scholarly journals Photocatalytic Performance of a Novel Sr-Ce-TiO2/HAp for Degradation of Methylene Blue Dye in the Presence of Visible Light

Author(s):  
Alireza Esmaeilzadeh ◽  
Felora Heshmatpour

Abstract In this study, Sr-Ce-TiO2/HAp as a novel and efficient nanocomposite was synthesized and characterized by Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), scanning electron microscopy (SEM), and surface area determination of porous using the Brunauer–Emmett–Teller (BET) method and degradation of methylene blue under visible radiation was investigated. Evaluations showed that doped with metal cations and the presence of hydroxyapatite reduced energy gap, increased surface area, increased adsorption and decreased electron-hole recombination. The results also showed that more than 92% of methylene blue was removed within 100 min. The pseudo-first order reaction synthetic was obtained.

2011 ◽  
Vol 403-408 ◽  
pp. 1205-1210
Author(s):  
Jaleh Babak ◽  
Ashrafi Ghazaleh ◽  
Gholami Nasim ◽  
Azizian Saeid ◽  
Golbedaghi Reza ◽  
...  

In this work ZnO nanocrystal powders have been synthesized by using Zinc acetate dehydrate as a precursor and sol-gel method. Then the products have been annealed at temperature of 200-1050°C, for 2 hours. The powders were characterized using X-ray diffraction (XRD), UV-vis absorption and photoluminescence (PL) spectroscopy. The morphology of refrence ZnO nanoparticles have been studied using Transmission Electron Microscope (TEM). During the annealing process, increase in nanocrystal size, defects and energy gap quantitative, and decrease in specific surface area have been observed.


2020 ◽  
Author(s):  
Chukwunonso Onyenanu ◽  
Lovet Emembolu

Abstract Photocatalytic activity of the natural semiconducting sphalerite mineral from Abuni, Nasarawa State, Nigeria was studied for the degradation of methylene blue (MB). Natural Sphalerite as a visible – light responsive photocatalyst was characterized by X ray diffraction (XRD), X ray fluorescence (XRF) and surface area analysis. To further enhance the photocatalytic activity of natural Sphalerite, the chemical composition of the sphalerite was varied via leaching with oxalic acids. The photocatalytic activity of the Natural sphalerite, leached sphalerite and as well as the calcined leachates was tested for MB degradation under visible light illumination. The result shows a very high percentage of MB degradation by natural sphalerite after 60mintues of light irradiation time. A composite of ZnO -α –Fe2O3 -ϒ-Fe2O3 with traces amount of MoO and MnO2 was synthesized by calcination of the obtained leachates at 1000°C for 4hours. The photocatalytic degradation of methylene blue dye follows pseudo first order kinetics.


Author(s):  
Sridharan Balu ◽  
Kasimayan Uma ◽  
Guan-Ting Pan ◽  
Thomas C.-K. Yang ◽  
Sayee Kannan Ramaraj

Semiconductor materials have been shown to have better photocatalytic behavior and can be utilized for the photodegradation of organic pollutants. In this work, three-dimensional flower-like SnS2 were synthesized by a facile hydrothermal method. Core-shell structured SiO2@α-Fe2O3 nanocomposites were then deposited on the top of the SnS2 flowers. The as-synthesized nanocomposites were characterized by X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM), Brunauer-Emmett-Teller (BET) and photoluminescence spectroscopy (PL). The photocatalytic behavior of the SnS2-SiO2@α-Fe2O3 nanocomposites was observed by observing the degradation of methylene blue (MB). The results show an effective enhancement of photocatalytic activity for the degradation of MB especially for the 15 wt. % SiO2@α-Fe2O3 nanocomposites on SnS2 flowers.


2010 ◽  
Vol 4 (2) ◽  
pp. 69-73 ◽  
Author(s):  
Marija Milanovic ◽  
Ivan Stijepovic ◽  
Ljubica Nikolic

Titanate structures were synthesized in highly alkaline solution using hydrothermal procedure. As-prepared powders were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). A specific surface area of the powders was measured by BET method. Results confirmed formation of layered trititanates, already after one hour of hydrothermal synthesis. To examine the photocatalytic activity of the as-prepared layered titanates, methylene blue (MB) was employed as a target compound in response to visible light at ambient temperature. It was observed that the specific surface area, size distribution and crystallinity are important factors to get high photocatalytic activity for the decomposition of MB. .


2019 ◽  
Vol 8 (2) ◽  
pp. 94-102
Author(s):  
Ghizlane Erradi ◽  
Farida El yousfi ◽  
Mostafa Stitou

Removal of industrial waste becomes increasingly critical for environmental protection. This study aims to search for effective and less expensive adsorbents in order to remove methylene blue (MB) commonly used in many industrial sectors. To this end, we experiment Helix aspersa snail shell as a biosorbent for the removal of MB. The raw snail shells were cleaned, smashed, and characterized afterwards using a scanning electron microscopy (SEM) coupled with an energy dispersive X-Ray analysis (EDX) and by X-ray diffraction. Different parameters were tested in order to identify the optimal conditions for the effective removal of MB. Our experimental results showed that, within the first ten minutes, a remarkable elimination of methylene blue dye reaching a percentage of 82%, with the following optimal conditions; 3.5 g of the adsorbent, initial MB concentration of 20 mg/L, the temperature of 15 °C, and agitation of 250 rpm. This study showed that the use of snail shell waste has inevitably a positive impact on the protection of the environment, in particular, the purification of industrial effluents.


Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2439 ◽  
Author(s):  
Maria Antoniadou ◽  
Michalis K. Arfanis ◽  
Islam Ibrahim ◽  
Polycarpos Falaras

A bifunctional thin film photocatalyst consisting of graphitic carbon nitride on tungsten trioxide (g-C3N4/WO3) is introduced for the improvement of photocatalytic activity concerning hexavalent chromium reduction and methylene blue dye removal in water, compared to the bare, widely used WO3 semiconductor. A bilayered structure was formed, which is important for the enhancement of the charge carriers’ separation. The characterization of morphological, structural, optoelectronic, and vibrational properties of the photocatalysts permitted a better understanding of their photocatalytic activity for both dye degradation and Cr+6 elimination in water and the analysis of the photocatalytic kinetics permitted the determination of the corresponding pseudo-first-order reaction constants (k). Trapping experiments performed under UV illumination revealed that the main active species for the photocatalytic reduction of Cr+6 ions are electrons, whereas in the case of methylene blue azo-dye (MB) oxidation, the activation of the corresponding photocatalytic degradation comes via both holes and superoxide radicals.


Author(s):  
Oluwadayo Francis Asokogene ◽  
Muhammad Abbas Ahmad Zaini ◽  
Misau Muhammad Idris ◽  
Surajudeen Abdulsalam ◽  
Aliyu El-Nafaty Usman

Abstract This study was aimed to evaluate the characteristics of chitosan from Pessu river crab shell and its derivatives as prospective adsorbent. The synthesized chitosan (CH) was modified with 10 % (w/v) oxalic acid (CHOx), while the composites (CHOx-ANL1, CHOx-ANL2 and CHOx-ANL3) were designated according to the amount of activated neem leave (ANL). The materials were characterized by Fourier transform infrared (FTIR), energy-dispersive X-ray (EDAX), X-ray diffraction (XRD), scanning electron microscope (SEM), Brunauer-Emmett-Teller (BET), thermal gravimetric (TGA) and methylene blue dye adsorption. The FTIR spectra of chitosan samples show the characteristics of primary and secondary amine/amide groups. The SEM images exhibit a tight, porous and fractured surface, which is covered with activated neem leave for the composites. The BET surface area of chitosan materials is in the increasing order of, CH < CHOx-ANL1 < CHOx-ANL2 < CHOx < CHOx-ANL3. CHOx-ANL3 displays a higher surface area of 389 m2/g, and 70.9 % mesoporosity. Despite its lower surface area of 258 m2/g (65.4 % mesoporosity), CHOx-ANL1 exhibits a greater methylene blue adsorption of 90.8 mg/g at dye concentration of 300 mg/L. The possible removal mechanisms include ionic interaction between dye molecules and functional groups, and surface adsorption due to the textural properties of chitosan samples. Chitosan from Pessu river crab shell and its derivatives are promising adsorbent candidate for dyes and heavy metals removal from water.


2014 ◽  
Vol 970 ◽  
pp. 29-32 ◽  
Author(s):  
Pongsaton Amornpitoksuk ◽  
Sumetha Suwanboon

The co-effect of PO43- and I- on the formation of a heterosturucture photocatalyst in the Ag3PO4-AgI system was studied by the co-precipitation method between AgNO3 and the precipitating agent. The precipitating agent was prepared by varying the mole ratios between Na2HPO4 and KI. At 10 mol.% KI, the product showed the mixed phase between Ag3PO4 and un-identified phase. For 30 - 90 mol.% KI, the un-identified phase and AgI were detected in the x-ray diffraction patterns. The un-identified phase strongly adsorbed the methylene blue dye. The product prepared from 30 mol.% KI had the highest content of un-identified phase and also showed the highest degree of decolorization in the dark. The photocatalytic properties of products in this system were confirmed by the decolorization of methylene blue under visible illumination.


2012 ◽  
Vol 727-728 ◽  
pp. 32-37 ◽  
Author(s):  
Antusia dos S. Barbosa ◽  
A. Santos Barbosa ◽  
Meiry Glaúcia Freire Rodrigues ◽  
J. M. Grau

The objective of this work was based on catalysts Pt, Ni and Ru supported on zeolite NH4ZSM-5 and characterize them. In this work monometallic bifunctional catalysts were prepared (Pt/NH4ZSM-5; Ni/NH4ZSM-5; Ru/NH4ZSM-5), all containing the same concentration of each metal supported by competitive ion exchange, using solutions of platinum complexes [Pt (NH3)4] Cl2, Nickel [Ni (NH3)6] Cl2and chloride Ruthenium III (RuCl3). The samples were characterized by chemical analysis by X-ray Spectroscopy Energy dispersive (EDS), X-Ray Diffraction (XRD), nitrogen adsorption (BET method). Through the analysis of X-ray diffraction, its possible to identify the preservation of the structure of zeolite ZSM-5 after the competitive ion Exchange with metals (Ni, Pt, Ru) and calcination. The dispersion of platinum and ruthenium in zeolite ZSM-5, didnt modify the textural characteristics of the zeolite, but the dispersion of nickel caused a change in values of surface area of catalysts.


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