| 摘要: |
| 以氢氧化钠改性后的蓖麻秸秆粉末为吸附剂,通过红外光谱仪和扫描电镜仪对改性前后蓖麻秸秆粉末的结构进行表征；采用正交设计法,研究了氢氧化钠浓度、时间和温度对改性后蓖麻秸秆粉末对Cd<sub><sup>2+</sup></sub>吸附的影响,并考察了改性前后蓖麻秸秆粉末对Cd<sub><sup>2+</sup></sub>的吸附热力学和动力学特征。结果表明：水热氢氧化钠改性使蓖麻秸秆中较多的羟基暴露出来,使得蓖麻秸秆的表面结构疏松、比表面积增加、有效吸附位点增加,提高了改性蓖麻秸的吸附能力；10% NaOH在150℃、反应8 h后制得的改性蓖麻秸秆粉末对Cd<sub><sup>2+</sup></sub>的吸附率最大,达71.24%。Langmuir和Temkin模型能较好地描述改性蓖麻秸秆粉末对Cd<sub><sup>2+</sup></sub>的吸附,改性前后蓖麻秸秆粉末对Cd<sub><sup>2</sup></sub><sub><sup>+</sup></sub>的最大吸附容量分别是62.78和138.81 mg.g<sub><sup>-1</sup></sub>,改性后是改性前的2.21倍；伪一级动力学、伪二级动力学和叶洛维奇方程能较好地描述改性前后蓖麻秸秆粉末对Cd<sub><sup>2+</sup></sub>的吸附过程,而伪二级动力学拟合后得到的Q<sub>e</sub>值更接近于真实值。 |
| 关键词: 改性蓖麻秸秆，吸附剂，Cd[sub_s][sup_s]2+[sup_e][sub_e]，吸附效果，动力学 |
| DOI： |
| 分类号:S153 |
| 基金项目:内蒙古自治区高等学校科学研究项目(NJZY16181)资助；内蒙古自然科学基金研究项目(2015MS0304)资助；内蒙古民族大学科学研究项目(NMDGP1402)资助； |
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| Structural characterization, preparation optimization and cadmium adsorption characteristics of modified castor straw |
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ZHANG Yu-fen
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Analysis Center of Inner Mongolia University of Nationalities
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| Abstract: |
| Key words: modified castor straw; adsorbent; Cd2+; adsorption efficiency; Kinetics
The structure of the modified castor straw powder was characterized by infrared spectroscopy and scanning electron microscopy with sodium hydroxide modified castor straw powder as adsorbent. The effect of concentration, time and temperature of sodium hydroxide on the adsorption of Cd2+ on the modified castor straw powder was studied by orthogonal design. Thermodynamic and kinetic characteristics of Cd2+ adsorption on castor straw powder before and after treatment. The results showed that the hydrothermal modification of sodium hydroxide exposed more hydroxyl groups in the castor straw, made the surface structure of the castor straw loose, the specific surface area increased, the effective adsorption sites increased, and improved the adsorption capacity of the modified castor straw; The modified castor straw powder prepared by 10% NaOH at 150℃ for 8 h has the highest adsorption rate of Cd2+ up to 71.24%.Langmuir and Temkin models could better describe the adsorption of Cd2+ on modified castor straw powder. The maximum adsorption capacity of Cd2+ on modified and unmodified castor straw powder was 62.78 and 138.81 mg.g-1, respectively, which was 2.21 times higher than that before modification. Pseudo-first-order kinetics, pseudo-second-order kinetics and Elovich equation could better describe the adsorption capacity of Cd2+ on modified castor straw powder before and after modification. The adsorption process of Cd2+ on the post-castor straw powder was similar to the real Qe value after pseudo-second-order kinetics fitting. |
| Key words: modified castor straw; adsorbent; Cd2+; adsorption efficiency; Kinetics |
