Environmental pollution from pharmaceutical waste, particularly antibiotics like chloramphenicol, poses significant risks to marine ecosystems. Chloramphenicol, widely used in aquaculture, is often found in wastewater, leading to bacterial resistance and disrupting aquatic environments. Adsorption techniques, particularly using natural adsorbents like coral-derived calcium oxide (CaO), are emerging as cost-effective methods for mitigating such pollution. However, the limited photocatalytic activity of CaO requires enhancement through the incorporation of semiconductor materials such as zinc oxide (ZnO). This study investigates the synthesis and performance of a CaO-ZnO composite derived from coral fragments for the photocatalytic degradation of chloramphenicol in water. The composite was characterized by XRF, FTIR, SEM, and XRD, and its photocatalytic activity was evaluated over a range of degradation times under UV light. Results demonstrated that the CaO-ZnO composite significantly improved chloramphenicol degradation compared to individual CaO and ZnO, with the highest efficiency observed at 240 minutes, reaching 66.99%. These findings highlight the potential of the CaO-ZnO composite as an effective and sustainable solution for chloramphenicol removal from wastewater.