Based on these results, medium-oxidized PhosO(1:4) nanoadsorbents (25% in oxygen content) show the optimal oxidizing degree for arsenic removal due to three main properties: i) higher adsorption strength for simultaneous As(III)/As(V) uptake compared to intrinsic phosphorene; ii) higher selectivity by As(III)/As(V) compared to the affinity by H2O molecules in aqueous solution, ensuring for low-pollutant mobility; and iii) straightforward recovery and reusability by a simple regeneration procedure via alkaline treatment (due to its strong selectivity by hydroxide anions at high pH). Considering these results, we choose the PhosO(1:4) nanoadsorbent as the best adsorbent candidate for further analyses in this work.