Papers by Keyword: 4-Nitrophenol

Abstract: Photocatalytic reduction of 4-nitrophenol is one of the most promising methods to remove this hazardous pollutant from wastewaters and generated a raw compound widely use in industrial processes. In the present work, three Bi₂S₃/TiO₂ catalysts with different Bi₂S₃ content, were synthesized by a hydrothermal method. The materials were characterized by XRD, X-ray fluorescence, physisorption of N₂, HRTEM, UV-Vis reflectance spectroscopy and zeta potential measurements. The catalytic activity of the synthesized materials was tested in the photoreduction of 4-nitrophenol in aqueous medium. Although the results indicate the formation of heterojunction for all the samples, the physicochemical properties of each material depend on the Bi₂S₃ content. The material with 6%wt of Bi₂S₃ exhibit the major catalytic activity, reducing 80% of the target molecule within 60 minutes of reaction.

Abstract: Large amounts of nitroaromatic compounds are discharged into the natural environment, leading to environmental pollution. The detection and removal of nitroaromatic compounds are therefore important environmental issues. In this study, the hybrid of molybdenum disulfide (MoS₂) and graphene (GR) was synthesized using a facile hydrothermal method. Sodium molybdate was selected as the precursors for MoS₂. While thiourea was used as reductant and sulfur sources at the same time. Samples were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), N₂ adsorption, Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), and Raman microscope. Compared to pure MoS₂, the obtained MoS₂/GR hybrid showed improved activity for electrochemical detection and chemical reduction of 4-nitrophenol. The activity enhancement should be due to the addition of GR, which could improve the conductivity as well as provide more active sites. The MoS₂/GR hybrid could therefore provide new multi-function catalyst for environment protection.

Abstract: In this research, reduced graphene oxide/zinc oxide nanocomposites (rGO/ZnO) were synthesized at different pHs (9, 10, 11 and 12) by using one-pot hydrothermal bath method., The obtained nanocomposites characterized by using X-ray diffractometer, Fourier transform infrared, Raman, scanning electronic microscope and diffuse reflection spectroscopy techniques. Photocatalytic activity of nanocomposites were evaluated by monitoring the photodegradation of 4-nitrophenol (4-NP) in water exposed to ultraviolet and visible light irradiation. The morphological and structural results have been shown that at pHs of 9 and 10, the ZnO nearly aggregated nanoparticle are crystalized, while at higher pHs (11 and 12), the preferential growth of ZnO in the form of nanorods is seen. Comparative studies on photocatalytic performance of the nanocomposites shows that ZnO nanorods have better photocatalytic activities than the others.

Abstract: Cadmium oxide was synthesized using oleic acid as the precursor and capping agent, the main role of oleic acid to cap the formed cadmium oxide and to control the particle size. The formed cadmium oxide nanoparticles were characterized by using FT-IR, XRD,FE-SEM and cyclic voltammetry. The electrochemical detection of pollutants (4-Nitrophenol and 2-Nitrophenol) was carried out by coating the cadmium oxide onto the glassy carbon electrode (GCE) by drop coating method. The electrocatalytic performance of the modified GCE electrode was best with 4-Nitrophenol. In case of 2-Nitrophenol the electrocatalytic performance was not observed but increase in current response indicates the ability of modified electrode to be a useful one for sensing the environmental pollutants.

Abstract: Lead sulphide nanoparticles was synthesized using hydrothermal method. The formed lead suplphide (PbS) nanoparticles were characterized by using FT-IR, XRD, FE-SEM and cyclic voltammetry. The electrochemical detection of pollutant (4-Nitrophenol) was carried out by coating the lead sulphide onto the glassy carbon electrode (GCE) by drop coating method. The electrocatalytic performance of the modified GCE electrode with 4-Nitrophenolwas better when compared with bare electrode.

Abstract: Cr, Ti-substituted TiO2-loaded MCM-41 (TiO2/Cr-Ti-MCM-41) catalysts were prepared, and their photocatalytic activities for decomposition of 4-nitrophenol (4-NP) in visible light were studied. The effect of H2O2 on the photocatalytic decomposition of 4-NP was investigated. Tisubstituted MCM-41 exhibited an absorption in UV range, and the incorporation of both Ti and Cr in the MCM-41 framework created visible light absorption. The visible light absorption capability of TiO2/Cr-Ti-MCM-41 increased with increasing TiO2 loading. The photocatalytic activity of Cr- Ti-MCM-41 for degradation of 4-NP in visible light increased with increasing TiO2 loading up to 33 wt%. The addition of H2O2 enhanced the photocatalytic activity of 33 wt% TiO2/Cr-Ti-MCM-41 for decomposition of 4-NP in visible light. H2O2 was found to promote the adsorption of 4-NP on the Cr-Ti-MCM-41 surface, leading to increased reaction rate. In addition, H2O2 may act as an electron acceptor during photocatalytic reaction, thereby lowering the electron-hole recombination and increasing the efficiency of hole utilization.