离子交换与吸附

利用不同的活化工艺,制备了水蒸汽活化和磷酸或氯化锌活化活性炭纤维,并借助扫描电镜(SEM)、X-射线衍射(XRD)和光电子能谱(XPS)等技术,研究了这些活性炭纤维对铂的还原吸附特征。结果表明,各活性炭纤维均能还原吸附铂离子,吸附容量为30mgPt/gC至90mgPt/gC之间。依据活性炭纤维种类的不同,还原吸附的铂呈粒状或放射性簇状存在于活性炭纤维表面,铂颗粒的粒径为几十nm至1μm之间。对纤维表面铂的XRD分析表明,还原吸附的铂呈无定型结构,但经过400℃高温处理后,颗粒转化为金属铂结晶形态。还原吸附铂后,活性炭纤维表面的含氧基团相应增加,显示其表面被氧化为羟基和羰基。

A number of Activated carbon fibers (ACF) activated with steam, Phosphoric acid, or Zinc Chloride were prepared. Their reduction-adsorption behaviors for Pt (IV) were studied using Scanning Electronic Microscopy (SEM), X-ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS). The results show that Pt (IV) ions in solution can be adsorbed by various ACFs and reduced to metallic platinum, the reduction adsorption capacities of ACF for Pt (IV) are about 30 to 90mg Pt/g C. Platinum adsorbed onto surface of ACF are grainy or clustery particles which depends on the species of ACF used, the particle diameters are around several dozens nm to 1μm. The XRD analysis indicates that the Pt particle on ACF surface is noncrystal; however, it will be turned to crystal while heated to 400 oC. After the reduction-adsorption of Pt (IV), surface carbon of ACF was accordingly oxidized to higher valence oxygen-containing group, such as hydroxyl group and carbonyl groups.