Microplastics are a global concern due to their toxic effects on marine life and human health. In the list of pollutants, microplastics are prominent and play a vital role in defragmenting the environment, particularly their presence in water bodies. This present study examines the efficacy of green synthesized magnetic nanoparticles in removing microplastics from water. The iron particles were synthesized through the black tea extract. For the experiments, two standard microplastic sizes were used (150 and 450 μm). The synthesis approach was selected to reduce the utilization of toxic chemicals. In addition, the polyphenol components in the black tea extract were the alternative to chemicals in the synthesis process of the magnetic nanoparticles. Experiments were performed at different water pH levels alongside different doses of nanoparticles (BTMNPs) and microplastics (PE) sizes. During experiments, it was observed that 0.5 g/l Black tea magnetic nanoparticles (BTMNPs) and 60 minutes of adsorption treatment were given ideal magnetization of polyethylene (PE) microplastics. By analyzing the removal of nanoparticles, it was revealed that 90% of the microplastics were removed. The removal mechanism was the adhesion of nanoparticles on the surface of polyethylene microplastics and employing a magnetic to attract the iron-coated microplastics. In addition, the magnetic particles were reutilized for the same purpose, and promising results were obtained after the reutilization of BTMNPs for several cycles. The magnetic nanoparticles proved highly efficient in the removal of polyethylene microplastics.