Decolorization of Reactive Red 2 in aqueous solutions using RPB-prepared nanoscale zero-valent iron

This investigation assesses the feasibility of decolorizing Reactive Red 2 (RR2) in aqueous solutions using nanoscale zero-valent iron (nZVI). nZVI was prepared in a rotating packed bed (RPB) at a rotational speed of 1400 rpm and liquid flow rates of 0.6 L/min. The effects of pH, nZVI dosage, and temperature on the decolorization of RR2 were experimentally investigated. The results thus obtained importantly reveal that a lower pH, higher nZVI dosage, and higher temperature yielded more efficient decolorization of RR2. Furthermore, the decolorization of RR2 using the prepared nZVI during the initial process was consistent with the pseudo-first-order kinetic model. Additionally, the prepared nZVI was more reactive in decolorizing RR2 than ZVI. With an nZVI dosage of 0.1 g/L, the prepared nZVI effectively decolorized RR2, yielding a decolorization efficiency of around 88% in 45 min at pH 4 and 50 °C. These promising results obviously demonstrate the potential of the prepared nZVI for effectively decolorizing dyes in aqueous solutions.