氧化石墨烯改性淀粉复合吸附剂的制备及对Cu^(2+)、Pb^(2+)的吸附性能

Preparation of graphene oxide modified starch and its adsorption performance of Cu^(2+) and Pb^(2+)

采用改进Hummers法制备了氧化石墨烯,再与淀粉进行反应制得了氧化石墨烯改性淀粉复合吸附剂(GO-Starch)。利用红外光谱、X射线衍射、扫描电镜等技术手段对GO-Starch的结构和官能团进行表征,研究GO-Starch对水中Cu^(2+)、Pb^(2+)吸附性能,探讨吸附时间、温度、吸附剂用量、初始浓度、pH等因素对吸附率的影响。结果表明:(1)在30℃、pH为5、Cu^(2+)初始质量浓度为40mg/L的条件下,GO-Starch对Cu^(2+)的吸附在90min达到吸附平衡。在30℃、pH为4、Pb^(2+)初始质量浓度为20mg/L的条件下,GO-Starch对Pb^(2+)的吸附在120min达到吸附平衡。(2)GO-Starch对Cu^(2+)的吸附符合Langmuir等温吸附模型,对Pb^(2+)的吸附符合Freundlich等温吸附模型;对Cu^(2+)、Pb^(2+)的吸附动力学特性均符合准二级动力学模型。

Graphene oxide,prepared by modified Hummers method and ultrasonic exfoliation,was chemically combined with starch basic solution.Characterization of the complex adsorbent was performed using various techniques,such as FT-IR,XRD and SEM analysis.The adsorption of the complex adsorbent on Cu^2+and Pb^2+under different adsorption time,temperature,dosing quantity,initial concentration and pH was investigated.The results showed that:(1)Cu^2+adsorption equilibrium was reached in90minutes under the condition of30℃,pH=5and initial concentration of40mg/L.The adsorption equilibrium of Pb^2+could reached in120minutes when the temperature was30℃at pH=4and the initial concentration was20mg/L.(2)The process of adsorbing Cu^2+fitted Langmuir isotherm model and the process of adsorbing Pb^2+fitted Freundlich isotherm model.Two processes were both well described by second-order kinetic model.