Chemiluminescence as a New Indicator for Monitoring Hydroxylated Intermediates in Persulfate-Based Advanced Oxidation Processes

Abstract

The formation of hydroxylated intermediates is the first step in the persulfate-based advanced oxidation processes (AOPs) and depends directly on the oxidation degree of recalcitrant pollutants. Therefore, the monitoring of hydroxylated intermediates plays a vital role in persulfate-based AOPs for evaluating the oxidation degree and understanding the degradation mechanism. In this work, based on the attractive amplification of luminol chemiluminescence (CL) signals by hydroxylated intermediates, we developed a rapid, sensitive, and simple CL-based method to monitor hydroxylated intermediate (i.e., 3,5-diethyl-1,4-benzenediol) generated in persulfate-based AOPs of 1,2-divinylbenzene (DVB). The possible mechanism of the proposed CL system was that hydroxylated intermediates could be oxidized by persulfate in alkaline solution to form superoxide anion radicals and thus lead to an increase in the luminol CL. Finally, the proposed CL system was successfully applied in monitoring hydroxylated intermediates generated during persulfate-based AOPs under different degradation conditions, whose validity and reliability were verified by liquid chromatography–mass spectrometry (LC-MS) and Fourier-transform infrared spectroscopy (FT-IR). The generality of the proposed CL system was verified by monitoring hydroxylated intermediates generated in persulfate-based AOPs of methylbenzene and benzoic acid. These results suggested that this present CL system provided a promising indicator for monitoring hydroxylated intermediates in persulfate-based AOPs.

Structurally Ordered Catalyst-Amplified Chemiluminescence Signals

“…Furthermore, ESR spectroscopy was utilized to confirm the formation of the reaction oxygen species. Figure B showed the ESR signals of two radical adducts, which were ascribed to O 2 •– and • OH radicals in combination with the results from the ESR spectrum simulation . Thus, O 2 •– and • OH radicals were generated in the proposed system.…”

Direct and Indirect Chemiluminescence: Reactions, Mechanisms and Challenges

“…It is also reported that luminol CL could be significantly enhanced in the presence of hydroxylated intermediates generated by persulfate-based advanced oxidation processes (AOPs) of 1,2-divinylbenzene (DVB). Since the emission of light found to be dependent on the oxidation efficiency of the recalcitrant pollutants, luminol CL was proposed (Figure 4) for tracking a wider range of hydroxylated intermediates generated during persulfatebased AOPs under different degradation conditions, and other relevant organic compounds [55]. It is also reported that luminol CL could be significantly enhanced in the presence of hydroxylated intermediates generated by persulfate-based advanced oxidation processes (AOPs) of 1,2-divinylbenzene (DVB).…”

Nonradical Activation of Peroxydisulfate with In Situ Generated Amorphous MnO2 in an Electro-Permanganate Process: Involvement of Singlet Oxygen, Electron Transfer, and Mn(III)aq

“…•− , to form stable adducts with different characteristic peaks. 22 As depicted in Figure 3b, no signals were observed for SO 4…”

“…ESR experiments were carried out using DMPO or TMP as the spin-trapping reagent to provide direct evidence for the involvement of possible oxidizing species. DMPO could capture short-lived free radicals, such as SO 4 •– , • OH, and O 2 •– , to form stable adducts with different characteristic peaks . As depicted in Figure b, no signals were observed for SO 4 •– or • OH.…”