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Photocatalytic degradation of methylene blue dye under visible light irradiation using In / ZnO nanocomposite
| Content Provider | Semantic Scholar |
|---|---|
| Author | Baeissa, Es |
| Copyright Year | 2016 |
| Abstract | A solgel method was used to prepare ZnO nanoparticles, and a photo-assisted deposition method was used to deposit indium into the surface of ZnO nanoparticles. BET, XRD, XPS, Pl, UV-Vis and TEM measurements were used to characterize the ZnO and Pt/ ZnO nanoparticles. The photocatalytic oxidation of methylene blue dye under visible light irradiation was used to determine the photocatalytic performance of the prepared nanoparticles. The results demonstrated that the indium was well dispersed on the surface of the ZnO nanoparticles. Additionally, the surface area of the In/ZnO nanoparticles was smaller than that of the ZnO nanoparticles because some of the pores of the ZnO nanoparticles were blocked by the deposited In metal. The In/ ZnO nanoparticles (0.6 wt%) exhibited the lowest band gap and the highest photocatalytic activity for the methylene blue dye. The photocatalytic performance of the 0.6 wt% In/ZnO nanoparticles was stable after the nanoparticles were reused five times for the oxidation of methylene blue dye. Introduction In recent years, the contamination of surface and ground water has increased due to population growth. The main sources of environmental contamination are organic dyes used in the food and textile industries due to their high toxicity and their nonbiodegradability, which have carcinogenic effects on humans. MB dye is used by different industries, for example, as a dye in silk; as a food colouring additive; and as a dye in wool, leather, cotton, jute, and paper [1-3]. Methylene blue dyes have strong effects on the immune and reproductive systems and exhibit potential carcinogenic and genotoxic effects [4,5]. Thus, these hazardous dyes must be removed from industrial effluents. Many methods, such as biological treatment [6,7], adsorption [8], and photocatalysis [9-13], have been used for removal of these dyes from industrial effluents. The use of photocatalysts to degrade organic compounds in contaminated air or water or to convert them into harmless chemicals has been extensively studied to decrease the damage caused by organic dye pollution to the environment and humans [14]. Therefore, heterogeneous photocatalysis is an interesting area of research because the method allows for complete mineralization of these environmentally hazardous dyes [13]. Among a variety of photocatalysts, TiO2 is the most common photocatalyst due to its non-toxicity, good activity and high resistance to corrosion. One of the disadvantages for the use of titanium dioxide is its absorption in the UV region, which represents approximately 5% of sunlight. Therefore, the absorption of the photocatalyst must be altered to move it from the UV to visible region. Many methods have been studied to extend the absorption of photocatalysts from the UV to the visible region, such as variation of the titanium dioxide by metal or non-metal [14,15]. Other attempts have focused on preparing new photocatalysts, such as multi-metal oxide photocatalysts [16-19]. Zinc Oxide (ZnO) belongs to a category of n-type semiconductors having wide energy band gap of 3.37 eV. Recently, ZnO has attracted much attention as a promising photocatalytic material for removal of organic pollutants, which present in wastewater, all because of its high catalytic activity, moderate preparation cost and environmentally benign nature [2023]. Nanoscale ZnO particles possess significant surface area and large number of active sites ensure increased surface catalyzed reaction rates thus promoting photocatalysis [24]. However, the large energy band gap of ZnO permits electronic excitations only with photons having energy below 400 nm (UV spectrum). High degree of recombination of photogenerated species is another limitation associated with ZnO which is responsible for low photocatalytic activity [25-28]. These shortfalls can be remediated by modifying ZnO such as to extend its absorption threshold to the visible spectrum and limiting the rate of electron/hole pair recombination. Different attempts were achieved recently to improve the activity of ZnO photocatalyst. Development of nanoscale core/shell materials is a worth mentioning technique receiving considerable attraction [29,30]. The functional groups attached on the outer shell provide with the surface charge and reactivity to the surface and may also help to stabilize and provide equal dispersion of the core material. On other hand the characteristic catalytic, optoelectronic or magnetic properties of the shell may also be imparted to the core particles. The main aim to synthesize core/ shell structured materials is to achieve a mix of the best qualities of the components in the composite materials. A number of studies focused on the synthesis of composite materials such as; NiO [31], V2O5 [32], TiO2 [33], Fe2O3 [34], Pt [35], and Ag [36-37] with SiO2 coatings have been reported. SiO2 has been given significant consideration as a shell candidate based on easy preparation, environmental friendliness and conformity with most other materials, which provides and ample motivation to synthesize the ZnO and SiO2 core/shell structured composite with expectation of achieving novel photocatalytic Correspondence to: Elham Baeissa, Chemistry Department, Faculty of Science, King Abdulaziz University, P.O. Box 80203 Jeddah 21589, Saudi Arabia, Tel.: +966-6400000; Fax: +966-2-6952292E-mail: elhambaeissa@gmail.com |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.oatext.com/pdf/FNN-2-134.pdf |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Adverse reaction to drug Artificial nanoparticles Chemical vapor deposition Conformity Corchorus capsularis Corrosion of Medical Device Material Dyes Electron hole Electronic band structure Elegant degradation Environmental Pollution Fax Fetal Growth Retardation GIS in environmental contamination Guilty Gear Xrd Indium Industrial PC License Light, Visible Mandibular right second molar tooth Maxima and minima Megabyte Methylene blue Nanocomposite Numerous Open XML Paper Specification Organic Chemicals Percent Mass per Mass Photons Physiologic calcification Preparation Promotion (action) Reproduction Semiconductor Semiconductors Silver Small Textile Industry Textiles Utility functions on indivisible goods Wool X-Ray Photoelectron Spectroscopy Zinc Oxide carbene metal oxide oxidation patent blue violet titanium dioxide vanadium pentoxide |
| Content Type | Text |
| Resource Type | Article |
