Issue 9, 2024

Efficacy and mechanism of the artificial sweetener saccharin degradation by thermally activated persulfate in aquatic environments

Abstract

Artificial sweeteners, which potentially pose threats to ecosystems, are prevalent emerging contaminants in aquatic environments. This study explored the efficacy and mechanism underlying the degradation of saccharin by thermally activated persulfate treatment (thermal/persulfate) for the first time. Saccharin degradation followed pseudo-first-order kinetics, with a kobs value of 0.023 min−1 under the following conditions: [saccharin]0 = 5 mg L−1, [persulfate]0 = 100 mg L−1, temperature = 70 °C and solution pH = 7.0. Optimal saccharin degradation occurred under neutral and weakly acidic pH conditions (pH 7 and 5), and the calculated apparent activation energy of saccharin was 113.3 kJ mol−1. The results from the scavenger experiments and electron paramagnetic resonance identification revealed that SO4˙ and ·OH were the predominant radical species involved in saccharin degradation, with ·OH likely playing the major role. HCO3, NO3, and dissolved organic matter competed with saccharin for free radicals, decreasing the saccharin degradation rate; however, Cl had a positive effect. Saccharin degradation involved monohydroxylation and dihydroxylation and produced TP1 and TP2, respectively. During treatment, 35% TOC reduction was achieved, and the Microtox® toxicity initially increased and then decreased, suggesting that saccharin and its transformation byproducts undergo mineralization and detoxification. The saccharin degradation rate was lower in actual water matrices than in deionized water. In conclusion, this work comprehensively investigated the degradation of saccharin by thermally activated persulfate treatment for future applications in water/wastewater treatment.

Graphical abstract: Efficacy and mechanism of the artificial sweetener saccharin degradation by thermally activated persulfate in aquatic environments

Supplementary files

Article information

Article type
Paper
Submitted
30 Apr 2024
Accepted
04 Jul 2024
First published
11 Jul 2024

Environ. Sci.: Water Res. Technol., 2024,10, 2130-2141

Efficacy and mechanism of the artificial sweetener saccharin degradation by thermally activated persulfate in aquatic environments

W. W. Lai and C. Chang, Environ. Sci.: Water Res. Technol., 2024, 10, 2130 DOI: 10.1039/D4EW00357H

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements