Covalent Organic Framework Materials And Composites For Adsorption Of Quinolone Antibiotics

With the development of society,the production and use of antibiotics continue to expand.A large amount of antibiotics are released into the water environment,which seriously threatens the survival of aquatic organisms and human beings.Removal of FQs from various water environments through relatively green methods with high efficiency is one of the most promising strategies to meet the growing demands for water treatments.In recent years,covalent organic frameworks have become a research hotspot in the field of environmental restoration due to their ordered pore structure,large porosity,structural diversity,and easy functionalization.This thesis focuses on the application of covalent organic framework and its hybrid materials in the adsorption and removal of environmental organic pollutants such as quinolone antibiotics,mainly including the following contents:1.An anionic covalent organic framework(TpPa-SO₃Na)was synthesized through a green two-in-one synthesis strategy with autocatalytic imine formation.The slowly generated acetic acid as a catalyst is favorable to sustain the reversibility of the COF formation reaction and improve crystallinity of TpPa-SO₃Na.TpPa-SO₃Na is consist of a homogeneous distribution of sulfonate groups to produce negatively charged regular channels.The strong electrostatic and hydrogen binding interactions between the sulfonate groups anchored in the nanochannels and the amine groups in organic pollutants improve the adsorption selectivity and capacity.These structures allow a high degree of control over adsorption processes to boost the adsorption kinetics and improve selective separation.TpPa-SO₃Na exhibits an ultra-fast adsorption of cationic antibiotics and dyes.Furthermore,TpPa-SO₃Na exhibits high selectivity for the uptake of dye molecules on the basis of the differences in charge and molecular size.This work explored functional designs and green manufacturing of anionic COF for removal of hydrophilic organic pollutants.2.Zwitterionic covalent organic frameworks(Tp-MTABs)were synthesized through a solvothermal route using 5,5',5''-methanetriyltris(2-aminobenzenesulfonic acid)(MTABs)as a zwitterionic linker and 1,3,5-triformylphloroglucinol(Tp)as neutral knots for efficient uptake of FQ antibiotics.Tp-MTABs consist of regular distributions of sulfonic acids and amines that produce zwitterionic binding sites,which produce complementary ion-pair interactions with zwitterionic FQ antibiotics.The charge on Tp-MTABs facilitates its initial self-exfoliation to few-layered ionic covalent organic nanosheets(iCONs)with controlled surface charge,which exposes more surface ionic sites and phenyl groups toward FQ antibiotics,improving ion-pair and ?–? interactions between iCONs and FQ antibiotics.These iCONs with multiple active sites allow a high degree of control over adsorption processes,boosting the adsorption kinetics and improving the selective separation of FQ antibiotics.Tp-MTABs exhibits ultrafast adsorption(<30s)of FQ antibiotics(average over99%).Furthermore,Tp-MTABs exhibit high selectivity for the uptake of FQs in complex systems containing multiple competing organic compounds and high-salinity natural seawater.This work explored the structural and functional design of iCONs for the removal of organic molecules in environmental remediation.3.A SO₃H-anchored covalent organic framework(TpPa-SO₃H)was deliberately designed by linking phenolic trialdehyde with triamine through Schiff reaction,then low-content Tb³+ ions were loaded onto covalent organic framework according to wet-chemistry immersion dispersion method which benefitting for efficient FQs antibiotics uptaking.Tb@TpPa-SO₃H functionalized with regularly distributed sulfonic acid groups and terbium ion which could provide difunctional binding sites.Tb³+ sites could capture carboxylic acid group of FQs molecules according to the complexes coordination effect and sulfonic acid sites play a significant role in the adsorption of FQs molecules through electrostatic interaction with amine group.Tb@TpPa-SO₃H with dual complementary function sites exhibited ultra-fast adsorption kinetics(<2min,average over 99% removing rate)and high adsorption capacities of 989,956,and 998mg g^-1 for Norfloxacin(NOR),ciprofloxacin(CIP),enrofloxacin(ENR),respectively.Furthermore,Tb@TpPa-SO₃H showed excellent selectivity for the adsorption of FQs in tanglesome system.This work not only explored synergistic adsorption in ion-functionalized 2D covalent organic framework with dual binding sites,but also delineated a promising strategy for the elimination of organic pollutants in environmental remediation.4.A SO₃H-anchored covalent organic framework(TpPa-SO₃H)was deliberately designed by linking phenolic trialdehyde with triamine,then Tb³+ and Eu^<sup>3+ were loaded onto covalent organic framework according to wet-chemistry immersion dispersion method which benefitting for efficient FQs antibiotics uptaking.Tb-Eu@TpPa-SO₃H functionalized with regularly distributed sulfonic acid groups,terbium ion and europium ion which could provide mulriple binding sites.Tb³+ and Eu³+ sites could capture carboxylic acid group of FQs molecules according to the complexes coordination effect and metal-to-metal charge-transfer effect,and sulfonic acid sites play a significant role in the adsorption of FQs molecules through electrostatic interaction with amine group.Tb-Eu@TpPa-SO₃ H with mulriple complementary function sites exhibited high adsorption capacities of 1111,1147,and1176mg g-1 for NOR,CIP,ENR,respectively.This work not only explored synergistic adsorption in double-lanthanide functionalized COF hybrid material with mulriple binding sites,but also delineated a potential strategy for the removal of organic pollutants in water environment remediation.