Herein, we report a kind of light-responsive metal–organic framework (MOF) adsorption material which was fabricated by covalently immobilizing photoactive spiropyran (SP) molecules onto a chromium(III)-based amino-tagged MIL-101 framework through amide linkages. The photoisomerization of SP moieties endows these materials with the unique feature of reversible binding to metal ions. In the dark, the SP-modified MOFs were capable of adsorbing multiple monovalent and divalent salts from saline water and effectively released the adsorbed ions into water upon exposure to simulated sunlight. The SP-modified MOFs showed excellent salt adsorption capacity, of which the MOF with an SP modification ratio of 39% had an ion uptake of 2.27, 1.72, 1.0, 0.8, and 0.39 mmol g–1 for the monocomponent solutions of LiCl, NaCl, KCl, CaCl2, and MgCl2, respectively. After 10 adsorption–desorption cycles, the regenerated adsorbent still exhibited a higher ion adsorption of 1.27 mmol g–1 for the NaCl solution. This work provides a synthetic strategy for salt adsorption materials with nonchemical regeneration ability, which are promising for water desalination and purification.
Stimuli-responsive separation membranes with adjustable interfacial properties are highly desired for energy-efficient and sustainable water purification , owing to their exceptional antifouling capability and separation selectivity. However, the construction of highly efficient responsive membranes continues to present a substantial challenge. Herein, photo-responsive spiropyran (SP) molecular aggregates obtained via a "good-poor" solvent self-assembly strategy were implanted into lamellar graphene oxide (GO) membrane. The obtained GO/SP membrane with enriched water transport channels and enhanced hydrophilicity demonstrated superior water permeability (95.0 L h −1 m −2 bar −1 ). Benefiting from the reversible photoisomerization of SP molecules between the hydrophobic SP upon light irradiation and the hydrophilic zwitterionic merocyanine (MC) in dark conditions, the GO/SP membrane possessed captivating photo-response property verified by tunable water permeability and molecular rejection. Theoretical calculation revealed that the thermodynamic interface energy between bovine serum albumin (BSA) and membrane surface changed from attraction in dark conditions to repulsion under light conditions. Consequently, the water permeability of BSA-fouled membranes could recover to 96.2 % of its initial level after light irradiation, exhibiting fascinating photo-driven self-cleaning capability. The designed photo-responsive membrane with feasible membrane fouling control holds great promise for efficient water purification .
危险品化学品经营许可证（带存储）