摘要
Reduction of Cr(VI)using zero-valent iron(ZVI)could not only decrease the amounts of chemicals used for reduction,but also decrease the discharge of sludge.In order to find a desirable ZVI material,reduction of Cr(VI)with a relative high concentration using different kinds of ZVI powders(mainly carbon differences)including reduced Fe,grey cast iron,pig iron,nodular pig iron was carried out.Parameters such as ZVI dosage,type and size affecting on Cr(VI)reduction were firstly examined and grey cast iron was selected as a preferable reducing material,followed by pig iron.Additionally,it was found that the parameters had significant influences on experimental kinetics.Then,morphology and composition of the sample before and after reaction were characterized by SEM,EPMA and XPS analyses to disclose carbon effect on the reducibility.In order to further interpret reaction mechanism,different reaction models were constructed.It was revealed that not only the carbon content could affect the Cr(VI)reduction,but also the carbon structure had an important effect on its reduction.
使用零价铁还原Cr(Ⅵ)不仅可以减少还原剂的用量,还能够减少污泥的排放量。为找到一种理想的零价铁基材料,对不同种类的零价铁粉还原相对高浓度的Cr(Ⅵ)进行研究。这些零价铁粉是还原铁粉、铸铁粉、生铁和球磨生铁,他们的差异性是由碳的不同所致。首先研究了零价铁粉用量、种类和粒度大小等参数对Cr(Ⅵ)还原的影响,筛选出了灰铸铁粉是较为理想的还原性铁基材料,其次是生铁。另外,发现这些参数对试验过程动力学有重要的影响。然后,采用SEM、EPMA和XPS等测试手段,研究了零价铁粉反应前、后形貌和组成的变化,证实了碳差异性对还原性的影响。为进一步理解其反应机理,构筑了不同的反应模型。得出不仅碳的含量对Cr(Ⅵ)还原有影响,碳的结构对Cr(Ⅵ)还原也有重要的影响。
基金
Project(51604131)supported by the National Natural Science Foundation of China
Project(2017FB084)supported by the Yunnan Province Applied Basic Research,China
Project(KKSY201563041)supported by the Talent&Training Program of Yunnan Province,China
Projects(2017T20090159,2018T20150055)supported by the Testing and Analyzing Funds of Kunming University of Science and Technology,China
