Synthesis and characterization of poly(3,5-diaminobenzoic acid) via enzymatic and oxidative polymerization and application in methylene blue adsorption

In the present study, polymers of substitute aromatic diamine were synthesized by oxidative and enzymatic polymerization. Enzymatic polymerization and oxidative polymerization of 3,5-diamino benzoic acid (DIABA) monomer in the presence of HRP (horse radish peroxidase) and H2O2 (hydrogen peroxide) were synthesized PDIABA-E and PDIABBA-O polymers. The structures of DIABA and polymers were confirmed by FT-IR, UV-Vis and NMR measurements. The characterizations of polymers were performed by GPC, TG-DTA, DSC, SEM and fluorescence measurements. Moreover, electrochemical fea-tures of polymers were performed with cyclic voltammetry (CV) measurements. The optical (E-g) and electrochemical (E'(g)) band gap values of PDIABA-O and PDIABA-E were calculated to be as 1.90 and 2.30 eV and 2.38 and 2.52 eV, respectively. The results showed that optical gaps and electrochemical band of PDIABA-E and PDIABBA-O were lower than those of DIABA due to their polyconjugated struc-tures. Quantum yield was calculated as 13% for PDIABA-O. Furthermore, PDIABA-O was used as a sorbent for the removal of methylene blue (MB) from aqueous solution. (C) 2020 Elsevier B.V. All rights reserved.