Natural Sunlight Active Copper‐Doped Carbon‐Based Nanocomposites to Enhanced Photocatalytic Degradation of Methyl Orange

ABSTRACT Copper‐doped carbon nanodots‐based nanocomposites have attracted a lot of attention from a range of fields due to their remarkable application in photocatalysis. This research covers the synthesis of copper‐doped carbon nanodot‐based nanocomposites using hydrothermal processes, which is feasible and easy to handle and cost‐effective. Extensively, to understand the various features of copper‐doped carbon nanodots‐based composite, different analytical techniques were utilized, such as scanning electron microscopy (SEM) and transmission electron microscopy (TEM) for morphological features, atomic force microscopy (AFM) for surface topography measurement, Fourier transform infrared (FTIR) spectroscopy for the detection of functional groups and zeta potential determination for assessing colloidal stability. Response surface methodology (RSM) was used to statistically analyze and optimize numerous factors, including dye concentration, irradiation duration, pH, and oxidant concentration. For methyl orange (MO), the optimal conditions were found to be pH 2, a reaction time of 1 h, an oxidant concentration of 10 mM, and a dye concentration of 50 ppm. The study demonstrates that enhanced ozonation considerably improves mineralization and methyl orange degradation (90.47%) when compared to conventional ozonation. The water quality treatments, such as chemical oxygen demand (COD), biological oxygen demand (BOD), and total organic content (TOC), were evaluated with reductions of 85%, 79%, and 82%, respectively. Reusability and substrate stability were also investigated up to 14 cycles with 35.78% degradation of wastewater. The incorporation of black pumice as the substrate additionally improved the stability and efficiency of this material, making it of potential value for large‐scale environmental applications. Compared to the previously synthesized photocatalysts, which can normally undergo only 7–8 cycles, reusability is almost doubled for the pumice‐supported copper‐doped nanodots, around 14 cycles. This black pumice‐based system is significantly more efficient and practical compared to previously reported materials due to its enhanced stability and its light‐harvesting capability.