Ammonia is one of the major pollutants of water resources, posing a serious threat to human health and the environment. Titania nanoparticles were used to examine the photocatalytic degradation of ammonia from an aqueous solution in this study. Titania nanoparticles (NPs) were first synthesized via the sol-gel method, then characterized using XRD, FTIR, DLS, EDX, FE-SEM, and TEM analyses. Four effective parameters (pH, initial concentration of pollutant, catalyst dosage, and irradiation time) for photocatalytic degradation were explored using Design-Expert Software. The greatest photocatalytic activity of titania NPs was found in optimal conditions, according to the findings (97%). The optimum amounts of catalyst dosage, initial pollutant concentration, irradiation time, and pH were obtained at 0.3 g/l, 1500 mg/l, 120 min, and 12, respectively. Furthermore, studies revealed that pH was the most efficient variable in comparison with others and that increasing the pH value from 8 to 12 boosted ammonia removal from 40 to 97%. NPs showed high stability as the ammonia removal decreased from 96.96% to 65% after four cycles. Generally, this research has created a precedent for the development of morphology-dependent photocatalysts for the degradation of organic contaminants.