Effect of aging on surface chemistry of rice husk‐derived biochar

Abstract

Herein, we aimed to determine the physicochemical properties of biochar produced from rice husk at 350 and 5508C, to characterize changes in the biochar properties during aging and to identify the effect of aging time on these changes. To simulate different stages in the aging process, samples were incubated at a constant temperature in the dark and maintained at 60% water holding capacity for 100-300 d. The transformation and morphology of the biochar particles were monitored by diffuse-reflectance Fourier transform infrared spectroscopy (DRIFTS), scanning electron microscopy (SEM) coupled with energy X-ray dispersive spectroscopy, and X-ray photoelectron spectroscopy (XPS). During aging, a layer formed on the surface and the content of easily oxidized substances increased with increased aging time. In addition, SEM indicated that oxidation occurred close to the biochar surface rather than in the biochar particle interior. Furthermore, the DRIFTS and XPS results indicated that the biochar surface produced at 5508C underwent decarboxylation and hydroxylation, while for the 3508C biochar, the increase in surface oxygen content was associated with the presence of hydroxyl moieties.

An Enhanced Reduction–Adsorption Strategy for Cr(VI): Fabrication and Application of L-Cysteine-doped Carbon@Polypyrrole with a Core/Shell Composite Structure

“…This confirms that −S–S– is further oxidized to -SO x by Cr­(VI). Similarly, the C1s peaks of GCS@PPy/ L -cys (Figure f) centered at 283.66, 284.69, 285.28, 286.22, and 288.04 eV are rationally attributed to pyrrole-C β , pyrrole-C α , C–S, C–N, and OC–O, respectively. ,− These data confirm the higher binding energy after adsorption of Cr­(VI) (284.29, 284.82, 285.41, 286.32, and 288.44 eV, respectively).…”

Hydrochar did not reduce rice paddy NH3 volatilization compared to pyrochar in a soil column experiment

“…high specific surface area and C/N ratio, at first. However, as the process of aging, the functionality of biochar was modified 40,41 . Therefore, significant relationship between PAV and soil properties were shown after PF.…”

Experimental and DFT investigations on adsorption–regeneration performance and deactivation mechanism over engineered carbon fiber: role of pore structure and functional groups

“…42 The peaks of O 1s spectra at 530.9, 532.0, 532.8 and 533.9 eV belonged to groups CO, OC-O-(C, H), C-O-C (C-OH) and OC-O-(C, H), respectively. 43,44 After six regeneration cycles, obvious peak shifts in C1s and O1s spectra were observed, indicating that a new stable chemical structure had been formed at the interface of the CBC adsorbent during this process. 45 To explore the element content of the interface structure, the proportion of total C, total O and other oxygen-containing groups on CBC adsorbents was calculated (Fig.…”