suggesting that DCF may be completely mineralized with extended reaction time. the viable count assay are summarized in Fig. . As can be seen, exposure to primary PhACs 20 obviously leads to a massive drop in bacterial viability. For instance, less than 20% of the E. coli 21 cells are viable after treatment with TC (5 mg L -1 ) for 24 h (Fig. ). Similarly, the survival rate 22 of E. coli is reduced to about 40%, when treated with 5 mg L -1 of DCF (Fig. ). Conversely, the direct exposure of E. coli cells to a cocktail of degraded secondary products, generated from 1 the same initial concentration of PhAC via FeCoNiCuZn-mediated photocatalysis, has little to 2 no impact on their viability. The non-toxic effect of the secondary product mixture on bacteria 3 can be ascribed to the photocatalytic degradation of the PhACs to less toxic secondary 4 compounds. Further, the presence of numerous secondary residues may result in an antagonistic 5 effect, manifesting in no observable toxicity. Alternatively, it may be noted that as the complex Although there is a minor drop in the degradation efficiency after each round of photocatalysis,