氧化老化过程对生物炭吸附镉的影响及机制  

Oxidative aging process of biochar and its adsorption mechanism for cadmium

作　　者：何玉垒 宋宁宁 林大松 孙约兵 王芳丽 HE Yulei;SONG Ningning;LIN Dasong;SUN Yuebing;WANG Fangli(Key Laboratory of Original Agro-Environmental Pollution Prevention and Control,Ministry of Agriculture and Rural Affairs,Agro Environmental Protection Institute,Ministry of Agriculture and Rural Affairs,Tianjin 300191,China;Tianjin Key Laboratory of Agro Environment and Agro-Product Safety,Agro-Environmental Protection Institute,Ministry of Agriculture and Rural Affairs,Tianjin 300191,China;Qingdao Rural Environmental Engineering Research Center,School of Resources and Environment,Qingdao Agricultural University,Qingdao 266109,China)

机构地区：[1]农业农村部环境保护科研监测所,农业农村部产地环境污染防控重点实验室,天津300191 [2]农业农村部环境保护科研监测所,天津市农业环境与农产品安全重点实验室,天津300191 [3]青岛农业大学资源与环境学院/青岛市农村环境工程研究中心,山东青岛266109

出　　处：《农业环境科学学报》2021年第9期1877-1887,共11页Journal of Agro-Environment Science

基　　金：国家自然科学基金项目(41877403)。

摘　　要：为研究氧化老化过程对生物炭性质及其对镉(Cd^(2+))吸附能力的影响及机制,以过氧化氢(H2O2)化学氧化方法模拟稻壳生物炭在自然环境中的氧化老化过程,通过等温吸附试验研究氧化老化过程对生物炭吸附Cd^(2+)能力的影响,运用扫描电镜和能谱分析(SEM-EDS)、傅里叶变换红外光谱(FT-IR)和13C核磁共振技术探究氧化老化过程中生物炭对Cd^(2+)的吸附机制。结果表明:氧化老化过程中生物炭的元素组成和比表面积变化不明显,但含氧基团增多,芳香性增强。老化前后生物炭对Cd^(2+)的吸附均符合准二级动力学模型,但氧化老化过程抑制了稻壳生物炭对Cd^(2+)的吸附能力,在298 K时,Langmuir预测Cd^(2+)在生物炭上的最大吸附量分别为未老化生物炭(BC,21.48 mg·g^(-1))>氧化老化1次生物炭(OBC1,15.07 mg·g^(-1))>氧化老化2次生物炭(OBC2,7.56 mg·g^(-1))>氧化老化3次生物炭(OBC3,7.51 mg·g^(-1))。生物炭吸附Cd^(2+)的机理主要有表面络合作用、阳离子-π作用和离子交换作用,氧化老化后碱金属元素的变化抑制了表面吸附作用。To study the effects of the aging process on the properties of biochar and its ability and mechanism of cadmium(Cd^(2+))adsorption,the hydrogen peroxide chemical oxidation method was used to simulate the aging process of rice husk biochar in the natural environment.An isothermal adsorption experiment was conducted to study the effects of the oxidative aging process on the ability of biochar to adsorb Cd^(2+).Scanning electron microscopy and energy spectrum analysis,Fourier transform infrared spectroscopy,and 13C nuclear magnetic resonance technology were used to explore the Cd^(2+)adsorption mechanism of biochar during oxidative aging.The results showed that the elemental composition and specific surface area of biochar did not change significantly during the oxidative aging process,whereas the oxygen-containing groups and the aromaticity increased.The adsorption of Cd^(2+)on biochar before and after aging was in line with the quasi-second-order kinetic model,but the oxidative aging process inhibited the Cd^(2+)adsorption capacity of rice husk biochar.The maximum Cd^(2+)adsorption capacity of the biochar predicted by the Langmuir isotherm at 298 K was in the order of unaged biochar(21.48 mg·g^(-1))>oxidative aging biochar 1(15.07 mg·g^(-1))>oxidative aging biochar 2(7.56 mg·g^(-1))>oxidative aging biochar 3(7.51 mg·g^(-1)).The Cd^(2+)adsorption mechanism of biochar mainly included surface complexation,cation-πinteraction,and ion exchange,and the change in alkali metal elements in the oxidative aging process inhibited surface adsorption.

关 键 词：生物炭 老化 镉 吸附性能 机制 

分 类 号：X505[环境科学与工程—环境工程]