Preparation Of Macroporous SiO₂ Monoliths And Its Application In Lipase Immobilization

In this paper,macroporous SiO₂ monoliths with different pore sizes were prepared by the method of sol-gel and high temperature sintering,using epoxy-based macroporous polymer monoliths as template.A monolithic P?GMA-co-HEMA?/SiO₂ macroporous material has been synthesized by in-situ polymerization via the macroporous material as substrate and glycidyl methacrylate?GMA?,2-hydroxyethyl methacrylate?HEMA?as functional monomers.Then,the macroporous material was employed as support for the immobilization of lipase from Candida rugosa?CRL?.Specifically as follows:1.3D skeletal epoxy-based macroporous polymer monoliths were prepared by the polymerization reaction induced phase separation of bisphenol A epoxy resins in PEG medium using TETA as curing agent.The influences of the weight ratio of epoxy and PEG,the amount of TETA and PEG20000 on the pore structure of the macroporous polymer monoliths were studied respectively.Macroporous polymer monoliths were characterized by FT-IR,SEM,BET and MIP,and used to adsorb heavy metal ions.Results show that the pore structure of macroporous polymer can be adjusted by changing the weight ratio of epoxy and PEG,the amount of TETA and PEG20000,and the pore sizes are adjusted in a range of 0.1².0 ?m.The specific surface area reaches the largest,about 84.4 m2/g,when the pore size of the monolithic macroporous polymer is minimum,however,the adsorption performance for Cu?II?ions is better when the pore size of the monolithic macroporous polymer is larger,which can reach up to 113.1 mg/g.2.Macroporous SiO₂ monoliths with different pore sizes were prepared by the method of sol-gel and high temperature sintering,using epoxy-based macroporous polymer monoliths as template.Researches show that the pore sizes of the macroporous SiO₂ monoliths are in a range of0.3² ?m.And when prepared in the medium of PEG1000 and PEG2000,the pore size of the macroporous SiO₂ monoliths is smaller,about 300⁶00 nm.However,it's about 1² ?m if prepared in the medium of PEG1000 and PEG20000.3.A monolithic P?GMA-co-HEMA?/SiO₂ macroporous material has been synthesized by in-situ polymerization via the macroporous material as substrate and GMA,HEMA as functional monomers.Then,the macroporous material was employed as support for the immobilization of CRL.Samples were characterized by SEM,EDS and TG-DTA.Results show that when the volume ratio of GMA and HEMA is 9:1,the monomers concentration is 6%,the amount of PEG20000 is 0.005 g and the concentration of lipase solution is 1.4 mg/m L,the immobilized lipasereaches its highest activity of 8843.3 U/g and remained 60.3% of its initial activity after 6consecutive batches.