## 3 Results and Discussion
### Adsorption  
The first analysis involved taking the measurement of the dye concentration in the separated supernatants. This is an indirect measurement of a dye bound with nanoclays that indicates synthesis performance. The first step was to obtain the calibration line for each dye in water solution. We added different concentrations of the most concentrated buffer phosphate solution to distilled water and obtained the calibration lines seen in Figure 2. Then we made up the supernatants to a known volume and took measurements with the spectrophotometer to know the dye concentration in the supernatant separated after the exchange process. Once the dye concentration added to each nanoclay dispersion was known, we calculated the dye percentage bound to the nanoclay as the adsorption percentage (Ads (%)). As Table 2 shows, adsorption (%) moved from 7% to 100% depending on the synthesis conditions. The influences of factors, such as their interactions, can be explained and were found in the analysis of variance (ANOVA) (Table 3). The significant factors observed for the Ads (%) response were the clay origin (CLAY), the silane concentration (SIL) and the silane concentration or silane clay interactions (\(p\)-Values lower than the significant level). As seen in Figure 3, the maximum adsorption in both dyes was found with the maximum added dye concentration using silane after dye addition. However, the presence of silane lowered the dye adsorption in PE, but increased adsorption in PC. Depending on the dye structure, the nanoclay modification with silane helped dye adsorption or inhibited adsorption in the laminar nanoclay structure. Both natural dyes are photosynthetic proteins and have prosthetic groups called bilins, which are responsible for color response. Classification as PC or PE depends on their absorption and emission; PC (610-620 nm) and PE (540-570 nm). Their sizes are also affected by their configuration. PE has a heavier molecular weight than PC: 240,000 Da vs. 36,700 Da. These configuration and volume differences explain the wide adsorption variations noted during PE synthesis compared to the adsorption variations for PC. PC molecules adsorption in nanoclay structures implied less energy than PE molecules. Figure 2: Pictures of the different synthesis steps and the results in the powder format for all the hybrid pigments with dyes PC and PE. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**REF.** & **Ads (\%) a** & **REF.** & **Ads (\%) b** \\ \hline nPE.1 & 67.15 & nPC.1 & 96.87 \\ nPE.2 & 78.16 & nPC.2 & 95.23 \\ nPE.3 & 18.27 & nPC.3 & 99.30 \\ nPE.4 & 7.90 & nPC.4 & 98.44 \\ nPE.5 & 76.18 & nPC.5 & 100.00 \\ nPE.6 & 29.35 & nPC.6 & 97.56 \\ nPE.7 & 31.65 & nPC.7 & 99.91 \\ nPE.8 & 80.54 & nPC.8 & 100.00 \\ nPE.9 & 28.80 & nPC.9 & 100.00 \\ nPE.10 & 39.42 & nPC.10 & 100.00 \\ nPE.11 & 16.71 & nPC.11 & 92.62 \\ nPE.12 & 8.76 & nPC.12 & 100.00 \\ nPE.13 & 7.54 & nPC.13 & 88.52 \\ nPE.14 & 63.80 & nPC.14 & 99.16 \\ nPE.15 & 15.87 & nPC.15 & 71.14 \\ nPE.16 & 14.52 & nPC.16 & 76.90 \\ \hline \end{tabular} a sample standard deviation: 27.25, b sample standard deviation: 8.76.  
\end{table} 
Table 2: Adsorption (%) from the initial PC and PE concentrations under different synthesis conditions (DOE) using supernatant measurements (UV-VIS). \begin{table}