Study on Non-Selective Photocatalytic Degradation of Organic Dyes in Presence of Hollow CdS Nanospheres

2014 ◽  
Vol 700 ◽  
pp. 302-305
Author(s):  
Han Wang ◽  
Jing Tang Zheng ◽  
Xing Zheng
Keyword(s):  
Photocatalytic Activity ◽  
Organic Dyes ◽  
Dye Degradation ◽  
Active Species ◽  
Sonochemical Method ◽  
Hollow Nanospheres ◽  
Sphalerite Structure ◽  
Decolorization Efficiency ◽  
Size Uniformity ◽  
Fluorescent Probe Method

In this study, template method was applied to synthesize CdS hollow nanospheres via sonochemical method. The morphology, size of the nanospheres and crystal structure of the synthesized hollow CdS were characterized. The results showed that the hollow CdS nanospheres formed have pure cubic sphalerite structure and exhibit good monodispersity and size uniformity. The photocatalytic activity of the samples was evaluated by the decoloration of Rhodamine B (RhB), Methylene Blue (MB) and Methyl Orange (MO) aqueous solution under UV-vis light irradiation. The results indicated the hollow CdS had a good photocatalytic activity and show little selectivity of attack and are able to oxidize various organic pollutants. Moreover, the results of hydroxyl radical (•OH) detection using fluorescent probe method was in accordance with the RhB decolorization efficiency, which the •OH is likely to be the main active species responsible for dye degradation.

Enhanced Photocatalytic Performance and Mechanism of Ag3PO4 Particles Synthesized via a Sonochemical Process

2018 ◽  
Vol 10 (3) ◽  
pp. 337-345 ◽  
Author(s):  
Chengxiang Zheng ◽  
Hua Yang ◽  
Yang Yang ◽  
Haimin Zhang
Keyword(s):  
Particle Size ◽  
Photocatalytic Activity ◽  
Reaction Time ◽  
Reaction Temperature ◽  
Ph Value ◽  
Dye Degradation ◽  
Sonochemical Method ◽  
Simulated Sunlight ◽  
Spherical Nanoparticles ◽  
Direct Oxidation

A facile sonochemical method was used to synthesize Ag3PO4 particles and the effect of pH value, reaction temperature and reaction time on the products was investigated. It is found that the samples prepared at neutral (pH = 7) and alkaline (pH = 11) environments exhibit a similar particle morphology and size. The particles are shaped like spheres with a size distribution majorly focusing on a range of 200–450 nm, and the average particle size is about 300 nm. The sample prepared at acidic environment (pH = 3) is composed of polyhedral microparticles with size of 5–8 μm. At relatively low temperatures of 20–50 °C, the spherical nanoparticles do not undergo obvious morphology/size changes; however, when the temperature is increased up to 80 °C, the nanoparticles are aggregated to form large-sized polyhedral microparticles in the size range of 4–7 μm. Compared to the pH value and reaction temperature, the reaction time has a minor effect on the morphology of Ag3PO4 particles. RhB was chosen as the target pollutant to evaluate the photocatalytic activity of the as-prepared Ag3PO4 samples under simulated-sunlight irradiation. It is shown that the samples consisting of spherical nanoparticles exhibit an extremely high photocatalytic activity, and the degradation percentage of RhB after reaction for 50 min reaches over 90%. The samples of polyhedral microparticles have a relatively low photocatalytic activity, which is possibly due to their large particle size. Hydroxyl (.OH) radical was detected by spectrofluorimetry using terephthalic acid as a .OH scavenger and was not found to be produced over the simulated-sunlight-irradiated Ag3PO4 catalyst. The effect of ethanol, benzoquinone and ammonium oxalate on dye degradation was also investigated. Based on experimental results, the direct oxidation by h+ is suggested to the dominant mechanism toward the dye degradation.

Magnetic field assisted photocatalytic degradation of organic dyes in the presence of Ag/TiO2 coated composite

2013 ◽  
Vol 67 (4) ◽  
pp. 722-728 ◽  
Author(s):  
Jian Wang ◽  
Jingqun Gao ◽  
Jun Wang ◽  
Yu Zhai ◽  
Zhongxing Wang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Photocatalytic Activity ◽  
Photocatalytic Degradation ◽  
Rotational Speed ◽  
Organic Dyes ◽  
Dye Degradation ◽  
Uv Light ◽  
Irradiation Time ◽  
Sol Gel ◽  
Heat Treated

Ag/TiO2 coated composite was prepared via sol-gel method in order to elucidate its application in magnetic field assisted photocatalytic degradation of dyes. Through the degradation of organic dyes, the key influences such as Ag amount, heat-treated temperature and time on the photocatalytic activity of Ag/TiO2, as well as UV irradiation time, rotational speed, dye concentration and magnetic sheet number on the photocatalytic degradation were studied. Results showed that the Ag/TiO2 with 25 wt% Ag content heat-treated at 550 °C for 60 min has the best photocatalytic activity. With the increase of UV light irradiation time, rotational speed and magnetic sheet number, the degradation rate is improved. Different dye degradation proved that the method could universally be used.

scholarly journals Facile Synthesis of “Boron-Doped” Carbon Dots and Their Application in Visible-Light-Driven Photocatalytic Degradation of Organic Dyes

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1560 ◽  
Author(s):  
Zhili Peng ◽  
Yiqun Zhou ◽  
Chunyu Ji ◽  
Joel Pardo ◽  
Keenan J. Mintz ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Photocatalytic Degradation ◽  
Carbon Dots ◽  
Organic Dyes ◽  
Dye Degradation ◽  
Average Diameter ◽  
Spherical Particles ◽  
Promising Alternative ◽  
Excellent Photocatalytic Activity ◽  
Doped Carbon Dots

Carbon dots (C-dots) were facilely fabricated via a hydrothermal method and fully characterized. Our study shows that the as-synthesized C-dots are nontoxic, negatively charged spherical particles (average diameter 4.7 nm) with excellent water dispersion ability. Furthermore, the C-dots have a rich presence of surface functionalities such as hydroxyls and carboxyls as well as amines. The significance of the C-dots as highly efficient photocatalysts for rhodamine B (RhB) and methylene blue (MB) degradation was explored. The C-dots demonstrate excellent photocatalytic activity, achieving 100% of RhB and MB degradation within 170 min. The degradation rate constants for RhB and MB were 1.8 × 10−2 and 2.4 × 10−2 min−1, respectively. The photocatalytic degradation performances of the C-dots are comparable to those metal-based photocatalysts and generally better than previously reported C-dots photocatalysts. Collectively considering the excellent photocatalytic activity toward organic dye degradation, as well as the fact that they are facilely synthesized with no need of further doping, compositing, and tedious purification and separation, the C-dots fabricated in this work are demonstrated to be a promising alternative for pollutant degradation and environment protection.

scholarly journals Bifunctional g-C3N4/WO3 Thin Films for Photocatalytic Water Purification

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2439 ◽  
Author(s):  
Maria Antoniadou ◽  
Michalis K. Arfanis ◽  
Islam Ibrahim ◽  
Polycarpos Falaras
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Dye Degradation ◽  
Active Species ◽  
Blue Dye ◽  
Pseudo First Order Reaction ◽  
Uv Illumination ◽  
Bilayered Structure ◽  
Reaction Constants

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.

Synthesis and Characterization of ZnO Doped with Gold Nanoparticles for Improved Photocatalytic Activity

2021 ◽  
Vol 13 (5) ◽  
pp. 944-948
Author(s):  
Juyoung Yu ◽  
Jongsung Kim
Keyword(s):  
Gold Nanoparticles ◽  
Photocatalytic Activity ◽  
Organic Dyes ◽  
Dye Degradation ◽  
Resonance Effect ◽  
Zno Nanorods ◽  
Hydrothermal Process ◽  
Trisodium Citrate ◽  
Zinc Nitrate ◽  
Nitrate Hexahydrate

Recently, gold nanoparticles have been widely employed to achieve the activation of the catalytic properties of semiconductors for the decomposition of organic dyes. In this study, gold nanoparticles were prepared by Turke-vich method using HAuCl4 and trisodium citrate dehydrate. gold nanoparticles with size of 18, 20, and 22 nm were prepared by controlling the trisodium citrate dehydrate concentration and reaction time. Furthermore, ZnO nanorods were prepared using zinc nitrate hexahydrate through a hydrothermal process. Finally, ZnO doped with gold nanoparticles nanocomposite photocatalysts were prepared by mixing ZnO and gold nanoparticles and drying at 60 °C. The photocatalytic activity of the nanocomposites was evaluated through the degradation of Rhodamine B dye under solar light. ZnO doped with 22 nm of gold nanoparticles showed the highest photocatalytic activity, providing up to 78.6% dye degradation. The highest photocatalytic activity of the ZnO doped with 22 nm of gold nanoparticles nanocomposite was probably due to the increased surface plasmon resonance effect of the gold nanoparticles.

scholarly journals Construction of Z-Scheme g-C3N4/CNT/Bi2Fe4O9 Composites with Improved Simulated-Sunlight Photocatalytic Activity for the Dye Degradation

Micromachines ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 613 ◽  
Author(s):  
Lijing Di ◽  
Hua Yang ◽  
Tao Xian ◽  
Xiujuan Chen
Keyword(s):  
Photocatalytic Activity ◽  
Dye Degradation ◽  
Active Species ◽  
Simulated Sunlight ◽  
Acid Orange 7 ◽  
Electron Mediator ◽  
Sunlight Irradiation ◽  
Highly Efficient ◽  
Electron Migration ◽  
Photoelectrochemical Measurement

In this work, ternary all-solid-state Z-scheme g-C3N4/carbon nanotubes/Bi2Fe4O9 (g-C3N4/CNT/BFO) composites with enhanced photocatalytic activity were prepared by a hydrothermal method. The morphology observation shows that ternary heterojunctions are formed in the g-C3N4/CNT/BFO composites. The photocatalytic activity of the samples for the degradation of acid orange 7 was investigated under simulated sunlight irradiation. It was found that the ternary composites exhibit remarkable enhanced photocatalytic activity when compared with bare BFO and g-C3N4/BFO composites. The effect of the CNT content on the photocatalytic performance of the ternary composites was investigated. The photocatalytic mechanism of g-C3N4/CNT/BFO was proposed according to the photoelectrochemical measurement, photoluminescence, active species trapping experiment and energy-band potential analysis. The results reveal that the introduction of CNT as an excellent solid electron mediator into the ternary composites can effectively accelerate the electron migration between BFO and g-C3N4. This charge transfer process results in highly-efficient separation of photogenerated charges, thus leading to greatly enhanced photocatalytic activity of g-C3N4/CNT/BFO composites. Furthermore, the g-C3N4/CNT/BFO composites also exhibit highly-efficient photo-Fenton-like catalysis property.

scholarly journals An Overview: Recent Development of Titanium Oxide Nanotubes as Photocatalyst for Dye Degradation

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Chin Wei Lai ◽  
Joon Ching Juan ◽  
Weon Bae Ko ◽  
Sharifah Bee Abd Hamid
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Textile Industry ◽  
Organic Dyes ◽  
Dye Degradation ◽  
High Surface ◽  
High Surface Area ◽  
Living Organism ◽  
Heterogeneous Photocatalysis ◽  
Titanium Oxide Nanotubes

Today, organic dyes are one of the largest groups of pollutants release into environment especially from textile industry. It is highly toxic and hazardous to the living organism; thus, the removal of these dyes prior to discharge into the environment is essential. Varieties of techniques have been employed to degrade organic dyes and heterogeneous photocatalysis involving titanium dioxide (TiO2) appears to be the most promising technology. In recent years, TiO2nanotubes have attracted much attention due to their high surface area and extraordinary characteristics. This paper presents a critical review of recent achievements in the modification of TiO2nanotubes for dye degradation. The photocatalytic activity on dye degradation can be further enhanced by doping with cationic or anionic dopant.

scholarly journals Synthesis of Spherical Bi2WO6Nanoparticles by a Hydrothermal Route and Their Photocatalytic Properties

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
B. Wang ◽  
H. Yang ◽  
T. Xian ◽  
L. J. Di ◽  
R. S. Li ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Dye Degradation ◽  
Average Particle Size ◽  
Active Species ◽  
Bandgap Energy ◽  
Average Particle ◽  
Simulated Sunlight ◽  
Hydrothermal Route

Spherical Bi2WO6nanoparticles were synthesized by a hydrothermal route. SEM observation shows that the size of the particles ranges from 60 to 120 nm and the average particle size is ~85 nm. TEM investigation shows that the particles are made up of subgrains with size of 5–10 nm. The bandgap energy of the particles is measured to be 2.93 eV by ultraviolet-visible diffuse reflectance spectroscopy. RhB was chosen as the target pollutant to evaluate the photocatalytic activity of the particles under irradiation of simulated sunlight, revealing that they exhibit an obvious photocatalytic activity. The effects of ethanol, KI, and BQ on the photocatalytic efficiency of Bi2WO6particles towards the RhB degradation were investigated. It is observed that ethanol has no effect on the photocatalytic degradation of RhB, whereas KI and BQ exhibit a substantial suppression of RhB degradation. No hydroxyl (•OH) is found, by the photoluminescence technique using terephthalic acid as a probe molecule, to be produced over the irradiated Bi2WO6particles. Based on the experimental results, photoexcited hole (h+) and superoxide (•O2-) are suggested to be the two main active species responsible for the dye degradation, while •OH plays a negligible role in the photocatalysis.

Novel Preparation of Bi/BiVO4 Catalyst Supported by Alkali-Modified Diatomite and its Visible Light-Driven Degradation Performance

NANO ◽  
2021 ◽  
pp. 2150034
Author(s):  
Mingwei Liu ◽  
Linhua Jiang ◽  
Mingxia Shen ◽  
Mingzhi Guo ◽  
Pengfei Zhu ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Pore Structure ◽  
Surface Area ◽  
Dye Degradation ◽  
Active Species ◽  
Composite Catalyst ◽  
Great Promise ◽  
Lemon Yellow

The manufacture of diatomite-supported composite catalyst with enhanced photocatalytic activity is of great interest for wastewater treatment. In this study, the pretreated diatomite (PD) with 5[Formula: see text]wt.% NaOH solution possessed better pore structure and large specific surface area. A facile hydrothermal-photoreduction method was adopted to prepare Bi/BiVO4/PD composite. The chemical composition, microstructure morphology and pore structure of samples were investigated by means of XRF, XRD, SEM, TEM, EDS, XPS and BET methods. The results showed that the metallic Bi was uniformly deposited on the BiVO4. After loaded on PD, both surface area and total pore volume had a significant increase. In addition, UV-vis diffuse reflectance spectra presented that the absorption capacity of Bi/BiVO4/PD-25% composite in the visible light range was remarkably high due to the surface plasmon resonance (SPR) caused by metallic Bi. From photoluminescence (PL) spectra and transient photocurrents, the heterojunction formed between Bi/BiVO4 and PD helped promoting the separation and migration of photo-generated carriers, which in turn led to higher photocatalytic activity. Compared with Bi/BiVO4, Bi/BiVO4/PD loaded with 25[Formula: see text]wt.% PD showed highest decolorization rate for rhodamine B (RhB), malachite green (MG), methylene blue (MB), methyl orange (MO) and lemon yellow (LY) under visible light irradiation. According to trapping experiments on free radicals, the active species that played a decisive role in RhB degradation were h[Formula: see text] and [Formula: see text]. Findings from this study suggest that Bi/BiVO4/PD-25% composite holds great promise for dye degradation and wastewater treatment.

scholarly journals Enhanced Visible-Light Photocatalytic Performance of SAPO-5-Based g-C3N4 Composite for Rhodamine B (RhB) Degradation

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3948
Author(s):  
Lingfang Qiu ◽  
Zhiwei Zhou ◽  
Mengfan Ma ◽  
Ping Li ◽  
Jinyong Lu ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Redox Reactions ◽  
Photocatalytic Performance ◽  
Dye Degradation ◽  
Thermal Polymerization ◽  
Light Illumination ◽  
Electron Hole ◽  
Visible Light Illumination ◽  
Visible Light Photocatalytic

Novel visible-light responded aluminosilicophosphate-5 (SAPO-5)/g-C3N4 composite has been easily constructed by thermal polymerization for the mixture of SAPO-5, NH4Cl, and dicyandiamide. The photocatalytic activity of SAPO-5/g-C3N4 is evaluated by degrading RhB (30 mg/L) under visible light illumination (λ > 420 nm). The effects of SAPO-5 incorporation proportion and initial RhB concentration on the photocatalytic performance have been discussed in detail. The optimized SAPO-5/g-C3N4 composite shows promising degradation efficiency which is 40.6% higher than that of pure g-C3N4. The degradation rate improves from 0.007 min−1 to 0.022 min−1, which is a comparable photocatalytic performance compared with other g-C3N4-based heterojunctions for dye degradation. The migration of photo-induced electrons from g-C3N4 to the Al site of SAPO-5 should promote the photo-induced electron-hole pairs separation rate of g-C3N4 efficiently. Furthermore, the redox reactions for RhB degradation occur on the photo-induced holes in the g-C3N4 and Al sites in SAPO-5, respectively. This achievement not only improves the photocatalytic activity of g-C3N4 efficiently, but also broadens the application of SAPOs in the photocatalytic field.

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