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[Display omitted] • Fe/N co-doped porous hydrochar by various synthesis schemes is used to remove Cr(VI). • Modified hydrochar shows excellent properties owing to Fe0 and heterocyclic‑N. • Porous activation facilitates the loading and dispersion of Fe particle on hydrochar. • The maximum adsorption capacity of MP 1 HC MW for Cr(VI) reaches 274.34 mg/g. • Adsorption, reduction, complexation, and precipitation are benefit to Cr(VI) removal. Four kinds of Fe/N co-doped porous hydrochar were prepared by one/two-step N-doping schemes using microwave/traditional pyrolysis methods for removing Cr(VI) from aqueous phase. Heterocyclic-N was introduced through CO(NH 2) 2 -based hydrothermal carbonization process, which could adjust the electronic structure of the hydrochar framework. Furthermore, Fe0 and Fe 3 O 4 were embedded into hydrochar via carbothermal reduction reaction using FeCl 3 as the precursor, which improved the reducibility and magnetism of the material. The modified hydrochar exhibited pH-dependency and rapid kinetic equilibrium, and the maximal adsorption amount of magnetic porous hydrochar obtained by microwave-assisted one-step N-doping (MP 1 HC MW) reached 274.34 mg/g. Meanwhile, the modified hydrochar had a high tolerance to multiple co-existing ions and the removal efficiency maintained above 73.91 % during five regeneration cycles. Additionally, MP 1 HC MW efficiently removed Cr(VI) via pore filling, electrostatic attraction, ion exchange, reduction, complexation, and precipitation. Summarily, Fe/N co-doped porous hydrochar was a feasible adsorbent with outstanding remediation potential for Cr(VI)-contaminated water. [ABSTRACT FROM AUTHOR]