Unraveling the synergistic mechanism in co-hydrothermal carbonization of sludge and Firmiana simplex bark via hydrochar component fractionation
Release time:2025-09-09 Hits:
DOI number:10.1016/j.jece.2025.119090
Journal:Journal of Environmental Chemical Engineering
Abstract:This study systematically investigated the synergistic mechanism during the co-hydrothermal carbonization (co-HTC) of municipal sewage sludge (SS) and Firmiana simplex bark (FSB). The results showed that at SS:FSB mixing ratios ranging from 3:2–2:3, the obtained hydrochar exhibited a significantly increased yield and a higher heating value (HHV), along with improved fuel properties characterized by a higher carbon content and a lower ash content. A gradient extraction method using ethanol and dichloromethane was employed to quantitatively assess the relative contributions of liquid-solid and solid-solid carbonization pathways, revealing that solid-solid conversion was the predominant source of the synergistic effect. To further elucidate the mechanism, model biomass systems were constructed using bovine serum albumin (BSA) and two types of lignin: alkaline lignin (AL) and dealkaline lignin (DAL). FTIR and SEM analyses indicated that in the BSA-AL system, spherical deposits formed through weak interactions such as hydrogen bonding and ether linkages. In contrast, in the BSA-DAL system, undissolved components underwent nitrogen heterocycles embedding and structural rearrangement, resulting in the formation of dense primary hydrochar. The results from both the model and real systems consistently demonstrated that the dense primary hydrochar formed via the solid-solid pathway contributed primarily to the increased hydrochar yield, while the liquid-solid pathway imparted more complex morphological characteristics to the product. These findings provide deeper insights into the synergistic carbonization mechanism between SS and lignin-rich biomass, and offer theoretical support for the co-utilization and process optimization.
Volume:13
Issue:5
Page Number:119090
Translation or Not:no
Date of Publication:2025-09-09
Included Journals:SCI
Links to published journals:https://www.sciencedirect.com/science/article/pii/S2213343725037868
