Binder-free La(OH)3 supported activated carbon fiber electrode with N-doped C layer for efficient phosphate electrosorption

•Lanthanum hydroxide was firmly loaded on N-doped C layer modified ACF without binder.•LNA exhibited stable P electrosorption behavior after 5 adsorption–desorption cycles.•The Langmuir maximum electrosorption capacity of P on LNA was 70.656 mg/g.•Co-existing anions improved P removal in the order of Cl->NO3–>SO42-> HCO3–>CO32–•N-doped C layer promoted P electrosorption by affecting electronic structure of La.