An Azo-Group-Functionalized Porous Aromatic Framework for Achieving Highly Efficient Capture of Iodine.

The strong radioactivity of iodine compounds derived from nuclear power plant wastes has motivated the development of highly efficient adsorbents. Porous aromatic frameworks (PAFs) have attracted much attention due to their low density and diverse structure. In this work, an azo group containing PAF solid, denoted as LNU-58, was prepared through Suzuki polymerization of tris-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-phenyl)-amine and 3,5-dibromoazobenzene building monomers. Based on the specific polarity properities of the azo groups, the electron-rich aromatic fragments in the hierarchical architecture efficiently capture iodine molecules with an adsorption capacity of 3533.11 mg g-1 (353 wt%) for gaseous iodine and 903.6 mg g-1 (90 wt%) for dissolved iodine. The iodine uptake per specific surface area up to 8.55 wt% m-2 g-1 achieves the highest level among all porous adsorbents. This work illustrates the successful preparation of a new type of porous adsorbent that is expected to be applied in the field of practical iodine adsorption.

Constructing Stable and Porous Covalent Organic Frameworks for Efficient Iodine Vapor Capture.

Covalent organic frameworks (COF) with periodic porous structures and tunable functionalities are a new class of crystalline polymers connected via strong covalent bonds. Constructing COF materials with high stability and porosity is attracting and essential for COFs' further functional exploration. In this work, two new covalent organic frameworks (TTA-TMTA-COF and TTA-FMTA-COF) with high surface area, large pore volume, and excellent chemical stability toward harsh conditions are designed and synthesized by integrating the methoxy functional groups into the networks. Both two COFs are further employed for iodine removal since radioactive iodine in nuclear waste has seriously threatened the natural environment and human health. TTA-TMTA-COF and TTA-FMTA-COF can capture 3.21 and 5.07 g g-1 iodine, respectively. Notably, the iodine capture capacity for iodine of TTA-FMTA-COF does not show any decline after being recycled five times. These results demonstrate both COFs possess ultrahigh capacity and excellent recyclability.

Advances in Porous Organic Polymers for Efficient Water Capture.

Desiccant driven dehumidification for maintaining the proper humidity levels and atmospheric water capture with minimum energy penalty are important aspects in heat pumps, refrigeration, gas and liquid purifications, gas sensing, and clean water production for improved human health and comfort. Water adsorption by using nanoporous materials has emerged as a viable alternative to energy-intensive industrial processes, thus understanding the significance of their porosity, high surface areas, vast pore volumes, chemical and structural features relative to the water adsorption is quite important. In this review article, important features of nanoporous materials are presented, including zeolites, porous carbons, as well as crystalline and amorphous porous organic polymers (POPs) to define the interactions between the water molecules and the polar/non-polar functional groups on the surface of these nanoporous materials. In particular, focus is placed on the recent developments in POPs in the context of water capture as a result of their remarkable stability towards water and wide range of available synthetic routes and building blocks for their synthesis. We also highlighted recent approaches to increase the water sorption capacity of POPs by modifying their structure, morphology, porosity, and chemical functionality while emphasizing their promising future in this emerging area.

Unusual ultra-hydrophilic, porous carbon cuboids for atmospheric-water capture.

There is significant interest in high-performance materials that can directly and efficiently capture water vapor, particularly from air. Herein, we report a class of novel porous carbon cuboids with unusual ultra-hydrophilic properties, over which the synergistic effects between surface heterogeneity and micropore architecture is maximized, leading to the best atmospheric water-capture performance among porous carbons to date, with a water capacity of up to 9.82 mmol g(-1) at P/P0 =0.2 and 25 °C (20% relative humidity or 6000 ppm). Benefiting from properties, such as defined morphology, narrow pore size distribution, and high heterogeneity, this series of functional carbons may serve as model materials for fundamental research on carbon chemistry and the advance of new types of materials for water-vapor capture as well as other applications requiring combined highly hydrophilic surface chemistry, developed hierarchical porosity, and excellent stability.