Methods of Reactive Red 141 Dye Decolorization, Treatment, and Removal from Industrial Wastewaters: A Critical Review

Reactive Red 141 (RR141) is a diazo reactive dye with bright red color, high molecular weight (1,774.15 g/mol), large molecular structure (C52H26Cl2N14Na8O26S8), and several reactive groups. It is a source of water contamination, because of its wide use in industry and potential toxicity. The purpose of this work is to compare different treatment methods applied to industrial water effluents polluted, especially, by this dye. Recently, several research articles have been published on decolorization of RR141 in wastewater effluents. From this survey, nanofiltration membranes prepared through single bilayer polyelectrolyte deposition and electrocoagulation appeared to be the best method, being able to ensure the highest percentage removal (99.9%) of RR141 within an application time of only about 11 min under optimum operating conditions. Nonetheless, other treatments appeared to be quite promising because of their ability to destroy the contaminant rather than simply remove it. Among them, the photo-Fenton reaction was shown to ensure the most effective chemical degradation (98%) of RR141 from aqueous solution within 30 min using CuFeO2 as a catalyst, and Bacillus lentus BI377 its best biodegradation (99.1%) within 6 h. Further development of these methods is expected to allow more effective full-scale applications than the current ones to remove or degrade these contaminants from wastewater in the future, with a focus on RR141.