Facile preparation of ZIF-8 functionalized basalt fiber felt and its high adsorption capacity for iodine

Successful integration of ideal amounts of porous materials onto the fibrous substrate requires a subtle balance between the loading ratio and structural robustness. In this study, zeolitic imidazolate framework-8 (ZIF-8) crystals could be controllably coupled on the surface of the fibrous basalt fiber felt via a mild synthetic route with a combination of biomimetic mineralization and layer-by-layer growth. Specifically, by regulating the deposition time and the number of growth cycles, a high loading ratio of 47.1% for ZIF-8 could be achieved without sacrificing the strength of the substrate. The remarkable stability of the composite against varied environmental factors such as high temperature, humidity, and solution corrosion circumstances were confirmed which could be attributable to the ultra-stability of single components and strong bonding between them. The high-quality loadings of the ZIF-8 ensured the fiber composite with abundant porosity, featuring a considerable specific surface area of 822 m2/g, which made it a promising candidate as a high-effective pollutant adsorbent. The maximum iodine vapor capacity of the optimal sample could reach 3614 mg/g. The mechanism of iodine adsorption was further explored in kinetics and thermodynamics aspects. This study is projected to overcome the defect of the MOF powder in the real application and further outline a facile method for the construction of MOF-fiber composite in a controllable manner.