A facile green synthesis of ultra small silver nanoparticles using aqueous branch extract of Dipterocarpus retusus (Hollong) promoting catalytic degradation of organic pollutants for environmental remediation
Pragyan Jyoti Goswami, Kanupriya Kashyap, Dipanka Dutta, Mohan Lal, Jehova Jire L. Hmar, Jugal Bori
Abstract
The development of green and eco-friendly synthetic strategies for the synthesis of silver nanoparticles (AgNPs) has gained significant attention due to their sustainability and broad environmental applications. This article reports a novel green synthesis of ultra-small AgNPs using Dipterocarpus retusus (DR) branch extract as a natural reducing and capping agent with the smallest reported average particle size of 2.76 nm using any reported green synthesis method. The high purity, stability, and average particle size of 2.76 nm were confirmed by using different analytical tools. This relatively smaller particle size could be obtained due to the presence of resveratrol oligomers in the DR-extract. Their catalytic efficiency was investigated for the degradation of two major highly hazardous and toxic water pollutants, namely 4-nitrophenol (4-NP) and methyl orange (MO). It catalytically reduced the 4-NP to 4-aminophenol, which is less toxic and has immense potential in the field of different industrial applications including drug synthesis. The reduction shows an excellent conversion efficiency of 100 % with a rate of 0.0515 per minute. Additionally, the catalyst exhibited excellent activity in the degradation and decolorization of MO, a toxic azo-dye and common water contaminant. The degradation was 99.1 % conversion efficiency with a rate of 0.0692 per minute. This excellent catalytic activity could be gained on the addition of a very small catalytic amount of DR-AgNPs i.e., 50 μg and 200 μg for the reduction of 4-NP and MO respectively, which is the least amount of catalyst loading for such kind of conversions using green synthesized silver nanoparticles. These catalytic reactions play a major role in environmental remediation by reducing hazardous organic pollutants. Thus, the utilization of DR branch extracts not only enhances but also promotes the sustainable approach towards nano-catalysis. The remarkable catalytic performances and environmentally sustainable synthesis route make these newly synthesized AgNPs a promising candidate for addressing environmental challenges and fostering a green chemistry solution for pollution control including wastewater treatment and industrial applications.