A unique composite bilayer tablet composed of porous organic frameworks and two kinds of green solvents for adsorption of fluoroquinolone antibiotics and anionic pigments from water

Abstract

Due to convenient use, adjustable composition and easy preparation, sorbent tablets are considered to have obvious characteristics in the field of separation, especially for water environmental pollutants. In this study, the green, facile and catalyst-free way was employed to synthesize deep eutectic solvent and ionic liquid@porous organic frameworks (DES@POF and IL@POF), which showed specific surface area and stability; and their adsorption capacities were 187.74 (ciprofloxacin) and 111.28 mg/g (carmine), respectively. Then the two complexes were mixed with diluent and pressed to become monolayer and bilayer composite tablets; especially, the latter had two sides like a coin, which were based on DES@POF and IL@POF, respectively. During the following studies, the tablets exhibited satisfied continuous working ability and adsorption efficiency (99.57% as the highest) for the selected antibiotics and pigments. The key influential factors for their preparation and performance were investigated systematically, and separation mechanisms as well as selectivity were also discovered. The whole process was well fitted by the Langmuir isotherm model and quasi second-order kinetic model. Such a kind of sorbent tablets can be reused and renewed, which can provide useful reference on the development for new forms of separation mediums.