论文部分内容阅读
由高能低温煅烧制备了硫酸盐修饰的含钛高炉渣(sulfate-modified titanium-bearing blast furnace slag,STBBFS)吸附剂。用X射线光电子能谱(X-ray photoelectron spectroscopy,XPS)、Fourier转换红外光谱(Fourier transform infrared spectroscopy,FTIR)、X射线衍射和扫描电镜对吸附剂的成分、物相以及表面结构进行了表征。研究了STBBFS的初始质量浓度、溶液pH值、温度对溶液中Cr(Ⅵ)吸附过程的影响。结果表明:Cr(Ⅵ)在STBBFS吸附剂表面上的吸附遵循Langmuir吸附等温线模型;最大吸附容量在pH=1.5时最大,为8.25mg/g。不同吸附温度和初始浓度下,Cr(Ⅵ)的吸附过程都遵循二级吸附动力学模型。通过计算Cr(Ⅵ)吸附过程中的热力学参数:焓变化ΔH°、自由能变化ΔG°、熵变化ΔS°,得出Cr(Ⅵ)吸附至STBBFS吸附剂表面具有自发性,且升高温度易于Cr(Ⅵ)的吸附。根据XPS和FTIR分析结果,可以认为Cr(Ⅵ)先吸附至吸附剂表面,然后被还原为Cr(Ⅲ)。
Sulfate-modified titanium-bearing blast furnace slag (STBBFS) adsorbent was prepared by high-energy low-temperature calcination. The composition, phase and surface structure of the adsorbent were characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction and scanning electron microscopy. The initial concentration of STBBFS, the pH value of solution and the temperature on the adsorption of Cr (Ⅵ) in solution were investigated. The results showed that the adsorption of Cr (Ⅵ) on the surface of STBBFS adsorbent followed the Langmuir adsorption isotherm model. The maximum adsorption capacity of Cr (Ⅵ) was 8.25 mg / g at pH = 1.5. Under different adsorption temperature and initial concentration, the adsorption process of Cr (Ⅵ) follows the second-order adsorption kinetics model. By calculating the thermodynamic parameters of adsorption process of Cr (Ⅵ): enthalpy change ΔH °, free energy change ΔG ° and entropy change ΔS °, it is found that the adsorption of Cr (Ⅵ) on the surface of STBBFS adsorbent is spontaneous, Adsorption of Cr (Ⅵ). According to the results of XPS and FTIR analysis, it is considered that Cr (Ⅵ) adsorbed to the surface of adsorbent and then reduced to Cr (Ⅲ).