## 4 Effect of Environmental and Physiological Parameters in the Synthesis of Nanoparticles
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**No.**} & **Bioresource** & **Type** & **Ions Source** & **Size (nm)** & **Biosynthesis Detail** & **Ref.** \\ \hline \multirow{8}{*}{6} & & & & & 10 mL of 0.1 N ascorbic acid (vitamin C) & \\  & & & & & was reacted with core CuCl\({}_{2}\) (2 mL, 0.1 \\  & & & Cu)-Shell (Au, & CuCl\({}_{2}\) and & & N) at room temperature, and then shell & \\  & & & Pt, Pd, and & HAuCl\({}_{4}\) +3H\({}_{2}\)O & & HAuCl\({}_{4}\) +3H\({}_{2}\)O (2 mL, 0.01 N) was added & \\  & & & Ag) & & & and allowed to react at room & \\  & & & & & temperature for 1 h. & & \\ \cline{2-6}  & & & & & & 70 mg citrate-coated Fe\({}_{3}\)O\({}_{4}\) nanoparticles & \\  & & & & & were dispersed in 20 mL double distilled & \\  & & & & & water and were sonicated for 20 min. To & \\  & & & & & this, 700 mL of freshly prepared gold & \\  & & & & & chloride solution (0.1 g/mL) was then & \\  & & & & & added maintaining a Fe\({}_{3}\)O\({}_{4}\) nanoparticle & \\  & & & Fe3O4 /Au & Fe\({}_{3}\)O\({}_{4}\) and & & & to gold chloride solution is in the ratio of & \\  & & & HAuCl\({}_{4}\) & & 1:1 (\(w/w\), 60–70 \({}^{\circ}\)C). The solution was & \\  & & & & & kept under constant stirring condition. & \\  & & & & & After 5 min, 560 mL of freshly prepared & \\  & & & & & ascorbic acid solution (0.5 g/mL) was & \\  & & & & & added maintaining gold chloride to & \\  & & & & & ascorbic acid ratio of 14 (\(w/w\), constant stirring). & \\ \hline \multirow{8}{*}{7} & & & & & 0.2 mmol of Se was dissolved in 18 mL of & \\  & & & & paraffin in a three-necked flask at 220 \({}^{\circ}\)C & \\  & & & & under vigorous stirring. In another flask, & \\  & & & & & the cadmium precursor was prepared by & \\  & & & & dissolving CdO (2 mmol) in a mixture of & 0.6 mmol oleic acid (2 mL) and paraffin & \\  & & & & liquid (8 mL) at 160 \({}^{\circ}\)C. 2 mL of the & \\  & & & & cadmium precursor solution was quickly & \\  & & & & injected into the Se solution, and the & \\  & & & & temperature was kept at 220 \({}^{\circ}\)C. After & \\  & & & & & 20 mins, the solution was cooled to & \\  & & & & zinc acetate & 100 \({}^{\circ}\)C, followed by the addition of & \\  & & & & Na\({}_{2}\)S-9H\({}_{2}\)O (0.5 mmol) into the solution. & \\  & & & & & The solution was heated to 160 \({}^{\circ}\)C under & \\  & & & & vigorous stirring followed by dropwise & \\  & & & & addition of the Zn precursor (3 mL) & \\  & & & & prepared by dissolving zinc acetate in & \\  & & & & liquid paraffin. The mixture was cooled & \\  & & & & to 100 \({}^{\circ}\)C and the reaction was allowed & \\  & & & & to continue for 90 mins to monitor the & \\  & & & & growth of the ZnS shell. & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: _Cont._The effect of pH is not limited only on the synthesis process for NPs, but is equally important in the performance of the ensuing NPs. [PERSON] et al. (in 2017) showed that an increase in the pH values ranging from 4 to 7 leads to 30 times enhancement in the removal efficiency of heavy metals ions by magnetic CoFe\({}_{2}\)O\({}_{4}\)@SiO\({}_{2}\) NPs. [PERSON] et al. (2018) showed that increase in shell thickness of Fe\({}_{3}\)O\({}_{4}\)-SiO\({}_{\rm x}\) core shell NPs led to decreases on r\({}_{2}\) relaxivity in magnetic resonance imaging (MRI). [PERSON] et al. studied the influence of shell thickness of Au@Ag core shell NPs on the antimicrobial activity against _Escherichia coli_ and _Staphylococcus aureus_; Au@Ag NPs with average shell thickness of 8.8 nm showed the higher antibacterial activity when compared with Au@Ag NPs with the shell thickness of 1.5 nm at the same concentration ([PERSON] et al., 2018). [PERSON] et al. (2017) reported citric acid mediated synthesis ZnO@CdS core shell nanorods with variable shell thickness (10-30 nm) and showed that the core shell nanorods with shell thickness of 30 have higher photocatalytic efficiency for the degradation of rhodamine B under simulated solar compared to ZnO@CdS core shell nanorods with shell thickness of 10 nm.