ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Synthesis of a new visible driven photocatalyst TiO₂/a-CNT/b-BiOBr/c-Bi₂S₃ and its application for RB19 removal: modeling and process optimization

Malihe Asadpoor, Mehdi Ardjmand, Mehrdad Farhadian, Mohammad Reza Omidkhah, and Ali Akbar Zinatizadeh

Department of Chemical Engineering, Islamic Azad University, South Tehran Branch, Tehran, Iran

E-mail: m_arjmand@azad.ac.ir

Received: 30 May 2020  Accepted: 22 September 2020

Abstract:

In present study, new visible driven photocatalysts (TiO₂/4-CNT/20-BiOBr/10-Bi₂S₃) with various loading of CNT (2, 4, 6 and 8 wt%), (10, 20, 30 and 40 wt%) and Bi₂S₃ (5, 10, 15 and 20 wt%) were successfully synthesized and characterized by XRD, FTIR, FESEM, PL, and DRS analysis. The DRS and PL analysis confirmed a redshift of modified TiO₂ into a visible light range and the reduction of the recombination rate of electron/hole. The photodegradation results showed the optimum weight percentage of CNT, BiOBr, and Bi₂S₃ was 4%, 20%, and 10% respectively. Besides, the central composite design (CCD) was applied to model and optimize the photocatalytic activity of nanocatalyst for photodegradation of reactive blue 19 (RB19) and assess the effects of four independent variables including RB19 concentration, catalyst concentration, pH, and irradiation time on the response. The photocatalytic activity performance of TiO₂/4-CNT/20-BiOBr/10-Bi₂S₃ under visible light irradiation for RB19 removal showed that 97.2% dye removal efficiency was obtained at optimum conditions of pH 4, catalyst dosage 1 g/L, RB19 concentration 50 mg/L, and contact time 60 min. The investigation of the effect of processing factors on the dye removal efficiency confirmed that increasing the catalyst concentration and time while decreasing pH and dye concentration resulted in the dye removal efficiency in a short time. The reusability of the catalyst was studied under optimum conditions ([RB19] = 50 mg/L, [TiO₂/4-CNT/20-BiOBr/10-Bi₂S₃] = 1 g/L, pH = 4 and irradiation time = 60 min).

Keywords: CNT/TiO2/BiOBr/Bi2S3; Visible light; Nanocomposite; Photocatalyst; Reactive blue 19

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-020-01372-2

Chemical Papers 75 (3) 1267–1278 (2021)