Adsorption and photoreduction of Cr(VI) via diatomite modified by Nb2O5 nanorods--颗粒学报PARTICUOLOGY

Du, Y., Wang, X., Wu, J., Qi, C., & Li, Y. (2018). Adsorption and photoreduction of Cr(VI) via diatomite modified by Nb2O5 nanorods. Particuology, 40, 123-130. https://doi.org/10.1016/j.partic.2017.11.005

Adsorption and photoreduction of Cr(VI) via diatomite modified by Nb₂O₅ nanorods

Yucheng Du ^*, Xuekai Wang, Junshu Wu, Chao Qi, Yang Li

Key Laboratory of Advanced Functional Materials, Ministry of Education, College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China

10.1016/j.partic.2017.11.005

Volume 40, October 2018, Pages 123-130

Received 3 July 2017, Revised 8 November 2017, Accepted 12 November 2017, Available online 21 February 2018, Version of Record 28 July 2018.

E-mail: ychengdu@bjut.edu.cn

Highlights

• Nb₂O₅ nanorod crystallized on diatomite substrate through a hydrothermal method.

• Specific surface area of Nb₂O₅-modified diatomite increased from 28 m²/g to 153 m²/g.

• The adsorption capacity increased consequently to 115 mg/g towards Cr(VI).

• Under UV light irradiation, surface adsorbed Cr(VI) could be photoreduced to Cr(III).

• The modified diatomite exhibited a synergistic effect of adsorption and photoreduction.

Abstract

We report the design and synthesis of Nb₂O₅@diatomite composite materials. The composite materials are prepared by the hydrothermal conversion of raw diatomite and activated niobic acid powder in ammonium oxalate aqueous solution, with various hydrothermal reaction durations. The specific surface area of the diatomite modified by Nb₂O₅ nanorods reaches a maximum of 153 m²/g, which is almost five times higher than that of raw diatomite. Insights are gained into the function of sodium dodecyl benzene sulfonate and the mechanism of loading Nb₂O₅ on diatomite in the solution phase. The controllable growth dynamics allow the morphology and production of the Nb₂O₅@diatomite structure to be controlled. Adsorption experiments indicate that the diatomite modified by Nb₂O₅ nanorods is an effective adsorbent for quickly removing Cr(VI) from wastewater at room temperature. The maximum adsorption capacity is 115 mg/g. The Cr(VI) removal capacity is further improved under ultraviolet light irradiation, owing to the synergistic effect of surface adsorption and Nb₂O₅ photoreduction. The composite therefore has potential practical application.

Graphical abstract

Keywords

Hydrothermal; Diatomite; Adsorption; Photocatalysis; Water purification

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