Preparation of konjac glucomannan-based zeolitic imidazolate framework-8 composite aerogels with high adsorptive capacity of ciprofloxacin from water

KGM/ZIF-8 aerogels were synthesized by combining konjac glucomannan (KGM) with zeolitic imidazolate framework-8 (ZIF-8) for the removal of ciprofloxacin (CIP) from water. The structure, morphology and properties were studied by TEM, SEM, FTIR, XRD and XPS. The effects of pH, ionic strength, contact time and temperature were investigated. Rheological studies indicated that KGM/ZIF-8 hydrogels were pseudoplastic fluid, and KZ0.5 performed the best in terms of the plasticity. KZ0.5 showed excellent CIP adsorption performance. The adsorption kinetics followed the pseudo-second-order model, and CIP adsorption was fit well by the Langmuir model (R-2 > 0.99), which suggested the monolayer adsorption of CIP due to the uniform pore size distribution on the surface of KZ0.5. The maximum adsorption capacity of the KZ0.5 reached to 811.03 mg/g at 303 K when the concentration of CIP was 1500 mg/L (pH= 7.0), which was higher than that of the other adsorbents. Thermodynamic parameters, such as Delta G, Delta H and Delta S, were estimated to understand the mechanism of CIP adsorption. KZ0.5 showed no significant decrease in CIP adsorption after six cycles. These features reveal that KGM/ZIF-8 aerogels may be promising adsorbents for CIP removal from water.