| 农业废弃物基生物炭对水溶液中镉的吸附效果与机制 |
| 摘要点击 3239 全文点击 1029 投稿时间：2021-09-18 修订日期：2021-11-16 |
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| 中文关键词 生物炭 吸附 镉(Cd) 畜禽粪便 作物秸秆 |
| 英文关键词 biochar adsorption cadmium(Cd) livestock and poultry manure crop straw |
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| 中文摘要 |
| 以畜禽粪便（牛粪、鸡粪、猪粪）为原料分别在300℃和700℃下制备生物炭，以作物秸秆（小麦秸秆、水稻秸秆、玉米秸秆）为原料分别在300℃和500℃下制备生物炭，利用比表面积和孔径分析仪、扫描电镜、傅里叶红外光谱仪、X射线衍射仪和CHN分析仪等对农业废弃物基生物炭的理化性质、表面结构和元素组成进行表征，研究生物炭理化性质差异和其对镉吸附效果和机制.结果表明，不同农业废弃物基生物炭对Cd2+的等温吸附符合Langmiur方程，拟合结果发现随着热解温度的升高，牛粪、鸡粪和猪粪基生物炭对Cd2+的最大吸附量分别从83.40、19.65和96.74 mg·g-1增加至106.54、268.89和164.53 mg·g-1；而不同热解温度下制备的秸秆基生物炭对Cd2+的最大吸附量差异不显著.农业废弃物基生物炭呈碱性，除牛粪生物炭外，灰分含量随热解温度上升而增加.随着热解温度的上升，生物炭孔隙结构变丰富，含氧官能团增加，出现芳香结构.通过定量分析，发现生物炭Cd2+总吸附量中离子交换贡献率为12%~52%，化学沉淀为27%~79%，络合作用为1%~8%，阳离子-π作用为1%~28%.随着热解温度的升高，阳离子-π作用贡献率增大（从1%~13%增加到8%~30%），但化学沉淀和离子交换贡献率依旧较高（达70%~93%）.因此，离子交换和化学沉淀仍是农业废弃物基生物炭吸附Cd2+的主要机制. |
| 英文摘要 |
| Twelve biochar types were derived from animal manure (cow manure, chicken manure, and pig manure) and crop straw (wheat straw, rice straw, and corn straw) at different temperatures (300℃/700℃ and 300℃/500℃) for Cd2+ in a solution system in the present study. A scanning electron microscope, Fourier infrared spectrometer, X-ray diffraction, and CHN analyzer were applied to analyze the physical and chemical properties, surface structure, and elemental composition of the biochar. The adsorption capacity and related mechanism of biochar for Cd2+ in an aqueous solution was studied. The results showed that the maximum adsorption capacity of cow manure, chicken manure, and pig manure biochar for Cd2+ increased from 83.40, 19.65, and 96.74 mg·g-1 to 106.54, 268.89, and 164.53 mg·g-1, respectively, with the increase in pyrolysis temperature. With the increase in pyrolysis temperature, the pore structure of biochar became more abundant, oxygen-containing functional groups increased, and the aromatic structure appeared. Quantitative analyses revealed that ion exchange accounted for 12%-52%, chemical precipitation accounted for 27%-79%, complexation accounted for 1%-8%, and cation-π accounted for 1%-28% of the total adsorption capacity of Cd2+. With the increase in pyrolysis temperature, the proportion of cation-π interaction increased from 1%-13% to 8%-30%, but the proportion of chemical precipitation and ion exchange were still very high (70%-93%). Therefore, ion exchange and chemical precipitation could be the main mechanisms of agricultural waste biochar adsorption for Cd2+. |
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