Silver nanoparticle synthesis using the serum obtained after rubber coagulation of skim natural rubber latex with chitosan solution

摘要

This research focused on a green synthesis of silver nanoparticles (AgNPs) using the serum from skim natural rubber latex (SNRL), which is simple and low cost. Chitosan in acetic acid was used as a coagulant to remove rubber particles from SNRL. This leftover serum was diluted with the same amount of water and used as a source of reducing agent in the synthesis of AgNPs. The effects of NaOH and AgNO3 concentrations were studied. The AgNP colloids were characterized by UV-vis spectrophotometry and transmission electron microscopy. Three AgNP samples were chosen and tested for their sensing ability when reacting with H2O2. The results showed that increasing NaOH concentration from 0.1 M to 1 M caused the absorbance peak to shift to a lower wavelength, implying that the AgNPs were smaller; the opposite trend was observed when increasing AgNO3 concentration from 1 to 3 mM. From these samples, three were chosen based on clear differences in absorbance peak positions, which were at 405, 417 and 424 nm, consistent with average sizes of 7.942, 8.464 and 9.284 nm with SDs of 4.000, 1.673, and 1.941 nm, respectively. In the test of sensing ability of AgNPs when reacting with H2O2, it was necessary to enhance the stability of diluted AgNP samples with 5 wt % polyethylene glycol. The three AgNP samples were reacted with H2O2 at various concentrations from 0.0625 to 0.5 mM. The AgNPs of small sizes yielded high sensitivity provided that the colloidal stability was adequate.