Layered Rare-Earth Hydroxide Unilameller Nanosheets: Synthesis, Characterization, and Adsorption

Abstract

Unilameller nanosheets with a lateral dimension of one nanometer have been isolated from a colloidal solution of europium-containing layered rare-earth hydroxide (LRH) material by the flocculation method. The nanosheets were achieved by changing pH of the colloidal solution from 6.7 to 11.5. The resultant flocculated nanosheets show high efficiency in sorption of fluoride anions from aqueous media (40 mmol/g), providing a potentially useful sorbent material for water purification technology. The sorbent material is demonstrated to be reusable for at least ten times without a significant loss of adsorption efficiency. And the results fit the Langmuir adsorption curve, indicating the chemisorption nature of the nanosheets. Most importantly, the isolated nanosheets are expected to widen the applicability and flexibility in material synthesis using two-dimensional nanomaterials.

The Role of Aggregation on Energy Transfer in Layered Rare-Earth Hydroxide/Naphthalene Diimide Hybrid Materials

“…The absorption peaks at 3360 and 1633 cm –1 are attributed to bound water molecules in the structure of LREH. The former is associated with the stretching vibrations (ν 1 and ν 3 ) of O–H bonds, and the latter is due to the bending mode (ν 2 ) of H–O–H bonds of both surface and interlayer water. , Note that the peak at 3360 cm –1 was absent in LEuH sample and the peak at 1633 cm –1 was relatively less intense in LEuH compared to LYH and LYH:Ce, which is attributed to the reduced layered charge density of LEuH, suggesting a different surface chemistry in these materials …”

Fluorination of Eu-doped layered yttrium hydroxides: the role of anionic composition

“…Fluorination of LRHs allows one to obtain a variety of phases of rare-earth fluoride compounds, including Ln 2 (OH) 5 F•nH 2 O [14,[18][19][20], Ln 2 (OH) [14,16,17,22,23], LnF 3 [16,21], MLn m F n (M=K, Na, NH 4 ; Ln = Y, Na, Pr-Lu) [14][15][16]23]. The conditions and compositions of fluorinated layered hydroxides are summarized in Table 1.…”

“…The factors of temperature and duration of fluorination are practically not investigated in the literature. Layered rare-earth hydroxynitrates are usually used to obtain rare-earth fluorides, but there are a few works on fluorination of lanthanum hydroxysulfate [21] and yttrium hydroxychloride [18,22]. The above-mentioned references do not allow us to unambiguously identify the role of anionic composition on the LRH fluorination process.…”

Layered Gadolinium-Europium-Terbium Hydroxides Sensitised with 4-Sulfobenzoate as All Solid-State Luminescent Thermometers

“…LRHs are currently the focus of attention due to their unique properties; they combine the features of both host rare earth hydroxide matrices and guest intercalated anions. LRHs are widely used as phosphors [5][6][7][8][9][10][11], sensors [12][13][14], sorbents [15,16], catalysts [17], and containers for drug delivery [18,19]. A unique feature of this class of compounds is the possibility to tune their anionic and cationic composition while preserving the main structural motif, which enables the precise setting of the properties of functional materials based on such compounds [20,21].…”