• 关键词：生物炭  热解条件  理化性质  NO₃^-  NH₄⁺  PO₄^3-  吸附机制

• 基金项目：教育部长江学者和创新团队发展计划(No.IRT13083);四川省教育厅重点项目(No. 12ZA124)

• 王章鸿
• 1. 四川农业大学生态环境研究所, 成都 611130;2. 四川农业大学环境学院, 成都 611130

• 郭海艳
• 1. 四川农业大学生态环境研究所, 成都 611130;2. 四川农业大学环境学院, 成都 611130

• 沈飞
• 1. 四川农业大学生态环境研究所, 成都 611130;2. 四川农业大学环境学院, 成都 611130

• 李阳
• 1. 四川农业大学生态环境研究所, 成都 611130;2. 四川农业大学环境学院, 成都 611130

• 王卿
• 1. 四川农业大学生态环境研究所, 成都 611130;2. 四川农业大学环境学院, 成都 611130

• 摘要：以橡木为原料,在不同的热解终温、升温速率和恒温时间下制备生物炭.对生物炭产率、pH、元素组分、工业组分、比表面积、红外光谱等理化特征进行分析,并考察生物炭对水溶液体系中NO₃^--N、NH₄⁺-N、PO₄^3--P的吸附性能.结果表明:生物炭的产率受热解终温影响最大(极差:54.57%),恒温时间次之(极差:1.16%),升温速率最小(极差:0.42%).随热解终温、升温速率和恒温时间的增加,所得生物炭的pH和C含量增加,而H和O含量降低.热解终温对生物炭表面官能团影响较大,升温速率和恒温时间基本无影响.生物炭对氮、磷的吸附性能主要受热解终温影响.NO₃^--N的吸附量最大可达2.80 mg · g^-1(600 ℃),且随热解终温的升高呈指数增加.比表面积、表面碱性官能团和表面金属氧化物与NO₃^--N吸附有关.随热解终温的增加,NH₄⁺-N吸附量降低,最大吸附量为3.12 mg · g^-1(300 ℃).阳离子交换量(CEC)是影响NH₄⁺-N吸附的主要因素.PO₄^3--P吸附量随热解终温的增加呈先增后减的趋势(在500 ℃达到最大,为9.75 mg · g^-1),且吸附过程主要受生物炭表面碱性官能团和表面金属氧化物的影响.

• Abstract：Oak sawdust was employed for biochar production by pyrolysis to investigate the effects of main conditions, including pyrolysis temperature, heating rate, and holding time, on biochar characteristics. The biochar adsorption to NO₃^--N,NH₄⁺-N and PO₄^3--P from aqueous solutions were also investigated to clarify the potential adsorption mechanisms. Based on the investigations on biochar yield, pH, ultimate analysis, and proximate analysis, results indicated that biochar yield was mainly relied on pyrolysis temperature (Yield_max-min of 54.57%), followed by holding time (Yield_max-min of 1.16%) and heating rate (Yield_max-min of 0.42%), respectively. pH and C content were increased with the increase of the pyrolysis temperature, holding time and heating rate, and obvious decrease can be observed on H and O contents. FT-IR results revealed that pyrolysis temperature was mainly responsible for surface functional groups of biochar, rather than heating rate and holding time. Furthermore, the adsorption abilities of biochar to NO₃^--N,NH₄⁺-N and PO₄^3--P were also mainly depended on pyrolysis temperature. The maximum NO₃^--N adsorption capacity was 2.80 mg · g^-1 at 600 ℃. The exponential relationship can be observed between the NO₃^--N adsorption capacity and pyrolysis temperature, which was potentially attributed to surface area, basic functional groups and metal oxides on biochar. The maximum NH₄⁺-N adsorption capacity was 3.12 mg · g^-1 at 300 ℃, and pyrolysis temperature negatively correlated to the NH₄⁺-N adsorption due to the cation exchange capacity (CEC) of the biochar. The highest adsorption capacity of PO₄^3--P (9.75 mg · g^-1) was achieved at pyrolysis temperature of 500 ℃, and a slight decrease was observed with increasing pyrolysis temperature to 600 ℃, which was mainly related to basic functional groups and metal oxides on biochar.

• Key words：biochar  pyrolysis conditions  physicochemical properties  NO₃^-  NH₄⁺  PO₄^3-  adsorption mechanisms

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