PDF《花生壳生物炭对硝态氮的吸附机制研究》

摘要: 以花生壳为原料,

300 益热解条件下制得生物炭.

通过批量平衡吸附试验, 结合吸附前后 FTIR、 XPS 图谱表征分析探索硝态 氮(NO-

3 -N) 在生物炭表面的吸附机制.结果表明, 生物炭对 NO-

3 -N 的吸附显著受溶液 pH 值影响, 当pH约6 时有利于吸附的进行. 随溶液初始 NO-

3 -N 浓度增加,生物炭对其吸附量逐渐增加,在初始浓度

800 mg ・ L-1 的吸附体系中,最大吸附量达

40 mg ・ g-1 , Freundlich 方程可较好地拟合 (R2 =0.975) 生物炭对 NO-

3 -N 等温吸附过程, 吸附为非均一的多分子层吸附;

生物炭对 NO-

3 -N 的吸附 可在

30 min 达到平衡, 伪二级动力学方程能够较好地描述吸附动力学过程, 表明吸附以化学吸附为主.FTIR、 XPS 图谱分析表明, 生物炭表面分布的羟基 (-OH) 、 芳香环羰基 (-C=O) 及脂肪族醚类 (-O-) 等官能团参与了吸附过程, 且与之相连的 C 原子结合能均 增加.结合生物炭表面金属离子分布状况, 综合分析认为, 通过氢键形成和金属桥键作用是生物炭对 NO-

3 -N 吸附的主要机制. 关键词: 生物炭;

硝态氮;

吸附动力学;

吸附等温线 中图分类号: X712 文献标志码: A 文章编号: 1672-2043 (2016) 09-1727-08 doi:10.11654/jaes.2016-0230 花生壳生物炭对硝态氮的吸附机制研究 王荣荣 1,

2 , 赖欣2,李洁2,常泓1* , 张贵龙 2* (1.山西农业大学生命科学学院, 山西 太谷 030800;

2.农业部环境保护科研监测所/天津市农田生态与环境修复技术工程中心, 天津300191) Adsorption of nitrate nitrogen by peanut shell biochar WANG Rong-rong1,2 , LAI Xin2 , LI Jie2 , CHANG Hong1* , ZHANG Gui-long2* (1.College of Life Science, Shanxi Agricultural University, Taigu 030800, China;

2.Agro-Environmental Protection Institute, Ministry of Agri原culture/Tianjin Engineering Research Center of Agricultural Ecological &

Environmental Remediation, Tianjin 300191, China) Abstract: Peanut shell was used to prepare biochar through low-oxygen pyrolysis (300 益) . FTIR and XPS results of the biochar before and after batch equilibrium adsorption test showed that adsorption of NO-

3 -N on the biochar was significantly affected by pH. The NO-

3 -N ad原sorption quantity by biochar increased gradually with initial concentrations of NO-

3 -N. At the initial concentration of

800 mg・ L-1 , the maxi原mum adsorption capacity was

40 mg ・ g-1 . Freundlich equation could be well fitted (R2 =0.975)to the NO-

3 -N isothermal adsorption. Adsorp原tion of NO-

3 -N by biochar was non-uniform multilayer process and could reach the equilibrium in

30 min. Pseudo secondary dynamic equa原tion could effectively describe the adsorption kinetics, indicating that the adsorption was mainly chemical adsorption. FTIR and XPS results also suggested that the functional groups such as hydroxyl (-OH) , aromatic ring carbonyl (-C=O) , and aliphatic ether (-o-) , which dis原tributed on the surface of biochar, were involved in the adsorption process, and that the binding energy of C atoms connected to those func原tional groups increased. Considering the distribution of metal ions on the biochar surface, it is concluded that formation of hydrogen bond and metallic bond would be the main chemical mechanism of NO-

3 -N adsorption by biochar. Keywords: biochar;

nitrate nitrogen;

adsorption kinetics;

adsorption isotherm 收稿日期: 2016-02-26 基金项目: 天津市自然科学基金 生物炭调控设施菜地土壤氮素过程的效应与机制 (13JCYBJC25400) ;