Evaluating the Effectiveness of Moringa oleifera in Microplastic Removal through Response Surface Methodology

The widespread presence of microplastics (MPs) in the environment has raised serious concerns due to their potential ecological and human health impacts. This highlights the urgent need for efficient and cost-effective MPs removal strategies. Conventional removal techniques often rely on synthetic chemicals, which pose environmental and economic limitations. As a sustainable alternative, this study investigated the use of Moringa oleifera (M. oleifera) seed powder as a natural coagulant for MP removal. The treatment process was optimized by Response Surface Methodology (RSM) in conjunction with a Box-Behnken Design (BBD). Key process parameters—pH, coagulant dose, and settling time—were varied to maximize MP removal efficiency. Characterization of MPs before and after treatment was performed using Fourier Transform Infrared (FTIR) spectroscopy and Scanning Electron Microscopy (SEM). Direct microscopic enumeration of MPs was also conducted using a counting chamber. The optimized conditions—pH 6.78, M. oleifera dose of 109.25 mg/L, and a settling time of 85.86 min—achieved a maximum MP removal efficiency of 84.32%. Statistical analysis via ANOVA confirmed the significance of the regression model, with a p-value less than 0.05. The study utilized MPs leached from common use paper cups, making this work a more realistic representation of natural systems. The application of natural coagulant, coupled with optimization is another novelty of this study. These findings demonstrated the potential of M. oleifera seed powder as a sustainable, plant-based coagulant for effective microplastic removal from aqueous systems.