| 苏 鹃,伍 钧,杨 刚,王章鸿.改性白果壳对水溶液中重金属镉的吸附研究[J].农业环境科学学报,2014,33(6):1218-1225. |
| 改性白果壳对水溶液中重金属镉的吸附研究 |
| Adsorption of Cd2+ from Solution by Modified Ginkgo Shell Powder |
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| DOI：10.11654/jaes.2014.06.024 |
| 中文关键词: 白果壳 改性 镉 动力学模型 等温吸附模型 扫描电镜图像 红外光谱 |
| 英文关键词: gingko shells chemical modification Cd2+ kinetic model isothermal adsorption model SEM FT-IR |
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| 摘要点击次数: 1823 |
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| 中文摘要: |
| 为实现农林废弃物的资源化利用和开辟廉价、高效的重金属吸附剂，利用1%KMnO4溶液对白果壳进行化学改性，制备成KMnO4改性白果壳（命名为WSK），用于水溶液中Cd2+的吸附，研究温度、pH、反应时间、初始Cd2+浓度4个因素对WSK吸附Cd2+的影响，并通过模型拟合、电镜扫描（SEM）和红外光谱（FTIR）分析，对吸附机理进行了初步探讨。结果表明，WSK是一种理想的Cd2+吸附剂，其吸附性能受温度、pH、反应时间、Cd2+初始浓度的影响。吸附量与体系温度呈正相关，温度越高吸附量越大；随pH的增加吸附量先升高后降低，pH为5.5时，吸附效果最佳；在60 min后基本达到吸附平衡；随着Cd2+初始浓度的升高，WSK对水中Cd2+的吸附量逐渐增加，当Cd2+浓度为300 mg·L-1时，去除率为94.49%，基本达到吸附饱和。WSK对水中Cd2+的吸附符合Freundlich模型，决定系数R2为0.94，最大吸附量为119.76 mg·g-1；吸附过程符合二级动力学吸附模型，R2为0.999 5。SEM照片显示WSK表面呈多孔结构，增加了WSK的比表面积、孔容及表面吸附位点，这有助于提高其吸附性能。红外光谱图分析表明，WSK主要靠-OH、-COO-、-NH-、C=O、-P=O、-CH-等离子活性官能基团与Cd2+配位结合，其中-COO-起重要作用。 |
| 英文摘要: |
| Utilizing agricultural or forestry wastes to remove heavy metals in water has recently received much attention. In this work, ginkgo shells were ground and modified with 1％KMnO4 solution to make a adsorbing material named WSK. The effects of temperature, pH, time and original Cd2+ concentrations on Cd2+ adsorption by WSK were investigated. Cadmium adsorption mechanisms were also discussed based on the adsorption model, SEM and FTIR data. The adsorption capacity of Cd by WSK enhanced as the temperature increased. Cadmium adsorption was increased at lower solution pH but reduced at higher pH, with adsorption peak occurred at pH5.5. The Cd2+ adsorption by WSK reached equilibrium in 60 mins. Increasing original Cd2+ concentrations enhanced Cd2+ adsorption, but decreased Cd2+ removal percentages. Adsorption of Cd2+ was fit to the Freundlich model with R2 of 0.94, and the largest adsorption was 119.76 mg·g-1. The adsorption kinetics was described by the second-order kinetic adsorption model with R2 of 0.9995. SEM indicated that WSK surface was porous, which might increase Cd2+ adsorption on WSK. IR-spectrum showed that Cd2+ was adsorbed to WSK via coordination of functional groups such as -OH, -COO, -NH-, C=O, -P=O and -CH-, with -COO- playing an important role. |
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