Co-Hydrothermal Carbonization of Sewage Sludge with Wood Chip: Fuel Properties and Heavy Metal Transformation Behavior of Hydrochars

作者：Lu, Xiaoluan; Ma, Xiaoqian^*; Qin, Zhen; Ke, Chuncheng; Chen, Limei; Chen, Xinfei

来源：Energy and Fuels, 2021, 35(19): 15790-15801.

DOI：10.1021/acs.energyfuels.1c02145

• CHEMICAL LOOPING GASIFICATION
• SOLID-FUEL
• ENVIRONMENTAL RISK
• TEMPERATURE
• REMOVAL
• BIOMASS
• WASTES
• LAND
• FATE
• IMMOBILIZATION

To further reduce the toxicity of heavy metals (HMs) in sewage sludge (SS), organic acid (oxalic acid, citric acid, acetic acid) washing was used before co-hydrothermal carbonization (co-HTC) with pinewood. The results showed the total concentrations of six HMs (As, Cu, Ni, Cr, Mn, and Zn) in hydrochar produced at 230 degrees C decreased obviously during co-HTC. More importantly, F1 + F2 fractions of Ni, Cr, Mn, and Zn were also lowered. With the pretreatment of citric acid, the hydrochar from co-HTC exhibited the lowest potential ecological risk among all simples. Compared with the hydrochar produced from SS, the coalification degree, higher heating values (5.61-6.19 MJ/kg), and combustion behavior of the hydrochar derived from co-HTC were upgraded and improved. These findings offered a viable technology that could lower the bioavailability of HMs and realize the energy value of SS.