“…The Fe/P mole ratios of each sample were 0.91, 1.04, 0.56, 1.28 and 1.06, respectively ( Supplementary Information ). It was previously reported that the molar ratio of Fe/P was 1.5 for the optimal formation of vivianite, and only about 0.2–0.4 of Fe/P ratio was needed before vivianite precipitation occurred ( Cao et al, 2019 , Prot et al, 2020 ). EDS results also indicated that the P-Fe mole ratio of each sample was similar and no obvious change was occurred during the aerobic and anaerobic transformation process, although the structure of P-Fe substances were changed totally.…”