Title: The catalytic role of nascent Cu(OH)(2) particles in the sulfite-induced oxidation of organic contaminants

Authors: Luo, T (Luo, Tao); Yuan, YA (Yuan, Yanan); Zhou, DN (Zhou, Danna); Luo, LT (Luo, Liting); Li, JJ (Li, Jinjun); Wu, F (Wu, Feng)

Source: CHEMICAL ENGINEERING JOURNAL Volume: 363 Pages: 329-336 DOI: 10.1016/j.cej.2019.01.114 Published: MAY 1 2019  

Abstract: In the recent years, sulfite-induced oxidation of various contaminants using oxysulfur radicals (SO4 center dot-, SO5 center dot- and SO3 center dot-) has been explored to establish novel advanced oxidation processes (AOPs). Although transition metals, such as cupric ions (Cu(II)), have been demonstrated to be capable of activating sulfite (S(IV)), the catalytic mechanism of the specific Cu(II) species is still not very clear. In this work, N-acetyl-para-aminophenol (APAP) was used as a basic substrate to investigate the process, mechanism and stability of the Cu(II)-S(IV) system with low dosages of Cu(II) (0.010 mmol L-1) in an alkaline solution (pH 10). The results show that 0.010 mmol L-1 Cu(II) can efficiently activate S(IV) for the oxidation of APAP and other contaminants (e.g., metoprolol, sulfanilamide, aniline, 4-chloroaniline, N,N-dimethylaniline, p-nitrophenol and 3-nitrophenol). Simulation calculations for the distribution of the Cu(II) species and pH-dependence of APAP oxidation in the Cu(II)-S(IV) system showed that Cu(OH)(2) particles are the major active species in the catalysis of S(IV). The surface complexation of S(IV) with the Cu(OH)(2) particles prior to the production of oxysulfur radicals is the basic mechanism of the alkaline Cu(II)-S(IV) system. Radical inhibition with scavengers (ethanol, tert-butyl alcohol or aniline) demonstrates that SO5 center dot-, SO4 center dot- and hydroxyl radicals (HO center dot) are responsible for the contaminant oxidation. Moreover, SO5 center dot- is believed to be the main active species in the Cu(II)-S(IV) system, which has a second-order rate constant of 2.98 x 10(8)M(-1) s(-1) with APAP. This work renews our recognition of the Cu(II)-S(IV) system applications and further understanding of the catalytic role of the nascent Cu(OH)(2) particles in the activation of S(IV).

Accession Number: WOS: 000457866400033

Document Type: Article

Language: English

Keywords: Cupric hydroxide; Sulfite autoxidation; Oxysulfur radical; Paracetamol; Alkaline pH; Surface complexation

Addresses of reprint authors:

Wu, F，Wuhan Univ, Sch Resources & Environm Sci, Wuhan 430079, Hubei, Peoples R China.

Luo, LT，Chinese Acad Sci, Wuhan Inst Phys & Math, Natl Ctr Magnet Resonance Wuhan, State Key Lab Magnet Resonance & Atom & Mol Phys, Wuhan 430071, Hubei, Peoples R China.

E-mail: liting.luo@wipm.ac.cn; fengwu@whu.edu.cn

Addresses:

[Luo, Tao; Yuan, Yanan; Li, Jinjun; Wu, Feng] Wuhan Univ, Sch Resources & Environm Sci, Wuhan 430079, Hubei, Peoples R China.

[Zhou, Danna] Guangdong Inst Ecoenvironm Sci Technol, Guangdong Key Lab Agro Environm Pollut Control &, Guangzhou 510650, Guangdong, Peoples R China.

[Zhou, Danna] China Univ Geosci, Fac Mat Sci & Chem, Wuhan 430074, Hubei, Peoples R China.

[Luo, Liting] Chinese Acad Sci, Wuhan Inst Phys & Math, Natl Ctr Magnet Resonance Wuhan, State Key Lab Magnet Resonance & Atom & Mol Phys, Wuhan 430071, Hubei, Peoples R China.

impact factor: 3.724