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生物质化学工程 ›› 2020, Vol. 54 ›› Issue (5): 15-24.doi: 10.3969/j.issn.1673-5854.2020.05.003

• 研究报告 • 上一篇    下一篇

热解温度和生物质类型对生物炭吸附U(Ⅵ)性能的影响

吕鹏1,王光辉1,2,*(),王冰1,胡德玉1   

  1. 1. 东华理工大学 水资源与环境工程学院, 江西 南昌 330013
    2. 核资源与环境国家重点实验室, 江西 南昌 330013
  • 收稿日期:2020-05-07 出版日期:2020-09-30 发布日期:2020-09-29
  • 通讯作者: 王光辉 E-mail:wgh68611@163.com
  • 作者简介:吕鹏(1995-),男,河南驻马店人,硕士生,主要从事土壤修复研究
  • 基金资助:
    国家自然科学基金资助项目(41761069);江西省自然科学基金重点项目(20181ACB20004)

Effect of Pyrolysis Temperature and Biomass Type on Adsorption of U(Ⅵ) by Biochar

Peng LYU1,Guanghui WANG1,2,*(),Bing WANG1,Deyu HU1   

  1. 1. Faculty of Water Resources and Environmental Engineering, East China University of Technology, Nanchang 330013, China
    2. State Key Laboratory of Nuclear Resources and Environment, Nanchang 330013, China
  • Received:2020-05-07 Online:2020-09-30 Published:2020-09-29
  • Contact: Guanghui WANG E-mail:wgh68611@163.com
  • Supported by:
    国家自然科学基金资助项目(41761069);江西省自然科学基金重点项目(20181ACB20004)

摘要:

以稻壳、竹子和杉木屑为原料,分别在不同热解温度下热解制备生物炭(DBC、ZBC和MBC)。采用傅里叶变换红外光谱(FT-IR)、扫描电子显微镜(SEM)、X射线能谱(EDS)和X射线衍射(XRD)表征其理化性质,并通过批量吸附实验研究生物炭对U(VI)的吸附特性与机理。结果表明:随着热解温度升高,3种生物炭pH值和灰分增加,产率下降,且ZBC与DBC表面更加粗糙,孔状形貌更加明显,芳香结构趋于完善,含氧官能团减少,无机元素占比增加,碳纤维结晶度降低;准二级吸附动力学模型能更好地拟合3种生物炭吸附U(VI)的过程(R22>0.96),在25℃、pH值4、固液比为1:1(g:L)的条件下3 h可达到吸附平衡;3种生物炭的吸附等温线拟合更符合Langmuir模型,以化学吸附为主,ZBC700对U(VI)的理论最大吸附量为18.55 mg/g;随着热解温度的升高,ZBC和DBC吸附U(VI)的能力增强,阳离子-π和离子交换作用贡献增加。MBC吸附U(VI)的能力与热解温度关系不明显,相同热解温度,ZBC和DBC的吸附量高于MBC。

关键词: 生物炭, 热解温度, 生物质类型, U(Ⅵ), 吸附

Abstract:

Biochar(BC) was made by pyrolysis of rice husk, bamboo and Chinese fir sawdust at different temperature, which respectively labeled DBC, ZBC and MBC in turn. The physicochemical properties of the product were characterized by Fourier transform infrared spectroscopy(FT-IR), scanning electron microscope(SEM), energy dispersive X-ray(EDS) and X-ray diffraction(XRD). The adsorption characteristic and mechanism of BC to U(Ⅵ) were studied by batch adsorption experiments. The results showed that, as the temperature increased from 300 ℃ to 700 ℃, the pH value and ash content of the three kinds of biochars increased, but the yield decreased. Meanwhile, the characterization of both ZBC and DBC was also changing with increasing pyrolysis temperature, such as the crystallinity of the carbon fiber and content of oxygen-containing functional groups decreased, the proportions of inorganic elements and pore shapes increased, and the surface was rougher. The adsorption processes on the three kinds of BCs were more consistent with the pseudo-second-order kinetic model(R22>0.96), and the adsorption equilibrium time was 3 h at reaction temperature 25 ℃, pH value 4, solid-liquid ratio 1:1(g:L). The adsorption isotherms of the three kinds of BCs were more consistent with Langmuir model, which indicated that chemical adsorption was the main process. The largest adsorption capacity of ZBC700 was 18.55 mg/g. The abilities of ZBC and DBC to adsorb U(Ⅵ) were enhanced with increasing pyrolysis temperature, simultaneously, the contribution utility of cation-π and ion exchange was increasing. Nevertheless, the relationship between the ability of MBC to adsorb U(Ⅵ) and pyrolysis temperature was not obvious, and the adsorption capacities of ZBC and DBC were higher than that of MBC at the same pyrolysis temperature.

Key words: biochar, pyrolysis temperature, biomass type, U(Ⅵ), adsorption

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