Preparation Of Novel Bio-based Metal-organic Aerogels And Their Adsorption Properties For Antibiotics

Antibiotic pollutants in wastewater have caused serious harm to the ecosystem and human health.Currently,the development of advanced technologies for efficiently removing them from wastewater has become a research hotspot.As a new type of porous materials,metal-organic aerogels（MOAs）feature unique advantages in capturing organic pollutants due to their low density,high specific surface area and large pores.In this paper,a novel Fe-centered metal-organic aerogel（Fe-MOA）was firstly synthesized in a mixed solution of N,N dimethylformamide and ethanol with bio-renewable 2,5-furandicarboxylic acid（FDCA）and Fe（NO₃）₃·9H₂O.And the explorement of its application in the removal of antibiotics in wastewater was conducted.The detail of studies are listed as follow:（1）The effects of preparation conditions of Fe-MOA on the adsorption performance were investigated.It was found that the optimal Fe-MOA adsorbent was obtained with the mixed solution of N,N dimethylformamide and ethanol as the solvent（the volume mixing ratio is 1:1）,the metal salt and ligand molar ratio of 1:1,the reactant concentration of 0.08 mol·L^-1,the reaction temperature of110℃,and the reaction time of 24 h.Subsequently,the Fe-MOA was characterized by FT-IR,XPS,SEM,TEM,EDX,TGA and N₂adsorption-desorption isotherm.The results showed that Fe-MOA presented a porous three-dimensional network structure assembled by Fe³⁺and organic ligand through the coordination bond Fe-O with the specific surface area of 512 m²·g^-1.（2）Density functional theory（DFT）tool was used to calculate the sizes of TC,CTC-HCl,CIP and MNZ for evaluating the accessibility of Fe-MOA for the bulky antibiotic molecules.Adsorption experiment results showed that the Fe-MOA exhibited the best adsorption capacity on TC and CTC-HCl and very few capacity on CIP,which may be related to the molecular structure,chargeability and hydrophily of the antibiotics.Notably,the Fe-MOAs still exhibited a high adsorption capacity after 4 cycles.（3）The adsorption kinetics,adsorption isotherm and thermodynamic analysis of TC on the Fe-MOA were investigated for exploring the adsorption mechanism.The results showed that the adsorption kinetics was well-fitted by the pseudo second-order kinetic model and liquid film diffusion.And the Freundlich model were considered to be the well-fitted adsorption isotherm and the adsorption reaction is a spontaneous endothermic reaction.The ultra-high adsorption capacity can be explained by the synergistic effect of the electrostatic interaction,hydrogen bond,cation bonding bridge andπ-πinteraction between the TC molecule and Fe-MOA.