Evaluation of SnO2 for sunlight photocatalytic decontamination of water

M Aslam; M Tariq Qamar; Shahid Ali; Ateeq Ur Rehman; M T Soomro; Ikram Ahmed; I M I Ismail; A Hameed

doi:10.1016/j.jenvman.2018.04.042

Evaluation of SnO₂ for sunlight photocatalytic decontamination of water

J Environ Manage. 2018 Jul 1:217:805-814. doi: 10.1016/j.jenvman.2018.04.042. Epub 2018 Apr 24.

Authors

M Aslam¹, M Tariq Qamar², Shahid Ali³, Ateeq Ur Rehman⁴, M T Soomro¹, Ikram Ahmed⁵, I M I Ismail⁶, A Hameed⁷

Affiliations

¹ Center of Excellence in Environmental Studies, King Abdulaziz University, Jeddah 21589, Saudi Arabia.
² Department of Chemistry, Forman Christian College (A Chartered University), Ferozepur Road, Lahore, 54600, Pakistan.
³ Center of Excellence in Nanotechnology, King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia.
⁴ School of Chemical Engineering, The University of Queensland, St Lucia, QLD, 4067, Australia.
⁵ Department of Applied Chemistry, Government College University, Faisalabad 38000, Pakistan.
⁶ Center of Excellence in Environmental Studies, King Abdulaziz University, Jeddah 21589, Saudi Arabia; Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia.
⁷ Center of Excellence in Environmental Studies, King Abdulaziz University, Jeddah 21589, Saudi Arabia; National Center of Physics, Quaid-e-Azam University, Islamabad 44000, Pakistan. Electronic address: ahfmuhammad@gmail.com.

PMID: 29660706
DOI: 10.1016/j.jenvman.2018.04.042

Abstract

The broad bandgap tin (IV) oxide (SnO₂) is the least investigated semiconductor material for photocatalytic water decontamination in sunlight exposure. A detailed study covering the synthesis, characterization and the evaluation of photocatalytic activity of SnO₂, in the natural sunlight exposure, is presented. The structural characterization by XRD revealed the formation of phase pure tetragonal SnO₂ with the average crystallite size of ∼41.5 nm whereas minor Sn²⁺ states in the material were identified by XPS analysis. As explored by diffuse reflectance (DR) and photoluminescence (PL) spectroscopy, the material exhibited a distinct absorption edge at ∼3.4 eV. The morphological and microstructure analysis of the synthesized SnO₂ was carried out by FESEM and HRTEM. The electrochemical impedance spectroscopy (EIS) and chronopotentiometry (CP) predicted the better charge transport and retention ability of the material under illumination whereas the Mott-Schottky extrapolation prophesied the n-type behavior with the flat-band potential of -0.60 V. The photocatalytic activity of SnO₂ was assessed in the exposure of complete spectrum natural sunlight for the removal of 2,4,6-trichlorophenol. The HPLC and TOC analysis monitored the progress of degradation and mineralization whereas the released chloride ions were evaluated by ion chromatography. The effect of the transition metal ions (Fe³⁺, Cu²⁺, Ni^2+, and Zn²⁺) as electron capture agents and H₂O₂ as ROS generator was explored during the degradation process. The utility of the material for the simultaneous removal of chlorophenols in the mixture was also investigated. The SnO₂ exhibited sustained activity in the repeated use. Based on experimental evidence congregated, the mechanism of the removal process and the efficacy of SnO₂ for sunlight photocatalytic decontamination of water was established.

Keywords: Sunlight photocatalysis; Superoxide radicals; TCP; Tin (IV) oxide.

MeSH terms

Catalysis
Decontamination
Hydrogen Peroxide
Sunlight*
Tin Compounds*
Water
Water Purification*

Substances

Tin Compounds
Water
Hydrogen Peroxide
stannic oxide