title: Synthesis, characterization and activity of an immobilized photocatalyst: natural porous diatomite supported titania nanoparticles.
abstract: Diatomite, a porous non-metal mineral, was used as support to prepare TiO2/diatomite composites by a modified sol-gel method. The as-prepared composites were calcined at temperatures ranging from 450 to 950 °C. The characterization tests included X-ray powder diffraction (XRD), scanning electron microscopy (SEM) with an energy-dispersive X-ray spectrometer (EDS), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption/desorption measurements. The XRD analysis indicated that the binary mixtures of anatase and rutile exist in the composites. The morphology analysis confirmed the TiO2 particles were uniformly immobilized on the surface of diatom with a strong interfacial anchoring strength, which leads to few drain of photocatalytic components during practical applications. In further XPS studies of hybrid catalyst, we found the evidence of the presence of Ti-O-Si bond and increased percentage of surface hydroxyl. In addition, the adsorption capacity and photocatalytic activity of synthesized TiO2/diatomite composites were evaluated by studying the degradation kinetics of aqueous Rhodamine B under UV-light irradiation. The photocatalytic degradation was found to follow pseudo-first order kinetics according to the Langmuir-Hinshelwood model. The preferable removal efficiency was observed in composites by 750 °C calcination, which is attributed to a relatively appropriate anatase/rutile mixing ratio of 90/10.
authors.affiliation: School of Chemical and Environmental Engineering, China University of Mining & Technology, Beijing 100083, PR China; School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld 4072, Australia. Electronic address: b.wang6@uq.edu.au.
authors.forename: Bin
authors.initials: B
authors.lastname: Wang
authors.affiliation: School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld 4072, Australia. Electronic address: f.condidegodoi@uq.edu.au.
authors.forename: Fernanda Condi
authors.initials: FC
authors.lastname: de Godoi
authors.affiliation: School of Chemical and Environmental Engineering, China University of Mining & Technology, Beijing 100083, PR China. Electronic address: zhiming.baxia@163.com.
authors.forename: Zhiming
authors.initials: Z
authors.lastname: Sun
authors.affiliation: School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld 4072, Australia. Electronic address: qingcong.zeng@uq.net.au.
authors.forename: Qingcong
authors.initials: Q
authors.lastname: Zeng
authors.affiliation: School of Chemical and Environmental Engineering, China University of Mining & Technology, Beijing 100083, PR China. Electronic address: shuilinzheng8@gmail.com.
authors.forename: Shuilin
authors.initials: S
authors.lastname: Zheng
authors.affiliation: Chemistry Discipline, Faculty of Science and Technology, Queensland University of Technology, Brisbane, Qld 4001, Australia. Electronic address: r.frost@qut.edu.au.
authors.forename: Ray L
authors.initials: RL
authors.lastname: Frost
keywords: Adsorption; Diatomite; Photocatalysis; TiO(2)