Characterization and chromium biosorption potential of extruded polymeric substances from Synechococcus mundulus induced by acute dose of gamma irradiation

This study characterized the extruded polymeric substances (EPS) secreted from Synechococcus mundulus cultures under the effect of 2-KGy gamma irradiation dose. The EPS demonstrated seven monosaccharides, two uronic acids and several chemical functional groups: O–H, N–H, =C–H, C=C, C=O, COO–, O–SO 3 , C–O–C and a newly formed peak at 1593 cm −1 (secondary imide). The roughness of EPS was 96.71 nm and only 28.4% total loss in weight was observed at 800 °C with a high degree of crystallinity quantified as CI DSC (0.722) and CI XRD (0.718). Preliminary comparative analyses of EPS exhibited high protein content in the radiologically modified (R-EPS) than control (C-EPS). Modified EPS were characterized with a high biosorption efficiency, which could be attributed to its high content of uronic acids, protein and sulphates as well as various saccharide monomers. Data revealed that 0.0213 mg L −1 h −1 is the maximum biosorption rate (SBR max ) of Cr(VI) for R-EPS, whereas 0.0204 mg L −1 h −1 SBR max for the C-EPS respectively.