A cost-effective melamine-based polyaminal covalent polymer (CPCMERI-2) has been prepared by a facile synthetic approach using the solvothermal condensation reaction and characterized by solid-state analytical tools like C NMR, PXRD, N sorption isotherm and FT-IR. The electron-rich moieties in the skeletal backbone induce hydrophobicity in the polymer with an appreciable water contact angle of 130°. AFM study establishes the plausible reason for the hydrophobicity. On account of its high thermal and chemical stability, the polymer CPCMERI-2 has been projected as a next-generation sorbent material for oil-like materials, and executed liquid-phase adsorption of kerosene over water surface. CPCMERI-2 selectively adsorbs kerosene and has a feeble adsorption affinity towards diesel and some other organic solvents like chloroform, benzene, nitrobenzene, and toluene. To improve the bio-compatibility and cost effectiveness of the material, a bio-waste material like the peel of is used in the composite material, and it unveils a new avenue towards exploring the use of naturally abundant bio-material peels as low-cost sorbent materials. Additionally, CPCMERI-2 has gained attention due to its enormous potential in wastewater purification, which has also been tested in a lab-scale experimental setup. We expect that this material (CPCMERI-2) will harbinger a new type of composite polymer, wherein naturally abundant waste bio-materials could be used as precursors to explore its usefulness as an adsorbent for the removal of oils and organic pollutants.