Organic Matter and Mineral Composition of Silicate Soils: FTIR Comparison Study by Photoacoustic, Diffuse Reflectance, and Attenuated Total Reflection Modalities

Abstract

This study aims to compare photoacoustic (FTIR–PAS), diffuse reflectance (DRIFT), and attenuated total reflection (ATR) FTIR modalities in the wide wavenumber range from NIR (7500 cm−1) to FIR (150 cm−1) for the same silicate soil samples under the same conditions. The possibilities of non-destructive rapid qualitative analysis of soils by these modalities without comprehensive data treatment were compared. The assignment of more than 100 bands for the chernozem and sod-podzolic as common types of silicate types of soil was made. The following groups of bands of organic matter and inorganic matrix were reliably found in spectra of all or at least two modalities: 3690–3680 cm−1 (hydrogen-bonded SiO–H…H2O stretch, not ATR), 2930–2910 cm−1 and 2860–2850 cm−1 (methylene stretch), 1390–1380 cm−1, (symmetric stretch carboxylate, DRIFT and FTIR–PAS); 2000–1990 cm−1, 1885 cm−1, and 1790–1783 cm−1 (SiO2 overtones, DRIFT and FTIR–PAS), 1163–1153 cm−1, SiO2 lattice (not FTIR–PAS), 1037 cm−1 (Si–O or Al–O stretch), 796 cm−1 (lattice symmetrical Si–O–Si stretch); 697 cm−1, SiO2; and 256 cm−1 (not FTIR–PAS). Amide I, II, and III bands appear in DRIFT and FTIR–PAS spectra while not in ATR. Except for methylene and carboxylate groups, CH vibrations (3100–2900 cm−1) are not seen in ATR. Bands at 1640–1630 cm−1, 1620–1610 cm−1, 1600–1598 cm−1 (primary water bands and probably carboxylate) appear in the spectra of all three modalities but are unresolved and require data treatment. It is preferable to use all three modalities to characterize both soil organic matter and mineral composition. DRIFT provides the maximum number of bands in all three modalities and should be selected as a primary technique in the NIR and 4000–2000 cm−1 regions for hydrogen-bonding bands, CHX groups, and the silicate matrix. ATR–FTIR complements DRIFT and provides a good sensitivity for soil water and the matrix in 2000–400 cm−1. FTIR–PAS in 4000–1500 cm−1 reveals more bands than DRIFT and shows the highest sensitivity for absorption bands that do not appear in DRIFT or ATR-IR spectra. Thus, FTIR–PAS is expedient for supporting either DRIFT or ATR–FTIR. This modality comparison can be a basis for methodological support of IR spectroscopy of soils and similar organomineral complexes.

Sustainable Management of Calcite Contaminated with Waste Toner Powder in the Construction Industry

“…In the case of sample C, the peak at 1794 cm −1 may be regarded as the combination band of υ 1 + υ 4 of carbonate ion [ 23 ]. The absorption band at 697 cm −1 in all tested materials can represent Si-O-Si stretching vibrations [ 24 ].…”

“…The absorption band at 697 cm −1 in all tested materials can represent Si-O-Si stretching vibrations [24].…”

Vertical SOC distribution and aromatic carbon in centuries old charcoal‐rich Technosols

“…The reason for this was the very low TOC and BC concentrations in non‐RCH soils , which failed to produce a strong enough signal in the spectra. The PLSR regression coefficients for the RCH soil model (Figure 6) suggested that higher BPCA‐C concentrations coincided with higher carboxyl C=O absorptions at 1732 cm −1 , aromatic C=C absorptions from ionised carboxyl (COO − ) groups or C=O absorptions at 1616 cm −1 (Rebollo et al, 2008; Volkov et al, 2021), aromatic C‐H vibrations at 3000–3100 cm −1 and lower absorptions at the aliphatic CH region at 2800–3000 cm −1 and aromatic C=C stretches associated with lignin at 1518 cm −1 (Ferrari et al, 2011; Volkov et al, 2021; White et al, 2011). Thereby, the coefficients show that BPCA‐C concentrations correlated mainly positive with wavenumber regions associated with charcoal contents in soils.…”

Biodeterioration Assessment of a Unique Old Pharaonic Kingdom Wooden Statue Using Advanced Diagnostic Techniques

“…As shown in Figure 4d, false-colour FPA The presence of thick layers of soil enveloping the wood of sample #2 together with diffuse mineral grains were clearly observed in the SEM images (Figure 3c). SEM-EDX spectrum (Figure 3d, wood sample #1) shows the presence of very high amount of Ca, Cl, and Si and lower amounts of Na, Mg, Al, S, K, Pb, and Fe; this might be attributed to the penetration of soil components inside the wood, as these elements are the main soil constituents [62].…”