In the study, African tulip fruit (ATF) waste biomass (lignin-rich) was applied to synthesize the activated (surface-functionalization using ZnCl₂ and KOH as reactive activation agents) ATF-derived biochar nanostructured materials using a simple hydrothermal and pyrolysis technique. As-prepared activated biochars were applied as adsorbent materials for the efficient removal of widespread pharmaceutical contaminant caffeine (CAF) in wastewater treatment. The functional and structural properties and pore models of obtained biochar adsorbent materials were characterized by high-resolution SEM, TEM, powder XRD, FTIR, Brunauer–Emmett–Teller, and X-ray photoelectron spectroscopy techniques. The obtained biochar nanostructured materials were applied to evaluate pharmaceutical drug CAF removal in wastewater treatment, and also its adsorption isotherm and kinetics were examined to explore the adsorption efficiencies. The ATF-derived biochars were identified to have a notable yield of carbon and oxygen functionalities to influence the chemical and textural properties of the ATF-derived biochars. The synergetic effect (high surface area and porous-rich sites) of hydrothermally assisted pyrolysis technique prepared ATF-derived biochar (PATF) showed excellent adsorption activity (108.6 mg g⁻¹) and higher sorption efficiency for CAF drug. These results proved that the prepared biochar materials could be applied as efficient and inexpensive adsorbent materials to completely eliminate widespread pharmaceutical contaminants in wastewater treatment.