Enhanced leachate concentrate degradation across variable pH ranges using Cu@ATP-CTS Fenton-like catalysts for H₂O₂ activation.

Landfill leachate nanofiltration concentrates (LLNC) contain complex organic pollutants that are difficult to treat. This study developed a copper-doped attapulgite-chitosan composite catalyst (Cu@ATP-CTS) for efficient LLNC degradation in a Fenton-like system. The incorporation of attapulgite extended the effective pH range of Fenton reactions from 2 to 8, overcoming traditional limitations. Optimized via response surface methodology, the catalyst achieved 89.02% UV254 removal, 73.86% COD removal, and 77.24% TOC removal within 115 min under optimal conditions. Copper played a crucial role in H₂O₂ activation, cycling between Cu0, Cu+, and Cu2+ to generate hydroxyl radicals (·OH), the key species driving pollutant degradation. The Cu@ATP-CTS catalyst also demonstrated strong stability and reusability over five cycles. This study provides a robust and sustainable method for LLNC treatment, offering significant potential for application in landfill leachate and wastewater management.