Oxidative removal of brilliant green by UV/S2O82‒, UV/HSO5‒ and UV/H2O2 processes in aqueous media: A comparative study

Faiza Rehman; Murtaza Sayed; Javed Ali Khan; Noor S Shah; Hasan M Khan; Dionysios D Dionysiou

doi:10.1016/j.jhazmat.2018.06.012

Oxidative removal of brilliant green by UV/S₂O₈^2‒, UV/HSO₅^‒ and UV/H₂O₂ processes in aqueous media: A comparative study

J Hazard Mater. 2018 Sep 5:357:506-514. doi: 10.1016/j.jhazmat.2018.06.012. Epub 2018 Jun 6.

Authors

Faiza Rehman¹, Murtaza Sayed², Javed Ali Khan³, Noor S Shah⁴, Hasan M Khan², Dionysios D Dionysiou⁵

Affiliations

¹ Environmental Engineering and Science Program, Department of Chemical and Environmental Engineering, University of Cincinnati, 705 Engineering Research Center, Cincinnati, OH, 45221-0012, United States; Radiation and Environmental Chemistry Laboratory, National Centre of Excellence in Physical Chemistry, University of Peshawar, 25120, Pakistan; Department of Chemistry, The University of Poonch Rawalakot, Azad Jammu & Kashmir, Pakistan.
² Radiation and Environmental Chemistry Laboratory, National Centre of Excellence in Physical Chemistry, University of Peshawar, 25120, Pakistan.
³ Environmental Engineering and Science Program, Department of Chemical and Environmental Engineering, University of Cincinnati, 705 Engineering Research Center, Cincinnati, OH, 45221-0012, United States; Radiation and Environmental Chemistry Laboratory, National Centre of Excellence in Physical Chemistry, University of Peshawar, 25120, Pakistan.
⁴ Environmental Engineering and Science Program, Department of Chemical and Environmental Engineering, University of Cincinnati, 705 Engineering Research Center, Cincinnati, OH, 45221-0012, United States; Radiation and Environmental Chemistry Laboratory, National Centre of Excellence in Physical Chemistry, University of Peshawar, 25120, Pakistan; Department of Environmental Sciences, COMSATS University Islamabad, Vehari Campus, 61100, Pakistan.
⁵ Environmental Engineering and Science Program, Department of Chemical and Environmental Engineering, University of Cincinnati, 705 Engineering Research Center, Cincinnati, OH, 45221-0012, United States; Nireas-International Water Research Centre, University of Cyprus, P.O. Box 20537, Nicosia, 1678, Cyprus. Electronic address: dionysios.d.dionysiou@uc.edu.

PMID: 30008383
DOI: 10.1016/j.jhazmat.2018.06.012

Abstract

The removal of brilliant green (BG), a toxic organic and cationic dye, has been examined by UV/S₂O₈^2- (PS), UV/HSO₅^- (PMS) and UV/H₂O₂ processes. BG showed insignificant direct photolysis at 254 nm (i.e., 8.6% after 30 min). However, enhanced BG degradation was observed in UV/PS, UV/PMS and UV/H₂O₂ systems as revealed from 63.1, 47.0 and 34.8% BG degradation, respectively, at 30 min of reaction time, using 0.05 mM BG and 1.0 mM oxidant initial concentration. The bimolecular rate constants of OH and SO₄^- with BG were determined to be 2.35 × 10⁹ and 2.21 × 10⁹ M^-1 s^-1, respectively. Electrical energy per order (EE/O) values for UV/PS, UV/PMS and UV/H₂O₂ processes were calculated to be 5.4, 6.8, and 7.8 KWh/m³/order, respectively. The addition of humic acid (HA) and inorganic anions inhibited the degradation of BG by UV/PS in the order of NO₂^- > HA > HCO₃^- > Cl^- > NO₃^- ≈ SO₄^2-. The results of frontier electron densities (FEDs) showed that C-atom holding the three rings (C7), and C-atoms at para positions to N-alkyl groups of the two rings (C4 and C14) are the predominant sites for radical addition. Furthermore, nine degradation products (DPs) of BG were detected experimentally using LC/MS/MS.

Keywords: Advanced oxidation processes (AOPs); Brilliant green; Degradation pathways; Dyes; Second order rate constant; Water treatment.

Publication types

Research Support, Non-U.S. Gov't