Novel anionic functionalized magnetic β-cyclodextrin composites with excellent adsorption capacity for moxifloxacin...

Antibiotics and heavy metals pose severe risks to human health and ecological environment. Therefore, developing a multifunctional adsorbent to remove these contaminants from wastewater is an urgent need. Herein, novel anionic sulfonic acid groups functionalized magnetic β-cyclodextrin (β-CD) composites (FCD@AA) were synthesized by coating poly(2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS)) on the surface of magnetic β-CD particles (FCD). Several characterization techniques were utilized to comprehensively analyze the surface physicochemical properties of FCD@AA. The adsorption properties of FCD@AA toward antibiotics (moxifloxacin (MOX) as model) and heavy metals (copper ion (Cu²⁺) as model) were systematically studied under different conditions on adsorption time, temperature, initial concentration, solution pH and coexisting ionic strength. In single systems, the adsorption isotherm data for MOX and Cu²⁺ were well fitted to Langmuir and Freundlich models, respectively. The maximum adsorption capacities of FCD@AA toward MOX and Cu²⁺ were 118.98 and 19.29 mg g^-1, respectively. The pseudo-second-order model could better describe the kinetic processes. In binary systems, the presence of Cu²⁺ exhibited a pronounced antagonism on the adsorption of MOX. The influence of co-existing MOX on the capture of Cu²⁺ changed from inhibition to promotion as the initial Cu²⁺ concentration increased. And after five adsorption cycles, FCD@AA still had satisfactory reusability. The results indicate that FCD@AA is a promising adsorbent for treating water contaminated by MOX and Cu²⁺, which broadens the application of magnetic β-CD adsorbents in environmental protection.