Synthesis of C@Ni-Al LDH HSS for efficient U-entrapment from seawater

Abstract

In this paper, a double hollow spherical shell composite modified with layered double hydroxide (C@Ni-Al LDH HSS) was fabricated for uranium(VI) (U(VI)) adsorption. Various batch experiments were carried out to investigate the influence of pH, concentration, time and coexistence ion on extraction. The results showed that the adsorption processes of U(VI) onto C@Ni-Al LDH HSS were spontaneous and endothermic and closely followed pseudo-second-order and Langmuir isotherm models. The equilibrium time and maximum adsorption capacity of C@Ni-Al LDH HSS was 360 min and 545.9 mg g −1 . FT-IR and XPS analyses proved that the adsorption behavior was primarily attributed to the strong interaction between oxygen-containing functional groups and U(VI). Moreover, the extraction of trace U(VI) (μg L −1 ) in artificial and natural seawater was also studied. The results showed that C@Ni-Al LDH HSS provided a promising application for the efficient extraction of U(VI) from seawater.

Zinc-chromium layered double hydroxides anchored on carbon nanotube and biochar for ultrasound-assisted photocatalysis of rifampicin

“…4 a-c). According to IUPAC classification, the isotherm type IV was detected for ZnCr LDH, ZnCr LDH/CNT, and ZnCr LDH/BC, establishing the mesoporous nature of the synthesized materials [27] . Also, similar studies reported isotherm type IV for the ZnCr LDH [28] , [29] .…”

Enhanced uranium extraction selectivity from seawater using dopant engineered layered double hydroxides

“…3b, which were measured using 3 ppm U in pH 8.5 sodium carbonate solution and V m À1 up to 10 000, with the capacities of previously synthesised LDH materials, which have typically been measured under conditions irrelevant to seawater, namely pH 5-6 nitric acid and U concentrations 30-500 mg L À1 . [30][31][32]64 Under these conditions, U would be expected to be present as (UO 2 ) 2 (OH) 2 2+ and (UO 2 ) 3 (OH) 5 + . 34 These cationic hydroxide complexes cannot be expected to behave the same as the anionic carbonate complexes present in seawater.…”

Mesoporous Layered Double Hydroxides: Synthesis for High Effective Uranium Ions Sorption from Seawater and Salt Solutions on Nanocomposite Functional Materials

“…To avoid the dissolution of LDH and the removal of metal ions that make up its crystal lattice into the filtrate, several authors have proposed a regeneration method using Na 2 CO 3 or NaHCO 3 solutions, which make it possible to remove intercalated forms of uranium from the interlayer space of LDH. The study [20] showed that at a Na 2 CO 3 concentration of 0.5 mol/L or more, the desorption efficiency is 80%. The authors [27] showed that after four cycles of adsorption-desorption with NaHCO 3 , the removal ratio of uranium by LDH was maintained at 90.27%.…”

“…To increase the sorption activity of LDH compared to analogues, a hydrothermal synthesis method is proposed, which includes the preliminary stages of obtaining carbon spheres and coating them with Ni-Al LDH [19]. In the article [20], a similar synthesis is implemented, where SiO 2 with AlOOH are used as microspheres. The study [21] proposed the preparation of three-dimensional hydroxyapatite materials based on Mg-Fe LDH (Mg-Fe-HAP) using ultrasonic synthesis, hydrothermal synthesis, and coprecipitation methods.…”