In this study, the synthesis of zeolitic imidazole framework (ZIF-8) in water was systematically studied using 6 zinc sources (Zn(OAc)₂, ZnSO₄, Zn(NO₃)₂, ZnCl₂, ZnBr₂, ZnI₂), respectively, under different conditions at room temperature without using any additives. It was found that Zn(OAc)₂ is the best precursor and the resultant ZIF-8 particles have the best quality with rhombic dodecahedron morphology. The concentration of 2-methylimidazole (Hmim), molar ratio Hmim/Zn and water content all have significant impacts on the morphology, particle size, and crystallinity of ZIF-8. Further result analysis reveals that 3 key reactions are involved in the ZIF-8 formation which needs five steps in ZIF-8 structural evolution. This study provides a deep understanding of the crystallization process of ZIF-8 particles in a water-based system.

Owing to the rich porosity and uniform pore size, metal-organic frameworks (MOFs) offer substantial advantages over other materials for the precise and fast membrane separation. However, achieving ultrathin water-stable MOF membranes remains a great challenge. Here, we first report the successful exfoliation of two-dimensional (2D) monolayer aluminum tetra-(4-carboxyphenyl) porphyrin framework (termed Al-MOF) nanosheets. Ultrathin water-stable Al-MOF membranes are assembled by using the exfoliated nanosheets as building blocks. While achieving a water flux of up to 2.2 mol m⁻² hour⁻¹ bar⁻¹, the obtained 2D Al-MOF laminar membranes exhibit rejection rates of nearly 100% on investigated inorganic ions. The simulation results confirm that intrinsic nanopores of the Al-MOF nanosheets domain the ion/water separation, and the vertically aligned aperture channels are the main transport pathways for water molecules.

Metal–organic frameworks (MOFs) have attracted increasing interest for adsorption applications due to their ultrahigh porosity and specific surface area. However, their adsorption performance in liquids, particularly for water treatment, is significantly limited by the poor accessibility of micropores inside the MOF matrix to most molecules and deficient active sites. Herein, we use a facile strategy, ligand selective thermolysis, to create oxygen vacancies and construct mesopores in water stable UiO-66. The obtained hierarchically porous UiO-66 (HP-UiO-66) has tunable oxygen vacancies and mesopores, and outperforms the state-of-the-art MOF based adsorbents reported so far in removing arsenic, achieving an ultrahigh adsorption capacity of 248.75 mg g⁻¹ under neutral conditions. Extended X-ray absorption fine structure (EXAFS) and X-ray absorption near-edge structure (XANES) analysis and density functional theory (DFT) calculations reveal that arsenic is mainly captured by forming bidentate Zr–O–As bonds between arsenate and HP-UiO-66 via occupying coordinatively unsaturated zirconium atoms. This study offers a new strategy for designing ultrahigh performance MOF based adsorbents.

Benefiting from wide solar energy access and high energy conversion efficiency, solar-driven interfacial water evaporation has shown great potential in critical separation processes such as desalination and waste brine treatment. However, salt accumulation on the evaporation surfaces of these evaporators still greatly limits their continuous and efficient operation, particularly in hypersaline brine desalination. Current methods suffer from either low salt tolerance or low energy efficiency. Here we show a novel self-rotating solar evaporator, which achieves ultrahigh salt tolerance (300 g L⁻¹) and energy efficiency (around 90%) simultaneously by periodic self-regeneration. This study advances the development of solar-thermal desalination technologies for practical applications.