The ongoing discharge of hazardous dyes from industrial processes has intensified global water pollution, posing serious threats to aquatic ecosystems and human health. Addressing this challenge, our study explores the potential of bio-based carbon nanomaterials (CNM), synthesized from onion peel biowaste and designated as ON11, as effective agents in dye removal. These CNMs were incorporated into a mixed matrix membrane (MMM), using polysulfone (PSU) as the membrane substrate, to enhance dye adsorption. The CNM synthesis was achieved through a simple, eco-friendly process. We examined their impact on adsorption efficiency by introducing ON11 nanoparticles at varying concentrations into the PSU membrane (ON11@PSU). This CNM-embedded membrane structure offers a solution to challenges associated with the large-scale application of nanomaterials, particularly by minimizing leaching into water and improving durability. The ON11 and ON11@PSU membranes were characterized using various techniques, including SEM, Raman spectroscopy, XRD, optical profilometer, and FTIR, to confirm their behavior, morphology, and structural integrity. The surface area of ON11 was 423.26 m