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ASSESSMENT OF HEAVY METALS IN HYDROCHAR PRODUCED BY HYDROTHERMAL CARBONIZATION OF DAIRY MANURE

《农业科学与工程前沿(英文)》 2023年 第10卷 第3期   页码 437-447 doi: 10.15302/J-FASE-2023507

摘要:

● Content of heavy metals in hydrochar varies considerably, from 50% to 100%.

关键词: heavy metals     dairy manure     hydrochar     hydrothermal carbonization     waste management    

Two-step hydrothermal conversion of biomass waste to humic acid using hydrochar as intermediate

《环境科学与工程前沿(英文)》 2023年 第17卷 第10期 doi: 10.1007/s11783-023-1719-8

摘要: Converting biomass materials to humic acid is a sustainable method for humic acid production and achieve biomass valorization. A two-step hydrothermal treatment method was adopted in this study to produce humic acid from corn stalks. In the first step of the process, hydrochar was prepared at different hydrothermal temperatures and pH values. Their chemical properties were then analyzed, and the hydrochar-derived humic acids were produced under alkaline hydrothermal conditions (denoted as HHAalk). The hydrochar, prepared under high temperature (200 °C) and strong acidic (pH 0) conditions, achieved high HHAalk yields (i.e., 67.9 wt% and 68.8 wt% calculated based on weight of hydrochar). The sources of HHAalk formation were as follows: 1) production in the hydrochar preparation stage, and 2) increment under the alkaline hydrothermal treatment of hydrochar. The degree of hydrochar unsaturation was suggested as an indicator for evaluating the hydrochar humification potential under alkaline hydrothermal conditions. This study provides an important reference for the preparation of suitable hydrochar with high hydrothermal humification potential.

关键词: Biowaste     Hydrochar     Humic acid     Hydrothermal parameter     Unsaturation    

Synthesis of porous carbon from orange peel waste for effective volatile organic compounds adsorption: role of typical components

《化学科学与工程前沿(英文)》 2023年 第17卷 第7期   页码 942-953 doi: 10.1007/s11705-022-2264-x

摘要: Volatile organic compounds have posed a serious threat to the environment and human health, which require urgent and effective removal. In recent years, the preparation of porous carbon from biomass waste for volatile organic compounds adsorption has attracted increasing attention as a very cost-effective and promising technology. In this study, porous carbon was synthesized from orange peel by urea-assisted hydrothermal carbonization and KOH activation. The role of typical components (cellulose, hemicellulose, and lignin) in pore development and volatile organic compounds adsorption was investigated. Among the three components, hemicellulose was the major contributor to high porosity and abundant micropores in porous carbon. Higher hemicellulose content led to more abundant –COOR, amine-N, and pyrrolic/pyridonic-N in the derived hydrochar, which were favorable for porosity formation during activation. In this case, the toluene adsorption capacity of the porous carbon improved from 382.8 to 485.3 mg·g–1. Unlike hemicellulose, cellulose reduced the >C=O, amine-N, and pyrrolic/pyridonic-N content of the hydrochar, which caused porosity deterioration and worse toluene adsorption performance. Lignin bestowed the hydrochar with slightly increased –COOR, pyrrolic/pyridonic-N, and graphitic-N, and reduced >C=O, resulting in comparatively poor porosity and more abundant micropores. In general, the obtained porous carbon possessed abundant micropores and high specific surface area, with the highest up to 2882 m2·g–1. This study can provide guidance for selecting suitable biomass waste to synthesize porous carbon with better porosity for efficient volatile organic compounds adsorption.

关键词: biomass waste     porous carbon     feedstock composition     urea-assisted hydrothermal carbonization     toluene adsorption     N-doped hydrochar    

Sorption of aromatic organophosphate flame retardants on thermally and hydrothermally produced biochars

Ziwen Du, Chuyi Huang, Jiaqi Meng, Yaru Yuan, Ze Yin, Li Feng, Yongze Liu, Liqiu Zhang

《环境科学与工程前沿(英文)》 2020年 第14卷 第3期 doi: 10.1007/s11783-020-1220-6

摘要: TPhP showed faster and higher sorption on biochars than TPPO. Pyrochars had higher sorption capacity for TPPO than hydrochar. Hydrophobic interactions dominated TPhP sorption by biochars. The π-π EDA and electrostatic interactions are involved in sorption. Aromatic organophosphate flame retardant (OPFR) pollutants and biochars are commonly present and continually released into soils due to their increasingly wide applications. In this study, for the first time, the sorption of OPFRs on biochars was investigated. Although triphenyl phosphate (TPhP) and triphenylphosphine oxide (TPPO) have similar molecular structures and sizes, TPhP exhibited much faster and higher sorption than TPPO due to its stronger hydrophobicity, suggesting the dominant role of hydrophobic interactions in TPhP sorption. The π-π electron donor–acceptor (EDA) interactions also contributed to the sorption process, as suggested by the negative correlation between the sorption capacity of the aromatic OPFRs and the aromatic index (H/C atomic ratios) of biochar. Density functional theory calculations further showed that one benzene ring of aromatic OPFRs has no electrons, which may interact with biochar via π-π EDA interactions. The electrostatic attraction between the protonated P = O in OPFRs and the negatively charged biochar was found to occur at pH below 7. This work provides insights into the sorption behaviors and mechanisms of aromatic OPFRs by biochars.

关键词: Organophosphate flame retardants     Hydrochar     Pyrochar     Adsorption     Emerging contaminants     Biochar    

标题 作者 时间 类型 操作

ASSESSMENT OF HEAVY METALS IN HYDROCHAR PRODUCED BY HYDROTHERMAL CARBONIZATION OF DAIRY MANURE

期刊论文

Two-step hydrothermal conversion of biomass waste to humic acid using hydrochar as intermediate

期刊论文

Synthesis of porous carbon from orange peel waste for effective volatile organic compounds adsorption: role of typical components

期刊论文

Sorption of aromatic organophosphate flame retardants on thermally and hydrothermally produced biochars

Ziwen Du, Chuyi Huang, Jiaqi Meng, Yaru Yuan, Ze Yin, Li Feng, Yongze Liu, Liqiu Zhang

期刊论文