-scan), when the sample dissolved in low viscosity and more polar solven

Carbon nanostructures (CNTs) have been prepared by a Hydrothermal deposition technique based on the polymer Polyethylene glycol (PEG) dissolved in water and Ethanol alcohol of a new carbon sources materials mixed with (PdCl 2 ) as a catalyst mixed with Sodium hydroxide (8gm NaOH) using Parr reactor at temperature (190°C) and forming the hybrid composite material (TiO 2 /Pd/MWCNTs) by the same way. Thence, deposited heterojunction material (TiO 2 /Pd/MWCNTs:n-Si) using the Pulsed Laser Deposition Technique (PLD), on the substrate of n-silicon wafer. The obtained (MWCNTs & TiO 2 /Pd/MWCNTs) are investigated by scanning electron microscope (SEM), X-ray diffraction (XRD) and X-ray Photo-electron Spectroscopy (XPS). Normal MWCNTs are formed multi-walled carbon nanotubes (MWCNTs) and carbon nanosheets (CNSs) but in little bit amount. MWCNTs were obtained as main products with lengths of (1.6-3 μm) and diameters of (30-60 nm) could be synthesized at as low temperature as (190°C). Deconvolution of the (C1s ) peaks which characteristic of C-C bonds, showed a main peak at (284.96 and 285.04 eV) with total amount (74.96 and 30.64 at%) for the product of MWCNTs and TiO 2 /Pd/MWCNTs composite respectively. Currentvoltage characteristics of heterojunction showed that forward bias current change exponentially approximately with applied voltage at dark and this agreement with tunneling-recombination model. Also (I-V) characteristics under illumination of TiO 2 /Pd/MWCNTs heterojunction deposited on p-Si substrate (η=10.5) efficiency in Solar Cell.