丁二酰化香蕉纤维素对Pb^(2+)的吸附性能及其结构表征

Biosorption of Pb^(2+) in Aqueous Solution and Structural Characterization with Succinic Anhydride Modified Banana Fiber

研究了丁二酸酐修饰的香蕉纤维素对水溶液中Pb^(2+)的吸附特性,明确改性香蕉纤维素吸附剂的添加量、溶液pH值、温度及Pb^(2+)初始质量浓度对吸附效果的影响,并探讨吸附过程的动力学特征。结果表明,改性香蕉纤维素对Pb^(2+)吸附的最佳pH值为5.0,单位吸附量随吸附剂添加量的减小、Pb^(2+)初始质量浓度的增加而增加。在优化试验条件下,1 g/L的吸附剂在30℃时,对pH5的50 m L 100 mg/L Pb^(2+)溶液中,单位吸附量达到44.3 mg/g。改性香蕉纤维素对Pb^(2+)的吸附动力学模型符合准二级动力学模型,拟合系数在0.999以上。结合傅里叶红外光谱、扫描电镜-热重分析和X射线衍射分析手段,发现改性香蕉纤维素对Pb^(2+)的吸附以物理吸附为主,同时包括螯合作用、离子交换等化学吸附及颗粒内扩散等过程。

In this study, the adsorption of Pb^2＋from aqueous solution by succinic anhydride modified banana fiber was investigated. The effect of experimental parameters,such as amount of sorbent, p H, temperature, and initial Pb^2＋concentration, as well as adsorption kinetics were also examined. The results showed that the optimum p H of adsorption Pb^2＋by modified banana fiber is 5.0. The unit biosorption capacity increased with the decreasing amount of sorbent and increasing initial Pb^2＋concentration. Under optimized conditions, unit biosorption capacity of 1 g/L sorbent reached 44.3mg/g from 50 m L 100 mg/L Pb^2＋solution at p H 5.0 and 30 ℃. The adsorption kinetics followed the pseudo-second order model and fitting coefficient more than 0.999. Combined with FTIR, SEM, TG and XRD methods, the process of adsorption Pb^2＋on modified banana fiber was found to be dominated by physical adsorption, accompanied with chelation,minor ion exchange and intra-particle diffusion process. The whole adsorption process is more complicated.