Melamine-Formaldehyde Polymer-Based Nanocomposite for Sunlight-Driven Photodegradation of Multiple Dyes and Their Mixture

Cadmiumsulfide (CdS)-decorated, cross-linked melamine-formaldehydepolymer-based nanocomposite (MFP-CdS) has been synthesized. MFP-CdSis utilized here as a photoactive material for the photodegradationof six model organic dyes and their mixture in an aqueous medium inthe presence of sunlight. The half-life values from the kinetic studyof multiple dyes strongly support the importance of sunlight on thefast degradation of all six dyes compared to bulb light and control(dark) conditions. A comparative H-1 NMR analysis of thedyes and their degraded products has been performed to support thebreakdown of the aromatic framework of organic dyes using MFP-CdSin sunlight. The mechanisms involved in the photodegradation of dyeshave been investigated based on radical trapping studies that supportthe significant involvement of superoxide radicals along with holes.Moreover, the dye removal efficiency using MFP-CdS from real industrialwastewater samples is evaluated via the external spiking of organicdyes and their mixture in unknown industrial effluents where theyshowed similar photodegradation results. Based on the high recyclabilityof MFP-CdS, these are used for multiple cycles.