The Treatment Of Fluoroquinolones Antibiotics In Water By Synthesizing Covalent Triazine Framework Nanomaterials By Microwave Radiation

The overuse of antibiotics seriously threatens the health of humans and ecosystems.Fluoroquinolone antibiotics are currently the most used type of antibiotics.How to effectively remove fluoroquinolone antibiotics from water has important practical significance.Covalent triazine framework nanomaterials(CTFs)are a new type of porous nanomaterials with good thermal/chemical stability,large pore volume and specific surface area,and have been successfully applied in the fields of adsorption and catalysis.In this study,the microwave source method was used to synthesize CTFs and magnetic covalent triazine framework nanomaterials(CTFs/Fe₃O₄),and these two materials were used to remove fluoroquinolone antibiotics in environmental water.The specific research content is as follows:(1)The synthetic CTFs by microwave irradiation technology was applied to the adsorption of fluoroquinolone antibiotics in water coupled with ionic liquid colloidal bundle method.Using terephthalonitrile(DCB)as monomer and zinc chloride(Zn Cl₂)as catalyst,CTFs were synthesized by microwave irradiation method.The nanomaterials were characterized by scanning electron microscopy(SEM),transmission electron microscopy(TEM),Fourier infrared spectroscopy(FTIR)and X-ray diffraction(XRD).Combined with ionic liquid,the nanomaterial is applied to adsorb 6 kinds of fluoroquinolone antibiotics,including ciprofloxacin,sparfloxacin,fleroxacin,danofloxacin,enrofloxacin and levofloxacin.The important influence parameters of adsorption efficiency were investigated,including ionic liquid type,ionic liquid volume,CTFs amount,solution p H value,temperature,and environmental factors.The results showed that when 1-hexyl-3-methylimidazole bromide([C₆MIm]Br)was used as the surfactant,the volume and amount are 200.0?L and 0.1 g·L^-1 respectively,the adsorption reached equilibrium;p H=5.0 is more conducive to the adsorption of FQs,temperature has no obvious effect on adsorption;Cl^-and SO₄^2-in water have no obvious effect on adsorption,HCO₃^-and HA have a certain inhibitory effect,and Cd²⁺and Zn²⁺mainly play a role in promoting.The fitting results show that the adsorption process of FQs on the surface of CTFs adsorbent is more in line with the quasi-second-order kinetic model and Freundlich model.The removal rate of CTFs for 6 kinds of FQs is more than 84%,and the adsorption efficiency is still very high when used in different actual water bodies,indicating that CTFs have a good application prospect in the removal of fluoroquinolone antibiotics in environmental water samples.(2)The synthetic CTFs/Fe₃O₄ by microwave irradiation technology was applied to the degradation of levofloxacin in water coupled with persulfate advanced oxidation technology.CTFs/Fe₃O₄ was synthesized by microwave irradiation method.SEM,TEM,FTIR,XRD,VSM and BET/BJH were used to measure and analyze the morphology,surface groups,microscopic mesoporous structure and saturation magnetization of the material.The synthesized CTFs/Fe₃O₄ was used to activate permonosulfate(PMS)to degrade levofloxacin.The main factors affecting the degradation of levofloxacin in the CTFs/Fe₃O₄/PMS system were studied,including the amount of CTFs/Fe₃O₄,PMS concentration,p H value,inorganic ions,and humic acid.The experimental results show that the degradation rate of levofloxacin can be reached 100%within 30 min under the room temperature conditions with the initial concentration of levofloxacin 0.05mmol·L^-1,the amount of CTFs/Fe₃O₄ 0.15 g·L^-1,and the PMS concentration 0.5mmol·L^-1.The initial p H has a greater impact on the degradation of levofloxacin,and a certain concentration of alkali can also activate PMS.SO₄^2-and HA have a certain inhibitory effect on the degradation of levofloxacin,while Cl^-has a dual effect.The reusability experiment shows that CTFs/Fe₃O₄ has good reusability.Through free radical quenching experiments,it is found that the active substances in the system are sulfate radicals(SO₄^-·)and hydroxyl radicals(·OH),which are mainly generated on the surface of the catalyst;the degradation pathway and degradation products of levofloxacin were estimated by UHPLC-MS/MS.