The MeB dye was significantly removed after 10 min only. However, the removal of FLU dye was not high, as illustrated in Figure . A slight decrease in the absorbance alongside four h was observed. These results indicate the selective adsorption of MeB in the presence of FLU dye on ZnO@N-doped C, as shown in Figure . The removal of MeB on ZIF-8, which approached > 95% after a short time (< 10 min), can be ascribed to the positively charged nature of ZIF-8 in water, as previously reported . Figure -e shows the adsorption percentages of MeB and FLU dyes on ZIF-8 and ZnO@N-doped C at different times. The removal percentages of MeB on ZIF-8 and ZnO@N-doped C achieved 98% and 92%, respectively. At the same time, the removal efficiencies of FLU dye on both ZIF-8 and ZnO@N-doped C were 24% and 30%, respectively (Figure ). ZnO@N-doped C requires a short contact time to reach the steady-state of the adsorption for both dyes compared to ZIF-8. Adsorption of MeB and FLU using different amounts of ZnO@N-doped C was also performed (Figure ). Adsorption capacities for MeB and FLU using ZnO@N-doped C as adsorbent are 900 mg/g and 100 mg/g, respectively. Even though the adsorption of dyes is an effective dye removal method, it requires a large amount of the adsorbent, material storage after adsorption, and several steps of optimization and separation. Therefore, ZIF-8 and ZnO@N-doped C were also investigated as photocatalysts for dye degradation.