Nanoporous Sulfonic Covalent Organic Frameworks for Selective Adsorption and Separation of Lanthanide Elements

Abstract

Lanthanides are a group of important elements and have been widely used in many fields. Their separation is crucial for technical applications, but it remains a troublesome task due to their subtly different properties. Herein, novel nanoporous sulfonic covalent organic frameworks were synthesized by the Schiff base reaction of 1,3,5-tris(p-formylphenyl)benzene (TFPB) and 2,5-diaminobenzene-1,4-disulfonic acid (DABDA) under mild conditions, which were defined as TFPB-DABDA iCOFs and used for highly selective adsorption separation of lanthanide elements. These iCOFs have uniform morphology, good stability, and excellent adsorption separation ability. The experiment results indicate that the adsorption capacity of TFPB-DABDA iCOFs is highly sensitive to the ionic radius. It means that the larger the size difference between ions, the higher the separation selectivity, especially in the early lanthanides (La3+, Ce3+, Pr3+, Nd3+, Sm3+, Eu3+, and Gd3+) and late lanthanides (Tb3+, Dy3+, Ho3+, Er3+, Tm3+, and Lu3+). The separation mechanism of lanthanide elements by TFPB-DABDA iCOFs may be related to the sulfonic acid groups in the ordered channels of the COFs. This work develops a simple and efficient strategy for the synthesis of iCOFs, which shows a promising application of effective adsorption separation of lanthanides.

Advancements and applications of three-dimensional covalent organic frameworks

“…Zhang et al reported an ionic sp 2 carbon-linked 3D COF with an adsorption capacity of 542.3 mg•g -1 for ReO 4ions (used as a substitute for TcO 4 -) [113] . Wang et al reported a phosphonium-containing coating on 3D COF-g-VBPPh3Cl using a gamma ray preradiation approach, which can remove > 98% of ReO 4ions in a minute [114] . Li et al developed a metal-free 3D ionic COF-2, with permanganate chosen as the model ion to substitute TcO 4 -, and almost 100% of MnO 4 ions can be removed in less than 20 min [76] .…”

Photochemical Strategies toward Precision Targeting against Multidrug-Resistant Bacterial Infections

“…With the negative potential on surface, BG NPs could bind to the positively charged ammonium groups of the LTA backbone on the cell membranes of G + bacteria to recognize and kill G + bacteria selectively, such as S. aureus and E. faecalis. 156 Besides, an organic−inorganic hybrid of organic semiconductor perylene diimide (PDI) and Sn 3 O 4 nanosheets formed a "hook-and-loop" sticky surface, capable of capturing E. coli and S. aureus via large numbers of hydrogen bonding and π−π stacking interactions. 142 The capture rate of the Sn 3 O 4 /PDINH heterostructure to E. coli has been measured to be around 82% (Figure 9D).…”

Ethylene Vinyl Alcohol Copolymer Nanofibrous Cation Exchange Chromatographic Membranes with a Gradient Porous Structure for Lysozyme Separation

“…Unfortunately, there is a poor link between the lysozyme and the weak cation exchange chromatography material, which prolongs the adsorption process. For example, Bo Feng et al [ 16 ] utilized calcium lignosulfonate to separate scheelite and calcite; Bo Li et al [ 17 ] prepared a nanoporous sulfonic acid covalent organic framework to separate lanthanides successfully. In addition, nanofibers are commonly exploited due to the advantages of tunable pore size, large specific surface area, easy functionalization, and simple fabrication [ 18 , 19 , 20 , 21 ].…”