Visible photocatalytic degradation of methylene blue on magnetic semiconducting La 0.2 Sr 0.7 Fe 12 O 19
- PDF / 1,768,857 Bytes
- 7 Pages / 595.276 x 790.866 pts Page_size
- 114 Downloads / 199 Views
Visible photocatalytic degradation of methylene blue on magnetic semiconducting La0.2Sr0.7Fe12O19 Debesh Devadutta Mishra1 · Yao Huang1 · Na Duan1 · Guolong Tan1 Received: 25 January 2018 / Accepted: 31 March 2018 © Springer Science+Business Media, LLC, part of Springer Nature 2018
Abstract Methylene blue (MB) is a representative of a class of dyestuffs resistant to biodegradation. This paper presents a novel photocatalytic degradation of MB by La0.2Sr0.7Fe12O19 compound, which is a traditional permanent magnet and displays a large magnetic hysteresis (M–H) loop. The remnant magnetic moment and coercive field are determined to be 52 emu/g and 5876 Oe, respectively. UV–Visible optical spectroscopy reveals that L a0.2Sr0.7Fe12O19 is simultaneously a semiconductor, whose direct and indirect band gap energies are determined to be 1.47 and 0.88 eV, respectively. The near infrared band gap makes it a good candidate to harvest sunlight for photocatalytic reaction or solar cell devices. This magnetic compound demonstrates excellent photocatalytic activity on degradation of MB under visible illumination. The colour of MB dispersion solution changes from deep blue to pale white and the absorbance decreases rapidly from 1.8 down to zero when the illumination duration extends to 6 h. Five absorption bands did not make any blue shifts along with the reaction time, suggesting a one-stepwise degradation process of MB, which makes La0.2Sr0.7Fe12O19 a unique magnetic catalyst and differs from TiO2 and other conventional catalysts.
1 Introduction As far back as Neolithic man first utilised a bit of suspended lodestone to explore, humankind has utilised attractive materials of different sorts. In any case, it was not until the approach of electricity that the magnetic processes started to be caught attraction. It is presently realised that lodestone is an iron mineral, magnetite, which is one of an extensive variety of magnetic ceramics, iron(III) oxide, called the ferrites having a cubic crystal structure. The ferrites or hard ferrites are also termed as oxide magnets have replaced older metal alloy permanent magnets and also its cost-effectiveness, lower weight and higher coercivity presented these materials as applications in dc motors electrical relays and ore separators [1]. Lots of research recently has been carried out on metal oxide and metal ferrite nanoparticles prepared using green * Debesh Devadutta Mishra [email protected] * Guolong Tan [email protected] 1
State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China
synthesis’ methods showing good photocatalytic activity. Some of the ferrites were prepared using tragacanth gum as the precursors such as Ni–Zn–Cu ferrite [2], Cu ferrite [3], Ni–Cu–Mg ferrite [4] and Mg ferrites [5]. Metal oxide nanoparticles such as NiO [6], ZnO [7], MgFe2O4–γ-Al2O3 [8], ZnO–CuO [9] and Ag/ZnO bimetallic alloy [10]. are also produced using natural gums and dyes such as Arabic gum, tragacanth ge
Data Loading...
