The spectral characteristics of biochar-derived dissolved organic matter at different pyrolysis temperatures

Changes of labile, stable and water-soluble fractions of biochar after two years in a vineyard soil

“…82,83 The SUVA 254 value of biochar through the aging process increased from 4.7 ± 0.4 to 10.7 ± 0.1 L mg −1 m −1 , indicating that highly hydrophobic substances were likely contained in the DOM from aged biochar and that aging induces increases in the hydrophobic and aromatic components and a decrease in the smaller molecules (low molecular weight) after two years in soil. 84 Therefore, after the incubation time biochar showed a rising trend in the levels of SUVA value as reported by Huang et al , 77 possibly implying the preferential utilization of non-aromatic fractions by microorganisms and/or the microbial transformation of simple labile substrates into aromatic carbon structures. 85 Furthermore, due to high molecular and aromatic substances in DOM samples, the biochar-derived DOM would generally remain stable, with high resistance, after the aging period in the field.…”

Na4P2O7-Modified Biochar Derived from Sewage Sludge: Effective Cu(II)-Adsorption Removal from Aqueous Solution

“…The results of FTIR spectra of SBC and SP-SBC (Figure 4) revealed peaks at around 790 and 1061 cm −1 , which were due to the aromatic C-H out-of-plane vibrations [61] and C-O stretching vibration, respectively [15, 62, 63]. The peak at around 1433 cm −1 represented the C=C stretching vibration of aromatic hydrocarbons [64]. The peak at 1629 cm −1 was associated with the –COOH stretching vibration [65].…”

Hydrochar and Its Dissolved Organic Matter Aged in a 30-Month Rice–Wheat Rotation System: Do Primary Aging Factors Alter at Different Stages?

“…To further elucidate the sequence of the change in the surface functional group of aged hydrochar in response to different aging time scales, 2D-COS analysis (Figure S6 and Table S4) was performed on the FTIR spectrum of the hydrochar samples (Figure S5d). According to Noda’s rule, the change sequence in surface functional groups (Table S4) of aged hydrochar, determined from the synchronous and asynchronous spectra (Figure S6 and Table S4), was as follows: C–O or Si–O (1025 cm –1 ) > −OH (3320 cm –1 ) > carbonyl CO or −OH deformationvibration (1420 cm –1 ) > benzene ring CC (1570 cm –1 ) > C–H aromatic (870 cm –1 ) > carboxyl CO (1650 cm –1 ) > aliphatic −CH 2 – (2850 and 2925 cm –1 ). Oxygen-containing functional groups, such as C–O or Si–O, carbonyl CO, and −OH, changed in the initial aging, probably interacting with soil minerals.…”

“…21 To further elucidate the sequence of the change in the surface functional group of aged hydrochar in response to different aging time scales, 2D-COS analysis (Figure S6 and Table S4) was performed on the FTIR spectrum of the hydrochar samples (Figure S5d). According to Noda's rule, 44 the change sequence in surface functional groups (Table S4) of aged hydrochar, determined from the synchronous and asynchronous spectra (Figure S6 and Table S4) S5, the total fluorescence volume (Φ, au nm 2 ) of the HDOM declined during aging, primarily due to the decomposition of fluorescence components. As indicated in Figure 1e, humic acid (region V) and microbial byproducts (region IV) constitute the main fluorescent components of HDOM.…”