ندا سیدی

In the present study, an eco-friendly and facile method for green synthesis of silver nanoparticles (AgNPs) on the surface of modified chitosan by vanilin has been developed using extract of Salvia leriifolia plant. AgNPs were decorated on chitosan after it had been functionalized with vanilin. Then, the catalyst was characterized and The reduction process of methylene blue (MB) with NaBH4 was used as a model reaction to evaluate the catalytic activity of synthesized AgNPs. MB is a thiazine dye, also known as methylthioninium chloride, that has a wide range of applications in chemical sciences and biochemistry, as well as as a stain and a pharmaceutical.1-3 When MB is oxidized, it is blue, but when it is reduced, it becomes colorless leucomethylene blue. In the utter lack of the AgNPs catalyst, the UV-Vis absorption spectra of MB reduction with NaBH4 are shown in Fig. 1a. The studying showed that partial reduction of MO occurred within 2h in the presence of NaBH4 alone. In contrast, upon addition of AgNPs (in the presence of NaBH4), complete reduction was achieved within 90 s. The kinetic data obtained for the reduction of MB was fitted to first-order rate equations.4 The catalytic efficiency of Ag nanocatalyst toward the degradation of the MB studied herein is shown in Figs. 1(b). The calculated rate constants for the reduction of MB was -0.0225 and also the catalyst exhibited high efficiency after 5th run.