# Removal of Contaminants in Water with Scallop Shell Waste
## 3 Results
### Characterization of Scallop Shell Waste
These images show different magnifications of the scallop shell waste powders obtained for the different ranges of particles studied (BS, MS, and SS). All the powders showed a similar morphology. The morphology of all the scallop shell waste is amorphous. These forms are distributed from fine particles (SS) to more elongated particles (BS), just as smaller particles are found as the amplitude increases used with the microscope. The morphology presented by scallop shell waste powders is similar to \"whiskers\"; this name is given to thin structures with a greater length to diameter ratio than what is usually seen. A study shows that by using \"whiskers\" as reinforcement in the manufacture of composite materials, these \"whiskers\" improve the mechanical properties of bending, tension, and impact of the obtained polymeric composite materials [44]. SEM images show no differences in the shape of the BS, MS, and SS samples. Nevertheless, there is a decrease in the particle size between the three sizes. Figure 7 shows the FTIR spectrum of the obtained CaCO\({}_{3}\) SS powder. From the FTIR spectrum profile, it is possible to observe the three characteristics absorption bands of calcite-CaCO\({}_{3}\), located at 712 cm\({}^{-1}\), 870 cm\({}^{-1}\), and 1390 cm\({}^{-1}\), ascribed to the vibrations of C-O stretching of the CO\({}_{3}\)\({}^{2-}\)[45; 46]. The most representative absorption peak at 1390 cm\({}^{-1}\) is attributed to amorphous calcium carbonate. Also, no bands were observed in the range of 3100 to 3500 cm\({}^{-1}\), associated with the presence of OH- groups. Figure 8 shows isotherms of scallop shell waste. The three analyzed materials (BS, MS, and SS) present type IVa isotherms because they show a loop of hysteresis. The hysteresis loop accompanies capillary condensation, which is H3 type; these loops are given by non-rigid aggregates of plate-like particles [47; 48]. The SEM images of the analyzed materials confirms the presence of this characteristic. Table 3 reports textural analysis, specifically specific superficiies, pore volume, and average pore diameter of the three materials analyzed. Figure 5: Thermogravimetric analysis (TGA) of scallop shell waste. Figure 6: SEM of scallop shells powder. Row 1, 2, 3, 4 and 5: BS, MS, and SS at \(\times\)27, \(\times\)95, \(\times\)1.2k, \(\times\)2.3k, and \(\times\)3.0k, respectively. Figure 8: Specific surface area (BET) of scallop shell waste. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Sample**} & **Surface Area** & **Pore Volume** & **Average Pore** & **CA Removal** & **As(III) Removal** \\  & **(m\({}^{2}\)/g)** & **(cm\({}^{3}\)/g)** & **Diameter (nm)** & **Percentage (\%)** & **Percentage (\%)** \\ \hline BS & 3 & 0.0055 & 7.6 & 0.0 \(\pm\) 0.0 & 10.0 \(\pm\) 0.6 \\ MS & 4 & 0.0095 & 10.4 & 88.0 \(\pm\) 1.6 & 17.0 \(\pm\) 0.2 \\ SS & 1 & 0.0050 & 18.0 & 100.0 \(\pm\) 0.0 & 23.0 \(\pm\) 0.3 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Textural properties of different particle size ranges and capacity of average contaminants removal percentages for scallop shell waste, \(p\) < 0.0001. Figure 7: FTIR spectrum of the CaCO\({}_{3}\) SS powder.