scholarly journals Comparison between the photocatalytic degradation of single and binary azo dyes in TiO2 suspensions under solar light irradiation

2015 ◽  
Vol 5 (4) ◽  
pp. 579-591 ◽  
Author(s):  
Ohm-Mar Min ◽  
Li-Ngee Ho ◽  
Soon-An Ong ◽  
Yee-Shian Wong

Textile industries discharge a large quantity of colored wastewater which is harmful to the ecosystem. In this study, two kinds of dyes were investigated: the mono azo Acid Orange 7 (AO7) and diazo Reactive Green 19 (RG19). The photocatalytic degradation of single (AO7, RG19) azo dye and binary (AO7 and RG19 mixture) azo dye aqueous solutions was photocatalyzed by commercial titanium dioxide (TiO2, P25) under solar light irradiation. The objectives of this study are to compare the photocatalytic degradation between single and binary azo dye aqueous solution and to study the various parameters such as the effect of different initial azo dye concentrations, different initial azo dye pH values, and compare the adsorption capacity of azo dyes with and without solar light irradiation, which influences the photocatalytic activities of single and binary azo dye aqueous solutions in a TiO2 suspension. The results showed that photocatalytic degradation of AO7 and RG19 in a single azo dye aqueous solution was faster than a binary azo dye solution under the solar light irradiation process. Chemical oxygen demand results revealed that complete mineralization could be achieved for both AO7 and RG19 azo dyes under solar light irradiation within 22 hours.

2018 ◽  
Vol 42 (18) ◽  
pp. 15405-15412 ◽  
Author(s):  
María Emilia Villanueva ◽  
Guillermo Javier Copello ◽  
Viviana Campo Dall’Orto

The photocatalytic degradation of different emergent contaminants in aqueous solutions has been studied by using oligomer-coated TiO2 nanoparticles under solar light irradiation.


2021 ◽  
Author(s):  
Sivakumar S ◽  
A. Muthamilarasu ◽  
G. Divya ◽  
M. Sivakumar ◽  
D. Sakthi

Abstract The photocatalytic degradation and mineralization of ReactiveOrange30 on NiO/CuO/TiO2 ternary composites has been studied using solar light irradiation. This NiO/CuO/TiO2 ternary composites were prepared by different mass ratios of NiO and CuO/TiO2(3wt% to 15wt.%) on the ethonalic dispersion and annealed at 300˚ C. SEM, UV- Vis DRS, PL, XRD and FTIR analysis has used to characterize the all photocatalysts. NiO/CuO/TiO2 ternary composites demonstrate enhanced photocatalytic activity than NiO/TiO2, CuO/TiO2and pure TiO2 due to separation of photogenerated electrons and holes charges. The NiO/CuO/TiO2ternary composites shows good photostability and the photocatalyst retain the 94% of its initial activity in the seventh cycle, respectively.


2012 ◽  
Vol 48 (1-3) ◽  
pp. 245-251 ◽  
Author(s):  
Soon-An Ong ◽  
Li-Ngee Ho ◽  
Yee-Shian Wong ◽  
Ohm-Mar Min ◽  
Li-Sze Lai ◽  
...  

Author(s):  
Brijesh Pare ◽  
Satish Piplode ◽  
Vaishali Joshi

Flower like bismuth oxy chloride (BiOCl) was successfully synthesized by a simple hydrolytic method at room temperature. The precursor and as-prepared samples were characterized by X-ray diffraction (XRD), High Resolution Field Emission Scanning Electron Microscope (HR FESEM). The results indicated that the as-prepared BiOCl sample is self-assembled hierarchically with nano sheets. The photocatalytic activity of BiOCl was tested on the degradation of the Oxamyl (OM) under solar light irradiation. The results showed that pesticide molecules could be efficiently degraded over BiOCl under solar light irradiation. All the experiment were carried out in the following reaction condition, [OM] = 10-4 mol dm-3, BiOCl NPs= 40mg/50ml, pH= 6.3. Effect of operational parameter such as concentration of H2O2, K2S2O8, FeCl3, Fenton’s reagent (Fe3+/H2O2) and N2, O2 purging on the photocatalytic degradation was observed.


2012 ◽  
Vol 9 (6) ◽  
pp. 558 ◽  
Author(s):  
Lei Wu ◽  
Xuefeng Hu

Environmental context Aromatic amines are widely used chemicals, which show enhanced toxicity and longer environmental persistence when halogenated. We investigated the chlorination of aniline in seawater and in natural aqueous solutions containing Fe3+ and Cl–, under simulated sunlight irradiation. The results increase our understanding of the transformation pathway of typical nitrogen-containing aromatic contaminants in the environment. Abstract Photochlorination of aniline was observed in aqueous solutions containing dissolved FeIII and chloride ions under simulated solar light irradiation. Effects of O2, Cl–, Fe3+ and pH on the formation of chloroanilines (CAs) were investigated. para-chloroaniline (4CA) was identified as the main chlorinated product. The formation of 4CA is enhanced with increased concentrations of Cl– or Fe3+, and decreased pH, whereas oxygen plays a negligible role in the process. The results indicate that, Cl• is formed mainly by the photodissociation of FeCl2+–FeCl2+ complexes, and reacts with Cl– to produce Cl2•–. Aniline is then oxidised by Cl2•– into an anilino radical cation, which further reacts with Cl2•– to generate CAs. The photochlorination of aniline in natural seawater was also observed. Other phototransformation products of aniline were detected and a transformation pathway was proposed. This work provides evidence for the photochemical chlorination path of aniline-based aromatic amines in aqueous solutions.


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