Cellulose-based sponge@ZIF-8 from waste straws for water disinfection

In this study, zeolitic imidazolate framework-8 (ZIF-8) nanoparticles can be readily in situ generated on the skeleton surface throughout the entire structure of cellulose-based sponges obtained from waste corn straws via a hydrothermal process. Taking natural corn straws as the basic ingredient, the Water Cellulose-based Sponge@ZIF-8 (WCSZ) composite inherits the highly porous structure of straws, which is beneficial for the movement of H2O molecules in both horizontal and vertical directions. A robust H-bond topological network is weaved between abundant hydroxyl groups of the corn straw cell wall matrix and H2O molecules in the honeycomb cellular structure. Based on the topological network, the WCSZ composite maintains sufficient mechanical compressibility and elasticity, which could sustain repeated squeezing without structural failure. The WCSZ composite can not only bear a compressive strain as high as 60% but also completely recover its original height after the load is removed, exhibiting excellent mechanical property. More importantly, the WCSZ composite also presents exceptional antibacterial activities after ZIF-8 nanoparticles were introduced (antibacterial rate: 99.9%). Consequently, the WCSZ composite is an ideal candidate for highly efficient elimination of bacteria as the reusable water treatment material.

Photocatalytic Biocidal Coatings Featuring Zr6Ti4-Based Metal-Organic Frameworks

The world is currently suffering socially, economically, and politically from the recent pandemic outbreak due to the coronavirus disease 2019 (COVID-19), and those in hospitals, schools, and elderly nursing homes face enhanced threats. Healthcare textiles, such as masks and medical staff gowns, are susceptible to contamination of various pathogenic microorganisms, including bacteria and viruses. Metal-organic frameworks (MOFs) can potentially address these challenges due to their tunable reactivity and ability to be incorporated as porous coatings on textile materials. Here, we report how incorporating titanium into the zirconium-pyrene-based MOF NU-1000, denoted as NU-1012, generates a highly reactive biocidal photocatalyst. This MOF features a rare ligand migration phenomenon, and both the Ti/Zr center and the pyrene linker act synergistically as dual active centers and widen the absorption band for this material, which results in enhanced reactive oxygen species generation upon visible light irradiation. Additionally, we found that the ligand migration process is generally applicable to other csq topology Zr-MOFs. Importantly, NU-1012 can be easily incorporated onto cotton textile cloths as a coating, and the resulting composite material demonstrates fast and potent biocidal activity against Gram-negative bacteria (Escherichia coli), Gram-positive bacteria (Staphylococcus epidermidis), and T7 bacteriophage virus with up to a 7-log(99.99999%) reduction within 1 h under simulated daylight.

High Water Adsorption MOFs with Optimized Pore-Nanospaces for Autonomous Indoor Humidity Control and Pollutants Removal

The indoor air quality is of prime importance for human daily life and health, for which the adsorbents like zeolites and silica-gels are widely used for air dehumidification and harmful gases capture. Herein, we develop a pore-nanospace post-engineering strategy to optimize the hydrophilicity, water-uptake capacity and air-purifying ability of metal-organic frameworks (MOFs) with long-term stability, offering an ideal candidate with autonomous multi-functionality of moisture control and pollutants sequestration. Through variant tuning of organic-linkers carrying hydrophobic and hydrophilic groups in the pore-nanospaces of prototypical UiO-67, a moderately hydrophilic MOF (UiO-67-4Me-NH₂ -38 %) with high thermal, hydrolytic and acid-base stability is screened out, featuring S-shaped water sorption isotherms exactly located in the recommended comfortable and healthy ranges of relative humidity for indoor ventilation (45 %-65 % RH) and adverse health effects minimization (40-60 % RH). Its exceptional attributes of water-uptake working capacity/efficiency, contaminants removal, recyclability and regeneration promise a great potential in confined indoor environment application.