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Partic. vol. 40 pp. 123-130 (October 2018)
doi: 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

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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.

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Keywords

Hydrothermal; Diatomite; Adsorption; Photocatalysis; Water purification