Jian Lin,Lin Zhu,Zenghui Yue,Chuang Yang,Wei Liu,Thomas E. Albrecht-Schmitt,Jian-Qiang Wang,Shuao Wang
Various types of polyoxometalates (POMs) have been synthesized since the 19th century, but their assortment has been mostly limited to Groups 5 and 6 metals. Herein, a new family of POMs composed of a carbon group element as the addenda atoms with two distinct phases, LnPbOClO 4 -1 (Ln = Sm to Ho, Y) and LnPbOClO 4 -2 (Ln = Er and Tm) is reported. Both structures are built from [Ln 6 O 8 ] rare-earth metal hexamers being incorporated in [Pb 18 O 32 ]/[Pb 12 O 24 ] polyplumbites, and unbound perchlorates as charge-balancing anions. Impressively, YPbOClO 4 -1 and ErPbOClO 4 -2 exhibit exceptional uptake capacities (434.7 and 427.7 mg g −1 ) toward ReO 4 − , a chemical surrogate for the key radioactive fission product in the nuclear fuel cycle 99 TcO 4 − , which are the highest values among all inorganic anion-exchange materials reported until now. The sorption mechanism is clearly elucidated and visualized by single-crystal-to-single-crystal structural transformation from ErPbOClO 4 -2 to a perrhenate-containing complex ErPbOReO 4 , revealing a unique ReO 4 − uptake selectivity driven by specific interaction within Pb···O-ReO 3 − bonds.
Jiayou Liao,Zhi Wang,Ming Wang,Chengyun Gao,Song Zhao,Jixiao Wang,Shichang Wang
An ion-exchange material – Poly(diallyldimethylammonium carbonate) (PDDACA) containing mobile carbonate has been prepared and it has been blended in a fixed carrier membrane material – polyvinylamine (PVAm) containing abundant amine-group to adjust the carrier microenvironment of the fixed carrier membrane. It makes the mobile carrier cruise around the fixed carrier. On one hand, the CO 2 can be transported continuously in the swing area of fixed carrier through the mobile carriers, the passivity of fixed carrier can be overcome and the utilization efficiency of fixed carrier can be enhanced. On the other hand, a loose and low crystalline system will be obtained by blending two polymers, the number of effective mobile carrier will be increased with mobile carriers unlocking from the crystalline area, and the loose and low crystalline system will provide a good environment for the movement of mobile carriers. These are conducive to enhance the performance of blend membrane in comparision with single polymer membrane. The CO 2 permeance and CO 2 /N 2 selectivity of PVAm-PDDACA membrane, which concurrently contains fixed amine carriers and movable carbonate carriers, can reach 909 GPU and 102 at 0.11 MPa, respectively. The performance of PVAm-PDDACA membrane is enhanced obviously in comparision with PVAm membrane and PDDACA membrane.