A Study On The Adsorption Property And Mechanism Of β-Cyclodextrin/Polyvinyl Alcohol/Polyacrylic Acid Hydrogel For Quinolone Atibiotic

Quinolone antibiotics are well-suited for fighting bacteria and are frequently employed in human medicine,aquaculture,and animal husbandry.However,most drugs reach the environment as technical drugs or metabolites,generating environmental contamination and posing a great threat to ecological security and public health due to their misuse and difficult degradability characteristics.As a result,it is critical to investigate a simple and effective method for removing quinolone antibiotics.Adsorption has become one of the best ways for removing quinolone antibiotics due to its simplicity,effectiveness,and low production cost.Hydrogels,one of these flexible structures with great three-dimensional cross-linking network function and excellent biocompatibility,have a lot of potential applications in the adsorption industry.As a result,the quinolone antibiotics levofloxacin（LEV）and ciprofloxacin CIP)in water were chosen as the research subjects in this paper.On the basis of their structural properties,β-cyclodextrin/polyvinylalcohol/polyacrylicacid（β-CD/PVA/PAA）hydrogels with good adsorption performance and simple recovery and separation were developed,and their adsorption performance and action mechanism for CIP and LEV were investigated.The main research results are as follows:（1）The results of the FTIR,XRD,and SEM analyses demonstrate that the successful copolymerization ofβ-cyclodextrin（β-CD）,polyvinyl alcohol（PVA）,and acrylic acid（AA）occurred in the presence of the initiator（APS）and cross-linking agent（MBA）.Theβ-CD/PVA/PAA hydrogel hydrogel synthesized by copolymerization is a macromolecular material with a three-dimensional porous network structure.（2）Theβ-CD/PVA/PAA hydrogel can attain the swelling equilibrium within the parameters of the experimental investigation in around 48 hours.The performance of theβ-CD/PVA/PAA hydrogel in swelling in distilled water is greatest when the ambient temperature is 35°C and the p H value of the solution is 12.The presence of interfering ions(Na⁺,Mg²⁺,Al³⁺)will significantly reduce the saturation swelling of hydrogels,and the general trend is:Al³⁺>Mg²⁺>Na⁺.（3）Lowering the ambient temperature and solution p H value is advantageous to the adsorption reaction ofβ-CD/PVA/PAA hydrogel for CIP and LEV,and the presence of interfering ions(Na⁺,Mg²⁺,Al³⁺)will diminish the adsorption capacity ofβ-CD/PVA/PAA hydrogel for CIP and LEV to varying degrees.The adsorption experiment is conducted when the initial concentration of CIP and LEV solution is 100mg/L,the ambient temperature is 25°C,and the p H value of the solution is 4.The highest adsorption capacities ofβ-CD/PVA/PAA hydrogel for CIP and LEV are 374.53and 275.62 mg/g,respectively.Theβ-CD/PVA/PAA hydrogel adsorption kinetics for CIP and LEV were consistent with the quasi second order reaction kinetics model（R²>0.997,25°C）.Boundary layer diffusion and intra particle diffusion are the main speed control steps of the whole adsorption process,and the adsorption process is mainly chemical adsorption.The adsorption isotherms ofβ-CD/PVA/PAA hydrogels for CIP and LEV are more compatible with Freundlich adsorption isotherm model（R²>0.983,25℃）.Additionally,the adsorption process tends to incline heterogeneous multi-molecular layer adsorption.A spontaneous exothermic reaction with disordered reduction underlies the entire adsorption process.（4）After three times of reverse adsorption examination,theβ-CD/PVA/PAA hydrogel can still adsorb CIP and LEV by more than 77%under ideal circumstances,and it has good recycling value.