Photocatalytic Degradation of Geosmin with Zn-Al Multi-metal Oxide Composites Derived from Layered Double Hydroxide Precursors

Weining Hu, Zhiliang Zhu, Hua Zhang, Hongtao Lu, Wei Zhang, Yanling Qiu

Abstract


Geosmin is one of the typical odor compounds in water environment, it has a very low odor threshold (10ng/L), and difficult to degrade in natural environment. In this study, a Zn-Al multi-metal oxide, based on Zn-Al-LDH as a precursor, was prepared and used as photocatalyst to investigate the photocatalytic degradation performance of geosmin in the range of ng level in aqueous solution. Firstly, Zn-Al-LDH was synthesized by co-precipitation method, and the Zn-Al multi-metal oxide was produced after calcination of Zn-Al-LDH at 1023 K in air. The obtained Zn-Al multi-metal oxide showed a good photocatalytic degradation performance. In the condition of simulated solar light, 1g/L catalyst dosage and initial geosmin concentration of 200ng/L, the apparent rate constant kapp is 0.017min-1. After 3 hours of photocatalytic reaction, the residual concentration of geosmin decreased to lower than 10ng/L, which can meet the requirements of "Standards for Drinking Water Quality" (GB5749-2006). The result showed that the photocatalytic reaction efficiency was mainly related with the part of ultraviolet light. The photocatalytic activity of the Zn-Al-MMO was little affected by pH over the range of 4–10. The possible photocatalytic degradation mechanism of the geosmin was also discussed.

Keywords


Photocatalysis, Multi-metal oxides, Geosmin, Layered double hydroxide


DOI
10.12783/dteees/icseep2017/12712

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