Conventional wastewater treatment is not able to effectively removal drugs such as antibiotics, so it is important to remove the remaining antibiotics from the environment. In this research, Zinc oxide (ZnO), nickel oxide (NiO) and p-NiO/n-ZnO heterostructure were synthesized. Then, prepared samples were characterized by several techniques. The photocatalytic degradation of erythromycin from aqueous solutions was studied by photocatalysts synthesized under sunlight. Design of Experimental (DOE) was used to evaluate the effective parameters in the degradation process of erythromycin. The effects of pH, time (min), photocatalytic mass (g) and erythromycin concentration (mg/L) were studied. Using Design Expert 7 software, the highest degradation efficiency of erythromycin was found 99.54%, under optimum conditions at pH 3.07, time 101.14 (min), photocatalyst mass 0.13 (g) and erythromycin concentration 41.04 (mg/L). Isothermal studies have shown that the Fritz-Schlander isotherm with the least error with the experimental data of p-NiO/n-ZnO (5%) photocatalytic degradation are the best fit. تفاصيل المقالة