Facile one-step synthesis of Au-ZnO/MWCNTs for photocatalytic treatment of Reactive Blue dye in aqueous solution Hassan A. Alshamsil, Qusay A. Nema, Salam H. Alwan Iop Conference Series Earth and Environmental Science, 2022 In this work, the multiwall carbon nanotubes (MWCNTs) based gold-zinc oxide (Au-ZnO) nanocomposite has been synthesized for visible light driven photocatalytic decolorization of reactive blue-4 (RB4) dye. The Au-ZnO/MWCNTs nanophotocatalyst has been successfully synthesized via thermal treatment method at 600 0C. The physico-chemical properties of MWCNTs and Au-ZnO/MWCNTs have been investigated via powder X-ray diffraction (XRD) spectroscopy, UV-visible diffuse reflectance spectroscopy (UV-DRS), Fourier transform infrared spectroscopy (FTIR)scanning electron microscope (SEM), atomic force microscopy (AFM) and transmission electron microscopy (TEM). The synergistic effect of MWCNTs and Au NPs doping could offers an interesting opportunity to design photocatalyst material with the maximum absorption shift to the visible region of the spectrum, where photocatalytic activity can be enhanced. The results exhibited the growth of Au and ZnO nanoparticles (NPs) on the MWCNTs surface with an average diameter of 20 – 30 nm. The photodecolorization of RB4 dye was investigated by changing pH (3-11), dosage of photocatalyst (0.2-1.4 g/L), and initial RB4 concentration (25–100 mg/L). Under best treatment conditions (pH 11 and catalyst dosage 1.0 g/L), the best photodecolorization efficiency was reached 94.91 %. Based to the obtained results, the photodecolorization efficiency adopting Au-ZnO/MWCNTs photocatalyst was stated to be a promising route for remediation the organic pollutants in aqueous solutions
Facile Green Synthesis of Reduced Graphene Oxide in L-cysteine Solution and its Structural, Morphological, Optical and Thermal Characteristics Hassan Abbas Alshamsi, Nuha Abd Al-Baqir Jaber, Salam H. Alwan Altaa Journal of Physics Conference Series, 2021 The current research reports a cost-effective, efficient ad green reducing agent (L-cysteine) to reduce the graphene oxide (GO) for large-scale reduced graphene oxide (rGO) synthesis. Fabrication of rGO was performed by the reduction of GO using different concentrations from L-cysteine. Synthesis of rGO was noticed by change in color of GO solution from brown to black. For additional confirmation, the structural, morphological, optical and thermal properties of synthesized rGO were analyzed using powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscope (SEM), energy dispersive X-ray Spectroscopy (EDX) atomic force microscopy (AFM), thermogravimetric analysis (TGA) and ultraviolet-visible spectrophotometer (UV-Vis). The XRD, FTIR and EDS results showed the oxygen-containing groups such as hydroxyl, carbonyl, and epoxy. The UV-Vis spectrum for GO exhibited an absorbance peak at 233 nm which undergoes a red shift of the absorbance peak to 265, 273 and 278 nm due to reduction of GO to rGO using 5, 8 and 10 mg/L of L-cysteine respectively. XRD patterns demonstrated the disappearance of the characteristics peak of GO (11.1) and reinforced this appearance of peak around ~26, indicating the efficient reduction of GO and restoration of graphene sp2 hybridized structure. Furthermore, FTIR spectroscopy showed the gradual disappearance of band at 1745 cm-1 assigned to GO as L-cysteine concentration was increased. The thermal stability of the GO was much lower than those of all the rGO powders where the increased concentration of L-cysteine resulted in enhanced more thermal stability and higher C/O ratio in rGO. The SEM images confirmed the successful structurally exfoliation of two dimensional rGO sheets and showed the folded, curled and flake-like morphology of the graphene nanosheets.
Visible light assisted photocatalytic degradation of Rhodamine B dye on CdSe-ZnO nanocomposite: Characterization and kinetic studies H. Abbas Alshamsi, M. Abbas. Al Bedairy, S. Hussein Alwan Iop Conference Series Earth and Environmental Science, 2021 The paper involves the heterogeneous photocatalytic degradation of Rhodamine B dye (RhB) employing ZnO and ZnO/CdSe nanocomposites as photocatalysts which was synthesized via chemical bath deposition (CBD) method. Nanocomposite CdSe-ZnO powders have been synthesized by varying CdSe/ZnO molar ratios. The structural, optical, morphological, and topological characteristics of as synthesized materials were investigated using the appropriate characterization instrument such as X-ray diffractometer (XRD), diffuse reflectance spectrophotometer (DRS), atomic force microscope (AFM) and field emission scanning electron microscope (FE-SEM). It seems that the growth of CdSe particles onto ZnO particles in a core-shell like structure. The photocatalytic performance of ZnO/CdSe nanocomposite has been investigated under affecting factors such as catalyst dosage, RhB concentration and initial pH of RhB solution. The photocatalytic degradation reactions were carried out by exposing the aqueous suspension of the dye and ZnO/CdSe system with visible light. The residual concentration of RhB dye was measured using a UV-visible spectrophotometer at maximum wavelength of dye (λmax 554 nm). The decolorization process was found to follow pseudo first-order kinetics which is well expressed by the represented by the Langmuir-Hinshelwood (L-H) kinetic model. The maximum decolonization efficiency of 99% was achieved within 180 min at optimum conditions, dye conc. 10 mg/L, pH 10, CdSe (10%)-ZnO dose 1.5 g/L. The ROS studies indicate that hydroxyl radicals and holes are the predominant reactive species within the same step. Furthermore, CdSe(10%)-ZnO shows a good stability after reuse for 15 successive cycles and hence it expected to be promising in polluted water treatment.
Adsorptive removal of Cd(II) from aqueous solution onto beans peel powder as low cost adsorbent Research Journal of Pharmaceutical Biological and Chemical Sciences, 2015
