Synthesis and characterization of rGO/Ag nanocomposite using cinnamon plant bark extract for methylene blue dye removal from aqueous solution

Abstract

In this study, green synthesis of a reduced graphene oxide silver nanoparticle hybrid nanocomposite (rGO/Ag) was carried out using an aqueous extract of cinnamon plant bark. Graphene oxide, and silver ions simultaneously reduced by cinnamon extract, then Methylene Blue dye removal capacity and efficiency of the resulting nanoparticles and nan ocomposite were also evaluated. The synthesized nanoparticle and nanocomposite were ch aracterized by using UV-DRS, SEM, P-XRD, and FTIR spectroscopy. The XRD results sho wed that the average particle sizes were 29.9 nm, 0.67 nm, and 13.35 nm for Ag NPs, rGO, and rGO/Ag NPs nanocomposite respectively. The UV-DRS analysis result showed that rGO/Ag nanocomposite exhibited two absorbance peaks at 272 & 334 nm which corresponds to rGO and Ag NPs respectively. The functional group information obtained from the FTIR spectral was in good agreement with the expected Phytochemicals in the plant extract for all synthesized samples and rGO functional groups exist in rGO/Ag nanocomposite. The surface morphology result obtained indicated that Ag NPs showed non-homogeneity and different shapes, rGO had thin flat layer sheet morphology and in the rGO/Ag nanocomposite, Ag NPs were found to be embedded on the surface of reduced graphene oxide nanosheets. The performance of Ag NPs adsorbent was found to be best at the optimum pH 10, adsorbent dose 80 mg, contact time 50 min, and initial concentration 10mg/l with a removal efficiency of 90.03%, for rGO nanosheets the optimized parameters adsorbent were at pH 2, adsorbent dose 80 mg, contact time 50 min, and initial concentration 10 mg/l with removal efficiency 96.97% and while the rGO/Ag NPs nanocomposite showed highest removal efficiency 99.98% at optimum pH 2, adsorbent dose 80 mg, contact time 50 min and initial concentration of 10 mg/l. The Adsorption isotherms results have well fitted to Langmuir isotherm than Freundlich isotherm for all three synthesized adsorbents. The adsorption kinetics results were best fitted to the pseudo second-order model. The study has revealed that green synthesized nanocomposite has the potential to act as an adsorbent agent and cyclic use more than five times showed that the nanocomposite has a good efficiency in adsorbing dye and has a promising effect as an environmentally friendly wastewater treatment application.