TY  - EJOU
AU  - Song, Xuefeng 
AU  - Sun, Minjuan 
AU  - He, Juan 
AU  - Wang, Lei 

TI  - Fluoride Ion Adsorption Effect and Adsorption Mechanism of Self-Supported Adsorbent Materials Based on Desulfurization Gypsum-Aluminate Cement
T2  - Journal of Renewable Materials

PY  - 2023
VL  - 11
IS  - 12
SN  - 2164-6341

AB  - The adsorption method has the advantages of low cost, high efficiency, and environmental friendliness in treating
fluorinated wastewater, and the adsorbent material is the key. This study combines the inherent anion-exchange
adsorption properties of layered double hydroxides (LDHs). Self-supported porous adsorbent materials loaded
with AFm and AFt were prepared from a composite cementitious system consisting of calcium aluminate cement
(CAC) and flue gas desulfurization gypsum (FGDG) by chemical foaming technique. The mineral composition of
the adsorbent material was characterized by X-ray diffraction (XRD) and Scanning electron microscopy (SEM).
Through the static adsorption experiment, the adsorption effect of the mineral composition of the adsorbent on
fluoride ions was deeply analyzed, and the adsorption mechanism was revealed. XRD and SEM showed that the
main hydration phases of the composite cementitious system consisting of CAC and FGDG are AFm, AFt, AH<sub>3</sub>,
and CaSO<sub>4</sub>·2H<sub>2</sub>O. FGDG accelerates the hydration process of CAC and inhibits the transformation of AFt to
AFm. The AFt content increased, and the AFm content decreased or even disappeared as the amount of FGDG
increased. Static adsorption experiment results showed that AFm and AFt in adsorbent materials could signifi-
cantly enhance the adsorption of fluoride ions. The adsorption of F− in aqueous solution by PAG tends more
towards monolayer adsorption with a theoretical maximum capacity of 108.70 mg/g and is similar to the measured value of 112.77 mg/g.
KW  - Flue gas desulfurization gypsum (FGDG); Calcium aluminate cement (CAC); AFm; AFt; Fluoride ions adsorption

DO  - 10.32604/jrm.2023.028885