H 700

The formations of silver nanoparticles were characterized by visual assessment as color changes of solution indicate the formation of nanoparticles. Reduction of pure silver ions were monitored by measuring UV-Vis spectra of the reaction mixture. UV-Vis spectra were measured using Hitachi, U-2800 spectrophotometer model UV- Visible double beam. For characterizing, absorption spectra of the samples were taken 200 to 700 nm. FTIR spectra were also performed and recorded with a Fourier Transform Infrared Spectrophotometer (IR Prestige-21, Shimadzu) in the range of 4000–500 cm⁻¹ at a resolution of 4 cm⁻¹. Size, shape and morphology of nanoparicles were determined by using Scanning Electron microscopy (2600SN Hitachi, Japan) from BCSIR, Bangladesh and Transmission Electron Microscopy (HITACHI H-700, Japan) from the Departmental laboratory of Applied Chemistry and Biochemistry, Kumamoto University, Japan.

UV-Vis spectra of ZnO-NPs powders were measured using a Lambda 25 spectrophotometer (Perkin Elmer, Waltham, MA, USA) at wavelengths ranging from 200 to 800 nm. The X-ray diffraction data were recorded by PXRD (Philips, X’pert, Almelo, The Netherlands) at 40 kV and 30 mA from 2θ = 10° to 80° with nickel-filtered Cu (λ = 1.542 Å) at room temperature. The morphology and size of ZnO-NP samples were examined by using a Transmission Electron Microscope (TEM, Hitachi H-700, Tokyo, Japan) in 120 kV. The particle electrostatic charge was evaluated using the laser doppler electrophoresis technique, whereby 100 µL of the solution was diluted in 1.5 mL of water. Subsequently, it was poured into a Zetasizer-nano instrument cuvette (Malvern, UK); the results are stated as zeta potential (ZP). Photoluminescence (PL) spectra were recorded using a spectrophotometer (LS 55, Perkin–Elmer, Beaconsfield, UK) with an excitation wavelength of 320 nm.

The ZnO NPs were characterized by PXRD (Philips, X’pert, Almelo, The Netherlands), at 40 kV and 30 mA from 2θ = 10° to 80° with nickel-filtered Cu (λ = 1.542 Å) at room temperature. FT-IR spectra of the samples were recorded over the range of 400–4000 cm⁻¹ by a Model spectrum 100 series (Perkin Elmer, Waltham, MA, USA) FTIR spectrophotometer. UV-vis spectra of ZnO NPs powders were measured using a spectrophotometer (Lambda 25-Perkin Elmer) in wavelength between 200 and 800 nm. The morphology and size of ZnO-NP samples were examined by using a Transmission Electron Microscope (TEM, Hitachi H-700, Tokyo, Japan) in 120 kV. The particle electrostatic charge was evaluated using the laser doppler electrophoresis technique, whereby 100 µL of the solution was diluted in 1.5 mL of water. Then it was poured into a Zeta sizer-nano instrument cuvette (Malvern, UK); the results are stated as zeta potential (ZP). Concentration of Zn²⁺ ions before and after addition of extract was measured using Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) model Perkin Elmer 1000. Following Equation was used to calculate percentage yield (%Y) using initial concentration (IC) and final concentration (FC) of Zn²⁺ ions: $\%\mathrm{Y}=\frac{\mathrm{Ic}-\mathrm{Fc}}{\mathrm{Ic}}\times 100\%$