<p>In this research, the potential of biochar obtained from co-pyrolysis of coal tar and corn straw as a sustainable solution for <i>p</i>-nitrophenol removal was investigated. Response surface methodology was performed to evaluate and optimize the co-pyrolysis parameters and their interactions on the iodine adsorption values, providing guidance for <i>p</i>-nitrophenol removal. Co-pyrolysis biochar prepared using response surface methodology exhibited abundant porous structure, higher content of O-containing functional groups and stronger polarity of surface binding sites. The Zeta potential of co-pyrolysis biochar was − 12.9, suggesting co-pyrolysis biochar is more stable and has a higher dispersibility in solution. Co-pyrolysis biochar exhibits that the average pore size is in the range of mesopores. There was a certain increase in I_D/I_G for co-pyrolysis biochar (i.e. 0.80) compared to individual pyrolysis biochar. The results showed that co-pyrolysis biochar demonstrated the higher <i>p</i>-nitrophenol removal capacity (60.24&#xa0;mg/g) than that of individual pyrolysis biochar. In addition, Fe- and Zn- modified co-pyrolysis biochar achieved excellent <i>p</i>-nitrophenol removal capacities of 140.23&#xa0;mg/g and 121.35&#xa0;mg/g, respectively. The kinetic data for all biochar samples were well fitted to the pseudo-second order kinetic model, revealing that chemisorption was the dominant mechanism. Isotherms revealed <i>p</i>-nitrophenol adsorption occurred through a homogeneous and monolayer mechanism, Fe and Zn modification changed the <i>p</i>-nitrophenol adsorption behavior from monolayer to multilayer adsorption. Moreover, the mechanism of <i>p</i>-nitrophenol removal enhancement by co-pyrolysis derived biochar was also summarized.</p> Graphical Abstract <p></p>