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Abstract:
The efficient uptake of phosphate from aqueous solutions was achieved on layered double hydroxides (LDHs)based electrodes via capacitive desalination in our previous study. The current follow-up work was mainly carried out to study the influence of various experimental parameters on the capacitive removal of phosphate using LDHs/activated carbon (LDHs/AC) composite electrodes. A series of batch experiments were implemented to investigate the experimental factors, including Mg2+/Al3+ ratios (2, 3, and 4), trivalent metal cations (Al3+, Fe3+, Cr3+), initial solution pH (from 3 to 10), coexisting anions (NO3- , Cl-,SO42-), and ion strengths, in capacitive deionization. The electrode materials before and after capacitive deionization were characterized to reinforce the analysis of the adsorption mechanisms by X-ray powder diffraction, scanning electron microscopy, energy dispersive X-ray, cyclic voltammetry, and electrochemical impedance spectroscopy. Results indicated that the Mg-Al LDHs/AC electrodes exhibited higher phosphate adsorption capacity (80.43 mg PO43-/g), more regular morphology, and higher degree of crystallinity than that of Mg-Fe LDHs/AC and Mg-Cr LDHs/AC. Increasing Mg2+/Al3+ ratios enhanced the adsorption capacity of phosphate. The uptake of phosphate by Mg-Al LDHs/AC under circumneutral pH and low ion strength reached the maximum level. Furthermore, the presence of coexisting anions lowered the adsorption capacity of phosphate mainly due to the occurrence of a compressed electrical double layer. Therefore, the influence of different experimental parameters on phosphate removal via capacitive deionization by Mg-Al LDHs/AC necessitates a systematic investigation to optimize the preparation conditions of LDHs-based electrodes and several important operating parameters.
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SEPARATION AND PURIFICATION TECHNOLOGY
ISSN: 1383-5866
Year: 2019
Volume: 215
Page: 454-462
5 . 7 7 4
JCR@2019
8 . 2 0 0
JCR@2023
ESI Discipline: CHEMISTRY;
ESI HC Threshold:184
JCR Journal Grade:1
CAS Journal Grade:2
Cited Count:
WoS CC Cited Count: 41
SCOPUS Cited Count: 47
ESI Highly Cited Papers on the List: 0 Unfold All
WanFang Cited Count:
Chinese Cited Count:
30 Days PV: 0
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