Enhancing the Degradation of All Moieties of the Environment Pollutant Congo Red Dye in Dark, White Light, and Solar Light by using CuS Nanoflowers: A Quantita tive Analysis

Objectives: To enhance the degradation rate of all moieties (azo, naphthalene, and phenyl) of Congo Red (CR) dye by using CuS nanoflowers under darkness, white light, and solar light. Method: CuS nanoflowers are synthesized by employing a simple wet chemical method. The sample is characterized by its microstructural and optical properties. The CuS nanoflower is added to the CR solution to investigate the degradation efficiency of CuS nanoflower in dark and light. Findings: The sample shows significant absorption between 300 and 700 nm, followed by a quick reduction. This study is the first to show that a CuS nanoflower can act as both a catalyst and a photocatalyst to degrade all moieties of Congo Red (CR), an environmental pollutant, in dark and light. 100% degradation of all CR dye moieties takes place in 24 min, 36 min, and 52 min in the presence of solar light, white light, and darkness, respectively. When comparing experimental settings (consecutively darkness, white light, and solar light), the change in degradation efficiency for the azo, naphthalene, and phenyl moieties with time is the highest under solar light followed by white light and darkness in order. The reactions followed pseudo-first-order kinetics according to the Langmuir-Hinshelwood (L-H) model. The degradation rate for all moieties of CR is the highest under solar light irradiation, lower under white light irradiation, and lowest in darkness. Additionally, CuS nanoflowers exhibit exceptional recyclability. Novelty: The phenyl moiety of CR is degraded 100% in dark and light. Additionally, the degradation rate of all moieties is enhanced due to the greater surface area of nanoflowers. To the best of our knowledge, the present study is the first one to report that the CuS nanoflower synthesized in this work can act as both a catalyst and a photocatalyst to degrade all moieties of Congo Red (CR), an environmental pollutant, in darkness and light.