Whatman filter papers no 1

Leaves of Phoenix dactylifera were collected from botanic garden, Dept. of Botany and Microbiology, King Saud University, with full permission has obtained from institute. The extract was prepared by drying leaves at room temperature and washed in distilled water, 5 g of this powder was homogenized completely in 100 ml Milli-Q water and extracted at ≤ 80 °C for 20 min. The resultant was filtered using Whatman filter papers No. 1. Then, extract was stored at 4 °C and used for generating biosynthesized zinc oxide nanoparticles. Zinc nitrate (99.999%) was purchased from Sigma. The synthesis of ZnO NPs was carried out by taking a 0.05 M of Zinc nitrate in 100 ml Milli-Q water. Then, 2:2 (v/v) of leaf extract and Zinc nitrate to obtain a mixture solution in a round-bottom flask, and incubated with constant stirring (100 rpm) at 40 °C for 24 h. The solution was cooled to room temperature and filtered using Whatman filter papers No. 1. The precipitate was washed with deionized water and absolute ethanol for several times using centrifugation (5000 rpm for 5 min), and dried in an oven at 60 °C for 24 h. Finally, the product was calcined at 600 °C for 3 h^{28 (link)}.

Extraction was performed according to the method described by Harborne [26 ]. Briefly, the methanolic extract was obtained by cold maceration of 200 g of L. eriocalyx bark powder in 750 ml of methanol (AR grade) in a 1 liter conical flask and regularly agitated for 48 hours. The mixture was carefully decanted and filtered using Whatman filter papers(No. 1) and concentrated in vacuo with a rotary evaporator at 50°C. The extract was transferred into a clean, dry, labelled, preweighed universal glass bottle and kept in a hot-air oven set at 35°C for five days to allow for complete drying.
On the other hand, the aqueous extract was obtained by warming 50 g of the powdered L. eriocalyx bark powder at 58°C in distilled water on a water bath for two hours. The resulting mixture was cooled to room temperature, filtered through a Whatman filter paper (No. 1), and transferred into clean freeze-drying flasks. The flasks were covered with solid CO₂-acetone mixture and then fitted into a freeze dryer for lyophilization for 48 hours. The dry and lyophilized extracts were transferred into clean, dry, preweighed, and labeled universal glass bottles. The percentage yields of the individual extracts were determined using the formula described by Harborne [26 ] and modified by Truong et al. [27 (link)]: $\begin{array}{c}\%\text{\hspace{0.17em}yield}=\frac{\text{weight\hspace{0.17em}of\hspace{0.17em}extract}}{\text{weight\hspace{0.17em}of\hspace{0.17em}macerated\hspace{0.17em}powder}}\times 100.\end{array}$

Nigella sativa seed extract was prepared by crushing seed in a grinder. Resultant seed powder was thoroughly washed in distilled water and 10 g of this powder was homogenized completely in 50 ml double distilled water and incubated with constant stirring (100 rpm) at 80 °C for 20 min. The resultant mixture then filtered using Whatman filter papers No. 1 to remove debris. This extract was used for generating green zinc nanoparticles. The extract was stored at 4 °C for future uses.