1. Adsorption and photocatalytic reduction of aqueous Cr(VI) by Fe3O4-ZnAl-layered double hydroxide/TiO2 composites.
- Author
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Yang, Yanting, Li, Jing, Yan, Tao, Zhu, Rixin, Yan, Liangguo, and Pei, Zhiguo
- Subjects
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PHOTOREDUCTION , *X-ray photoelectron spectra , *LAYERED double hydroxides , *ADSORPTION (Chemistry) , *SPECTRUM analysis , *SOL-gel processes , *PHOTOELECTROCHEMISTRY , *ADSORPTION capacity - Abstract
To evaluate the synergetic adsorption capacity of layered double hydroxide (LDH) and photocatalytic reduction property of TiO 2 for aqueous Cr(VI), the Fe 3 O 4 -ZnAl-LDH and TiO 2 composites (FLT) were prepared via sol-gel method. The removal efficiency of FLT composites for Cr(VI) changed with the mass ratio of Fe 3 O 4 -LDH/TiO 2 , and the optimal ratio was 20% (FLT-2). The adsorption efficiencies of 100 mg FLT-2 were 74% and 64% for 20 and 50 mg/L Cr(VI) solution, and the total removal ratios of Cr(VI) were all over 97% after UV irradiation. The experimental data of adsorption kinetic, adsorption isothermal, and photocatalytic reduction were consistent with the pseudo-second-order, Langmuir, and first-order reaction equations, respectively. From the X–ray photoelectron spectra analysis, FLT composites adsorbed Cr(VI) directly via surface complexation, also reduced aqueous Cr(VI) to Cr(III). The photocurrent and electrochemical impedance spectroscopy of FLT composites indicated the photo-induced electron-hole pairs were separated effectively. The regeneration results show that the FLT composites had good stability and reusability after five consecutive cycles. Therefore, FLT composites are promising materials in the disposal of wastewater containing Cr(VI). [ABSTRACT FROM AUTHOR]
- Published
- 2020
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