Effect of DAS on the optical and photocatalytic properties of metastable γ-MnS nanoparticles

Metastable gamma manganese sulphide (gamma-MnS) was synthesized by a simple solvothermal route and successfully embedded into dialdehyde starch (DAS) matrix. Both gamma-MnS and MnS-DAS composite were characterized using various analytical techniques in order to understand its phase confirmation, optical properties, morphology and chemical composition. The colour of the composite was light brown as expected from its absorption spectrum. The morphology of gamma-MnS was spherical which changed to mixtures of spheres and rods in the composite. The photocatalytic activity of both gamma-MnS and MnS-DAS composite was assessed based on the aqueous solution of malachite green oxalate (MG) under ultraviolet (UV) light (wavelength lambda= 253.7 nm). It was observed that the composite showed preferential decomposition of MG in comparison to gamma-MnS in the dye solution.