posted on 2024-01-17, 18:34authored byJianhui Ren, Yao-Yao Huang, Dongmei Li, Miao Yu, Lin Chen, Jun Wang, Kun Xiong
By virtue of the hydroxyl and carboxyl
groups on the graphene oxide
(GO) plane, three-dimensional tremella-like Zn–Al–Zr-layered
double-hydroxide/GO (Zn–Al–Zr LDH/GO) nanocomposites
have been successfully prepared via the self-assembly process. As
compared to Zn–Al–Zr LDH, the Zn–Al–Zr
LDH/GO nanocomposite (LDH/GO-4) possesses a hierarchical pore structure;
it shows an enlarged pore width which endows it with enhanced phosphorus
(P) adsorption capacity, and the fitting of nonlinear Langmuir showed
that the maximum adsorption capacity reaches 36.86 ± 0.76 mg-P/g.
The fitting of the kinetic model confirmed that the adsorption process
was predominantly chemisorption. Meanwhile, fitting of the thermodynamic
model indicated that the adsorption process was endothermic, stochastic,
and spontaneous. For LDH/GO-4, the [−C–O–Zn(OH)x] and [−COO–ZrO(OH)x] groups are its chief active sites to chemically
absorb P. In this study, LDH/GO-4 can make the total phosphorus (TP)
concentration of the real river water decline from 0.28 mg/L to near
zero in 24 h, while the Phoslock commercial product only achieves
a TP removal rate of 46.43% under the same conditions. Moreover, LDH/GO-4
also has good reusability in a steady recovery of P, and the removal
rate of TP was still over 95% after it experienced the adsorption–desorption
of P for five cycles. Thus, LDH/GO-4 shows great potential for application
in the sustainable P recovery field.