Green Synthesis and Antibacterial Effects of Silver Nanoparticles on Novel Activated Carbon

A green and simple method was proposed for the synthesis of silver nanoparticles (AgNPLs) on novel Activated Carbon (AC) using glucose and dextrin as reducers and stabilizers of silver ions. Semecarpus Anacardium (SA) nutshells, an agricultural waste, were used as precursors to prepare low-cost Activated Carbon (AC) with a high surface area by chemical activation with KOH as an activator and different ratios of activating agents to the precursor. Silver nanoparticles (AgNPLs) on AC samples were synthesized using chemical and green procedures. Silver nanoparticles (AgNPLs) on AC samples were synthesized using chemical and green procedures. Surface functional groups in Fourier transform infrared spectroscopy (FTIR) spectra and X-Ray powder Diffraction (XRD) diffractograms including a broad peak in the range of 2θ =15–28◦ and a weak and broad peak in the range of 2θ =40–48◦, confirmed successful synthesis of AC. Also, the reduction of Ag+ to Ag0 and the presence of Ag2O were confirmed by XRD and SEM/EDX analysis. Scanning Electron Microscopes (SEM) reveals that the particles are spherical in shape and the Transmission Electron Microscopes (TEMs) images confirm the particle size distribution of the silver nanoparticles mainly in the range of 1–5 nm. EDX mapping was used to observe the exact distribution of silver nanoparticles on the planar carbon surface. The BET results indicate that the AC synthesized with the activating agent to precursor ratios of 1 has the highest surface area (717 m2/g) and the largest pore volume (0.286 cm3/g). Finally, the resulting Ag-AC was applied to study antimicrobial activity against gram-negative bacteria by risk diffusion and the agar well method. Silver nanoparticles distributed on the activated carbon surface had significant antibacterial properties. The sample from green synthesis with an AgNO3 solution concentration of 0.1 M  showed the most antibacterial effect.