Toxicity and decontamination strategies of Congo red dye

Congo red (CR) dye is an organic pollutant of environmental concern. It is applied in textile, printing, dyeing and rubber industries as colorant. The carcinogenicity, mutagenicity and various associated toxicities of CR to flora, fauna and humas have necessitated the requirements for removal of CR from industrial CR-laden (waste)water. In this review, a total number of 300 research and review-based publications are selected and reviewed for more assessment. The modelled toxicity effects of CR dye on aquatic fauna and flora are discussed, with CR found to be phytotoxic to aquatic flora and also capable of interfering with the reproductive activity of aquatic fauna. In addition, the removal strategies for CR were thoroughly explored and discussed, with adsorption technology offering best route for decontamination of CR due to some inherent advantages like regenerability of (ad)sorbents, lack of production of secondary toxic contaminant, simplicity and low-cost nature, when compared with others. This synthesis concludes by recommending research in areas of column adsorption and assessment of adsorption/removal of CR in the presence of co-organic/inorganic contaminant(s).