Efficient and rapid adsorption of methylene blue dyes by novel metal-organic frameworks and organic/inorganic hybrid alginate-based dual network gel composites

To address the limitations of gel-based adsorbents, such as inadequate mechanical strength, low adsorption capacity, and limited reusability, this study presents an innovative approach employing a dual network gel. The dual network consists of calcium alginate (CA) ionic crosslinked organic networks, and vinyl silica-based nanoparticles (VSNP) as crosslinking agents in acrylic acid (AA) free radical polymerization networks (denoted as P (AA-co-VSNP), abbreviated as PAV). After freeze-drying, ultimately yielding an organic/inorganic hybrid dual network gel (referred to as CA/P(AA-co-VSNP), abbreviated as CPAV), enriched with abundant functional groups, thereby enhancing material reusability. To further enhance the adsorption capacity, CPAV undergoes hydrothermal reactions to obtain metal-organic frameworks (MOFs) composite dual network gel adsorbent (UiO-66@CPAV). UiO-66@CPAV exhibited a density of 0.165 g/cm3 and showcased a unique pore structure with nested macropores and mesopores, featuring a uniform distribution of pore holes. Notably, the specific surface area was measured at 96.3 m2/g, and an average pore diameter was 17.9 nm. Most impressively, the actual maximum adsorption capacity reached 841.7 mg/g, and even after 10 cycles of use, the adsorption capacity remained 91.9 % of its initial value. Overall, this research introduced a novel methodology for the development of dual network MOFs@gel adsorbents, showcasing promising advancements in the field.