The nZVI was synthesized by the dropwise addition of 0.16 M NaBH4 aqueous solution to 0.1 M FeCl3∙6H2O aqueous solution while stirring with amagnetic stirrer, as described by Wang and Zhang [12]. The nZVI was filtered and sonicated to disperse it completely in a pre-measured amount of pure water, and the sonicated nZVI was mixed with the Orange II solution. The specific surface area of the synthesized nZVIwas 27.9 m2/g, which was slightly low, but still higher than the values
previously reported under the same synthesis conditions [13].