Synthesis Of Cucurbituril Polymers And Their Adsorption To Tetracycline Antibiotics

Because of the good antibacterial effect of Tetracycline antibiotics,it was used as the antibacterial broad spectrum antibiotics,and widely used in animal husbandry.Tetracycline antibiotics are currently characterized as a contaminant,mainly due to animal farm faeces will tetracycline antibiotics into the environment,the accumulation of more and more in the environment,and ultimately endanger human health,causing enamel hypoplasia and other diseases.Tetracycline antibiotic abuse led to a variety of bacteria produce serious resistance,so the effect is reduced.Therefore,the governance of living environment,especially in domestic wastewater Tetracycline antibiotic is very urgent.Since cucurbituril has a barrel-shaped hydrophobic rigid cavity and the barrel ends are hydrophilic ports consisting of multiple carbonyl groups,it becomes a concern of the macrocyclic compounds.The hydrophobic cavity of the cucurbituril was used in the field of molecular recognition,and the hydrophilic port of the cucurbituril was used in the field of molecular assembly,even widely used in the field of sewage treatment.In this experiment,cucurbit[6]uril(CB[6])was synthesized and the recognition of oxytetracycline(OTC)was studied.The results show that CB[6] and OTC form a 1: 1 inclusion under acidic conditions,and can not form an inclusion under alkaline conditions.The thermodynamics and inclusion constants of CB[6] and OTC inclusion were also studied,and ?G <0 at different temperatures.The main forces of CB[6] and OTC inclusion processes are hydrogen bond force and ion-dipole force.CB[6] on the molecular recognition of OTC is a spontaneous process of heat absorption.Hydroxy cucurbit[6]uril was synthesized,and then fluorescent polymer(CP-1)was prepared by polymerizing hydroxy cucurbit[6]uril and m-dichlorobenzene.The scanning electron microscopy revealed that CP-1 had a rod-like nanostructure.The effects of tetracycline(TC)and OTC on the fluorescence intensity of CP-1 were studied and the results showed that TC and OTC have a fluorescent sensitization effect on CP-1.The fluorescence intensity of CP-1 increased with the increasing of the amount of TC and OTC,and showed a good linear relationship.CP-1 on TC,OTC adsorption time is very fast,but the adsorption capacity is very low.The adsorption process of CP-1 on TC is consistent with the intra-particle diffusion model and the adsorption process of CP-1 on OTC in accordance with the pseudo first-order model.Both the pH and the cation(Na+,Ca2+)in the solution have a great effect on the adsorption.In this study,cucurbituril polymer(CP-2)was synthesized with the use of hydroxyl cucurbit[6]uril and trans-1,4-dibromo-2-butene,by scanning electron microscopy found that CP-2 is intertwined with sub-nano.The adsorption kinetics and thermodynamics of TC and OTC by CP-2 were studied,and the effects of pH and cation on the adsorption were simulated.The results showed that the adsorption of TC and OTC by CP-2 reached the adsorption equilibrium at 24 h and 40 h,respectively.The adsorption process of CP-2 on the two antibiotics was in accordance with the pseudo second-order kinetics.The adsorption of TC and OTC on CP-2 had the highest adsorption capacity at pH = 5-6,and the adsorption capacity is very low in the strong acid and the strong alkaline wastewater.Na+ and Ca2+ significantly reduced the adsorption of TC and OTC on CP-2,while Fe3+ significantly increased the adsorption.The data of adsorption thermodynamics showed that the adsorption of CP-2 to TC and OTC is ?G <0 at different temperatures,indicating that the adsorption process of CP-2 for TC and OTC is a spontaneous process.?H> 0,indicating that CP-2 on the TC and OTC adsorption process is an endothermic process and the force of CP-2 on the adsorption process of TC and OTC is hydrogen bond and dipole.It was found that the adsorption mechanism of CP-2 to TC and OTC was hydrogen bond reaction by changes of infrared spectra,respectively.