Statistical Evaluation of the Pertinent Parameters in Bio-synthesis of Ag/MWf-CNT Composites Using Plackett-Burman Design and Response Surface Methodology

Green chemistry - also called sustainable chemistry - as the cost-effective and environmentally friendly techniques have been gaining more attention recent years. Here, we introduced a fast, non-toxic and sustainable method to synthesize Ag nanoparticles. Various parameters are involved in the bio-synthesis of Ag nanoparticles/multi-walled carbon nanotubes (Ag/MWf-CNT) composites, including silver nitrate concentration, initial pH, temperature, CNT concentration, agitation time, biomass and stirring rate. The Plackett–Burman Design (PBD) approach indicated that the initial pH, the carbon nanotube concentration and the weight of biomass are the major effects of the Ag/MWf-CNT biosynthesis. A quadratic polynomial model was developed using Central Composite Design (CCD) to statistically evaluate the effect of the initial pH (3.5-7), the carbon nanotubes concentration (0.2-1 g/L) and the weight of wet biomass (6-16 g) on the response- reduction percentage of Ag ions. The significant factors and their interactions in the biosynthesis process were examined by means of analysis of variance (ANOVA). The results showed that the wet biomass weight has the most significant effect on the response compared to the other variables. Additionally, the model predicted that up to 89% of Ag+ reduction to Ag nanoparticles were obtained at the optimum range conditions– weight of biomass 13 g, the initial pH range 5.5-6.2 and concentration of carbon nanotubes 0.6 g/L.