Fabrication of Magnetic Fe/Zn Layered Double Oxide@Carbon Nanotube Composites and Their Application for U(VI) and ²⁴¹Am(III) Removal

Abstract

Magnetic Fe/Zn layered double oxide decorated carbon nanotubes (M-Fe/Zn-LDO@CNTs) composites were synthesized via a hydrothermal method with further calcination treatment. The fabricated M-Fe/Zn-LDO@CNTs were characterized by X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, UV–vis spectroscopy, scanning electron microscopy, and transmission electron microscopy and then applied for U­(VI) elimination under diversiform experimental conditions, such as pH, temperature, ionic strength, contact time, and coexisting ions. The experimental results demonstrated that the U­(VI) adsorption performance of M-Fe/Zn-LDO@CNTs was much higher than bare CNTs. The thermodynamic parameters revealed that U­(VI) adsorption on M-Fe/Zn-LDO@CNTs was endothermic and spontaneous. More importantly, the adsorption performance of U­(VI) on M-Fe/Zn-LDO@CNTs was still higher than ∼89% after five cycles. Furthermore, ∼95.9% of 241Am­(III) could be removed by M-Fe/Zn-LDO@CNTs from solution at pH = 8.0, which confirmed that M-Fe/Zn-LDO@CNTs was an excellent material for efficient removal of long-lived lanthanides and actinides from environmental aqueous solutions in radionuclides’ pollution remediation.

Sorption of Fluoride and Bacterial Disinfection Property of Biosynthesized Nanofibrous Cellulose Decorated Ag–MgO–Nanohydroxyapatite Composite for Household Water Treatment

“…The surface charges distributions of the CNF-AgMgOnHaP adsorbent in fluoride sorption at different initial solution pH values (3–12) were also evaluated by its point of zero charge (pHpzc). The pHpzc is defined as that pH value at which the net surface charge density of an adsorbent is zero [ 60 ]. As shown in Figure 8 b, the pHpzc value of the CNF-AgMgOnHaP was at ~4.7, which is lower than the optimum pH value of 5.…”

In situ Preparation of Chitosan/ZIF-8 Composite Beads for Highly Efficient Removal of U(VI)

“…As shown in Figure 5, at pH of 3, U(VI) mainly exits in the form of UO22+ cation, as the pH increases, it will be hydrolyzed to oligomeric or colloidal species, such as (UO 2 ) 3 (OH)5+, (UO 2 ) 4 (OH)7+, (UO 2 ) 2 (OH)22+, and UO 2 (OH) + etc. (Chen et al, 2018). Due to the increased dimensions of these species, a decrease of adsorption efficiency is resulted with pH increasing (Wang C. H. et al, 2018).…”

“…Among these, adsorption method is one of the most extensive technologies because of low cost, simple operation, high efficiency, and good removal effect (Li et al, 2018a; Wang L. et al, 2018). The adsorbents adopted in the uranium adsorption technique include oxides (Yu et al, 2013), sulfides (Manos and Kanatzidis, 2012), hydroxides (Li R. et al, 2017), poly (amid oxime) and its derivatives (Wang D. et al, 2018), carbon nanotubes (Chen et al, 2018), phosphates (Zheng et al, 2015; Cai et al, 2017), porous silica (Huynh et al, 2017), and porous carbon (Starvin and Rao, 2004) etc. However, most of the adsorbents have some disadvantages, like low adsorption capacity, poor stability, or inability to circulate etc.…”

Three-step-in-one synthesis of supercapacitor MWCNT superparamagnetic magnetite composite material under flow

“…The XPS C 1s spectrum for Fe 3 O 4 @MWCNT (retained and collected) is shown in Fig. 6a and c respectively, with three peaks, at 285.1 eV, 286.8 eV and 289.1 eV, corresponding to C-C, C-O and C]O groups, 60,61 respectively. Fig.…”