Optimization of preparation conditions of ZnO–SiO2 xerogel by sol–gel technique for photodegradation of methylene blue dye

Abstract

The ZnO-SiO 2 xerogel photocatalyst was prepared via the sol-gel technique and applied for photodegradation of methylene blue (MB) dye. The optimum conditions for preparation of ZnO-SiO 2 gel is 30:70 ZnO:SiO 2 molar ratio and TEOS:C 2 H 5 OH:H 2 O:HNO 3 is 1:16:12:0.04 molar ratios at 30°C for 30 min, at these conditions the photoactivity of ZnO-SiO 2 xerogel was 99% at a surface area of 500 m 2 /g after 60 min. The optimum loading of ZnO-SiO 2 photocatalyst was 0.050 wt% that gives 99% MB dye removal efficiency after 40 min. The overall kinetics of photodegradation of MB dye using ZnO-SiO 2 photocatalyst was found to be of the first order.

Zeolite Y from rice husk ash encapsulated with Ag-TiO2: characterization and applications for photocatalytic degradation catalysts

“…Given the current concern regarding environmental issues, it is anticipated that applications for TiO 2 will grow at increasing speed; in particular, urgent improvement of the TiO 2 photocatalytic degradation is needed for large-scale industrial treatment processes, such as wastewater treatment and de-NOx. From the green chemistry viewpoint, the photocatalytic decomposition of organic compounds in wastewater has attracted a great deal of attention [11][12][13][14][15][16][17][18][19][20][21][22]. The TiO 2 is one of the most effective photocatalysts because it is generally biologically and chemically inert, and is photostable with near-UV band gap energy.…”

Photocatalytic Degradation of Methylene Blue by Fe/ZnO/SiO2Nanoparticles under Visiblelight

“…In previous study, we prepared ZnO/SiO 2 xerogel by conventional solgel method, in which tetraethyl orthosilicate (Si(OC 2 H 5 ) 4 ) was used as the precursor and zinc nitrate hexahydrated (Zn(NO 3 ) 2 ·6H 2 O) was the source of zinc. The prepared xerogel examined as photocatalyst for the degradation of methylene blue dye in aqueous solution under UV-light irradiation [6]. But because the solar spectrum usually contains about 5% UV-light, the solar energy could not be utilized efficiently in the photocatalytic process.…”

Applying facilely synthesized CuO/CeO2 photocatalyst to accelerate methylene blue degradation in hypersaline wastewater

“…18 In addition, the Cu 2p 1/2 and Cu 2p 3/2 shake up intensively at binding energies of 961.9 and 942.0 eV, respectively, which are the characteristic peaks of Cu 2+ ions. [19][20][21] In the XPS spectrum of Ce 3d ( Figure 2C), m 1 and n 1 represent Ce 3d 3…”

“…During the past decades, many researchers have showed concern for advanced oxidation processes (AOPs), and it provides a promising solution for the treatment of refractory dyeing wastewater. Among AOPs, heterogeneous photocatalysis can be applied to degrade and mineralize refractory organic pollutants using only light, catalysts, and air or H 2 O 2 . However, the dye degradation reactions are largely affected by pH, coexisting anions, and other factors.…”