Removal of Chromate(VI) from Water Using Kaolinite Enhanced by Nano-Zero-Valent Iron and Its Mechanism

Abstract

Abstract: Nano-zero-valent iron (nZVI) has received widely attention as an environmental protection material for the treatment of heavy metal and nuclide pollutants. Clay mineral, as a common heavy metal adsorption material, has low cost and wide sources, but its removal performance is generally limited. nZVI/Kao(nZVI/kaolinite) was prepared by liquid phase reduction method for the efficient removal of Cr(VI) from water. XRD, SEM and TEM were used to characterize the phase and structure of the composite. The effects of Cr(VI) initial concentration, nZVI/Kao dosage and temperature on the removal rate of Cr(VI) by the composite were studied. Meanwhile, the removal ability and mechanism of Cr(VI) from water were also discussed. The results show that nZVI has the low crystallinity and its particle size is between 50 nm and 100 nm. The Cr(VI) removal rate of the nZVI/Kao is 91.7% in 60 min, which is 2.7 times and 18.5 times than that of the single nZVI and kaolinite, respectively. The removal kinetics fits well with the pseudo-second order kinetic model and the apparent activation energy is 27.97 kJ/mol. The removal process is the result of common action of adsorption, reduction and co-precipitation. The application prospect of kaolin in water treatment and environmental remediation can be strengthened by loading nZVI.

Key words: kaolinite, nano-zero-valent iron, liquid phase reduction method, Cr, kinetic model, removal rate

CLC Number:

TD985

LIU Liu, HU Peiwei, GAO Runqin, CHENG Gangli, YAO Yao. Removal of Chromate(VI) from Water Using Kaolinite Enhanced by Nano-Zero-Valent Iron and Its Mechanism[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2021, 40(5): 1529-1535.

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