仿生FeS复合材料的制备及其对Cr(Ⅵ)的吸附性能

Preparation and its Cr(Ⅵ)adsorption properties of biomimetic FeS composites

纳米FeS比表面积大且还原性强,对Cr(Ⅵ)吸附性能优异,但不稳定、易团聚,为解决这一问题,本文以油菜花粉为生物模板,通过共沉淀-焙烧法制得仿生FeS复合材料(bioFeS)。通过SEM、XRD及XPS等方法对bioFeS复合材料的表面微观形态和结构进行了表征。以Cr(Ⅵ)为目标污染物,分别考察了吸附剂用量、反应时间、反应温度、初始Cr(Ⅵ)浓度和pH对bioFeS复合材料吸附Cr(Ⅵ)性能的影响,探究了反应机制。结果表明:油菜花粉生物模板成功分散了FeS,制得的bioFeS复合材料比表面积大,在反应时间为120 min、pH值为1、吸附剂投加量为0.2 g·L^(-1)、反应温度为25℃的条件下,bioFeS复合材料对Cr(Ⅵ)的吸附量可达88.95 mg·g^(-1);该吸附过程符合准二级动力学和Langmuir等温吸附模型;共存离子NO_(3)^(-)和SO_(4)^(2-)会抑制Cr(Ⅵ)的去除。结合吸附动力学、热力学及XPS表面元素分析可知bioFeS复合材料除铬机制主要是吸附及化学还原作用。bioFeS复合材料处理含铬废水具有广阔的应用前景。

Nano FeS has excellent adsorption performance for Cr(Ⅵ)because of large specific surface area and strong reducibility,but it is unstable and prone to agglomeration.In order to overcome these disadvantages,the biomimetic FeS composites(bioFeS)were prepared by co-precipitation-roasting method using rape pollen as a biological template.The surface morphology and structure of bioFeS composites were characterized by SEM,XRD and XPS.The effects of adsorbent dosage,reaction time,reaction temperature,initial Cr(Ⅵ)concentration and pH on adsorption capacity of Cr(Ⅵ)on bioFeS composites were studied to investigate the reaction mechanism using Cr(Ⅵ)as the target pollutant.The results show that rape pollen biotemplate successfully disperse FeS with a large specific surface area.The adsorption capacity of Cr(Ⅵ)on bioFeS composites can reach 88.95 mg·g^(-1)at a reaction time of 120 min,pH of 1,adsorbent dosing of 0.2 g·L^(-1)and a reaction temperature of 25℃.The adsorption process conforms to quasi-secondary kinetics and the Langmuir isothermal adsorption model.The coexisting ions NO_(3)^(-)and SO_(4)^(2-)will inhibit the adsorption capacity of Cr(Ⅵ).Combining with adsorption kinetics,thermodynamics and XPS surface element analysis,the mechanism of chromium removal by bioFeS composites mainly involves adsorption and chemical reduction.The method of removal of Cr(Ⅵ)in wastewater by bioFeS composites has a promising application.