**4. Conclusion**

By using the solid-state dispersion (SSD) method, photocatalyst composites made of cockle shell/TiO2 and mussel shell/TiO2 were successfully prepared. Using a suspension system and methylene blue as a model pollutant, we investigated the adsorption and photocatalytic activity of the material. The mussel shell/TiO2 composite photocatalyst with the smallest particle size gives the highest MB removal when compared to the cockleshell/TiO2 photocatalyst. Therefore, mussel shells have the potential to be utilized as useful materials for the removal of reactive dyes compared to cockle shells. In order to increase the MB removal, it would be suggested that the particle sizes or mussel shells should be nanosized and integrated with TiO2 to form nanocomposite photocatalysts.
