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International Conference on

Recent Trends in Environmental Sustainability

ESCON22/NMsB/31
Synthesis of titania/reduced graphene oxide (TiO2/rGO) nanocomposites for the
photocatalytic degradation of brilliant green in aqueous media: synergistic role of
peroxymonosulfate

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1
Qaiser Khan and Murtaza Sayed
1 Radiation and Environmental Chemistry lab, National Centre of Excellence in Physical
Chemistry, University of Peshawar, Pakistan.
Correspondence: qaiserkhan78612@uop.edu.pk , murtazasayed@uop.edu.pk

Abstract
The discharge of various types of dyes into water body is one of the key factors responsible for
water pollution. Advance oxidation processes (AOPs) that involves the production of highly
•
•−
reactive radical species (OH and SO4 ) are considered as an effective technique responsible
for wastewater treatment especially, dye contaminated wastewater. In the current study we
have synthesized different weight percent (0.5, 1, 2 and 3 %) titania/reduced graphene oxide
(TiO2/rGO) nanocomposite material using hydrothermal method. The as-synthesized
TiO2/rGO nanocomposite was characterized by various spectroscopic techniques (XRD, TGA,
SEM, EDX, TEM, FTIR, UV-Drs and PL) that shows high crystallinity, small crystallite size
(18.4 nm), high thermal stability and low band gape energy (Eg) of as-synthesized TiO2/rGO
nanocomposite material.The efficiency of as-synthesized TiO2/rGO nanocomposites were
determined in terms of brilliant green (BG) degradation in aqueous media under UV light
illuminations. The results revealed that 2 % TiO2/rGO (TrG2) showed high efficiency for BG
−1
degradation under UV irradiations with the rate constant of 0.023 min i.e., more than 90 %
degradation occurred in 60 mints. The rate of BG degradation was further improved by the
incorporation of peroxymonosulphate (PMS) in BG contaminated wastewater i.e., 99 %
−1
degradation of BG was observed in 60 mints with the rate constant of 0.0438 min .
Furthermore, the degradation of BG was also examined in various media (neutral, acidic and
basic). The results revealed that by increasing pH of the medium the rate of BG degradation
increases significantly. Moreover, the photocatalytic degradation of BG followed the pseudo-
•
•−
first-order kinetics. The radical scavenging experiments revealed that OH and SO4 are the
dominant species involved in the photocatalytic degradation of BG under UV irradiations.
Besides, the degradation products (DPs) of BG, their pathway and mechanism of degradation
is proposed accordingly.

Keywords: AOPs (Advanced Oxidation Processes), Wastewater treatment, Heterogeneous
Photocatalysis, Titania/reduced Graphene Oxide (TiO2/rGO), Peroxymonosulfate (PMS).

Department of Environmental Sciences, COMSATS University Islamabad, Vehari Campus

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