AT present, the main source of germanium includes two types of ore deposits: some sulfide-rich Pb, Zn,Cu, Ag and An deposits and some coal deposits. Germanium occurs as an associated element in these oredeposits. The ...AT present, the main source of germanium includes two types of ore deposits: some sulfide-rich Pb, Zn,Cu, Ag and An deposits and some coal deposits. Germanium occurs as an associated element in these oredeposits. The Lincang germanium deposit discovered recently in China occurs in a basin where there areexposed the Neogene coal-bearing clastic rocks with Indosinian Ge-rich (（1.9-5.0）×10<sup>-6</sup>) granitesas the basement in Lincang County, Yunnan Province. Germanium is mainly concentrated in the coalseams of the first coal-bearing horizon (N<sub>th</sub><sup>2</sup>) and in regard to its grade (normally n×100×10<sup>-6</sup> with themaximum over 1000×10<sup>-6</sup>) and scale （the proven reserve about 800 t）, no such germanium mineralization has been reported so far in other parts of the world. What is the reason? The available studies have indicated that this germanium deposit is of epigenetic origin, whichdetermines that germanium must have been transferred into coal with the help of a kind of medium. It isnoticed that （i） organic germanium in natural waters is stable and it is never involved in its展开更多
Ge-containing Lewis acidic zeolites are typically synthesized using a conventional hydrothermal strategy from amorphous silica sources,through a long time-and energy-consuming approach limiting their wide applications...Ge-containing Lewis acidic zeolites are typically synthesized using a conventional hydrothermal strategy from amorphous silica sources,through a long time-and energy-consuming approach limiting their wide applications.This study reports a rapid synthesis strategy for a series of IWV aluminogermanosilicate zeolites(T-x-Al)with a wide range of Si/Ge molar ratios(5–15)by interzeolite transformation of dealuminated FAU(DA-FAU).Notably,Ge-rich IWV could be obtained with crystallization time as short as one day by the equimolecular Si/Ge ratio gel.The effect of synthetic parameters was investigated and the obtained T-x-Al samples were characterized by XRD,SEM,EDS,ICP,^(29)Si and^(27)Al MAS NMR,FTIR,and N_(2)physisorption analyses.Compared with a previously reported IWV germanosilicate(H-3),T-x-Al displayed a better catalytic activity in Baeyer-Villiger(BV)oxidation,attributed to the presence of the active framework Ge sites with the assistance of the extraframework Al species.The cyclic catalysis tests revealed that the presence of framework Al species contributed to the stability of the T-x-Al.Specifically,T-x-Al,with 14-membered ring(MR)supercages,outperformed the typical 12-MR Sn-beta catalyst in the BV oxidation of large ketone-like 2-admantanone,indicating a promising potential application in the macromolecular catalytic process.展开更多
文摘AT present, the main source of germanium includes two types of ore deposits: some sulfide-rich Pb, Zn,Cu, Ag and An deposits and some coal deposits. Germanium occurs as an associated element in these oredeposits. The Lincang germanium deposit discovered recently in China occurs in a basin where there areexposed the Neogene coal-bearing clastic rocks with Indosinian Ge-rich (（1.9-5.0）×10<sup>-6</sup>) granitesas the basement in Lincang County, Yunnan Province. Germanium is mainly concentrated in the coalseams of the first coal-bearing horizon (N<sub>th</sub><sup>2</sup>) and in regard to its grade (normally n×100×10<sup>-6</sup> with themaximum over 1000×10<sup>-6</sup>) and scale （the proven reserve about 800 t）, no such germanium mineralization has been reported so far in other parts of the world. What is the reason? The available studies have indicated that this germanium deposit is of epigenetic origin, whichdetermines that germanium must have been transferred into coal with the help of a kind of medium. It isnoticed that （i） organic germanium in natural waters is stable and it is never involved in its
基金supported by the National Natural Science Foundation of China(22302116)the Natural Science Foundation of Shanxi Province(202203021212412)。
文摘Ge-containing Lewis acidic zeolites are typically synthesized using a conventional hydrothermal strategy from amorphous silica sources,through a long time-and energy-consuming approach limiting their wide applications.This study reports a rapid synthesis strategy for a series of IWV aluminogermanosilicate zeolites(T-x-Al)with a wide range of Si/Ge molar ratios(5–15)by interzeolite transformation of dealuminated FAU(DA-FAU).Notably,Ge-rich IWV could be obtained with crystallization time as short as one day by the equimolecular Si/Ge ratio gel.The effect of synthetic parameters was investigated and the obtained T-x-Al samples were characterized by XRD,SEM,EDS,ICP,^(29)Si and^(27)Al MAS NMR,FTIR,and N_(2)physisorption analyses.Compared with a previously reported IWV germanosilicate(H-3),T-x-Al displayed a better catalytic activity in Baeyer-Villiger(BV)oxidation,attributed to the presence of the active framework Ge sites with the assistance of the extraframework Al species.The cyclic catalysis tests revealed that the presence of framework Al species contributed to the stability of the T-x-Al.Specifically,T-x-Al,with 14-membered ring(MR)supercages,outperformed the typical 12-MR Sn-beta catalyst in the BV oxidation of large ketone-like 2-admantanone,indicating a promising potential application in the macromolecular catalytic process.
