离子交换与吸附

本文采用6种分别属于褐藻门、绿藻门、红藻门的海边常见大型海藻对重金属镉离子进行吸附比较实验,镉离子浓度较低时,其吸附容量排列顺序为:海黍子>海带>孔石莼>节荚藻>刺松藻>内枝藻,海黍子的吸附量高达181mg/g,超出文献报道值,对3种吸附容量较高的海藻进行了较详细的研究,研究溶液的pH值、初始Cd2+ 离子浓度等因素对Cd2+ 的吸附特性的影响,对吸附机理进行了初步的探讨,发现镉离子与海藻中的钙离子发生离子交换作用,交换率占总吸附量的33~34%。得出了适宜的吸附等温线方程。

Six marine algae such as Sargassum kjellmanum, Laminaris japonica, Codium fragile, Ulva pertusa, Lomentaria hakodatensis and Entocladia wittrockii as biosorbents were investigated under the following experimental conditions: pretreatment, pH, initial cadmium concentration. Among them, Sargassum kjellmanum, Laminaris japonica and Ulva pertusa have relatively high adsorption capacity of 181mg/g, 124.7 mg/g, 143.3 mg/g, respectively. pH value has different effects on those three algae. Results demonstrate the existence of ion exchange between Ca2+ in algae and Cd2+ in solution and the uptake ratio produced by ion exchange between Ca2+ and Cd2+ is about 33-34% of total Cd2+ uptake. Freundlich equation has modeled the adsorption processes by Sargassum kjellmanum and by Ulva pertusa well, Dubimim-Radushkevich equation fits the adsorption process by Laminaris japonica well.