Visible Light Driven MnO2/MnS Hybrid Nanostructures for Photocatalytic Degradation of Organic Pollutants: A Synergistic Approach for Wastewater Treatment

The environment is being threatened by rapid industrialization and water pollution. Different heterojunctions of metal oxides/sulfides have been used for photocatalytic degradation due to their catalytic and oxidative properties. This research is focused on the hydrothermal synthesis of MnO2 and MnS binary nanocomposite and its application as a photocatalyst for degradation of Rhodamine B (RhB) dye under sunlight. Different techniques such as FTIR, XRD Sem and EDX were utilized for structural characterization. During photocatalytic degradation, the optimization of various factors such as catalyst dosage, oxidant dosage, pH, time, and concentration of dye was carried out. It is found that MnO2/MnS nanocomposite performed excellently and achieved 93% degradation of RhB was attained after 120 minutes at pH 4, catalyst amount (20 mg/50 mL), and an oxidant dosage of 15 mM. Different radical scavengers were used to find the radical tappers (OH, e- and h+) that were effective in the degradation mechanism under sunlight. The kinetics was studied using two (1st and 2nd order) kinetic reaction models. Response surface methodology was used for identifying the interaction between various variables. It has been confirmed that MnO2/MnS nanocomposite can be efficiently applied in many other real-world applications of wastewater treatment under solar irradiation.