Triatomic-doped MXene based catalyst with sodium alginate encapsulation their molecular and DFT calculation study for efficient photocatalytic removal of disinfected by-product from drinking water

This study reports the development of a novel, recoverable photocatalyst, Ti 3 C 2 T x @TACs-SA, for the efficient degradation of carcinogenic disinfection byproducts (DBPs) in drinking water. The composite was fabricated via a simple, eco-friendly strategy involving the growth of transition metal atom clusters (TACs: Co, Fe, Ni) on MXene (Ti 3 C 2 T x ) nanosheets, followed by incorporation into a crosslinked sodium alginate (SA) biopolymer matrix. Comprehensive characterization via SEM-EDX, XPS, XRD, HAADF-STEM, XANES, TGA, BET, and DFT confirmed the composite's structure and properties. The photocatalytic performance of the composite was systematically investigated for the degradation of DBPs in drinking water. Key experimental conditions, including pH, initial pollutant concentration, irradiation time, and thermodynamic study, were carefully optimized to determine their effect on the overall degradation performance. Five common DBPs, trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs), halonitromethanes (HNMs), and dichloroacetaldehyde (DCAL), were chosen as target contaminants. The composite exhibited excellent photocatalytic activity across a wide pH range. At neutral pH (7.0) and an initial DBP concentration of 100 μg/L, the photocatalyst achieved degradation efficiencies of 83.8% for THMs, 84.4% for HAAs, 85.3% for HANs, 83.8% for HNMs, and 83.4% for DCAL after 60 min of UV irradiation. At acidic pH 3.0, removal efficiencies were slightly reduced to 80.1%, 78.3%, 79.3%, 77.6%, and 75.8%, respectively. In contrast, alkaline conditions significantly enhanced DBPs removal, achieving 90.0%, 92.0%, 93.6%, 95.4%, and 96.0% for the respective contaminants. These findings demonstrate the strong potential of the Ti 3 C 2 T x @TACs-SA composite as a practical and efficient photocatalyst for eliminating carcinogenic DBPs from water.