A novel approach to redox active polymers: Decolorization of methylene blue by heterogeneous reduction with redox active azo polymer

The existing reducing agents used in the literature to decolorization of methylene blue are soluble in water and the reduction process is carried out in a homogeneous redox reaction medium. After the decolorization process, the reducing agents and its by-products remain in a homogeneous redox reaction medium. Many of these reducing agents are toxic and cause chemical pollution of textile wastewater. Therefore, there is a need for reducing agents that can be mixed heterogeneously with water from which the reducing agent can be easily removed from a redox reaction medium. For this purpose, water-insoluble redox active azo polymer was synthesized from redox active 1,4-dihydroxybenzene and p-phenylenediamine. The synthesized redox active azo polymer was used for decolorization of methylene blue by heterogeneous reduction and various kinetic parameters were investigated for this redox reaction. At the same time, the investigated results of azo polymer and monomer (1,4-dihydroxybenzene) were compared.