scholarly journals A Comparative Study of Microcystin-LR Degradation by UV-A, Solar and Visible Light Irradiation Using Bare and C/N/S-Modified Titania

Catalysts ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 877 ◽  
Author(s):  
Khedr ◽  
El-Sheikh ◽  
Abdeldayem ◽  
Ismail ◽  
Kowalska ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Degradation Rate ◽  
Ph Value ◽  
Mesoporous Structure ◽  
Light Irradiation ◽  
Solar Irradiation ◽  
Bare Tio2 ◽  
Cyanobacteria Blooms ◽  
Degradation Rate Constant

In an endeavor to tackle environmental problems, the photodegradation of microcystin-LR (MC-LR), one of the most common and toxic cyanotoxins, produced by the cyanobacteria blooms, was examined using nanostructured TiO2 photocatalysts (anatase, brookite, anatase–brookite, and C/N/S co-modified anatase–brookite) under UV-A, solar and visible light irradiation. The tailoring of TiO2 properties to hinder the electron–hole recombination and improve MC-LR adsorption on TiO2 surface was achieved by altering the preparation pH value. The highest photocatalytic efficiency was 97% and 99% with degradation rate of 0.002 mmol L−1 min−1 and 0.0007 mmol L−1 min−1 under UV and solar irradiation, respectively, using a bare TiO2 photocatalyst prepared at pH 10 with anatase to brookite ratio of ca. 1:2.5. However, the bare TiO2 samples were hardly active under visible light irradiation (25%) due to a large band gap. Upon UV, solar and vis irradiation, the complete MC-LR degradation (100%) was obtained in the presence of C/N/S co-modified TiO2 with a degradation rate constant of 0.26 min−1, 0.11 min−1 and 0.04 min−1, respectively. It was proposed that the remarkable activity of co-modified TiO2 might originate from its mixed-phase composition, mesoporous structure, and non-metal co-modification.

scholarly journals Study on synthesis of MoS2 modified g-C3N4 materials for treatment of Direct black 38 dye

2018 ◽  
Vol 9 (3) ◽  
pp. 169-176
Author(s):  
Thi Lan Phung ◽  
Thi Kim Giang Nguyen
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Photocatalytic Performance ◽  
Ph Value ◽  
Light Irradiation ◽  
Order Kinetic ◽  
Two Factors ◽  
Pseudo Second Order ◽  
Enhanced Adsorption ◽  
Adsorption Desorption

Pure g-C3N4 and MoS2 modified g-C3N4 materials were synthesized using a facile heating method and a low-temperature hydrothermal method, respectively. The obtained samples were characterized by XRD pattern and N2 adsorption-desorption technique at 77K. The adsorption and photocatalytic performance of all obtained samples were investigated by discoloration of direct black 38 dye in the dark and under visible light irradiation. The results showed that all obtained samples exhibited good discoloration efficiency of direct black 38 dye. The two factors including pH values and Mo loading effected mainly on elimination efficiency of direct black 38 dye. MoS2 modified g-C3N4 materials possessed the more enhanced adsorption and photocatalytic performance in comparison to pure g-C3N4 at pH value of 3.5, with adsorbent dosage of 0.1 g/L. Furthermore, it was found that the adsorption process and photo-catalysis simultaneously occurred under visible light irradiation and followed up a pseudo-second-order kinetic reaction of Langmuir - Hinshelwood model. g-C3N4 và g-C3N4 biến tính bởi MoS2 đã được tổng hợp theo phương pháp nung đơn giản và phương pháp thủy nhiệt ở nhiệt độ thấp tương ứng. Các mẫu tổng hợp đã được đánh giá đặc trưng bởi các phương pháp hiện đại như giản đồ nhiễu xạ tia X, phương pháp hấp phụ-khử hấp phụ N2 ở 77K. Khả năng hấp phụ và quang hóa xúc tác của các vật liệu tổng hợp đã được nghiên cứu bởi quá trình phân hủy màu thuốc nhuộm direct black 38 trong điều kiện bóng tối và chiếu sáng bởi ảnh sáng nhìn thấy của đèn chiếu sáng sợi đốt wolfram (220V-100W). Các kết quả nghiên cứu chỉ ra rằng các mẫu tổng hợp đều có hiệu suất xử lý màu cao đối với thuốc nhuộm direct black 38. Hai yếu tố gồm pH dung dịch và hàm lượng MoS2 ảnh hưởng chính đến hiệu suất xử lý màu direct black 38. g-C3N4 biến tính bởi MoS2 luôn thể hiện hiệu suất hấp phụ và quang hóa cao hơn so với g-C3N4 tinh khiết. Hơn nữa, khi được chiếu sáng bởi ánh sáng nhìn thấy thì quá trình hấp phụ và quá trình quang hóa thuốc nhuộm direct black 38 trên các vật liệu tổng hợp đã xảy ra đồng thời và mô hình Langmuir - Hinshelwood động học bậc 2 đã được đề xuất cho quá trình này.

scholarly journals Enhanced Transformation of Atrazine by High Efficient Visible Light-Driven N, S-Codoped TiO2Nanowires Photocatalysts

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Yanlin Zhang ◽  
Honghai Wu ◽  
Peihong Liu
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Advanced Oxidation Process ◽  
Light Irradiation ◽  
Solar Irradiation ◽  
Electron Hole ◽  
Toc Removal ◽  
High Efficient ◽  
Endocrine Disrupting ◽  
Visible Light Driven

Advanced oxidation process using titanium dioxide as a photocatalyst under solar irradiation is one of the most attractive technologies to eliminate atrazine, an endocrine disrupting and carcinogen contaminant. The N, S-codoped TiO2nanowires at the calcination of 600°C obtained by a facile hydrothermal method revealed the best photocatalytic performance for the degradation of atrazine under visible light irradiation compared to N, S-codoped TiO2nanoparticles and S-doped TiO2nanowires. TOC removal experiment also exhibited the similar result and achieved 63% of atrazine mineralization within 6 h. The degradation of atrazine was driven mainly by•OH and holes during the photocatalytic process. Reactive species quantities such•OH andO2•-generated by N, S-codoped TiO2nanowires under visible light irradiation were much more than those of S-doped TiO2nanowires and N, S-codoped TiO2nanoparticles. These results were mainly attributed to the synergistic effect of N and S doping in narrowing the band gap, remarkable increase in electron-hole separation, extending the anatase-to-rutile transformation temperature above 600°C, and preferentially exposing high reactive{001}crystal facets of anatase.

scholarly journals Nanocrystalline N-DopedTiO2Powders: Mild Hydrothermal Synthesis and Photocatalytic Degradation of Phenol under Visible Light Irradiation

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Junna Xu ◽  
Feng Wang ◽  
Wenxiu Liu ◽  
Wenbin Cao
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Ph Value ◽  
Guanidine Hydrochloride ◽  
Initial Pressure ◽  
Light Irradiation ◽  
Titanyl Sulfate ◽  
Visible Absorption ◽  
Light Region ◽  
Initial Ph

Nitrogen-doped TiO2powders have been prepared using technical guanidine hydrochloride, titanyl sulfate, and urea as precursors via a mild hydrothermal method under initial pressure of 3MPa,150∘Cholding for 2h without any postheat treatment for crystallization. The nanocrystalline N-doped TiO2powders were composed of anatase TiO2by XRD. The grain size was estimated as about 10 nm, and the BET specific surface area of the powder was measured as 154.7 m2/g. The UV-visible absorption spectra indicated that the absorption edge of the N-doped TiO2powders had been red shifted into the visible light region. The photocatalytic performance of the synthesized powders was evaluated by degradation of phenol under visible light irradiation. And the effects of the catalyst load and the initial pH value on the photodegradation were also investigated.

Optimum Conditions of Ag/BiVO4 Photocatalytic Performance on Degradation of Paracetamol by Response Surface Methodology

2014 ◽  
Vol 1073-1076 ◽  
pp. 336-339
Author(s):  
Tian Qi Li ◽  
Hui Wang ◽  
Ya Qi Zhu ◽  
Zhao Yong Bian
Keyword(s):  
Response Surface Methodology ◽  
Visible Light ◽  
Response Surface ◽  
Visible Light Irradiation ◽  
Ph Value ◽  
Light Irradiation ◽  
Catalyst Loading ◽  
Optimum Conditions ◽  
Initial Ph ◽  
Ag Catalyst

Response surface methodology was applied to investigate the optimum degradation conditions of paracetamol using Ag/BiVO4 photocatalysts under the visible light irradiation. Experimental results show that the optimum degradation conditions were: catalyst dosage quantity was 80 mg, Ag-catalyst loading was 5%, and the initial pH value of the solution was 6, respectively. Under this condition, the degradation efficiency of paracetamol was 77.9% within 5 h under the visible light irradiation.

Photocatalytic Activity of Nonprecious Metal WSe2/g-C3N4 Composite Under Visible Light Irradiation

NANO ◽  
2020 ◽  
Vol 15 (04) ◽  
pp. 2050042
Author(s):  
Jieqiong Wang ◽  
Jie Yang ◽  
Jian Fang ◽  
Yuhang Li ◽  
Hongyuan Zhang ◽  
...  
Keyword(s):  
Methyl Orange ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Degradation Rate ◽  
Low Cost ◽  
Photogenerated Electron ◽  
Methyl Orange Solution ◽  
Light Irradiation ◽  
New Material ◽  
Orange Solution

The WSe2/g-C3N4 (graphite carbon nitride) composite with photocatalytic properties was synthesized using a hydrothermal method. This synthesis pathway can be characterized by being simple, inexpensive and nonpolluting, integrating the concept of green chemistry. The WSe2/g-C3N4 composite could effectively degrade methyl orange solution under visible light irradiation. The decolorization experiment of methyl orange solution shows that the degradation rate of the 30[Formula: see text]wt.% WSe2/g-C3N4 composite can reach 98.7% after 100[Formula: see text]min of illumination, while the degradation rate of pure g-C3N4 was only 87.6% under the same conditions. This can be attributed to the fact that the combination of WSe2 and g-C3N4 nanosheets can increase the number of active binding sites, increasing the rate of charge separation and transport ability, decreasing the recombination rate of the photogenerated electron–hole pairs. Therefore, the WSe2/g-C3N4 composite will have potential development as a new material with low cost, easy synthesis and excellent performance in photocatalytic degradation of water pollution.

scholarly journals Fabrication of metal-free PTET-T-COOH/g-C3N4 heterostructure for enhancing photocatalytic activity

RSC Advances ◽  
2020 ◽  
Vol 10 (15) ◽  
pp. 9116-9125 ◽  
Author(s):  
Linlin Liu ◽  
Xingyue Song ◽  
Xiangxin Kong ◽  
Qian Duan ◽  
Enwei Zhu
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Degradation Rate ◽  
Light Irradiation ◽  
Metal Free ◽  
High Degradation Rate

The metal-free PTET-T-COOH/g-C3N4 heterostructure exhibits a high degradation rate for RhB under visible light irradiation.

Synthesis of Uranium Doped TiO2 Nanomaterial and its Visible Light Degradation Property

2010 ◽  
Vol 148-149 ◽  
pp. 1208-1211 ◽  
Author(s):  
Shao You Liu ◽  
Qing Ge Feng
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Ph Value ◽  
Pure Tio2 ◽  
Anatase Tio2 ◽  
Light Irradiation ◽  
Reaction Route ◽  
Light Region ◽  
Tio2 Nanomaterials ◽  
Visible Light Degradation

Uranium doped TiO2 (U-TiO2) nanomaterials, determined by scanning electron micro- graphy (SEM), were successfully synthesized via a simple, effective and environmental benign solid state reaction route. The characterizations via XRD and XPS showed that the uranium has been entered into the framework of anatase TiO2. The DRUV-Vis revealed that the adsorption region of U-TiO2 nanomaterials shifts to the visible light region compared with the pure TiO2. Moreover, the U-TiO2 nanomaterials for photodegradation of quinoline showed a good photocatalytic properties under visible light irradiation. At 298K, within 60 min visible light irradiation, 54.9 % of the initial quinoline was degraded by the U-TiO2 (U/Ti=3:20) catalyst. The visible light degradation rate of the U-TiO2 nanomaterials is negative to the pH value of surface but positive to the visible light absorption range.

Structural assembly from 1D to 3D motivated by the linear co-ligands, and the magnetic and photocatalytic properties of five NiII coordination polymers with 5-(4′-carboxylphenyl)nicotinic acid

2018 ◽  
Vol 42 (22) ◽  
pp. 17991-18000 ◽  
Author(s):  
Zhixiang Wang ◽  
Yixia Ren ◽  
Jia Cao ◽  
Long Tang ◽  
Meili Zhang ◽  
...  
Keyword(s):  
Visible Light ◽  
Nicotinic Acid ◽  
Coordination Polymers ◽  
Visible Light Irradiation ◽  
Degradation Rate ◽  
Structural Diversity ◽  
Light Irradiation ◽  
Photocatalytic Properties ◽  
Structural Assembly

Five structural diversity nickel(ii) complexes based on 5-(4′-carboxylphenyl) nicotinic acid and linear co-ligands are described. The antiferromagnetic interactions exist in them expect for 2. All of them could accelerate the degradation rate of MO under visible light irradiation.

Synthesis and Photocatalytic Activities of Bamboo-Like FeVO4 Nanocrystalline

2017 ◽  
Vol 46 ◽  
pp. 123-134 ◽  
Author(s):  
Guo Qiang Tan ◽  
Chi Xu ◽  
Hui Jun Ren ◽  
Wei Yang ◽  
Cheng Cheng Zhao ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Degradation Rate ◽  
Energy Gap ◽  
Hydrothermal Reaction ◽  
Uv Light ◽  
Light Irradiation ◽  
Molar Ratio ◽  
Microwave Hydrothermal ◽  
Photocatalytic Activities

The bamboo-like FeVO4 nanocrystallines were synthesized by a two-step method of the microwave hydrothermal-calcination, using Fe (NO3)3·9H2O and NH4VO3 as raw materials. The physical and photophysical properties of the as-prepared photocatalysts were fully characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), UV-vis diffuse reflectance spectra and photoluminescence (PL) analysis. The photocatalytic activities were evaluated by the decolorization of RhB solution under UV and visible light irradiation. The results reveal that the precursor solution concentration is 0.15 mol/L, the molar ratio n (Fe)/n (V) is 1, pH=3.0. The microwave hydrothermal reaction is at 180 °C for 120 min and then calcinated under 550 °C for 3 h so as to obtain the triclinic FeVO4 nanocrystalline. Along [120] and [110], the fore and aft phases of the crystal orientation are bonded self-assembly to grow into the bamboo-like nanocrystalline with the energy gap of 2.42 eV. Under the UV-light irradiation for 240 min, the degradation rate of RhB is up to 91.2%. Adding 0.1 mL H2O2 to the solution, the out-phase photo-fenton reaction occurs and the degradation rate to RhB can reach to 98.8% after 8 h visible-light irradiation.

Sign in / Sign up

Export Citation Format

Share Document