Construction And Catalytic Properties Of Aminoclay And Its Nanocomposite Structure

Aminnoclay is a kind of synthetic layered organic clay.In this paper,we have been studied the Fe aminoclay of different synthesis consitions.Then,we developed Fe aminoclay-glucose oxidase（FeAC-GOx）.The properties of the FeAC-GOx assayed and compared with the free enzymes.Finally,different ratios of bimetallic Fe Cu aminoclay were synthesized.The structure and morphology were characterized.（1）Study on Preparation and Catalytic Properties of Fe aminoclay.In this chapter,a range of Fe aminoclay were prepared by sol-gel chemistry at room temperature.These FeAC were characterized through X-ray difractometry（XRD）and Fourier transform infrared spectroscopy（FTIR）.The peroxidase and catalase activity of FeAC was studied.The results have shown that the layered structure of the Fe aminoclay with different Si/Fe ratios remains unchanged,but the addition of Na OH in the synthesis medium affect the crystallinity of FeAC.The FeAC simultaneously possessed peroxidase and catalase mimetic activities.And,these two kinds of mimetic enzyme activities could be swititch by pH and temperature.The catalase mimics of FeAC exhibited activity in basic pH range.On the contrary,FeAC showed peroxidase-like activity only under weak acdic condition.（2）Study on Preparation and Catalytic Properties of FeAC-Fox.Glucose oxidase（GOx）and Fe-aminoclay（FeAC）were combined to construct a mimic multi-enzyme system（FeAC-GOx）for cascade reaction.FeAC exhibit peroxidase-like activity which can catalyze the H₂O₂generated by GOx and trigger color reaction.The obtained FeAC-GOx was characterized by scanning electron microscope（SEM）,XRD,FTIR.The enzymatic kinetics,catalytic stability and reusability were evaluated.As a result,the GOx immobilization efficiency could reach to76.4%,and FeAC-GOx exhibited excellent cascade catalysis activity.Compared with the free enzyme,FeAC not only possessed a strong tolerance toward temperature and pH but also presented excellent reusability.The catalytic activity of reused FeAC barely changed after six repetitions.This strategy may lay the foundation to the development of a new glucose biosensor,and provide a novel approach to design multi-enzyme cascade system.（3）FeAC-GOx Colorimetric Detection of Glucose.In this chapter,the effects of reaction temperature,pH,reaction time,FeAC-GOx concentration and substrate concentration on the FeAC-GOx cascade reaction were studied.Then,a novel one-step colorimetric glucose biosensor was fabricated with a linear range of 1-1000μM and a detection limit（LOD）of only6.07Îœm.This newly developed assay is successfully applied for the determination of glucose with excellent selectivity,sensiticity and stability.（4）Study on Preparation and Catalytic Properties of Bimetallic Aminoclay.In this chapter,bimetallic aminoclay（FeCuAC）with different Fe/Cu molar ratios was synthesized.The morphology and structure of FeCuACwere characterized using SEM,XRD and FTIR.Compares the enzyme-like activities and enzyme kinetics of FeCuAC and FeAC,Cu AC.The FeCuAC have the same layered structure as FeAC and Cu AC.Kinetics studies indicate that FeCuAC show better catalytic capability than FeAC and Cu AC.In addition,FeCuAC also has oxidase-like activity.Finally,it constructed a FeCuAC based assayfor highly sensitive and selective colorimetric detection of Pb²⁺in tap water,and a detection limit（LOD）of 28.18μM.The FeCuAC detection assay could be applied for determination of Pb²⁺in tap water with wide detection range and excellent stability.