**Abstract**

Mollusk shell is abundant in particular areas and frequently deposited in landfills, contributing to environmental pollution. However, mollusk shell waste has been proven as an absorbent that has a high possibility of acting as a photocatalyst when integrated with metal support in composite form due to the synergistic effect. Therefore, in this study, mussel and cockle shells as agricultural wastes were selected to be innovated as support for photocatalysts. The solid-state dispersion (SSD) method was used to prepare a composite photocatalyst where mussel and cockle were integrated with titanium dioxide (TiO2) nanoparticles at a ratio of 9:1. In total, 100% of mussel and cockle were used as control samples. The prepared composite photocatalyst was evaluated with methylene blue (MB) removal in the suspension system. The result reveals that mussel/TiO2 and cockle/TiO2 composite photocatalyst show 25.92 and 24.08% for MB removal within 2 hours. It is due to the prepared composite photocatalyst particle sizes, where mussel/TiO2 and cockle/TiO2 were 259 and 268 nm, respectively. It is interesting to note that the prepared composite photocatalyst particle size should be in nanosize, where it can enhance the photocatalytic performance. Overall, agricultural waste should be utilized to ensure a clean environment for future generations.

**Keywords:** mollusk shell waste, composite photocatalyst, methylene blue removal
