Tan X, Zhang Y, Liu M, Cao J, Duan G, Cui J, Lin A. Ultrasonic-assisted preparation of interlaced layered hydrotalcite (U-Fe/Al-LDH) for high-efficiency removal of Cr(VI): Enhancing adsorption-coupled reduction capacity and stability.
CHEMOSPHERE 2022;
308:136472. [PMID:
36122742 DOI:
10.1016/j.chemosphere.2022.136472]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 09/09/2022] [Accepted: 09/12/2022] [Indexed: 06/15/2023]
Abstract
Cr(VI) contamination in aquatic systems has been a challenge for environmental science researchers. To environmental-friendly, stable, and efficiently remove Cr (VI), a novel layered double hydroxide was prepared through the ultrasonic-assisted co-precipitation method. The ultrasonic-assisted step prevented the Fe2+ oxidation, improved the morphology and performance, and finally, the adsorption-coupled reduction capacity and stability were enhanced. By adding U-Fe/Al-LDH (1.0 g/L) for Cr(VI) (100 mg/L), the removal rate reached 82.24%. The removal data were well fitted by the pseudo-second-order kinetic and Langmuir isotherm model. Using U-Fe/Al-LDH can be performed over a wide pH range (2-10), with a theoretical maximum removal capacity of 118.65 mg/g. The Cr(VI) with high toxicity was adsorbed and reduced to low-toxicity Cr(III). In the final phase, stable Cr(III) complex precipitates were generated. After 30 days, the dynamic leaching amounts of total Cr in used U-Fe/Al-LDH-2 were 0.1052 mg/L. Combined with the results of the influence experiment of coexisting anions and oxidants and the SO42- release experiment, the stability of the removal effect and the safety of U-Fe/Al-LDH were proved. In conclusion, U-Fe/Al-LDH-2 is a promising remediation agent and a feasible Cr(VI) removal method for the practical remediation.
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