Eco-friendly synthesis and surface modification of ZnO nanoparticles using Pueraria montana root extract: enhanced photocatalytic performance with trisodium pyrophosphate

Abstract

ABSTRACT The synthesis of zinc oxide (ZnO) nanoparticles using Pueraria montana (kudzu) plant extracts highlights advancements in green nanotechnology. This study explores the use of Pueraria montana roots, rich in phytochemicals such as phenols, terpenoids and flavonoids, which serve as natural reducing and stabilizing agents for nanoparticle synthesis. The eco-friendly production and surface modification of ZnO nanoparticles were achieved using these plant extracts, enhancing their photocatalytic performance with trisodium pyrophosphate (TSPP).Characterization techniques, including XRD, TEM, and FE-SEM, confirmed the nanoparticles’ crystalline structure, with a BET surface area of 14.01 m²/g and a type II adsorption isotherm. The synthesized nanoparticles exhibited exceptional dye degradation capabilities, achieving 99.9% removal of malachite green (MG) and 97.78% for aniline blue (AB). Kinetic analysis revealed a steady-state rate constant (k) of 2 × 10⁻⁴ min⁻¹ for MG where as the response rate constant(k) for the photocatalytic degradation of AB using modified ZnO nanostructures was 3.0 × 10−3 min−1 allowing near-total dye removal within 600 minutes for MG and 350 min for AB . Adsorption studies were well described by Langmuir and Freundlich isotherms, indicating maximum adsorption capacities of 59.7 mg/g for MG and 61.2 mg/g for AB. Surface modification with TSPP improved charge carrier separation and enhanced the generation of reactive oxygen species under UV exposure, further increasing dye degradation efficiency.Statistical analysis indicated high reproducibility, with close mean adsorption values of 99.125 for MG and 97.3125 for AB, supported by small standard deviations. The findings affirm the potential of using Pueraria montana in synthesizing efficient photocatalysts, providing a sustainable and cost-effective approach for water treatment applications. Overall, this research underscores the effectiveness of plant-based materials in advancing eco-friendly nanotechnology solutions.