1. Efficient removal of aqueous organic pollutants by well-ordered layered manganese oxide nanocomposites: Impacts of interlayer spacing and nanoconfinement.
- Author
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Wang, Zhiqiang, Shi, Yafang, Yang, Kangjie, Yang, Huiqiang, Zhao, Haoran, Xi, Mengning, Zhang, Chi, Zhu, Lingyan, and Jia, Hanzhong
- Subjects
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POLLUTANTS , *WATER purification , *MANGANESE oxides , *NANOCOMPOSITE materials , *STERIC hindrance , *RADICALS (Chemistry) , *CETYLTRIMETHYLAMMONIUM bromide - Abstract
[Display omitted] • Well-ordered layered manganese oxides were prepared using CTAB as guest molecule. • The layered structures of LMOs were dependent on the molar ratio of CTA+ to Mn. • Nanoconfinement is conducive to the interaction of pollutant with active species. • Constrained reaction environment promotes the production and enrichment of O 2 •−. Although manganese oxide is able to spontaneously oxidize organic contaminants in nature, the slow kinetics limit its application in engineered water treatment processes. Herein, we prepared well-ordered layered manganese oxides (LMOs) with adjustable interlayer distances using cetyltrimethylammonium bromine as a guest molecule, which were applied to degrade 3-chlorophenol as an example of organic pollutants. The ordering of the layered structure was found to be highly dependent on the molar ratio of cetyltrimethylammonium ion (CTA+) to Mn in the solutions (range 0–1.2). The maximum interlayer spacing (11.27 Å) was obtained at a molar ratio was 1.0 (LMO-1.0), which reduces the steric hindrance for 3-chlorophenol entering the interlayers. Additionally, the surface of the LMOs becomes more hydrophobic as their molar ratio increased, further favors adsorption of 3-chlorophenol on the LMO-1.0. The LMO-1.0 provides a constrained reaction environment, which increases the probability of 3-chlorophenol interacting with the active species as well as promotes the production and enrichment of superoxide radical (O 2 •−). Consequently, the degradation rate constant of 3-chlorophenol (0.446 min−1) is two orders of magnitude higher compared to the unconfined bulk phase (0.004 min−1). These findings provide useful insights into the development of Mn-based layered materials for water purification. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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