Metal recovery based magnetite near-infrared photocatalyst with broadband spectrum utilization property

Magnetite near-infrared (NIR) photocatalysts with upconversion properties are put forward to meet the requirements of high solar energy utilization efficiency and sustainability based on the resource utilization of electroplating wastewater (EPW). The Ca-Zn magnetite precursor (CZ) was initially prepared from the mixed-ferrites (M-Fe3O4) produced from EPW and the photocatalyst (Zn2+) and upconversion host material (Ca2+)-related metal ions included in EPW and its effluents. With the addition of lanthanides and F- ions, a novel magnetite NIR photocatalyst of Er3+/Tm3+/Yb3+-(CaF2/ZnFe2O4/ZnO) (ETY-FCZ) was further synthesized. In the crystal phases of ETY-FCZ, (Ca0.8Yb0.2)F-2.2 is used as the upconversion host material for Er3+/Tm3+/Yb3+ ions. The magnetic agents including ZnFe2O4 display the heterojunction with ZnO, as well as the broadband spectrum utilization property for ETY-FCZ. ETY-FCZ possesses efficient electron-hole pair separation ability, and all the upconversion luminescence emitted from ETY-FCZ can be absorbed for photocatalysis, which result in higher removal rates of methyl orange and salicylic acid compared to those of CZ. ETY-FCZ is an excellent magnetite NIR photocatalysts with magnetic recycling performance, and it has promising applications in the reuse of EPW and the wastewater treatment. (C) 2015 Elsevier B.V. All rights reserved.