The investigation of Amido black 10B adsorption-photocatalytic degradation using the synergistic effect of Cr-doped ZnO/CDs nanocomposite under solar light

In this work, the modification of ZnO nanoparticles with green synthesized carbon dots and Cr yielded a nanocomposite named Cr-doped ZnO/CDs. Further, 0.48 g/L of this nanocomposite was able to remove (95 +/- 1) % of 25 mg/L Amido black 10B (AB10B) from a solution, by adsorption process less than 5 min. The photocatalytic property of Cr-doped ZnO/CDs was able to improve the removal efficiency of AB10B to 99% during irradiation of sunlight within 15 min. The maximum adsorbent capacity of Cr-doped ZnO/CDs nanocomposite was 152.4 mg/g. Unmodified ZnO nanoparticles (0.48 g/L) were able to remove only 30% of the dye within 60 min of irradiation. Its modification showed coupling the absorption and photocatalytic process dramatically increased the dye removal efficiency. Adsorption isotherm investigation indicated that the experimental data were fitted satisfactorily by the Langmuir model. This method is an economical method because the Cr-doped ZnO/CDs synthesis was easy and inexpensive, the dye removal time was very short, and infinite sunlight is required to remove the dye with high efficiency. Graphical abstract