【作者】 董娟；

【导师】 汪永辉；

【作者基本信息】 东华大学 ， 环境工程， 2007， 硕士

【摘要】 针对高铁酸钾制备条件严苛、稳定性差，对高铁酸钾的制备和稳定性进行研究，并将高铁酸钾用于有机废水处理。通过次氯酸盐氧化法制备高铁酸钾的工艺，探讨了次氯酸盐浓度、铁盐投加量、反应温度、反应时间、后续处理工艺等对高铁酸钾纯度、产率的影响。在水浴条件下，控制反应时间为1小时，当初始ClO^-浓度为137.3g／L，铁盐投加量为化学计量的30％，可得到纯度为96.4％、产率为45.3％的高铁酸钾固体。后续纯化工艺如二次提纯氢氧化钾浓度、析出温度、洗涤溶剂等对高铁酸钾纯度和产率均有影响。用XRD、FIRT和SEM对制备产品进行了表征分析，证明产物为高铁酸钾晶体。改进了亚铬酸盐滴定法测定高铁酸钾。用紫外分光光度法在最大吸收波长为510nm处测定高铁酸钾浓度。初步研究了高铁酸钾母液中KOH、KCl、KNO₃、Fe（NO₃）₃、KClO等杂质及外加掺杂离子对高铁酸钾溶液稳定性的影响，为高铁酸钾稳定剂的筛选奠定基础。结果表明碱度越高，高铁酸钾溶液稳定性越强，KCl、KNO₃使高铁酸钾溶液稳定性略有降低，KClO对高铁酸钾溶液具有强稳定性，三价铁盐的存在能促进高铁酸钾溶液的快速分解。KIO₄、NaSiO₃、CuCl₂对高铁酸钾溶液具有稳定作用；NaSiO₃和KIO₄组成的稳定剂对高铁酸钾溶液稳定作用最强，KIO₄与NaSiO₃、KClO、CuCl₂等配合在减缓高铁酸钾分解中无明显协同作用；硅酸钠和氯化铜组成的复合稳定剂对高铁酸钾溶液的稳定作用不如次氯酸钾明显。硝基苯初始浓度为55.04mg／L，pH=9.0时，反应时间为30min，高铁酸钾（摩尔比为10：1）对硝基苯和CODcr的去除率分别可达到85％和55％左右；改变反应过程pH值，硝基苯和CODcr的去除率均有提高，硝基苯去除率可达98.2％，CODcr去除率可达91.9％；通过紫外光谱、红外光谱、色质联机分析，发现硝基苯降解过程没有难降解中间产物产生，最终硝基苯被降解为一系列脂环烃，对高铁酸钾降解硝基苯机理进行初步探讨；经过经济核算，高铁酸钾处理硝基苯价格昂贵，宜与其他水处理剂联用，以达到低成本、高去除率的处理效果。苯胺初始浓度为62.04mg／L，pH=9.0时，反应时间为20min，高铁酸钾（摩尔比为1：1）对苯胺和CODcr的去除率分别为91.03％和56.14％；改变反应过程pH值，苯胺去除率变化较小，CODcr去除率可达94.8％；通过紫外光谱、红外光谱、色质联机分析，发现苯胺降解过程有中间产物偶氮苯产生，苯胺最终被降解为链状脂环烃分子，对高铁酸钾降解苯胺机理进行初步探讨；经过经济核算，每处理1吨苯胺废水需费用19.99元。更多还原

【Abstract】 The preparation and stability of potassium ferrate is studied, as its harsh preparing condition、terrible stability. Potassium ferrate is used to dispose organic wastewater.The influence of hypochlorite concentration、ferric salt dose, reaction temperature、reaction time、follow up depuration processes etc. on yield and purity of potassium ferrate is studied by hypochlorite oxidation method. Potassium ferrate with purity of 96.4%, yield 45.3% is prepared, when initial hypochlorite concentration is 137.3g/L, reaction time is 1 hour and ferric dose is as 30% as stoichiometric in water bath. Follow up depuration processes such as concentration of KOH in 2nd depuration、separating out time、washing solvent etc. also produce an effect on the purity and yield of potassium ferrate. The sample is characterized by XRD、FIRT and SEM. Results show that product is potassium ferrate crystal. Determination of potassium ferrate by redox titration based on the oxidation of chromate is improved. The maximum absorption wavelength is 510nm, when concentration of potassium ferrate solution is determined by ultraviolet spectrophotometry.Potassium ferrate solution containing KOH, KCl, KNO₃, Fe（NO₃）₃、KClO and additional ions are used to investigate the effect of the coexisting ions on the ferrate stability which lays the foundation of screening stabilizer for potassium ferrate. It is found that the stability of ferrate（Ⅵ） solution increases with increasing alkalinity, KCl, KNO₃ have a little effect on the stability of ferrate（Ⅵ）, hypochlorite retards the ferrate decomposition significantly, but potassium ferrate decomposes more rapidly with the coexisting ion of ferric. The stability of potassium ferrate can be increased when KIO₄、NaSiO₃, CuCl₂ are added respectively. Stabilizer composed of KIO₄ and NaSiO₃ plays the greatest part in the stability of potassium ferrate solution. KIO₄ has no collective effect on retarding the ferrate decomposition with NaSiO₃、KClO or CuCl₂. Influence of stabilizer which is made up of NaSiO₃ and CuCl₂ is not apparent as KClO on stability of potassium ferrate.When the initial concentration of nitrobenzene is 55.04 mg/L, pH= 9.0, controlling reaction time as 30min, the removing efficiency of potassium ferrate to nitrobenzene （mole ratio is 10:1） can attain to probably 85% and 55%. Changing pH in reaction, the removing efficiency of nitrobenzene and CODcr both come up to a fairly level, the former reach to 98.2%, the latter to 91.9%. Degradation solution is analyzed by ultraviolet spectrum, FIRT, GC/MS Spectrum etc.. The results show that no refractory material is generated during nitrobenzene’s degradation, aliphatic hydrocarbon is its terminal product. Mechanism of nitrobenzene degradation is preliminarily investigated. In order to achieve the goal of low-cost, high-removing efficiency, it’s better to apply potassium ferrate with other water treatment agents in nitrobenzene wastewater treatment, as its high disposing expenditure.When the initial concentration of aniline is 62.04 mg/L, pH=9.0, controlling reaction time as 20min, the removing efficiency of potassium ferrate to aniline （mole ratio is 1:1） can attain to 91.03% and 56.14% respectively. Changing pH in reaction, has little influence on the removing efficiency of aniline, but removing efficiency of CODcr come up to 94.8%. Degradation solution is analyzed by ultraviolet spectrum、FIRT、GC/MS Spectrum etc.. The results show that Azobenzene is generated as intermediate product during aniline’s degradation. Finally, aniline is decomposed into aliphatic hydrocarbon. Mechanism of aniline degradation is also discussed. The cost of 1 ton aniline wastewater treatment is 19.99 yuan.Dong Juan（Environmental Engineering）Supervised by Vice Professor Wang Yonghui更多还原