Preparation of Highly Porous Thiophene-Containing DUT-68 Beads for Adsorption of CO₂ and Iodine Vapor

Zirconium-based metal-organic frameworks (Zr-MOFs) have great structural stability and offer great promise in the application of gas capture. However, the powder nature of MOF microcrystallines hinders their further industrial-scale applications in fluid-phase separations. Here, Zr-based DUT-68 was structured into nontoxic and eco-friendly alginate beads, and the gas capture properties were evaluated by CO₂ and volatile iodine. DUT-68 beads were synthesized via a facile and versatile cross-linked polymerization of sodium alginate with calcium ions. The composite beads keep the structural integrity and most of the pore accessibility of DUT-68. The resulting DUT-68@Alginate (2:1) porous bead processes a surface area of 541 m²/g and compressive strength as high as 1.2 MPa, and the DUT-68 crystals were well-dispersed in the alginate networks without agglomeration. The DUT-68@Alginate bead with a 60% weight ratio of MOFs exhibits a high carbon dioxide capacity (1.25 mmol/g at 273 K), as well as an excellent high adsorption capacity for iodine, reaching up to 0.65 g/g at 353 K. This work provides a method to construct thiophene-contained composite beads with millimeter sizes for the capture of gases in potential industrial applications.