Synthesis And Application Of Melamine-Formaldehyde-Aspartic Acid Chelating Resin/activated Carbon Composite (PMA/AC)

Melamine-formaldehyde-aspartic acid chelating resin/activated carbon composite(PMA/AC)was synthesized by microwave-decompression-impregnation method.The structure and morphology were characterized by FE-SEM,FT-IR arid TG.The PMA particles were well distributed at the surface of AC with a size of 50±20nm,and the suitable operating temperature is below 100?.The uptake of PMA/AC towards Fe(?),Pb(?),L-Thr and L-Glu were studied,respectively.The results as follow:the four substances were more suitable for quasi-second-order kinetic model and Langmuir thermodynamic adsorption model.Under the initial concentration is 10 mM,pH 5.0 ??45 ? and 4 h,the maximum adsorptive capacities for Fe(?),Pb(?),L-Thr and L-Glu could react to 64.27 mg/g,98.23 mg/g,103.39 mg,/g and 108.51 mg/g,respectively.Under the optimum adsorption conditions,7%(wt%)fermented crude product solution of L-Thr was treated using PMA/AC(mass rate,L-Thr crude product:PAM/AC of 9:1).The product quality of L-Thr could meets the criterion of the 2015 national pharmacopoeia standard.A nano-silver/poly quercetin composites modified paraffin-impregnated graphite electrode was prepared by electrochemical method(Ag/Qu/WGE).A mixture of L-Glu,chitosan and Nafion was coated on the surface of Ag/Qu/WGE?L-Glu(template molecule)was removed by electrochemical cleaning using potentiostatic method.As a result,a molecular imprinted polymer modified electrode based on chitosan/nano-silver/poly quercetin composites could be obtained for L-Glu sensing(MIP-Ag/Qu/WGE).The characteristics of the modified electrode were investigated by means of FE-SEM IR and electrochemical techniques.The result indicated that the MIP-Ag/Qu/WGE displayed good electro-catalysis towards the oxidation of L-Glu,which could sensitively and quickly sense L-Glu.The differences of oxidation peak current of L-Glu(1.45 V)showed a good linearity at a concentration range of 0.1-1[imol/L.The electrode was successfully applied in the determination of L-Glu in fermentation broth.