Photocatalytic Potential of Biogenic Silver Nanoparticles and its Process Optimization for Methylene Blue Decolorization

Abstract

Due to the exponential growth of industries in recent years, there is intensification in the release of dyes directly into environment, hence resulting in water pollution, which detriments the human as well as aquatic life. Therefore, reliable and impactful solution is required to deal with this problem. Different physical and chemical methods are used to degrade the dyes, like ultrafiltration, electrochemical destruction, membrane filtration, ozonation etc. Nanoparticles grabbed the attention of scientists as nanoparticles have unique physical, chemical and optical properties from its bulk counterpart, and hencecan be utilized for different applications. Chemical as well as physical methods for nanoparticle synthesis are toxic and are not feasible, but the biogenic synthesis is eco-friendly, cheap and efficient. In this study, rapid biogenic synthesis of silver nanoparticles (AgNPs) from pineapple peel waste (Ananas comosus) is reported. The core size of synthesized AgNPs is 14-42 nm as depicted from characterization, established by UV- Vis spectroscopy, dynamic light scattering (DLS), fourier- transform infrared spectroscopy (FT-IR). Moreover, decolorization of pollutant dye- Methylene blue was undertaken in direct sunlight to study the photocatalytic potential of biogenically synthesized AgNPs. Optimization for the photocatalytic reaction was done with the Response Surface Methodology (RSM) andsilver nanoparticles demonstrated with efficient decolorization of (MB) methylene blue within few hours. The decolorization of dye was confirmed by UV- Vis spectrophotometric analysis with a decrease in absorbance of MB at 664 nm with respect to time. Biogenic Ag Nps efficiently degrades MB dye upto 98.04±0.23% within 173 min of exposure time. Even biogenic Ag NPs shows prominent anti-bacterial activity against Pseudomonas aeruginosa and Bacillus subtilis. These results clarify the application of biogenic Ag NPs synthesized by Ananas comosus in wastewater plants, textile industries and also in pharmaceutical industries.