In this study, the synthesis and characterization of exopolysaccharide-stabilized sliver nanoparticles (AgNPs) was carried out for the degradation of industrial textile dyes. Characterization of AgNPs was done using surface plasmon spectra using UV-Vis spectroscopy, X-ray diffraction (XRD) and Raman spectroscopy. The morphological nature of AgNPs was determined through transmission electron microscopy (TEM), scanning electron microscopy (SEM) and atomic force microscopy (AFM), which indicated that the AgNPs were spherical in shape, with an average size of 35 nm. The thermal behaviour of AgNPs revealed that it is stable up to 437.1 °C and the required energy is 808.2J/g in TGA-DTA analysis. Ability of EPS stabilized AgNPs for degradation of azo dyes such as Methyl orange (MO) and Congo red (CR) showed that EPS stabilized AgNPs were found to be efficient in facilitating the degradation process of industrial textile dyes. The electron transfer takes place from reducing agent to dye molecule via nanoparticles, resulting in the destruction of the dye chromophore structure. This makes EPS-AgNPs a suitable, cheap and environment friendly candidate for biodegradation of harmful textile dyes.

Concentration levels of Mn, Pb, Zn, Cd, Cu and Cr in six seaweed samples (Acetabularia calyculus, Corallina sp., Galaxura marginata, Sargassum duplicatum, Sargassum swartzi and Dictyota bartayresiana) were determined from Wandoor, south Andaman Island. Metals were extracted from sample homogenates and quantified by atomic absorption spectrometry. In the present investigation, heavy metal concentration levels in the following order: Mn>Pb>Cd. It is observed that Zn was only present in free floating brown seaweed S. swartzi. Cu and Cr did not show its presence in any of the seaweeds that was sampled. Metal pollution index (MPI) of six seaweed species were observed in the following decending order: A. calyculus>Corallina sp.>D. bartayresiana>G. marginata>S. duplicatum>S. swartzi. Results showed that chlorophyta, A. calyculus contained the highest concentration of heavy metals as compared to other algal species. One-way analysis of variance (ANOVA) showed that the concentration of metals was significantly different (p<0.05) with respect to different species around the study area