**2.3 Synthesis of composite photocatalyst**

The composite photocatalyst of mussel shell/TiO2 and cockle shell/TiO2 was prepared using the solid-state dispersion (SSD) method. There were two different samples of mussel shell/TiO2 and cockle shell/TiO2 with a ratio of 9:1 with a 10 g basis and also two control samples consisting of 100% of mussel shell and cockle shell. The samples were evaporated for 24 hours in a 35°C oven. Finally, the samples were calcined in a muffled furnace for 5 hours at 450°C.
