Synergistic efficiency of modified banana leaf derived cellulose-g-C3N4 hybrid composite: a sustainable approach for visible-light-driven photodegradation of dyes†

The adverse effects on human health and water supplies due to widespread use of dyes including methylene blue (MB) and rhodamine B necessitate their removal. Photocatalytic decontamination offers an alternative method which is cost effective and ecofriendly compared to other costly dye removal processes. The combination of graphitic carbon nitride (g-C₃N₄) and cellulose from readily available modified banana leaves (MBLC) has not been explored for color degradation. The present work investigates the application of a promising g-C₃N₄–MBLC composite for the photocatalytic removal of methylene blue and rhodamine B dyes. The two-component hybrid composite was synthesized utilizing the one-pot in situ thermal polymerization techniques. Furthermore, multiple analytical methods were exploited to comprehensively assess the structural and morphological characteristics of the synthesized g-C₃N₄–cellulose hybrid composite. The composites exhibited photocatalytic activity, successfully degrading 93.35% of RhB and 92.06% (30 mg L⁻¹) of MB dyes within 120 minutes under visible irradiation. Analysis of scavenging effects indicated that ˙O₂⁻ and h⁺ radicals were the primary reactive oxygen species (ROS) responsible for the photodegradation of the dyes. Additionally, the synthesized composite showed excellent reusability, maintaining 81% efficiency after five consecutive cycles, highlighting its potential for practical applications, particularly in pollutant removal.