Magnetically recyclable phytogenic MBC-ZnO nanocomposite for sustainable environmental cleanup with a forensic edge

In this work, a green-synthesized MBC-ZnO nanocomposite (NCs) was developed and evaluated for photocatalytic and forensic applications. Murraya koenigii (curry leaves) powder was used to carbonize an iron-based precursor, forming a MBC-ZnO material. Comprehensive characterization using XRD, FT-IR, HR-TEM, FE-SEM, BET, XPS, MPMS, Mott-Schottky analysis, and UV-Vis DRS were performed to investigate the structural, morphological, surface, compositional, optical, and magnetic properties of the synthesized NCs. UV-Vis DRS revealed a reduced bandgap of 2.88 eV compared to 3.10 eV for pure ZnO, contributing to the enhanced photocatalytic performance. The MBC-ZnO NCs effectively degraded multiple dyes, including methylene blue (MB), methyl orange (MO), rhodamine B (RhB), and crystal violet (CV), achieving 88.17 % MB removal in 135 min and 92.45 % at pH 10 under optimized conditions. Their performance was further validated in pond and river water sample added with dyes, demonstrating efficiency in complex aqueous matrices. Additionally, clear ridge patterns developed using the Powder Dusting Method (PDM) confirmed the applicability in forensic applications.