scholarly journals Photocatalytic removal of eosin dye from aqueous solution over titanium dioxide

Author(s):  
Hazim Y Al-Gubury ◽  
Suad T Saad ◽  
Nour Abd Alrazzak ◽  
Ruqaia M Naif
2012 ◽  
Vol 433-440 ◽  
pp. 172-177 ◽  
Author(s):  
Chen Zhong Jia ◽  
Qiao Yan Qin ◽  
Yan Xin Wang ◽  
Cai Xiang Zhang

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.


Author(s):  
Ying Liang ◽  
Guohe Huang ◽  
Xiaying Xin ◽  
Yao Yao ◽  
Yongping Li ◽  
...  

Author(s):  
Rusmidah Ali ◽  
Boon Siew Ooi

Dalam kajian ini, ZnO dan TiO2 digunakan sebagai fotomangkin dalam pendegradasian pewarna New Methylene Blue N (NMBN). Kadar fotodegradasi diukur menggunakan alat spektrofotometer UV-Vis. Dalam kajian ini, New Methylene Blue N menunjukkan nilai serapan pada λ = 590 nm dan λ = 286 nm. Lampu UV (λ = 354 nm) digunakan dalam proses fotodegradasi. Dalam proses degradasi menggunakan ZnO menunjukkan 81.42% NMBN terdegradasi pada λ = 590 nm dan 77.75% pada λ = 286 nm. Sebaliknya, degradasi menggunakan TiO2 adalah 25.68% pada λ = 590 nm dan 26.37% pada λ = 286 nm. Peratus degradasi New Methylene Blue N ialah 88.89% dan 68.94% pada masing-masing λ = 590 nm dan λ = 286 nm apabila ditambahkan dengan H2O2. Campuran ZnO dan TiO2 dalam nisbah 85: 15 (0.085 g; 0.015 g) merupakan campuran fotomangkin yang paling optimum iaitu dengan peratus degradasi NMBN sebanyak 96.97% dan 93.61% pada λ = 590 nm dan λ = 286 nm. Penambahan ion logam Cu2+ memberikan peratus degradasi tertinggi berbanding ion logam lain iaitu 83.83% pada λ = 590 nm. Penambahan ion logam Pb2+ memberikan peratus degradasi tertinggi pada λ = 286 nm iaitu 81.25% pewarna terdegradasi. Keadaan optimum dicapai pada pH 5.90, dengan peratus degradasi tertinggi iaitu 92.84% dan 89.30% pada masing-masing λ = 590 nm dan λ = 286 nm. Kata kunci: New Methylene Blue N; fotodegradasi; larutan; ZnO; TiO2 In this study, ZnO and TiO2 are used as photocatalyst to degrade the dye, New Methylene Blue N (NMBN). The photodegradation rate was measured using UV-Visible spectrophotometer. In this study, New Methylene Blue N showed absorption values at λ = 590 nm and λ = 286 nm. UV lamp (λ = 354 nm) is used in the photodegradation process. Results showed that ZnO is a better photocatalyst compared to TiO2. The degradation by ZnO showed that 81% of NMBN was degraded at λ = 590 nm and 77.75% at λ = 286 nm. In contratst, the degradation using TiO2 was 25.68% at λ = 590 nm and 26.37% at λ = 286 nm. The percent degradation of New Methylene Blue N is 88.89% and 68.94% at λ = 590 nm and λ = 286 nm respectively when H2O2 was added. A mixture of ZnO and TiO2 in the ratio of 85: 15 (0.085 g: 0.015 g) is the most optimum ratio for the mixed photocatalyst where the degradation percentage of NMBN are 96.97% and 93.61% at λ = 590 nm and λ = 286 nm. The addition of Cu2+ metal ion gave the highest percentage of degradation (83.83% at λ = 590 nm) compared to other metal ions. The addition of Pb2+ gave the highest percentage of degradation at λ = 286 nm with 81.25% degradation of the dye. The optimum condition was achieved at pH 5.90, which gave the highest percentage degradation, 92.84% and 89.30% at λ = 590 nm and λ = 286 nm respectively. Key words: New Methylene Blue N; photodegradation; aqueous; ZnO; TiO2


1981 ◽  
Vol 10 (7) ◽  
pp. 957-960 ◽  
Author(s):  
Takayoshi Sasaki ◽  
Yu Komatsu ◽  
Yoshinori Fujiki

2014 ◽  
Vol 2 (1) ◽  
pp. 13
Author(s):  
Francisco Carlos Bontorim ◽  
Milton Carlos Kuga ◽  
Sabrina Spinelli Cioffi ◽  
Marcus Vinicius Reis Só ◽  
Gisele Faria ◽  
...  

PURPOSE: This study evaluated the effect of 10% sodium ascorbate (10SA), in gel (10SAg) or aqueous solution (10SAs) formulations, on fracture resistance of endodontically treated tooth submitted to dental bleaching procedures with 15% hydrogen peroxide associated with titanium dioxide (15HP-TiO2) nanoparticles and photoactivated by LED-laser. MATERIAL AND METHODS: Forty maxillary premolars were endodontically-treated and embedded in acrylic resin up to the cement-enamel junction. The specimens were divided into four groups (n=10): G1 (negative control): no bleaching, coronal access restored with composite resin; G2 (positive control): three dental bleaching  sessions using 15HP-TiO2 and LED-laser photoactivation and restored with composite resin (positive control); G3 (10SAg): similar procedures to G2, but applied  10SA, in gel formulation, for 24 hours before restoration; G4 (10SAs): similar procedures to G3, but applied  10SA, in aqueous solution formulation.  The 15HP-TiO2 was applied on buccal and lingual surfaces of the crown tooth and inside the pulp chamber and photoactivated by LED-laser. Between each bleaching session, the teeth were maintained in artificial saliva, at 37oC, for 7 days. In sequence, the teeth were submitted to fracture resistance testing using an eletromechanical machine test. The data was analyzed using Kruskal Wallis test (p = 0.05) RESULTS: There are no differences significant among the groups in relation to fracture resistance of endodontically treated teeth (p>0.05). CONCLUSIONS: The use of 10% sodium ascorbate, in gel or aqueous solution formulations, did not interfered on the fracture resistance teeth after dental bleaching using 15HP-TiO2 and LED-laser photoactivation.


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