Pressure relief-dipping-microwave assisted polymerization of melamine-l-aspartic acid resin at activated carbon for purification of l-threonine fermented crude product

Abstract

Abstract l -threonine ( l -Thr) obtained by fermentation often contains vestigial hydrosoluble Pb(II), Fe(II), l -glutamic acid ( l -Glu) etc., which affect the product quality. Poly melamine and l -aspartic acid ( l -Asp) resin functional coconut shell activated carbon composite (PMA/AC) was prepared by a pressure relief-dipping-microwave assisted polymerization method for the simultaneous removals. The adsorption capacities of Pb(II), Fe(II) and l -Glu could reach to 82.34 mg·g− 1, 57.82 mg·g− 1 and 102.58 mg·g− 1 at conditions of pH 5.0, 45 °C and 4 h with an initial concentration of 0.01 mol·L− 1, respectively. The present PMA/AC was successfully used to the simultaneous removals of vestigial Pb(II), Fe(II) and l -Glu from the fermented crude product solution of l -Thr. Moreover, the PMA/AC was carefully characterized by FE-SEM, IR et al. analysis techniques, the results show that abundant PMA particles evenly distributed at the inner and outside surface of AC with a size of (50 ± 20) nm.