Indigenous north eastern India fern mediated fabrication of spherical silver and anisotropic gold nano structured materials and their efficacy for the abatement of perilous organic compounds from waste water-A green approach

Abstract

Herein, we presented a hitherto unexplored native fern of north eastern India; Diplazium esculentum mediated biogenic fabrication of spherical silver and anisotropic gold nano structured materials. The effects of various reaction parameters such as concentration and temperature were investigated in detail and the results revealed the formation of silver nano structures with spherical morphology and gold nano structured materials of spherical, triangular and decahedral shapes. Using a suite of analyzing techniques, the intrinsic crystallinity, size, morphology, elemental composition and the functional moieties associated with the reduction and surface stabilization were also disclosed. Significantly, the catalytic properties of these synthesized nano structured materials for the remediation of two carcinogenic and lethal textile dyes, Methyl Violet 6B and Rose Bengal and one hazardous phenolic compound, 4-nitro phenol from aqueous solution were evaluated and plausible mechanisms that drive these critical processes were also proposed. Approximately, 98.4 and 98.2% of Methyl Violet 6B and Rose Bengal dye were degraded within 240 minutes using the synthesized silver nano structured materials and 98 and 98.9% of Methyl Violet 6B and Rose Bengal dye were degraded within 180 minutes employing gold nano structures as the catalyst, respectively. While about 96.8 and 97.3% of 4-nitro phenol was reduced within 70 and 80 minutes respectively using silver and gold nano structured materials. Additionally, the exhausted nano structured materials were regenerated and their photo catalytic capability was evaluated for three continuous rounds of cycles. The exhausted nano structured materials and the intermediates of the degradation process were respectively analysed using TEM and LC-MS techniques. Hence, the present study has unfastened a pioneering way for synthesizing nano structured materials of different sizes and morphologies and their applicability for the remediation of hazardous compounds make these nano structured materials ideal candidates for waste water treatment.