Fly ash-based geopolymer as a novel photocatalyst for degradation of dye from wastewater--颗粒学报PARTICUOLOGY

Zhang, Y., & Liu, L. (2013). Fly ash-based geopolymer as a novel photocatalyst for degradation of dye from wastewater. Particuology, 11(3), 353–358. https://doi.org/10.1016/j.partic.2012.10.007

Fly ash-based geopolymer as a novel photocatalyst for degradation of dye from wastewater

Yaojun Zhang^*, Licai Liu

School of Materials and Mineral Resources, Xi’an University of Architecture and Technology, Xi’an 710055, China

10.1016/j.partic.2012.10.007

Volume 11, Issue 3, June 2013, Pages 353-358

Received 7 May 2012, Revised 8 October 2012, Accepted 14 October 2012, Available online 8 April 2013.

E-mail: yaojzhang@yahoo.com.cn

Highlights

• Fly ash-based geopolymer was used for photocatalytic degradation of dye.

• The experimental data conform to a pseudo-second-order rate equation.

Abstract

The geopolymer synthesized by alkali-activated fly ash was firstly used as a novel photocatalyst for degradation of methylene blue (MB) dye from wastewater. The geopolymer is composed of nanoparticulates with an average particle size of about 50 nm. More than 90% of pore volume in the fly ash-based geopolymer predominately centralized on the pore size in the range of 17−700 nm. The degradation efficiency of MB dye by fly ash-based geopolymer catalyst was up to 92.79% under UV irradiation due to the synergistic effect of adsorption and semiconductor photocatalysis. The pseudo-first-order and pseudo-second-order rate equations as well as intra-particle diffusion rate equation were employed to correlate analysis for the adsorption kinetics of MB dye. The experimental data agreed well with pseudo-second-order rate equation in both cases of with UV and without UV irradiations. The intra-particle diffusion process is not the rate determining step. The photocatalytic degradation of MB dye in solution obeys third-order reaction kinetics.

Graphical abstract

Keywords

Fly ash-based geopolymer; Photocatalysis; Adsorption kinetics; Degradation efficiency; Reaction kinetics

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