Fabrication Of Zr-MOF Modified Nanofiber Membranes For Hemodialysis Application And Their Properties Investigation

About 10%of the global population suffers from chronic kidney disease(CKD).The kidney,as the main detoxification organ of the human body and a part of the urinary control system,is responsible for filtering toxins from the blood and maintaining fluid and electrolyte balance.End-stage renal disease patients need to clean their blood by hemodialysis,thus high-performance and low-cost hemodialysis membrane has huge prospect in application.The removal of toxins depends only on the pore size and lack of specificity,as well as the inability to remove the toxic substances bound by small molecules,middle molecules and albumin.Therefore,it is very necessary to develop novel and high-efficiency hemodialysis membrane.Metal organic frameworks(MOFs),as a new kind of porous material,have been extensively studied by researchers due to its special pore structure.MOFs are formed by coordination bonds between metal ions and organic compounds.Compared with other traditional porous materials,MOFs have a larger specific surface area,adjustable pore size and structure,and unsaturated metal sites for coordination.Zr-based MOF has becoming an emerging research hotspot especially in the field of hemodialysis due to its large specific surface area,good chemical stability,and blood compatibility.UIO-66(Zr)MOF is composed of octahedral[Zr₆O₄(OH)₄]clusters coordinated with twelve1,4-benzene dicarboxylic acid molecules.UIO-66(Zr)MOF has attracted more attention recently due to its high thermal and chemical stability.However,similar to other powder nano-porous adsorbents,MOFs are difficult to separate,which limit their practical application.Electrospinning is a versatile and attractive technology that produces ultra-fine nanofibers with diameters from a few microns to even a few nanometers.Compared with other nanofiber materials,electrospun nanofibers have some unique characteristics,such as ultra-fine diameter,huge specific surface area,large porosity,good mechanical properties,reusability,and easy modification.In this paper,we combined electrospinning nanofibers with MOF materials,the specific surface area and adsorption sites of the nanofiber membrane were increased after the modification by MOF,thereby improving the selective removal ability of the nanofiber membrane for uremic toxins and protein retention rate.In this paper,we focus on the preparation of Zr-MOF modified nanofiber membranes and their application in hemodialysis.This paper is mainly divided into the following two contents:1.UIO-66-NH₂ modified nanofiber membrane(UNPNFM)were prepared by the combination of electrospinning method and hydrothermal synthesis method.UIO-66-NH₂ nanocrystals were successfully grown on the surface of nanofiber membrane with a content of 38.10%.The specific surface area of the composite nanofiber membrane increased significantly after the modification by MOF,reaching 113.6 m~2/g.The mechanical properties and hydrophilic properties of the nanofiber membrane were improved.The cytotoxicity,APTT,hemolysis and platelet adhesion test of the composite nanofiber membrane showed that the UNPNFM was non-toxic,did not cause thrombosis and had good blood compatibility.The UNPNFM showed good adsorption performance for creatinine and hippuric acid,and the Langmuir isotherm and pseudo-first-order kinetic model can be applied to better describe the adsorption process.The maximum adsorption capacities of UNPNFM for creatinine and hippuric acid were96.43 mg/g and 125.63 mg/g,respectively.The simulated hemodialysis experiment was performed on UNPNFM.After 4 hours,the clearance of creatinine and hippuric acid was 259.54 m L/min and 254.66 m L/min.The removal efficiencies of creatinine and hippuric acid were 60.3%and 63.56%,respectively,the retention rate to bovine serum albumin(BSA)was 90.83%.2.A flexible UIO-66-(COOH)₂ modified nanofiber membrane(UAPNFM)was designed by the methods of in-situ growth and adhesion modified.UIO-66-(COOH)₂nanocrystals were uniformly and stably grown on the nanofibers with a content of54.99 wt%.The obtained UAPNFM showed excellent adsorption and removal performance for creatinine.The Langmuir isotherm and pseudo-second-order kinetic model can be applied to better describe the adsorption process.The maximum adsorption capacity of UAPNFM for creatinine was 168.63 mg/g.After 4 h of simulate dialysis,the creatinine clearance for UAPNFM was 226 m L/min,which was 1.24 times larger than that of commercial FX60 dialyzer.The clearance rate of creatinine was82.48%and the protein retention rate of bovine serum albumin(BSA)by the UAPNFM was 93.09%.The composite nanofiber membrane has good mechanical properties and regenerability.After four cycles,the removal efficiency for creatinine still remained at82.31%.In addition,the coagulation,hemolysis,blood routine and platelet adhesion tests of the composite nanofiber membrane showed that UAPNFM had excellent blood compatibility.