原子吸收光谱法研究纳米纤维膜对Cr(Ⅵ)的吸附性能

Adsorption Properties of Modified Nanofiber Membranes Towards Cr(Ⅵ) by Atomic Absorption Spectrometry

利用静电纺丝技术制备了醋酸纤维素和聚乙烯吡咯烷酮纳米纤维膜。此纤维膜材料经水和NaOH处理后,除去了聚乙烯吡咯烷酮,脱乙酰化后进一步在表面接枝氨基(—NH_2)。用红外光谱图和扫描电镜图表征了合成的功能化纳米纤维膜,然后将胺基化纳米纤维膜用于Cr(Ⅵ)离子的吸附研究,重点用火焰原子吸收光谱法分析了溶液酸度和吸附时间对吸附容量的影响;同时通过Langmuir、弗兰德列希等吸附模型和一级、二级动力学方程对吸附行为进行线性拟合,发现改性后的纳米纤维膜材料对Cr(Ⅵ)离子的最大吸附量为55.55mg/g;符合二级动力学模型,化学吸附是主要的吸附方式。

Cellulose acetate（CA）/polyvinylpyrrolidone（PVP） nanofiber membranes were produced using the electrospinning technique.Subsequently,the membranes were treated by water and NaOH.After being treated with water to remove partially the PVP,the membranes were further functionalized with amido groups using triethylene diamine.Related materials were characterized using infrared and SEM.The adsorption capacity of the amido-functionalized nanofiber membranes（ACM） was evaluated against Cr（Ⅵ） ion.Adsorption conditions（acidity and contacting time） for Cr（Ⅵ） ion were optimized.Results showed that the adsorption behaviour of the selected metal ion could be described using Langmuir model.The maximum adsorption capacities of Cr（Ⅵ） ion on ACM were estimated at 55.55mg/g.And pseudo-first-order and pseudo-second-order were employed to interpret the experimental data,results showed that the pseudo-second-order equation was the model that furthered the best fit for the experimental kinetic data,suggesting chemical adsorption as the ratelimiting step of the adsorption mechanism.