改性花生壳粉对钙离子的吸附特性研究
Study on adsorption characteristics of calcium ions on modified peanut shell
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摘要: 利用改性花生壳粉吸附去除水中产生硬度的主要离子钙离子，考察了改性花生壳粉的吸附动力学和吸附平衡特性，并利用傅立叶红外光谱（FTIR）对其结构特性进行了表征。结果表明，钙离子吸附量的85%发生在45 min时，其吸附平衡基本在4 h内完成，可以通过准二级吸附动力学准确地表征该吸附过程，且改性花生壳粉对钙离子的吸附能够很好地遵循Langmuir等温吸附模型。当pH由2升高至12时，钙离子吸附量随之增加，且在强碱性时吸附效果尤为显著。在花生壳粉固定床吸附实验中，钙离子的穿透曲线很好地遵循Thomas方程。通过FTIR分析发现，改性花生壳粉中较高含量的不饱和基团（CC，CO）和C—O官能团在对钙离子的吸附过程中作用最强。Abstract: Modified peanut shell was used to adsorb calcium ions from water to reduce hardness. The kinetic and equilibrium characteristics of adsorption were investigated in the uptake of calcium ions， and fourier transform infra-red (FTIR) analysis was employed to characterize the adsorbent. Results showed that 85% of the uptake by the modified peanut shell occurred in 45 min， and the adsorption equilibrium was obtained within 4 h， which was well described by a pseudo-second-order kinetic model. The equilibrium adsorption was effectively described by Langmuir adsorption isotherm. Furthermore， the adsorption increased when pH increased from 2 to 12， and a significantly high adsorption was caused by strong basicity. In fixedbed column adsorption， the breakthrough curve was well fitted by the Thomas model. According to the FTIR analysis， the high content of unsaturated structures (CC， CO) and C—O groups in modified peanut shell contributed to the adsorption of calcium ions significantly.
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Key words:
- modified peanut shell /
- calcium ions /
- kinetic model /
- adsorption isotherm /
- FTIR
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