Novel strategies to sustainable water treatment utilizing strain-engineered AC/Cu composites through ball milling for enhanced photocatalytic applications

Ensuring the sustainability and availability of clean water is a priority, especially in the case of textile pollution, such as that caused by methylene blue (MB). MB is a difficult-to-decompose dye that can cause severe environmental problems and health problems such as cancer and skin diseases. As a solution, we used different ball milling times (0.5, 1, 2, 4, 8, 16, 20, 28, 32, and 48 h) to produce non-uniform Cu strains, and then composited them with activated carbon (AC) through a mechanical mixing strategy. Material characterization using XRD, FTIR, SEM, BET, and UV–Vis, which showed changes in d-spacing, C-H vibration shifts, increased \({\varepsilon }_{2}\), surface pit-shaped traps, and consistent \({p}_{d}\) have a Linear relationship with improving photocatalytic performance. Kinetic analysis follows a pseudo-first-order model with a kinetic rate constant of 0.957 min⁻¹. The AC/Cu composite (4 h) achieved 90.35% MB degradation within 15-min after irradiation using 1 g of catalyst, demonstrating significant performance enhancement. This study highlights a scalable and straightforward strategy to engineer metal–carbon composites with tunable properties for effective wastewater treatment.