Green synthesis of silver/montmorillonite/chitosan bionanocomposites using the UV irradiation method and evaluation of antibacterial activity

Figures & data

Figure 1 Schematic illustration of the synthesized silver/montmorillonite/chitosan bionanocomposites from silver nitrate/montmorillonite/chitosan (A0) by ultraviolet irradiation method.

Figure 2 Photograph of montmorillonite, silver nitrate/montmorillonite/chitosan (A0), silver/montmorillonite/chitosan bionanocomposites (A2, A4, and A5) for 3, 48, and 96 hours of ultraviolet irradiation times.

Figure 3 Ultraviolet-visible adsorption spectra of silver nitrate/montmorillonite/chitosan (A0) and silver/montmorillonite/chitosan bionanocomposites (A1–A5) at different ultraviolet irradiation times.

Figure 4 Powder X-ray diffraction, patterns of montmorillonite, montmorillonite/chitosan, and silver/montmorillonite/chitosan bionanocomposites for (A2) three hours, (A4), 48 hours, and (A5) 96 hours of ultraviolet irradiation times.

Figure 5 Powder X-ray diffraction patterns of montmorillonite, silver/montmorillonite/chitosan bionanocomposites for different ultraviolet irradiation times (A1) 1 hour, (A2) 3 hours, (A3) 18 hours, (A4) 48 hours, and (A5) 96 hours.

Figure 6 Transmission electron microscopy images and their corresponding particle size distributions of silver/montmorillonite/chitosan bionanocomposites for A2 (A, B), A4 (C, D), and A5 (E, F).

Figure 7 Scanning electron microscopy micrographs and energy dispersive x-ray fluorescence spectra, respectively, for the montmorillonite (A, B), montmorillonite/chitosan (C, D) and silver/montmorillonite/chitosan bionanocomposites [A5 (E, F)].

Figure 8 Fourier transform infrared spectra for A) chitosan, B) montmorillonite/chitosan, and C) montmorillonite.

Figure 9 Fourier transform infrared spectra of A) silver/montmorillonite/chitosan bionanocomposites for (A5) and B) montmorillonite/chitosan.

Figure 10 Comparison of the inhibition zone test between montmorillonite, silver nitrate/montmorillonite/chitosan (A0), and silver/montmorillonite/chitosan bionanocomposites (A2, A4, and A5) against different bacteria.

Table 1 Average inhibition zone and standard deviation for Ag/montmorillonite/chitosan bionanocomposites (A2, A4, and A5) and AgNO₃/montmorillonite/chitosan (A0)

Inhibition zone (mm)					Control negative (mm)		Control positive (mm)
Bacteria	A0	A2	A4	A5	MMT	Cts	Cefotaxime	Chloramphenicol
					(5 mg/mL)	(0.2 mg/mL)
E. coli	8.2	8.6	8.7	8.7	NA*	NA*	21.8	16.7
S. aureus	8.4	8.5	8.6	8.8	NA	NA	23.6	16.4
MRSI	8.2	8.3	8.4	8.6	NA	NA	18.9	15.5

Notes: Mean standard deviation values for the E. coli = ±0.16 mm, S. aureus = ±0.15 mm and MRSI = ±0.13 mm for A0, A2, A4, and A5.

* Abbreviations: NA, not appearing; MMT, montmorillonite; Cts, chitosan; MRSI, magnetic resonance spectroscopic imaging.