Table 2 Observed peak positions for ATR-FTIR spectra. Peak assignments and references supporting assignment are included

1585–1570

Asymmetric COO⁻ stretch

Heckman et al. [42]; Lackovic et al. [39]

1530–1520

Aromatic C=C stretch

Chen et al. [8, 14]; Gu et al. [41]

1400

Symmetric COO-stretch

Gu et al. [41]; Fu and Quan [40]; Heckman et al [42]; Lackovic et al. [39]

1384

COO-Fe stretch

Chen et al. [8, 14]; Fu and Quan [40]; Lackovic et al. [39]

1270

Stretching of phenolic OH

Gu et al. [41]; Artz et al. [46]; Chen et al. [8, 14]

1250

OH deformation of COOH

Gu et al. [8, 14]; Heckman et al. [42]

1120

Polysaccharides: C–O stretch

Chen et al. [8, 14]; Heckman et al. [42]

1080

Polysaccharides: C–O stretch

Artz et al. [46]; Chen et al. [8, 14]; Heckman et al. [42]

1040

Polysaccharides: C–O stretch

Chorover and Amistadi [27]; Grube et al. [47]