纤维素对Co(Ⅱ)的吸附性能

Adsorptivity About Cobalt Sorptioned to Cellulose

实验采用了静态批式法研究了离子强度、pH值、吸附时间、温度等因素对Co(Ⅱ)在纤维素上吸附性能的影响。结果表明,离子强度和pH对吸附过程有显著影响,在低pH值下,Co(Ⅱ)在纤维素上的吸附主要通过外层络合和离子交换,在高pH值下,主要通过内层络合和表面沉淀。利用Langmuir和Freundlich模型对吸附等温线进行拟合研究,表明Freundlich可以更好的拟合吸附行为。升高温度有利于Co(Ⅱ)在纤维素上的吸附,由热力学数据(ΔH-〇,ΔS-〇和ΔG-〇)计算结果得知,Co(Ⅱ)在纤维素上的吸附是个自发且吸热的过程。

The sorption of cobalt to cellulose was studied by batch technique as a function of various environmental parameters such as ionic strength, pH, contact time, and tempera- ture. The results indicate that the Sorption of Co（ Ⅱ ） on cellulose is strongly dependent on pH and ionic strength. The sorption of Co（ Ⅱ ） is dominated by outer-sphere surface comple- xation and ion exchange at low pH, whereas inner-sphere surface complexation or surface precipitation is the main sorption mechanism at high pH values. The Langmuir and Freundli- ch models were used to simulate the sorption isotherms at three different temperatures of 283.15, 303.15 and 323.15 K. The thermodynamic parameters （△Hθ, △Sθ and △Gθ） calculated from the temperature dependent sorption isotherms indicate that the sorption process of Co（ Ⅱ） on cellulose is spontaneous and endothermic.