摘要
Electrochemical oxidation of aniline in aqueous solution was investigated over a novel Ti/TiOxHy/Sb-SnO2 electrode prepared by the electrodeposition method.Scanning electron microscopy,X-ray diffraction,and electrochemical measurements were used to characterize its morphology,crystal structure,and electrochemical properties.Removal of aniline by the Ti/TiOxHy/Sb-SnO2electrode was investigated by ultraviolet-Visible spectroscopy and chemical oxygen demand（COD）analysis under different conditions,including current densities,initial concentrations of aniline,pH values,concentrations of chloride ions,and types of reactor.It was found that a higher current density,a lower initial concentration of aniline,an acidic solution,the presence of chloride ions（0.2wt%NaCl）,and a three-dimensional（3D） reactor promoted the removal efficiency of aniline.Electrochemical degradation of aniline followed pseudo-first-order kinetics.The aniline（200 mL of 100mg·L-（-1）） and COD removal efficiencies reached 100%and 73.5%,respectively,at a current density of 20 mA·cm-（-2）,pH of 7.0,and supporting electrolyte of 0.5 wt%Na2SO4 after 2 h electrolysis in a 3D reactor.These results show that aniline can be significantly removed on the Ti/TiOxHy/Sb-SnO2electrode,which provides an efficient way for elimination of aniline from aqueous solution.
苯胺是一种重要的化工原料,广泛应用于印染、制药、造纸、橡胶等领域.随着化工行业的迅速发展,苯胺的需求量越来越大.然而,苯胺毒性高,大量使用势必造成水体中苯胺浓度的升高,给人类健康及生态环境造成危害.因此,急需一种高效、洁净、经济的方法处理含苯胺废水.电化学氧化法比较新颖,相比传统废水处理方法,它具有高效、简单、清洁等优点,因此被应用于很多废水处理当中,但过多的能耗限制了其进一步广泛应用.阳极作为电化学氧化技术的核心部件,直接影响到电化学氧化反应性能.因此开发出一种高效、经济的阳极材料很有必要.此外,对苯胺降解条件的优化也同样重要.关于苯胺电化学氧化,已有的研究包括Pt电极、PbO_2电极和石墨电极等阳极材料.比较而言,Ti/Sb-SnO_2电极具有制备工艺简单,析氧过电位较高,材料廉价和电催化性能较强等优点.然而,它的稳定性仍有待提高.因此本文制备了一种高稳定性的Ti/TiO_xH_y/Sb-SnO_2电极,并用于处理苯胺废水.较为系统地研究了电流密度、苯胺初始浓度、pH、NaCl投加量及反应器类型对苯胺电催化氧化性能的影响,同时采用扫描电镜(SEM)、X射线衍射(XRD)和电化学测试对该电极进行了表征,并应用紫外-可见光谱、化学需氧量、电流效率及能耗对不同参数进行评定和优化.SEM及XRD结果表明,Ti/TiO_xH_y/Sb-SnO_2电极涂层覆盖比较完全、紧实,未出现裂缝的发生,因而有利于提高电极稳定性.循环伏安测试结果表明,此电极具备较高的析氧过电位(2.0 V vs Ag/AgCl)及电化学孔隙度(76.31%),因此有利于电极催化性能的提高.苯胺电化学氧化实验结果发现,该反应符合准一级动力学模型,且高电流密度、酸性环境、适当NaCl投加量(0.2 wt%)更有利于苯胺的降解.另外,Ti/TiO_xH_y/Sb-SnO_2电极在三维反应器中对苯胺的处理效果要远远好于在二维反应器中.可以看出,Ti/TiO_xH_y/Sb-SnO_2电极具有较好的处理苯胺性能,可为苯胺废水处理的应用提供了一定的理论指导.
基金
supported by the National Natural Science Foundation of China(21507104)
the Fundamental Research Funds for the Central Universities of China
