不同原料生物炭对铵态氮的吸附性能研究  

Adsorption of ammonium nitrogen by biochars produced from different biomasses

作　　者：宋婷婷[1,2] 赖欣 王知文[3] 方明 杨殿林 居学海 李洁 张贵龙[1,2] 

机构地区：[1]沈阳农业大学植物保护学院,沈阳110866 [2]农业部环境保护科研监测所,天津300191 [3]东北农业大学资源与环境学院,哈尔滨150030 [4]农业部农业生态与资源保护总站,北京100125

出　　处：《农业环境科学学报》2018年第3期576-584,共9页Journal of Agro-Environment Science

基　　金：国家自然科学基金项目(41571292);国家科技支撑计划课题(2014BAD14B05);中央级科研院所基本科研业务费专项;国家重点研发计划项目(2016YFD0201201)~~

摘　　要：为探讨不同原料生物炭对铵态氮吸附量及吸附机制,以花生壳、玉米秆、杨木屑和竹屑为原料,在500℃下充N_2保护热解制备生物炭,通过电镜扫面图(SEM)与傅立叶红外光谱图(FTIR)表征NH_4^+-N在生物炭表面的吸附特征,结合批量平衡吸附试验,对比研究不同原料生物炭对NH_4^+-N的吸附性能。结果表明:吸附后生物炭表面附着颗粒或粉末物质,孔隙被填充,表面变得较为平坦。四种生物炭表面分布的-OH、-C=O、-C-O,以及花生壳生物炭与玉米秆生物炭表面的-CH_3、-CH_2、-O-参与了吸附;Langmuir方程可以较好地拟合四种生物炭对NH_4^+-N的等温吸附;吸附均在50 min内达到平衡,伪二级动力学方程均可以较好地描述生物炭对NH_4^+-N的动力学吸附过程;在溶液pH=7.00条件下,初始浓度为800 mg·L^(-1)的体系中,四种生物炭对NH_4^+-N的最大吸附量为9.5~15 mg·g^(-1),吸附能力大小为花生壳生物炭>玉米秆生物炭>竹屑生物炭>杨木屑生物炭。研究表明,生物炭表面含氧官能团对吸附NH_4^+-N起到决定性作用,吸附为单分子层吸附,且由快速反应所控制,四种生物炭中吸附性最好的是花生壳生物炭。In order to study the effects of different biomasses on the adsorption capacity of ammonium and the adsorption mechanism, peanut shell, maize straw, aspen chips, and bamboo chips were used in the preparation of biochars through N2 protection pyrolysis at 500 ℃. The biochar adsorption mechanism of NH4^＋-N was explored via batch equilibrium adsorption test, SEM, and FTIR. The results showed that the surfaces of the four biochars were filled with particles or powders and the pores were filled, which demonstrated that the surface of biochars could be flattened after adsorption of ammonium. Functional groups, such as -OH, -C=O, and -C-O, were distributed on the surface of the different biochars, and the -CH3, -CH2, and -O- groups that distributed on the biochar prepared from peanut shell and maize straw were all involved in their adsorption process. The Eangmuir equation could be better fitted to the NH4^＋-N isothermal adsorption of the four kinds of biochars; the pseudo-second-order kinetics equation could more effectively describe the NH4^＋-N kinetic adsorption, and equilibrium could be achieved in 50 min. Under the condition of pH =7.00, the adsorption capacity of different biochars reached equilibrium with the initial concentration of 800 mg·L^-1, and the maximum adsorption capacity of the biochars varied from 9.5 to 15 mg·g^-1. The adsorption capacity of the biochars followed peanut shell 〉 maize straw 〉 aspen chips 〉 bamboo chips. Our main findings are as follows：oxygen-containing functional groups might play a decisive role in enhancing the adsorption capacity; adsorption was of the single molecular layer type; adsorption was controlled by rapid reactions; and peanut shell showed the highest adsorption.

关 键 词：生物炭 铵态氮 吸附等温线 动力学吸附 含氧官能团 

分 类 号：X712[环境科学与工程—环境工程]