Constructing Porous Aromatic Frameworks For Metal Ion Adsorption And Catalysis Applications

Porous aromatic frameworks?PAFs?as a new kind of porous organic material are constructed entirely by rigid aromatic building blocks via.covalent bonds.Due to their unique talents,they have attracted greatly attention from researchers in a wide range of applications,such as gas sorption,gas separation,proton conductivity,catalysis,etc..Uranium is an urgent desired nuclear material that has significant implications in energy industry.Because of the limitations including low adsorption capacity,trifling selectivity,weak binding affinity,and poor hydro-chemical stability,it is of vital importance to develop new adsorbents for uranium ion from seawater.In this work,we use a high surface area porous aromatic framework?PAF-1?as the platform to endow the ion imprinted sites.After post-modification,the resultant PAF-IIP exhibits strong affinity toward UO₂²⁺ion over 70000 mL/g of distribution coefficient?K_d?.It could extract uranium ion from simulated seawater in a high capacity?30 mg/g?and reveals excellent selectivity against interfering ions(Mg²⁺,Co²⁺,Pb²⁺,Ni²⁺,Zn²⁺,Ca²⁺,Mn²⁺,Cr²⁺,Cd²⁺etc)exceeding 1000 of selectivity coefficient?S_u?,which makes a potential promise for application in the extraction of UO₂²⁺ion from seawater.Frustrated Lewis pair plays a very important role in hydrogenation reactions.However,FLP catalysts are highly sensitive to the external environment,such as water and oxygen,thus ineluctably lead to a dramatic loss in catalytic activity upon recycling.How to use frustrated Lewis pair as a heterogeneous catalyst is a remarkable challenge.In order to deal with this question,we prepare the ultrathin layer porous aromatic framework?PAF-6?with two Lewis base groups.After loaded with Lewis acid?tris?pentafluorophenyl?borane?,the sterically hindered Lewis acid and base generate the frustrated Lewis pair and show excellent performance in hydrogenation catalysis.