Nanoscience Advances in CBRN Agents Detection, Information and Energy Security by Plamen Petkov Dumitru Tsiulyanu Wilhelm Kulisch & Cyril Popov

Author:Plamen Petkov, Dumitru Tsiulyanu, Wilhelm Kulisch & Cyril Popov
Language: eng
Format: epub
Publisher: Springer Netherlands, Dordrecht

25.2 Experimental

The synthesis of SiO2-TiO2-SnO2 oxides is described in detail in [22, 23]. Tin(IV) chloride was introduced into a glass reactor where silica and water were stirred. Thereupon TiCl4 was added. The calculated concentration of TiO2 was 15 wt% against SiO2, that of CSnO2 was varied from 0.14 to 30 wt% with respect to TiO2. The amount of each sample was halved. One half was subjected to thermal treatment at 600 °C, the other one was left non-calcined. XRD results indicated [23] that all calcined samples (SiO2-TiO2-SnO2-c) contain crystalline anatase but non-calcined ones (SiO2-TiO2-SnO2-nc) show its presence in a very narrow range of SnO2 concentrations (CSnO2 = 4–6 wt%).

The photocatalytic activity of SiO2-TiO2-SnO2 samples was studied during the photodegradation of bisphenol A (Sigma-Aldrich, Poland) in a photochemical batch reactor (Heraeus, System 2, 0.75 L) equipped with an UV low-pressure lamp TQ 150 (λ = 254 nm). A model solution prepared from BPA and a photocatalyst (10 mg/L and 0.5 g/L, respectively) were stirred at 500 rpm and kept in the dark during 30 min to attain an adsorption-desorption equilibrium before starting the photodestruction. The concentration of bisphenol A was evaluated by means of high-performance liquid chromatography (Waters, Alliance e2695, DAD, H2O:CH3CN = 30:70, flow rate = 0.5 mL/min) using a C18 Waters PAH column. Commercially available titania P25 (rutile/anatase = 80/20) produced by Degussa-Evonik was used as a reference.

The decrease of the BPA concentration c in the course of the treatment time t is described by means of pseudo first-order kinetics related to the equation:

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