皂化麦麸对锌的吸附性能

Saponification of Wheat Bran on the Adsorption of Zinc

以麦麸制备生物吸附剂研究其对重金属Zn2+的吸附作用。利用DPS软件进行回归正交试验,分析pH、麦麸生物吸附剂加入量、温度、初始Zn2+浓度和吸附时间对吸附率影响,得出最佳吸附条件,与活性炭、麦麸纤维吸附效果作比较,对皂化麦麸进行解吸;同时研究等温吸附和吸附动力学,电镜和傅立叶红外光谱图研究吸附机理。吸附时间3 h、加入量0.2 g、pH值9、70℃、Zn2+溶液浓度为80 mg/L时,吸附率达最大值,且低浓度时,麦麸生物吸附剂吸附效果优于活性炭与麦麸纤维,至少可以进行四次重复利用。麦麸生物吸附剂对Zn2+吸附符合Freundich等温式,更适合拟二级动力学模型,即符合多分子层多位点物理化学混合吸附。SEM知皂化麦麸有明显褶皱,疏松多孔,表面积增大;FTIR分析出,麦麸生物吸附剂含-OH、-NH-、-C≡C-、-C≡N等多个官能团,对吸附过程起到很大的作用。

The adsorption of heavy metal Zn2+ by wheat bran was studied. DPS software was used for regression orthogonal test to analyze the influence of pH, the amount of wheat bran biosorbent, temperature, the initial concentration of Zn2+ and the adsorption time on the adsorption rate. The optimal adsorption conditions were obtained, and the saponification of wheat bran was desorbed by comparing the adsorption effect with activated carbon and wheat bran fiber. Isothermal adsorption and adsorption kinetics, electron microscopy and Fourier infrared spectroscopy were also studied. For the amount of adsorption time is 3 h, 0.2 g, pH9, 70℃, Zn2+ solution concentration of 80 mg/L, maximum adsorption rate, and low concentration, wheat bran biological adsorbent adsorption effect is better than activated carbon and wheat bran fiber, can be reused four times at least. The adsorption of Zn2+by wheat bran biosorbent conforms to Freundich isothermal formula and is more suitable for the quasi-secondary kinetic model, that is, it conforms to the multi-molecular layer and multi-site physicochemical mixed adsorption. SEM showed that saponified wheat bran had obvious folds, porosity and surface area increase.FTIR analysis showed that wheat bran biosorbent contains multiple functional groups, such as -OH,-NH-,-C≡C-,-C≡N, which play an significant role in the adsorption process.