Degradation of environment pollutant dyes using phytosynthesized metal nanocatalysts

•Gold and silver nanoparticles are synthesized using the juice of Punica granatum.•The synthesized nanocatalysts are used in the degradation of organic dyes.•Pseudo first order kinetics is suggested and rate constants calculated.•Comparative study on percentage removal of dyes.•Phenolic hydroxyls play a vital role in the reduction of metal ions.

We present for the first time biogenic reduction and stabilization of gold and silver ions at room temperature using fruit juice of Punica granatum. The formation, morphology and crystalline structure of the synthesized nanoparticles are determined using UV–Visible, XRD and TEM. An attempt to reveal the partial role of phenolic hydroxyls in the reduction of Au3+ and Ag+ is done through FTIR analysis. The synthesized nanoparticles are used as potential catalysts in the degradation of a cationic phenothiazine dye, an anionic mono azo dye and a cationic fluorescent dye. The calculated values of percentage removal of dyes and the rate constants from pseudo first order kinetic data fit give a comparative study on degradation of organic dyes in presence of prepared gold and silver nanoparticles.

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