Solid-State, Rapid Mechanochemical Pathway for Zinc Phthalocyanine-Embedded Schiff-Base Polymer-TiO2 Nanocomposite for LED Assisted Efficient Photochemical Remediation of Hexavalent Chromium

The processing and elimination of heavy metals and toxic components from water is indispensable due to its potentially hazardous and carcinogenic impacts on the well-being of people and the environment. Successful heavy metals and toxic components mitigation ensures adequate water quality for consumption, prevents ingestion in to living organisms, and limits the contamination of the environment. The present work details the development of a zinc phthalocyanine based polymeric Schiff-Base encapsulated TiO 2 (ZnPc_SB@TiO 2 ) nano-composite via solid-state, mechanochemical pathway for the effective photochemical remediation of Cr(VI) in the presence of energy efficient LED as source of visible light. To comprehensively understand the structure, size, morphology, and optical properties of the newly synthesized photoactive materials, they were subjected to Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (XRD), Scanning electron microscopy (SEM), and Solid-state diffuse reflectance spectrophotometer characterization. The photoreduction of Cr(VI) was carried out under the impact of a 100 W LED as visible light source to investigate the photocatalytic competence of TiO 2 and ZnPc_SB@TiO 2 . The implications of several factors on the photocatalytic performance, such as photocatalyst dosage, interaction time, pH of the medium, and photocatalyst re-usage, are investigated. The photocatalytic activity for Cr(VI) photochemical remediation was found to be 88% for ZnPc_SB@TiO 2 where as TiO 2 alone exhibited less than 10%. The findings suggested that photosensitization of TiO 2 with ZnPc_SB significantly boosted photocatalytic activity for Cr(VI) photochemical remediation.