In this study, disk-shaped copper sulfide nanoparticles (CuS-NPs) were synthesized via a simple co-precipitation method and used as a photocatalyst for the reduction of carbonate species derived from marble dust into acetic acid (AcOH). The photocatalytic reaction was carried out under monochromatic light (525 nm) in a hydrogen peroxide-water mixture using CuS-NPs. Key parameters such as solvent composition, light source, catalyst concentration and reaction time were optimized to get the maximum yield of AcOH. The reaction mechanism was investigated using radical scavenging experiments. The practical applicability of the approach was further tested on two additional real-life carbonate waste materials, i.e., chalk dust and carbonate scale.