摘要
以玉米秸秆生物炭为实验材料,研究了生物炭吸附重金属Cd2+的性能,分析了吸附温度、吸附时间、初始pH值以及生物炭粒径对吸附的影响,并对吸附前后生物炭样品进行傅里叶变换红外光谱分析(FITR)、X-射线衍射(XRD)和X-射线光电子能谱(XPS)表征以分析吸附机理。结果表明:玉米秸秆生物炭对Cd2+的吸附可用Langmuir等温方程较好地拟合,在不同温度下其饱和吸附量分别为18.49 mg·g-1(288.15 K)、23.51 mg·g-1(298.15 K)、23.59 mg·g-1(308.15 K)和24.43 mg·g-1(318.15 K),吸附动力学过程可以由准二级动力学方程很好地拟合,约40 min即达平衡,pH值为5时吸附量最大,生物炭粒径对吸附无明显影响。结构表征表明,生物炭对Cd2+的吸附机理主要为表面羟基(-C-OH)和羰基(-C=O)与Cd2+发生络合化学反应作用。
Biochar has large surface and may be used to adsorb heavy metals from water. A lab experiment was carried out to investigate the effects of time, temperature（288.15-318.15 K）, solution pH, and biochar particle size on adsorption of aquatic Cd2＋ by biochar. The surface characteristics of biochar before and after Cd^2＋ adsorption were examined using X-ray diffraction analysis（XRD ）, Fourier transform infrared spectroscopy（FTIR） and X-ray Photoelectron Spectroscopy（XPS）. The results showed that the equilibrium adsorption was better fit by Langmuir model than Freundlich model. The maximum adsorption capacity of the biochar for Cd^2＋ at different temperatures was 18.49 mg ·g-1 （288.15 K）, 23.51 mg·g-1（298.15 K）, 23.59 mg·g-1（308.15 K） and 24.43 mg·g-1（318.15 K）, respectively. The adsorption kinetics could be well described by pseudo-second order kinetics model, The adsorption process was quick and the equilibrium was attained within 40 minutes. The optimum adsorption pH value was 5.0. The particle size of biochar had no significant effects on Cd2~ adsorption. The biochar adsorbed Cd^2＋ mainly via Cd^2＋ chelation with hydroxyl（-C-OH） and carbonyl（-C=O） as confirmed by XRD, FTIR and XPS.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2014年第5期958-964,共7页
Journal of Agro-Environment Science
基金
国家自然科学基金项目(201107056
21177068
31200397)
公益性行业(农业)专项(201203045)
农业部农业科研杰出人才项目
中央级公益性科研院所基本科研业务费专项
关键词
生物炭
镉
吸附
吸附动力学
影响因素
biochar
aquatic Cd^2＋
adsorption
adsorption characteristics
influencing factors
