National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, State Environmental Protection Key Laboratory for Lake Pollution Control, State Environmental Protection Scientific Observation and Research Station for Lake Dongtinghu, State Environmental Protection Key Laboratory of Estuarine and Coastal Environment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, State Environmental Protection Key Laboratory for Lake Pollution Control, State Environmental Protection Scientific Observation and Research Station for Lake Dongtinghu, State Environmental Protection Key Laboratory of Estuarine and Coastal Environment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
Ecotoxicol Environ Saf. 2021 Jan 1;207:111309. doi: 10.1016/j.ecoenv.2020.111309. Epub 2020 Sep 15.
Cadmium (Cd), as the primary contaminant in Chinese soils, is dangerous to human health and ecological security. Invasive plant Spartina alterniflora in Chinese coastal wetlands presents a promising feedstock for biochar, which is an efficient adsorbent for heavy metal removal. S. alterniflora harvested in summer, autumn and winter were pyrolyzed to produce biochars. We analyzed the effects of harvest time and desalination of feedstock on biochar properties and Cd adsorption capacity in aqueous solution. Biochars were characterized by pH probe, elemental analyzer, SEM, BJH, BET, and FTIR, and the Cd concentrations were measured using AAS. Except pH (9.85-10.95) and nitrogen contents (0.71-1.59%), other biochar properties had no linear correlations with harvest time. Biochars produced from feedstock harvested in autumn had the highest carbon contents (73.25%) and lowest functional groups diversity (CC and -CH). The pH and carbon contents (64.44-73.25%) were increased by desalination treatment. The surface area (0.48-2.27 m/g), total pore volume (0.0015-0.0055 mL/g), mesopore volume (0.0015-0.0052 mL/g), and Cd adsorption capacities (16.29-32.34 mg/g) were affected by desalination treatment, and the effects varied with harvest time. Biochars produced from desalted feedstock harvested in summer and untreated feedstock harvested in winter showed higher surface area, porosity, and Cd adsorption capacity. Moderate salt contents (1.5-3.0% in chloride content) in feedstock promote the formation of biochars with higher surface area and porosity.
镉（Cd）是中国土壤中的主要污染物，对人类健康和生态安全构成威胁。中国沿海湿地的入侵植物互花米草是生物炭的一种很有前途的原料，生物炭是一种去除重金属的有效吸附剂。我们分别在夏季、秋季和冬季收获互花米草，然后将其热解制成生物炭。我们分析了收获时间和原料脱盐对生物炭特性和水溶液中 Cd 吸附能力的影响。采用 pH 探针、元素分析仪、SEM、BJH、BET 和 FTIR 对生物炭进行了表征，并采用原子吸收光谱法（AAS）测量了 Cd 浓度。除 pH（9.85-10.95）和氮含量（0.71-1.59%）外，其他生物炭特性与收获时间均无线性相关性。秋季收获的原料制成的生物炭具有最高的碳含量（73.25%）和最低的官能团多样性（CC 和-CH）。脱盐处理增加了 pH 和碳含量（64.44-73.25%）。表面积（0.48-2.27 m/g）、总孔体积（0.0015-0.0055 mL/g）、中孔体积（0.0015-0.0052 mL/g）和 Cd 吸附能力（16.29-32.34 mg/g）受到脱盐处理的影响，并且这种影响因收获时间而异。脱盐处理后的夏季收获原料制成的生物炭和未经处理的冬季收获原料制成的生物炭具有更高的比表面积、孔隙率和 Cd 吸附能力。原料中适度的盐含量（氯化物含量为 1.5-3.0%）促进了具有更高比表面积和孔隙率的生物炭的形成。
