• 关键词：生物碳  玉米秸秆  颗粒粒径  吸附  锶

• 基金项目：国家自然科学基金（No.21307100）；四川省教育厅重点项目（No.13ZA0171）；西南科技大学博士基金（No.12zx7111）；西南科技大学研究生创新基金（No.17ycx039）

• 杨慧敏
• 1. 西南科技大学环境与资源学院环境工程系, 绵阳 621010;2. 四川省低成本废水处理技术国际科技合作基地, 绵阳 621010

• 李云桂
• 1. 西南科技大学环境与资源学院环境工程系, 绵阳 621010;2. 四川省低成本废水处理技术国际科技合作基地, 绵阳 621010

• 孙权
• 云南开发规划设计院, 昆明 650217

• 乔淑风
• 西南科技大学环境与资源学院环境工程系, 绵阳 621010

• 夏焜
• 西南科技大学环境与资源学院环境工程系, 绵阳 621010

• 魏良
• 西南科技大学环境与资源学院环境工程系, 绵阳 621010

• 摘要：以玉米秸秆为原材料，采用限氧裂解法于350℃下制备了不同粒径的生物碳（BC-9.31、BC-20.26、BC-60.77、BC-71.07、BC-101.9，数字代表样品的中值径μm），研究颗粒粒径对生物碳吸附锶的影响.结果表明：生物碳的颗粒粒径对核素锶的吸附速率和吸附容量均有显著影响.生物碳对锶的吸附动力学符合准二级动力学模型（R²，0.99），颗粒最细的BC-9.31吸附速率最大（4.48 mg·g^-1·h^-1）.随着颗粒粒径的增加，锶的吸附速率呈指数降低，其吸附速率差异高达20倍.生物碳对锶的吸附等温曲线符合准Langmuir模型（R²，0.94~0.99），饱和吸附容量为9.09~23.81 mg·g^-1.随着粒径的增大，锶的吸附容量先降低后增高又降低，粒径最小的BC-9.31（23.81 mg·g^-1）吸附容量最大，吸附容量最小的则是BC-60.77（9.09 mg·g^-1），两者相差2.6倍.pH对生物碳吸附锶具有重要影响.在溶液pH值较低时（1.93~4.74），对锶的吸附去除率急剧增加（3.94~9.17倍）；而pH值较高时（4.74~11.85），吸附去除率缓慢提高（1.11~1.68倍）.pH值也是颗粒粒径影响的重要参数，随pH值增加颗粒粒径对生物碳吸附锶的影响程度显著减小.生物碳极性指数与锶饱和吸附量和吸附速率均呈正相关关系，表明极性官能团是锶的重要吸附位点.

• Abstract：Five biochar samples of different particle sizes (BC-9.31, BC-20.26, BC-60.77, BC-71.07 and BC-101. 9, number represents particle size, μm) were produced by pyrolyzing maize straw powder at 350℃ under an oxygen-limited condition. The effect of biochar particle size on adsorption of strontium was investigated. The result shows that both adsorption rate and capacity of strontium are dependent on particle size of biochars. Sorption kinetics of strontium onto biochar follow pseudo second order kinetic model (R², 0.99). The highest adsorption rate (k₂) of strontium is observed for BC-9.31, reaching 4.48 mg·g^-1·h^-1. With the increase of biochar particle size, the adsorption rate decreases exponentially. Adsorption isotherm fit well with Langmuir equation (R², 0.94~0.99). The highest adsorption capacity (Q_m) is observed for BC-9.31, reaching 23.81 mg·g^-1. The value of Q_m decreases from BC-9.31 to BC-60.77, and then increases when the particle size of biochar further increases. The removal efficiency of strontium increases 3.94~9.17 times for different biochars when the initial pH increases from 1.93 to 4.74, and then rises gradually (1.11~1.68 times) when pH further increases from 4.74 to 10.07. With the increase of pH, the difference of strontium adsorption among biochars of different particle sizes decreases significantly. The positive correlations of Q_m and k₂ with polarity index of biochar are observed, suggesting the polar fractions of biochar are the most powerful adsorptive regions of strontium.

• Key words：biochar  maize straw  particle size  adsorption  strontium

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