Photocatalytic degradation of MC-LR in water by the UV/TiO2/H2O2 process

2015 ◽  
Vol 16 (1) ◽  
pp. 34-43 ◽  
Author(s):  
Wei-ying Li ◽  
Yao Liu ◽  
Xiu-li Sun ◽  
Feng Wang ◽  
Lin Qian ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Titanium Dioxide ◽  
Free Radicals ◽  
Synergistic Effect ◽  
Photocatalytic Degradation ◽  
Uv Irradiation ◽  
Removal Rate ◽  
Optimum Conditions ◽  
Initial Concentration ◽  
High Production

The ultraviolet (UV)/titanium dioxide (TiO2)/hydrogen peroxide (H2O2) process (UTHP) has been proven to be effective in removing organics because of its high production of free radicals. In this study, UTHP was further investigated for the photocatalytic degradation of microcystin-LR (MC-LR). Results showed that three mechanisms could realize MC-LR photocatalytic degradation using TiO2. H2O2 could effectively inhibit recombination and considerably improve the production of radicals and superoxides. From a correlation of the removal rate with the isomerization and decomposition of MC-LR under UV irradiation it was inferred that isomerization was crucial for MC-LR degradation during photocatalysis given the vulnerability of the exposed conjugated double bonds. The photocatalysis of MC-LR was apparently dependent on pH and MC-LR initial concentration. Under the optimum conditions of pH 3.5, 0.05 g/L TiO2, and 0.05 mmol/L H2O2, 100% MC-LR (308 μg/L) could be removed within 60 min. This process was accompanied by a synergistic effect during the initial 10 min.

Study on the Photocatalytic Degradation of Ammonia Nitrogen in Aquaculture Wastewater by Fe3+-Doped Nano-TiO2 under UV Irradiation

2012 ◽  
Vol 476-478 ◽  
pp. 2001-2004
Author(s):  
Xiao Cai Yu ◽  
Peng Fei Zhu ◽  
Kui Sheng Song ◽  
Dong Dong Hu ◽  
Qian Du
Keyword(s):  
Reaction Time ◽  
Photocatalytic Degradation ◽  
Uv Irradiation ◽  
Volume Fraction ◽  
Ph Value ◽  
Removal Rate ◽  
Ammonia Nitrogen ◽  
Nano Tio2 ◽  
Initial Concentration ◽  
Aquaculture Wastewater

The Fe3+-doped nano-TiO2 catalyst with various amounts of dopant Fe3+ irons was prepared by a sol-gel method. The products were characterized by XRD and SEM. The photocatalytic degradation of ammonia nitrogen in aquaculture wastewater was investigated by using Fe3+-doped nano-TiO2 under UV irradiation. In the experiment, the effect of Fe3+/TiO2 dosage, the ratio of dopant Fe3+, ammonia-N initial concentration, pH value, H2O2 volume concentration, and reaction time, respectively, on the removal of ammonia-N was investigated. The experimental results can be stated as follows: when the ratio of dopant Fe3+ was 0.25% wt, the dosage of Fe3+/TiO2 was 0.7 g/L, the initial concentration of ammonia-N was 10 mg/L, H2O2 volume fraction was 4 %, respectively, if the reaction time may last 4 h, the removal rate of ammonia-N was expected to reach 97.17 %.

Photocatalytic Degradation of Bisphenol A in Aqueous Suspensions of Titanium Dioxide

2012 ◽  
Vol 433-440 ◽  
pp. 172-177 ◽  
Author(s):  
Chen Zhong Jia ◽  
Qiao Yan Qin ◽  
Yan Xin Wang ◽  
Cai Xiang Zhang
Keyword(s):  
Aqueous Solution ◽  
Titanium Dioxide ◽  
Kinetic Model ◽  
Bisphenol A ◽  
Photocatalytic Degradation ◽  
Rate Constant ◽  
Removal Rate ◽  
Mercury Vapor ◽  
Initial Concentration ◽  
Photocatalytic Removal

Photocatalytic degradation of bisphenol A in aqueous solution by UV-TiO2 was studied in self-made photocatalysis reactor. The results showed that BPA was degraded effectively in UV-TiO2 photocatalysis system, and the processe followed Langmuir-Hinshelwood kinetic model. When TiO2 was dosed at 1.0 g/L, air amount was 1.2 L/min, BPA initial concentration was 10 mg/L with pH=5.5, and irradiated by a 15 W low pressure mercury vapor discharge lamp, the removal rate of BPA was up to 97%, and BPA was completely removed in 80 min when pH≥9.5; The photocatalytic removal rate constant was strongly related to the above factors.

PHOTOCATALYTIC DEGRADATION OF PYRENE IN POROUS Pt/TiO2–SiO2 PHOTOCATALYST SUSPENSION UNDER UV IRRADIATION

NANO ◽  
2008 ◽  
Vol 03 (05) ◽  
pp. 317-322 ◽  
Author(s):  
ZHAOHUI LUO ◽  
KEIKO KATAYAMA-HIRAYAMA ◽  
KIMIAKI HIRAYAMA ◽  
TETSUYA AKITSU ◽  
HIDEHIRO KANEKO
Keyword(s):  
Molecular Weight ◽  
Photocatalytic Degradation ◽  
High Molecular Weight ◽  
Uv Irradiation ◽  
Degradation Kinetics ◽  
Degradation Process ◽  
Bet Surface Area ◽  
Experimental Conditions ◽  
Initial Concentration ◽  
X Ray

Pyrene is a high molecular weight polycyclic aromatic hydrocarbon (PAH) that is found in water systems worldwide. It is harmful to living organisms, even when taken in very small amounts. The photocatalytic degradation of pyrene in porous Pt / TiO 2– SiO 2 photocatalyst (PPtPC) suspension under UV irradiation was investigated in this study. PPtPC was prepared by a simple heat treatment of the compacted powder mixtures of anatase TiO 2 and amorphous SiO 2 with camphor as a pore directing template, followed by coating platinum by the dip-coating method. X-ray diffraction (XRD), scanning electron microscopy (SEM) with an integrated energy-dispersive analysis of the X-ray (EDX) system, and Brunauer–Emmett–Teller (BET) were used to characterize PPtPC. The degradation kinetics of pyrene in different experimental conditions, such as initial concentration of pyrene, oxygen concentrations, pH, and temperature, were investigated. The durability of PPtPC was also tested. The results indicate that the structure of TiO 2 in PPtPC is anatase. The aggregated size of PPtPC is in the range of 10–100 μm, the mean pore diameter is 3 nm, and the BET surface area is 109 m2 g-1. The photocatalytic degradation process of pyrene follows pseudo-first-order kinetics. The rate constants increase as the initial concentration of pyrene and pH decrease. Higher temperature slightly enhances the rate constant. The dissolved oxygen in the photocatalytic degradation process is not as important as in the photolysis process. The recovered PPtPC still shows high photoactivity. This work suggests that PPtPC offers a promising method for high molecular weight PAH removal.

Hydrogen peroxide-assisted photocatalytic degradation of textile wastewater using titanium dioxide and zinc oxide

2017 ◽  
Vol 40 (10) ◽  
pp. 1223-1232 ◽  
Author(s):  
Fernando Santos Domingues ◽  
Thábata Karoliny Formicoli de Souza Freitas ◽  
Cibele Andrade de Almeida ◽  
Renata Padilha de Souza ◽  
Elizângela Ambrosio ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Zinc Oxide ◽  
Titanium Dioxide ◽  
Photocatalytic Degradation ◽  
Textile Wastewater

Study on the Photocatalytic Degradation of Diesel Pollutants over a Sol-Gel Prepared TiO2

2012 ◽  
Vol 476-478 ◽  
pp. 1926-1929
Author(s):  
Xiao Cai Yu ◽  
Dong Dong Hu ◽  
Qian Du ◽  
Xv Zheng ◽  
Ji Yao Guo
Keyword(s):  
Reaction Time ◽  
Photocatalytic Degradation ◽  
Room Temperature ◽  
Ph Value ◽  
Removal Rate ◽  
Sol Gel ◽  
Initial Concentration ◽  
Five Factors ◽  
Degradation Reaction ◽  
Diesel Degradation

Nanoscale titanium dioxide (TiO2) has been fabricated through a sound sol-gel method at room temperature with Tetra-n-butyl Titanate as the precursor, and the particles are characterized by XRD and TEM techniques. The results manifest that the as-prepared TiO2 is amorphous with the anatase structure and its size is around 33.2nm. Five factors, including dosage of TiO2, initial concentration of diesel, pH value, photocatalytic degradation reaction time and the presence of H2O2, are considered in the diesel degradation experiments. An orthogonal test is carried out to optimize the photocatalytic degradation of diesel pollutants based on the single-factor experiments. It reveals that when the dosage of TiO2 is 1.0g/L, the initial concentration of diesel is 0.5g/L, pH value is 6, the reaction time is 4h and the H2O2 dosage is 0.09%, the removal rate of diesel pollutants can up to 88%. Besides, the influence of each factor on removing diesel can be arranged in decreasing order: initial concentration of diesel> photocatalytic reaction time> pH value> TiO2 dosage> H2O2 dosage.

Effects of pH, Temperature and Various Anions on Thiourea Disappearance in Aqueous Media with Titanium Dioxide Under UV-Irradiation. Photomineralization Kinetics

2001 ◽  
Vol 66 (4) ◽  
pp. 676-684 ◽  
Author(s):  
Abdelghani Boussaoud ◽  
Gerard Duc ◽  
Jean Pierre Meille ◽  
Michelle Petit-Ramel
Keyword(s):  
Titanium Dioxide ◽  
Uv Irradiation ◽  
Initial Rate ◽  
Aqueous Media ◽  
Inorganic Anions ◽  
Disappearance Rate ◽  
Initial Concentration ◽  
Effects Of Ph ◽  
Nitrite Nitrate ◽  
Kinetics Of

Disappearance of thiourea in aqueous suspensions of TiO2 or ZnO occurs under near-UV irradiation. The effects of some parameters such as initial concentration of thiourea, temperature, pH and common inorganic anions were examined. The results indicate that the process follows the Langmuir-Hinshelwood type kinetics. In the presence of anions such as nitrates, chlorides and sulfates, the initial disappearance rate of thiourea at pH 6 drops. It is found that the initial rate of thiourea disappearance increases when temperatue of reaction mixture increases. Finally, kinetics of thiourea photomineralization to nitrite, nitrate, sulfite and sulfate are established.

Experiments of Separating and Featuring an Efficient SRB

2012 ◽  
Vol 170-173 ◽  
pp. 2344-2347
Author(s):  
Yan Li Jiang ◽  
Ai Hua Li ◽  
Jun Zhen Di ◽  
Xiao Li Niu ◽  
Jian Zheng ◽  
...  
Keyword(s):  
Acid Mine Drainage ◽  
Theoretical Foundation ◽  
Mine Drainage ◽  
Removal Rate ◽  
Sulfate Reducing Bacteria ◽  
Optimum Conditions ◽  
Initial Concentration ◽  
Sulfate Reducing ◽  
Acid Mine ◽  
Reducing Bacteria

By experiments, separate and purify efficient sulfate—reducing bacteria (SRB), which is identified as Desulfobacter. With its treatment of acid mine drainage(AMD) containing Fe2+ and Mn2+, obtain the optimum conditions that pH=6,temperature=37,vibrating intensity=100r/min, COD/SO42- =2.Under this condition ,the removal rate of SO42-、Fe2+ and Mn2+ is 88.16%、99.37% and 59.18% respectively with the initial concentration 1411mg/L for SO42-,257mg/L for Fe2+ and 325mg/L for Mn2+.This puts a theoretical foundation for the further study.

Fabrication of Smooth Surface on 4H-SiC Substrate by Ultraviolet Assisted Local Polishing in Hydrogen Peroxide Solution

2012 ◽  
Vol 523-524 ◽  
pp. 24-28 ◽  
Author(s):  
Akihisa Kubota ◽  
Kazuya Kurihara ◽  
Mutsumi Touge
Keyword(s):  
Hydrogen Peroxide ◽  
Oxide Layer ◽  
Uv Irradiation ◽  
Process Parameters ◽  
Removal Rate ◽  
Single Crystal Silicon ◽  
Interference Microscopy ◽  
Process Time ◽  
Crystal Silicon ◽  
Synthetic Quartz

In this study, we investigated the possibility of removing and smoothing a single-crystal silicon carbide (SiC) surface under ultraviolet (UV) irradiation in hydrogen peroxide (H2O2) solution. In this method, a SiC substrate was excited by UV irradiation that transmitted synthetic quartz, and then an oxide layer on the SiC substrate was formed by photochemical reaction. Simultaneously, hydroxyl radical (OH*) was generated by the decomposition of H2O2 solution by UV irradiation. OH* plays an important role of oxidation of SiC surface. With these chemical reactions, oxide layer was effectively formed on the SiC surface. Finally, the oxide layer generated on a SiC substrate was chemically and/or mechanically removed by synthetic quartz and solutions. The polishing characteristics of this method were investigated by controlling the process parameters. Additionally, surface quality and removal depth were measured and evaluated by a phase-shift interference microscopy. Obtained results show that the surface morphology and the removal rate are strongly dependent on the existence of the UV irradiation. Moreover, it is shown that the removal characteristics of the SiC substrate depend on the process parameters such as the process time, reciprocating speed, and contact load. The processed surface has revealed that many scratches on the preprocessed surface was completely removed. The microroughness of the processed surface was improved to 0.15 nm (Rms) and 1.62 nm (p-v), respectively. These results provide useful information for obtaining an atomically smooth SiC surface.

Photocatalytic Degradation of the Cyanotoxin Cylindrospermopsin, using Titanium Dioxide and UV Irradiation

2001 ◽  
Vol 35 (5) ◽  
pp. 1245-1255 ◽  
Author(s):  
P.-J Senogles ◽  
J.A Scott ◽  
G Shaw ◽  
H Stratton
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Degradation ◽  
Uv Irradiation
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