The pH values of the MeB and FLU mixture in the presence of different amounts of ZnO@Ndoped C were in the range of 7.40 (± 0.39) and 8.25 (±0.41) as illustrated in Figure . The pH values during the adsorption of these two dyes were less than the pH indicator range of MeB, which is ~ 9.4. Hence, the selective adsorption of MeB might be ascribed to the interactions between ZnO@N-doped C and the MeB . As indicated from the XPS results illustrated in + H2O, fluorescent agent, Figure ) . The fluorescence emission of TPA with and without catalyst was recorded (Figure ). The spectra show the hydroxyl terephthalic acid emission signal for ZnO, ZIF-8, ZnO@N-doped C indicating the formation of •OH (through the pathway O2 → O2 -˙ → H2O2 → ˙OH) under light radiation. The observed signal can be ordered in the ZnO@N-doped C >ZIF-8 > ZnO (Figure ). Interestingly, there is an observation of hydroxylation in the presence of ZnO@N-doped C with visible daylight. This observation is due to the small bandgap of ZnO@N-doped C. Furthermore, the emission signal of TPA-OH is increased over time (Figure ). ( • OH) radicals. The degradation process can be evaluated using MS spectra (Figure ). After photocatalysis, the entire mass spectrum shows no peaks related to the FLU dye indicating the complete degradation. The fragmentation pathway reveals the fragmentation of FLU to phthalic anhydride followed by the release of CO2 and CO (Figure ). All proposed fragments can be observed in the mass spectrum, as shown in Figure . A summary of the adsorption and photocatalysis of some dyes using ZnO-based materials is tabulated in Table . The synthesis of ZnO@N-doped C is simple and requires only carbonization of ZIF-8, which can be synthesized at room temperature quickly. The carbonized material is adsorbent and photocatalyst without combining two-hybrid materials such as ZnO-ZIF-8 . In addition, it required no expensive chemicals . A ternary Photocatalyst can be immobilized to improve recyclability and offer simple separation with minimal metal leaching via immobilization into a substrate .