scholarly journals Graphene-Based TiO2 Nanocomposite for Photocatalytic Degradation of Dyes in Aqueous Solution under Solar-Like Radiation

2021 ◽  
Vol 11 (9) ◽  
pp. 3966
Author(s):  
Martina Kocijan ◽  
Lidija Ćurković ◽  
Davor Ljubas ◽  
Katarina Mužina ◽  
Ivana Bačić ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Photocatalytic Degradation ◽  
Energy Gap ◽  
Visible Region ◽  
Pure Tio2 ◽  
Solar Irradiation ◽  
Degradation Of Dyes ◽  
Visible Part ◽  
Vis Spectroscopy ◽  
Improved Performance

This study presents a novel method for the development of TiO2/reduced graphene oxide (rGO) nanocomposites for photocatalytic degradation of dyes in an aqueous solution. The synergistic integration of rGO and TiO2, through the formation of Ti–O–C bonds, offers an interesting opportunity to design photocatalyst nanocomposite materials with the maximum absorption shift to the visible region of the spectra, where photodegradation can be activated not only with UV but also with the visible part of natural solar irradiation. TiO2@rGO nanocomposites with different content of rGO have been self-assembled by the hydrothermal method followed by calcination treatment. The morphological and structural analysis of the synthesized photocatalysts was performed by FTIR, XRD, XPS, UV-Vis DRS, SEM/EDX, and Raman spectroscopy. The effectiveness of the synthesized nanocomposites as photocatalysts was examined through the photodegradation of methylene blue (MB) and rhodamine B (RhB) dye under artificial solar-like radiation. The influence of rGO concentration (5 and 15 wt.%) on TiO2 performance for photodegradation of the different dyes was monitored by UV-Vis spectroscopy. The obtained results showed that the synthesized TiO2@rGO nanocomposites significantly increased the decomposition of RhB and MB compared to the synthesized TiO2 photocatalyst. Furthermore, TiO2@rGO nanocomposite with high contents of rGO (15 wt.%) presented an improved performance in photodegradation of MB (98.1%) and RhB (99.8%) after 120 min of exposition to solar-like radiation. These results could be mainly attributed to the decrease of the bandgap of synthesized TiO2@rGO nanocomposites with the increased contents of rGO. Energy gap (Eg) values of nanocomposites are 2.71 eV and 3.03 eV, when pure TiO2 particles have 3.15 eV. These results show the potential of graphene-based TiO2 nanocomposite to be explored as a highly efficient solar light-driven photocatalyst for water purification.

Boron Nitride Doped Polypyrrole Hybrid Composites for Photocatalytic Degradation of 2-Chlorophenol from Aqueous Solution

2020 ◽  
Vol 301 ◽  
pp. 145-152 ◽  
Author(s):  
Faizah Yunus ◽  
Muhammad Syazwan Kassim ◽  
Syed Shahabuddin ◽  
Nur Rahimah Said ◽  
Siti Nor Atika Baharin
Keyword(s):  
Aqueous Solution ◽  
Boron Nitride ◽  
Photocatalytic Degradation ◽  
Hybrid Composites ◽  
Hexagonal Boron Nitride ◽  
Solar Irradiation ◽  
X Ray Diffraction ◽  
Initial Concentration ◽  
Polymerization Method

This investigation focused on the photocatalytic degradation of o2-chlorophenol in aqueous solution by using hexagonal boron nitride (h-BN) doped polypyrrole (PPy) composite under solar irradiation. The composite was prepared via in-situ oxidation polymerization method using FeCl3 as oxidation agent. The synthesized h-BN/PPy composite were comprehensively characterized using x-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The photodegradation of 2-chlorophenol was performed under direct sunlight for 180 minutes with initial concentration (50-250 mg/L) and pH (3-9). h-BN/PPy composite efficiently degraded 2-chlorophenol (91.1%) with optimum conditions at pH 6 and 50 mg/L initial concentration compared to PPy and h-BN.

scholarly journals Enhanced visible light photocatalytic degradation of dyes in aqueous solution activated by HKUST-1: performance and mechanism

RSC Advances ◽  
2020 ◽  
Vol 10 (61) ◽  
pp. 37028-37034
Author(s):  
Jianyu Zhang ◽  
Chunli Su ◽  
Xianjun Xie ◽  
Peng Liu ◽  
Md. Enamul Huq
Keyword(s):  
Aqueous Solution ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Metal Organic Framework ◽  
Surface Charges ◽  
Degradation Of Dyes ◽  
Metal Organic ◽  
Visible Light Photocatalytic ◽  
Performance And Mechanism ◽  
Organic Framework

HKUST-1 is a copper-based metal–organic framework (MOF). The HKUST-1/PMS/Vis system can effectively degrade RhB and MB but accomplish poor removal of AO7 and MR, which is attributed to the repulsion between surface charges.

scholarly journals Photo-Transformation of Effluent Organic Matter by ZnO-Based Sunlight Irradiation

2020 ◽  
Vol 10 (24) ◽  
pp. 9002
Author(s):  
Thao Thi Nguyen ◽  
Seong Nam Nam ◽  
Jeill Oh
Keyword(s):  
Organic Matter ◽  
Photocatalytic Degradation ◽  
Removal Efficiency ◽  
Treatment Plant ◽  
Wastewater Effluent ◽  
Solar Irradiation ◽  
Effluent Organic Matter ◽  
Sunlight Irradiation ◽  
Vis Spectroscopy ◽  
The Impact

This study investigated the impact of effluent organic matter (EfOM) from wastewater effluent on the properties of organic matter in receiving water and the efficiency of its removal using photocatalysis. The organic matter is characterized using fluorescence excitation-emission matrices coupled with parallel factor analysis (EEM-PARAFAC), UV-Vis spectroscopy, and dissolved organic carbon (DOC) measurements. The experiments are conducted with water samples that were collected from upstream waters (used as a source of dissolved organic matter (DOM)), wastewater effluent (a source of EfOM), and waters downstream of a wastewater treatment plant, and with upstream water and wastewater effluent being mixed at different ratios in the lab (DOM/EfOM). EEM-PARAFAC analysis identifies three components: a humic-like component (C1), a tyrosine-like component (C2), and a terrestrial-like humic component (C3). When compared to DOM, EfOM has a higher specific ultraviolet absorbance at 254 nm (SUVA254), a higher fluorescence index (FI), and more abundant humic-like components. As the EfOM contribution increased, an increase in both humic-like components and a simultaneous decrease in the protein-like components are observed. The photocatalytic degradation of the organic matter using simulated solar irradiation with ZnO as a catalyst is examined. The removal efficiency of photocatalysis is calculated using the DOC, UV absorbance at 254 nm (UV254), and the maximum fluorescence intensity (Fmax) of the PARAFAC components. After 120 min of irradiation, the removal efficiency of photocatalysis differs between the DOM, EfOM, and EfOM-impacted samples due to the change in the properties of the organic matter in the source water. The photocatalytic degradation of organic matter follows pseudo-first-order kinetics, with the DOC and UV254 exhibiting a lower removal efficiency with the increasing contribution of EfOM, which indicated that EfOM has a potentially negative impact on the performance of drinking water treatment. The removal of PARAFAC components follows the order C3 > C1 > C2, indicating that humic-like components are preferentially removed when compared to protein-like components under sunlight irradiation.

scholarly journals MoS2/Cu/TiO2 nanoparticles: synthesis, characterization and effect on photocatalytic decomposition of methylene blue in water under visible light

2018 ◽  
Vol 2017 (1) ◽  
pp. 184-193 ◽  
Author(s):  
Desireé M. de los Santos ◽  
Sara Chahid ◽  
Rodrigo Alcántara ◽  
Javier Navas ◽  
Teresa Aguilar ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Tio2 Nanoparticles ◽  
Visible Region ◽  
Pure Tio2 ◽  
Photocatalytic Decomposition ◽  
Tio2 Sample ◽  
X Ray ◽  
Vis Spectroscopy

Abstract Photodegradation processes are of great interest in a range of applications, one of which is the photodecomposition of pollutants. For this reason, analysing nanoparticles that improve the efficiency of these processes under solar radiation are very necessary. Thus, in this study, TiO2 was doped with Mo and Cu using low-temperature hydrolysis as the method of synthesis. Pure TiO2 and x%MoS2/Cu/TiO2 nanoparticles were prepared, where x is the theoretical quantity of MoS2 added (0.0%, 1.0%, 5.5%, 10.0%), setting the nominal quantity of Cu at 0.5 wt.%. The samples obtained were characterized by X-ray diffraction, Raman spectroscopy, X-ray electron spectroscopy and UV-Vis spectroscopy in diffuse reflectance mode. The results suggest that the TiO2 structure was doped with the Mo6+ and Cu2+ ions in the position of the Ti4+. The x%MoS2/Cu/TiO2 samples presented lower band gap energy values and greater optical absorption in the visible region than the pure TiO2 sample. Lastly, the photocatalytic activity of the samples was assessed by means of the photodegradation of methylene blue under visible light. The results show that when the quantity of Mo in the co-doped samples increased (x%MoS2/Cu/TiO2) there were significant increases of up to 93% in the photocatalytic activity.

scholarly journals Visible Region Response of Cobalt Doped TiO2 via Sol Gel Technique

2018 ◽  
Vol 26 (8) ◽  
pp. 240-244
Author(s):  
AbdulKareem AbdulHusssein Kareem Al-Khafajia ◽  
AbdulNaser Hasan Al-Zurfy
Keyword(s):  
Sol Gel ◽  
Visible Region ◽  
Dip Coating ◽  
Pure Tio2 ◽  
Cobalt Ions ◽  
Force Microscopy ◽  
Vis Spectroscopy ◽  
Coating Method ◽  
Gel Technique ◽  
Dip Coating Method

TiO2 nanoparticles were prepared via sol-gel technique and then doped with cobalt ions to form TiO2 doped cobalt sol. Thin films were prepared from this sol using dip coating method and underwent calcination at a temperature of 550 C.The films were characterized by UV–Vis spectroscopy, X-ray diffraction (XRD), and atomic force microscopy (AFM). The UV–Vis. Absorption spectra show a redshift, which indicates that TiO2 doped cobalt will respond to the visible region of the spectrum rather than UV- region for pure TiO2.  

scholarly journals Photocatalytic degradation of dyes in water by analytical reagent grades ZnO, TiO<sub>2</sub> and SnO<sub>2</sub>: a comparative study

2017 ◽  
Vol 10 (2) ◽  
pp. 109-117 ◽  
Author(s):  
Dnyaneshwar R. Shinde ◽  
Popat S. Tambade ◽  
Manohar G. Chaskar ◽  
Kisan M. Gadave
Keyword(s):  
Photocatalytic Activity ◽  
Metal Oxides ◽  
Photocatalytic Degradation ◽  
Diffuse Reflectance Spectroscopy ◽  
Dye Degradation ◽  
Low Cost ◽  
Solar Irradiation ◽  
Degradation Of Dyes ◽  
Photocatalytic Activities ◽  
Analytical Reagent

Abstract. In this study, we evaluated the photocatalytic activities of analytical reagent (AR) grade ZnO, TiO2, and SnO2 to identify a low-cost photocatalyst for dye degradation. The obtained samples of ZnO, TiO2, and SnO2 were characterised by X-ray diffractogram (XRD), scanning electron microscope imaging, and UV-VIS diffuse reflectance spectroscopy. The decolourisation of three structurally diverse dyes, namely crystal violet, basic blue, and methyl red under solar irradiation, was used to evaluate the photocatalytic activities of three metal oxides. The photocatalytic activities of the received three metal oxides were tested with the photocatalytic degradation of dyes and compared with Degussa P-25. Dye solutions with each metal oxide at initial pH 9 were subjected to irradiation under sunlight and monitored for up to the stage of complete decolourisation. The results indicate that ZnO exhibited the highest photocatalytic activity as compared to TiO2 and SnO2 as well as that of Degussa P-25 (TiO2). The photocatalytic dye decolourisation rates with ZnO were 1.14–1.35, 1.70–3.1, and 4–8.5 times higher than those of the Degussa P-25, TiO2, and SnO2, respectively. The percentage COD removal was studied for ZnO and partial removal was observed at the decolourisation stage. To enhance photocatalytic activity of AR grade ZnO, it was loaded with Ag metal and about 20 % enhancement in the activity was observed.

scholarly journals Modeling and optimization of the photocatalytic degradation of Tartrazine in aqueous solution

2021 ◽  
pp. 133-145
Author(s):  
Mirvet Assassi ◽  
Farid Madjene ◽  
Sara Harchouche ◽  
Hind Boulfiza
Keyword(s):  
Aqueous Solution ◽  
Reaction Time ◽  
Photocatalytic Degradation ◽  
Batch Reactor ◽  
Heterogeneous Photocatalysis ◽  
Active Species ◽  
Influential Factor ◽  
Solar Irradiation ◽  
Uv Lamp ◽  
Positive Effect

The application of heterogeneous photocatalysis process using ZnO photocatalyst for the degradation of Tartrazine (TRZ) dye in aqueous solution was investigated in a batch reactor. The estimation, the comparison of the parameter?s effects and the optimization of the removal yield of TRZ were realized by using Box-Behnken experimental design (BBD). The results suggested that the most influential factor on the photocatalytic degradation of the dye was the initial TZR concentration with an effect of (-23.24), the second in the order was the amount of the catalyst with an effect of (+18.09), the third was the reaction time with an effect of (+15.38) and the fourth was stirring speed with a positive effect of (+4.41). The model obtained by BBD led to the following optimal conditions for degradation yield of TRZ: initial concentration of TZR equal to 20.035 mg/L, reaction time equal to 88.635 min, 0.6409 mg/L of ZnO amount and 404.9 rpm for the stirring speed, which gave 98.576% of degradation efficiency. The study of irradiation type effect shows that a solar irradiation gave higher yield than photocatalysis by UV lamp. The O2?- radicals were the principal active species responsible of the degradation of TRZ. The BOD5/COD ratio increased from 0.26 to 0.41 after 60 minutes of photocatalysis under solar light, indicating the feasibility of coupling the photocatalysis process to biological treatment for the removal of TRZ.

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