O3/H2O2处理嘧啶废水的研究

采用O3/H2O2法对嘧啶废水进行处理,考察了不同反应条件对嘧啶和COD去除率的影响,并对O3/H2O2降解嘧啶的反应机制和动力学进行了初步探讨.实验结果表明,在pH值为11,反应时间为70 min,O3流量为4g/h,H2O2投加量为50 mmol/L的条件下,废水的嘧啶和COD的去除率分别达到86.46%和74.9...     

玉裂废水粘度对二氧化锰臭氧催化氧化处理特性的影响

通过FT-IR和GC—MS检测分析，表明了压裂废水中有机物主要以苯环结构为主的芳香类化合物和其他杂环化合物，苯环及杂环上的主要官能团包括酮、酯、羧酸、醛、酚、氨基等。同时，压裂废水中的粘度为常规水粘度的2～3倍。针对压裂废水高粘度和高COD污染水质特征，实验研究了压裂废水二氧化锰臭氧催化氧化处理特性以及粘度对处理效果的影响，研究结果表明，在粘度较高（2．2×10-3 Pa·s）压裂废水中，投加的化学药剂很难扩散，羟基自由基·OH的利用效率较低，处理效果较差。通过投加过硫酸钾（5g／L）降粘后，可在很大程度上提高二氧化锰臭氧催化氧化的处理效果。通过对压裂废水中有机物分子量分布、FT-IR分析以及GC—MS分析可知，二氧化锰臭氧催化氧化处理压裂废水是通过激发羟基自由基，破坏水中有机物极性和有机物化学构造，将复杂长链有机物转变为简单有机物，其出水COD可达到国家污水综合排放标准中的二级排放标准。     

pH dependence of persulfate activation by EDTA/Fe(III) for degradation of trichloroethylene

The ability of free ferrous ion activated persulfate (S₂O₈²⁻) to generate sulfate radicals (SO₄^{−radical dot" title="radical dot" border="0">}) for the oxidation of trichloroethylene (TCE) is limited by the scavenging of SO₄^{−radical dot" title="radical dot" border="0">} with excess Fe²⁺ and a quick conversion of Fe²⁺ to Fe³⁺. This study investigated the applicability of ethylene-diamine-tetra-acetic acid (EDTA) chelated Fe³⁺ in activating persulfate for the destruction of TCE in aqueous phase under pH 3, 7 and 10. Fe³⁺ and EDTA alone did not appreciably degrade persulfate. The presence of TCE in the EDTA/Fe³⁺ activated persulfate system can induce faster persulfate and EDTA degradation due to iron recycling to activate persulfate under a higher pH condition. Increasing the pH leads to increases in pseudo-first-order-rate constants for TCE, S₂O₈²⁻ and EDTA degradations, and Cl generation. Accordingly, the experiments at pH 10 with different EDTA/Fe³⁺ molar ratios indicated that a 1/1 ratio resulted in a remarkably higher degradation rate at the early stage of reaction as compared to results by other ratios. Higher persulfate dosage under the EDTA/Fe³⁺ molar ratio of 1/1 resulted in greater TCE degradation rates. However, increases in persulfate concentration may also lead to an increase in the rate of persulfate consumption.     

铈离子光催化降解茜素绿的性能和机理

主要研究了简单铈离子（Ce3＋）在紫外光（uv）的作用下对蒽醌染料茜素绿（AG）的光催化降解效果和反应机理。结果表明，UV／Ce3＋体系能够有效降解AG，初始反应速率随AG浓度的倒数值和Ce3＋浓度的增加而线性增加，随初始溶液pH的增加先降低后增加，在酸性条件下有很高的TOC去除率。荧光探针实验表明，反应过程中可以产生·OH自由基。UV／Ce3＋体系对其他类型染料和对硝基苯酚都有较好的降解效果。     

活性炭-臭氧体系处理含氰废水的作用机理

针对活性炭催化臭氧化降解低质量浓度含氰废水体系,研究了活性炭吸附、催化作用在催化臭氧化体系中的作用,提出了吸附-催化臭氧化协同作用机理。在活性炭-臭氧体系中,活性炭吸附CN-的能力很弱,活性炭在反应体系中主要起了吸附、催化臭氧的作用。活性炭-臭氧体系降解CN-的过程是臭氧直接氧化、活性炭吸附臭氧与活性炭催化臭氧产生.OH自由基间接氧化三者共同作用的结果。     

压裂废水粘度对二氧化锰臭氧催化氧化处理特性的影响

通过FT-IR和GC-MS检测分析,表明了压裂废水中有机物主要以苯环结构为主的芳香类化合物和其他杂环化合物,苯环及杂环上的主要官能团包括酮、酯、羧酸、醛、酚、氨基等。同时,压裂废水中的粘度为常规水粘度的2~3倍。针对压裂废水高粘度和高COD污染水质特征,实验研究了压裂废水二氧化锰臭氧催化氧化处理特性以及粘度对处理效果的影响,研究结果表明,在粘度较高(2.2×10^-3Pa·s)压裂废水中,投加的化学药剂很难扩散,羟基自由基·OH的利用效率较低,处理效果较差。通过投加过硫酸钾(5 g/L)降粘后,可在很大程度上提高二氧化锰臭氧催化氧化的处理效果。通过对压裂废水中有机物分子量分布、FT-IR分析以及GC-MS分析可知,二氧化锰臭氧催化氧化处理压裂废水是通过激发羟基自由基,破坏水中有机物极性和有机物化学构造,将复杂长链有机物转变为简单有机物,其出水COD可达到国家污水综合排放标准中的二级排放标准。     

碳纳米管负载纳米四氧化三铁多相类芬顿降解亚甲基蓝

在课题组前期研究的基础上,以碳纳米管(MWCNTs)为载体制备了Fe3O4/MWCNTs复合物并作为催化剂,以染料亚甲基蓝(MB)为降解对象,研究了该催化剂催化H2O2对亚甲基蓝溶液的降解特性及其影响因素,并考察了催化剂的重复使用效果,探讨了催化反应的机理.结果表明,在pH值3~8的范围内,催化反应体系都能有效降解MB,最佳pH值为3.5.随着催化剂投量的增加,MB的降解率明显提高,500 mg·L-1催化剂投量条件下,MB的降解率最高.随着H2O2初始浓度的增加,MB的降解率增加,10 mmol·L-1时MB的降解率最高.溶液中共存的阴离子会降低MB的降解率.在最佳条件,即温度25℃、H2O2浓度10 mmol·L-1、催化剂浓度500 mg·L-1的条件下,0.20 mmol·L-1MB在30 min内的降解率达到99.1%.催化剂重复使用后仍然具有较好的催化活性,说明Fe3O4在MWCNTs表面负载比较牢固,催化剂具有反复使用的能力.催化反应机理是催化剂催化H2O2产生羟基自由基,高活性的羟基自由基氧化MB.     

Heterogeneous Fenton-like degradation of 4-chlorophenol using iron/ordered mesoporous carbon catalyst

Ordered mesoporous carbon supported iron catalysts(Fe/OMC) were prepared by the incipient wetness impregnation method and investigated in Fenton-like degradation of 4-chlorophenol(4CP) in this work. XRD and TEM characterization showed that the iron oxides were well dispersed on the OMC support and grew bigger with the increasing calcination temperature. The catalyst prepared with a lower calcination temperature showed higher decomposition efficiency towards 4CP and H2O2, but more metals were leached. The effect of different operational parameters such as initial pH, H2O2 dosage, and reaction temperature on the catalytic activity was evaluated. The results showed that 96.1% of 4CP and 47.4% of TOC was removed after 270 min at 30°C, initial pH of 3 and 6.6 mmol/L H2O2. 88% of 4CP removal efficiency was retained after three successive runs, indicating Fe/OMC a stable catalyst for Fenton reaction. 4CP was degraded predominately by the attack of hydroxyl radical formed on the catalyst surface and in the bulk solution due to iron leaching. Based on the degradation intermediates detected by high performance liquid chromatography, possible oxidation pathways were proposed during the 4CP degradation.