Background The high consumption of acetaminophen leads to high concentrations in surface water causing impacts on aquatic organisms, which is highlighting the need for investigation of alternative water and wastewater treatments. Therefore, the present study objective was to evaluate the adsorption capacity of acetaminophen onto Moringa oleifera Lam. seed husks after chemical and thermal treatment. Results The characterization of the adsorbent revelaed heterogeneous morphology with the presence of micro- and mesopores. Adsorption studies showed that the adsorption did not altered between pH 3 and 9, and that there was no significant effect of the ionic strength, indicating that the mechanism does not involve electrostatic interactions. In fact, Fourier transform infrard spectra showed that acetaminophen was adsorbed by hydrogen bonds and pi-stacking. The kinetic data were adjusted to the pseudo-first-order model, indicating an equilibrium time of 18 h. The equilibrium study showed that adsorption occurred in a monolayer and was favoured by the increase in temperature. The maximum adsorption capacity was 17.48 mg g(-1), at 318 K, higher than some capacities found in the literature. The thermodynamic parameters indicated that the process was spontaneous, endothermic and physical. Conclusions The characteristics and results found compared to the recent literature verified the possibility of applying this residue as a low-cost adsorbent for the removal of acetaminophen. (c) 2019 Society of Chemical Industry