【作者】 廖琳；

【导师】 尹光彩； 侯梅芳；

【作者基本信息】 广东工业大学 ， 环境科学， 2012， 硕士

【摘要】 零价铁是一种来源广泛,价格低廉的材料,近年来在染料废水处理中受到越来越多研究者的青睐。本学位论文主要研究了零价铁-水体系还原偶氮染料活性艳红X-3B(X3B)和零价铁-双氧水体系氧化氧杂蒽染料罗丹明B(RhB)的动力学与机理：(1)利用零价铁-水体系还原X3B。研究结果表明,相对于染料亚甲基蓝和罗丹明B,零价铁可有效还原降解X3B。通过分析溶液pH值、零价铁投加量和染料初始浓度对上述过程的影响,发现X3B的降解率随溶液pH的升高而降低；随零价铁投加量的增加而增大；随染料初始浓度的增加而降低。对X3B浓度为80mg·L-1反应的最佳条件为,溶液pH=4.0,零价铁投加量1.0g·L-1。零价铁还原X3B的过程呈准一级反应动力学特点,线性相关系数R2>0.96。利用紫外可见分光光度计、离子色谱等仪器分析了反应中间产物,发现零价铁还原偶氮染料X3B过程中并没有C1-和SO42-的产生,推测其可能的染料去除路径为：偶氮基被零价铁还原生成胺基,大的偶氮染料分子被降解成小分子芳胺。(2)利用零价铁-双氧水体系氧化RhB。研究结果表明,零价铁-双氧水体系可产生强氧化的羟基自由基·OH,在暗态下高效氧化降解RhB。本论文进行了溶液pH、零价铁投加量、双氧水投加浓度和染料初始浓度对上述过程的影响研究。研究发现,RhB的降解率随溶液pH的升高而降低,随零价铁投加量和双氧水浓度的增加呈先升高后降低的变化,随染料初始浓度的增加而降低。对RhB浓度为50mg·L-1反应的最佳条件为,溶液pH=4.0,零价铁投加量1.0g·L-1,双氧水浓度10mmol·L-1。零价铁还原RhB的过程呈准一级反应动力学特点,线性相关系数R2>0.90。利用紫外可见分光光度计、离子色谱、总有机碳仪等分析了中间产物,推测RhB经历了脱乙基、发色基团／芳香环开裂,然后矿化的途径,30min内约70%的RhB被矿化成CO2和H2O。更多还原

【Abstract】 Zero-valent iron (ZVI) technologies for contaminated land and groundwater remediation have attracted much attention in recent years. Due to its low cost and benignity to environment, ZVI has been applied to deal with the reducible inorganic and organic contaminants. In this paper, reactive brilliant red X-3B (X3B) was used as a model pollutant of azo dye to examine the reductive capacity of the ZVI/H2O system. Rhodamine B (RhB) was used as a model pollutant of xanthene dyes to examine the oxidative capacity of the ZVI-based Fenton process with low dose of H2O2and the pH value over4.0was concentrated. The degradation kinetics and mechanism of X3B and RhB were discussed.(I) Degradation of X3B by ZVI in aqueous solution was investigated. The effects of ZVI dosage, initial concentration of X3B and initial pH value on the degradation of X3B were examined. The removal of X3B decreased with the increase of pH value and initial concentration of dye, but increased with the increase of ZVI dosage. The degradation of X3B could be described by the pseudo first-order kinetic model, and linear correlation coefficient R2>0.96. The degradation of80mg·L-1X3B achieved best with1.0g·L-1ZVI at pH4.0.The intermediates of X3B were analyzed with UV-Vis spectrophotometry and ion chromatography and the mechanism of reductive degradation of X3B was also discussed. The ion chromatography analysis showed that there were no Cl-and SO42-produced through ZVI/H2O systems, indicating that chloride ion and sulphonic groups could resist cut off from triazene ring and naphthalene ring, respectively.(Ⅱ) Degradation of RhB by ZVI-based Fenton process with H2O2was investigated. The effects of H2O2concentration, ZVI dosage, and initial concentration of RhB and initial pH value on the degradation of RhB were examined. The removal of RhB decreased with the increase of pH value and initial concentration of dye, but increased with the increase of ZVI dosage and H2O2concentration up to top then decreased. The degradation of RhB could be described by the pseudo first-order kinetic model, and linear correlation coefficient R2>0.90. The optimum degradation condition for50mg·L-1of RhB is pH=4.0with ZVI dosage1.0g·L-1and H2O210mmol·L-1.The results showed that the degradation and mineralization of RhB occurred with low dose of H2O2and ZVI. The intermediates of RhB were analyzed with UV-Vis spectrophotometry and ion chromatography and the mechanism of oxidative degradation of RhB was also discussed. The reactive oxygen species (·OH) produced in ZVI-based Fenton process with H2O2is the key to the degradation of RhB by ways of N-de-ethylation, chromophore cleavage, ring-opening and mineralization. It can be seen that about70%of RhB decomposed into CO2and H2O within30min.更多还原