## 3 Results and Discussions
### Sem  
The morphology of ZS-ZnO-NPs synthesized using different zinc salts was investigated using a green synthesis method under the same conditions, and SEM characterization was performed to determine their shape and size. The results showed that the type of zinc salt used significantly affected the morphology of the nanoparticles. As shown in Figure 3, SEM characterization revealed that ZS-ZnO-NPs synthesized using ZnCl\({}_{2}\) exhibited a unique mixture of random, conglomerated, packed, clustered, and rod-shaped NPs with face-centered rhombohedral, spherical, hexagonal, and cubic-like structures. ZnSO\({}_{4}\cdot\)H\({}_{2}\)O resulted in the formation of nanorods, nanoplate flower-like nanalyered, and hollow spherical morphologies, while Zn(CH\({}_{3}\)COO)\({}_{2}\cdot\)2H\({}_{2}\)O promoted the formation of needle-shaped nanorods, thinner nanoplate, and flower-like nanalyered morphology. In contrast, Zn(NO\({}_{3}\))\({}_{2}\cdot\)6H\({}_{2}\)O led to the formation of larger nanorods, flower-like, nanalyered, and some cubic structures. Previous literature has reported similar morphologies [20; 53]. The diameter distribution and rod length (grain size) of the ZS-ZnO-NPs varied depending on the type of zinc salt used, as summarized in Table 1. The size distribution of the ZS-ZnO-NPs followed the order of ZnCl\({}_{2}\) < ZnSO\({}_{4}\cdot\)H\({}_{2}\)O < Zn(CH\({}_{3}\)COO)\({}_{2}\cdot\)2H\({}_{2}\)O < Zn(NO\({}_{3}\))\({}_{2}\cdot\)6H\({}_{2}\)O, with distribution diameter average ranging from 6.4 \(\pm\) 1.7 to 19.6 \(\pm\) 2.5 nm (Figure 3). The use of different zinc salts resulted in differences in the size and morphology of the green-synthesized ZS-ZnO-NPs. The anions used can affect nanoparticle stability and aggregation, and the Hofmeister series can be used to predict their effectiveness. Sulfate (SO\({}_{4}\)) and chloride (Cl\({}_{2}\)) ions are more effective in reducing aggregation and stabilizing the surface charge, while carboxylate (COOH) and nitrate (NO\({}_{3}\)) ions tend to promote aggregation and result in larger nanoparticles. Therefore, the smaller size of the nanoparticles synthesized using ZnSO\({}_{4}\cdot\)H\({}_{2}\)O and ZnCl\({}_{2}\) compared to Zn(CH\({}_{3}\)COO)\({}_{2}\cdot\)2H\({}_{2}\)O and Zn(NO\({}_{3}\))\({}_{2}\cdot\)6H\({}_{2}\)O could be due to the higher effectiveness of sulfate and chloride ions in reducing aggregation and stabilizing the surface charge. On the other hand, the smaller size of the ZnO-NPs synthesized using Zn(CH\({}_{3}\)COO)\({}_{2}\cdot\)2H\({}_{2}\)O compared to Zn(NO\({}_{3}\))\({}_{2}\cdot\)6H\({}_{2}\)O could be due to the lower hydration of carboxylate ions compared to nitrate ions [54]. The dissociation of nitrate ions is known to be more effective in solution due to their higher solubility and ability to form more hydrated species. In contrast, carboxylate ions exhibit  
Figure 2: Zeta potential values of ZS-ZnO-NPs synthesized using different zinc salts and a plant extract of _Phoenix dactylifera_ L. at pH 12: (a). ZnCl\({}_{2}\), (b). ZnSO\({}_{4}\cdot\)H\({}_{2}\)O, (c). Zn(CH\({}_{3}\)COO)\({}_{2}\cdot\)2H\({}_{2}\)O, and (d). Zn(NO\({}_{3}\))\({}_{2}\cdot\)6H\({}_{2}\)O.  
lower hydration tendencies. This difference in hydration levels may have influenced the nucleation and growth processes during synthesis, resulting in the smaller size observed in the ZnO-NPs synthesized using Zn(CH3 COO)2-2H2O. However, it is crucial to note that the study referenced [54] obtained its results using reverse microemulsion systems and an acidic environment. Emphasis was placed on the use of ethanol as the washing solvent and drying at 30 \({}^{\circ}\)C in that study. In contrast, our work employed a green synthesis method utilizing _Phoenix dactylifera_ L. extract in an alkaline environment, with nanoparticles washed using water. Although our results align with those of [54], recognizing the differences in experimental conditions is crucial.