分光光度计法测定硝基苯电解还原液

重点介绍了以Berthelot试剂为显色剂的分光光度法来测定硝基苯电解还原液中氨基苯酚的含量。并考察了显色时间、吸光波长对吸光度的影响,并讨论了硝基苯、苯胺及待测液的pH值对测定结果的影响。结果表明,以Berthelot试剂为显色剂的分光光度法测定精度高且快速,显色时间10 m in以上就可以使溶液显色充分且吸光度在633 nm具有最大值,硝基苯、苯胺及待测液的pH值对测定结果无影响。     

铁炭微电解法对处理含盐硝基苯废水的实验研究

对不同的盐分在铁炭微电解降解硝基苯过程中的作用机理进行了研究。在铁炭微电解的条件下,以硝基苯为研究对象,选择盐分为参数,在降解过程中,一定时间下取样检测浓度,并计算硝基苯降解率。铜离子、氯离子能促进硝基苯的去除;钙离子对硝基苯的去除率无明显作用;六价铬离子和磷酸根离子对硝基苯的去除有抑制作用;低浓度的硫酸根离子可促进硝基苯的降解,高浓度的硫酸根离子则会减弱对硝基苯降解的促进作用。铁炭微电解过程中盐分对硝基苯的降解率影响很大。     

催化铁内电解法预处理硝基苯废水

在传统的铁炭内电解反应器中加入铜,对硝基苯废水进行预处理,可以使废水中的硝基苯转化为苯胺,从而提高废水的可生化性。结果表明,在中性和弱碱性条件下,催化铁内电解法对硝基苯废水的处理效果明显优于铁屑内电解法。本文还研究了催化内电解法的影响因素。     

2,2''''-二氯氢化偶氮苯电合成工艺的研究

采用电解还原法还原邻氯硝基苯,得到产物2,2'-二氯氢化偶氮苯,讨论了电解液浓度、催化剂、电流密度、电解液温度等因素对电解还原反应的影响。     

铁碳微电解处理含硝基苯废水

以硝基苯为模型污染物,研究了铁碳微电解过程中硝基苯初始浓度、铁屑用量、铁碳比及pH(pH<3.0)等因素对降解过程的影响规律。研究结果表明,硝基苯废水初始浓度越大,达到一定去除率时所需的铁屑用量越大。外加活性炭会与降解底物竞争电子,导致电子利用率不高,微电解的还原效率并没有因此提高。低pH可以加速铁碳微电解处理速率,反应过程中pH的升高对硝基苯还原中间产物羟基苯胺和苯胺的形成及分布影响较大,有限停留时间内主要还原产物是二者的混合物。     

电Fenton法降解硝基苯废水的研究

实验使用钛基二氧化铅电极为阳极，泡沫镍作阴极对模拟硝基苯废水，研究了不同因素对硝基苯去除率的影响。并通过单因素实验分析确定了最佳反应条件：硝基苯浓度为123mg／L，辅助电介质Na2S04浓度为7．5g／L，FeS04浓度为0．45g/L．电解电压为18V，电解时间为80min，极板间距为4cm。在此条件下去除率可达到90％。     

硝基苯在发泡铜阴极上电还原为对氨基苯酚研究

研究了以发泡铜为阴极材料 ,硝基苯电解还原制备对氨基苯酚。考察了反应物浓度、介质酸度、电解温度、电解电流、电极尺寸等因素对对氨基苯酚产率的影响。在 80℃ ,硫酸介质体积分数为 2 0 % ,硝基苯在体积分数为 2 0 %正丁醇水溶液中的浓度 1 .8mol L ,通氮气 75mL min ,电解电流 4A条件下 ,电解 2h ,对氨基苯酚的产率达到 93%以上 ,电流效率高于 92 %。     

工业废水中苯胺、硝基苯含量的测定

用混合萃取液萃取水质样品中的微量硝基苯、苯胺,经安捷伦7890A气相色谱毛细柱/FID测定水样中的硝基苯、苯胺含量,以保留时间定性,峰面积定量。并探讨了测定过程的影响因素。     

铁碳微电解预处理硝基苯废水工艺研究进展

铁碳微电解是一种高效、廉价的废水预处理技术,反应过程主要包括氧化还原、电富集、物理吸附和混凝沉降等。本文介绍了其预处理硝基苯废水的研究进展,对铁碳微电解预处理硝基苯废水的工艺影响因素进行了总结和分析,得出最适宜p H值为2~3之间,铁/碳剂质量比为(2∶1)~(1∶1)之间,铁类型为工业废铁,溶解氧具有抑制作用;并对对反应机理研究进行介绍。最后对铁碳微电解技术未来研究重点作了展望。     

2，2′-二氯氢化偶氮苯电合成工艺的研究

采用电解还原法还原邻氯硝基苯，得到产物2，2′-二氯氢化偶氮苯，讨论了电解液浓度、催化剂、电流密度、电解液温度等因素对电解还原反应的影响。     

Study of the hypophosphite effect on the electrochemical reduction of nitrobenzene on Ni

The effect of the hypophosphite ion on the electrochemical reduction of nitrobenzene on Ni was evaluated from a cyclic voltammetric study and from constant potential electrolysis in an aqueous-ethanol alkaline medium. The results were compared with the data obtained in an hypophosphite-free solution. It was found that in an hypophosphite containing solution an unusual selective reduction of nitrobenzene to nitrosobenzene occurs. It is the first time that nitrosobenzene is detected as the reaction product of the nitrobenzene electrochemical reduction in an aqueous-ethanol solution. It is proposed that the Ni modified surface which is formed upon hypophosphite oxidation is responsible for the non reducibility of nitrosobenzene. The effect of the electrode potential on the nitrobenzene electrolysis on a Ni modified electrode was analysed. It was concluded that the highest nitrosobenzene yield (33%) and selectivity (82%) is achieved at −1.1 V. It was also found that the formation of nitrosobenzene leads to an electrode poisoning effect in the electrolysis process.     

高铁酸盐的制备及对硝基苯的氧化作用

采用双阴极室隔膜电解槽,以平板灰口铸铁为阳极,用电解法现场制备高铁酸盐,电解150min,得到27.1mmol/L的FeO42+。并以其氧化降解硝基苯模拟废水,结果表明,在pH值为7,高铁酸盐与硝基苯的质量比约为15时,硝基苯的去除率达98.3%,CODCr的去除率达92%以上。高铁酸盐与硝基苯的反应符合一级动力学规律。     

The effect of electrolytic oxidation on the electrochemical properties of multi-walled carbon nanotubes

Multi-walled carbon nanotubes (MWNTs) were electrochemically oxidized by a constant-potential electrolysis method and then investigated in detail using scanning electron microscope, transmission electron microscope, FT-IR, electrical impedance spectroscopy, and cyclic voltammetry. The FT-IR spectra showed that the amount of hydroxyl generated on the surface of MWNTs increased with increasing the electrochemical oxidation time of MWNTs. The CV results, being conducted in nitrobenzene solution, showed that the nitrobenzene reduction current increased with the increase in oxidation time of the MWNTs within the first 60 min of electrolysis. An electrical equivalent circuit model for electrical impedance spectroscopy was further established to analyze the surface capacitance and resistance of the MWNTs, and the model results showed that the capacitance of the oxidized MWNTs increased greatly while the charge transfer resistance decreased, suggesting electrochemical oxidized MWNTs modified pyrolytic carbon electrode being an effective electrochemical sensor for nitrobenzene determination.     

微电解与催化氧化法预处理二硝基苯废水的试验研究

二硝基苯生产废水具有硝基苯类化合物浓度高,盐量高,难降解等特点。CODCr的平均浓度为10 000 mg/L,含盐量达30 g/L。本研究采用微电解与催化氧化法对该废水进行处理。结果表明:微电解处理后硝基苯类物质的去除率可达90%以上,但CODCr的去除率较低,只有30%~50%;催化氧化处理后废水的CODCr去除率可达90%以上,但所需Fenton试剂量大,处理成本偏高;采用微电解-催化氧化法处理后CODCr去除率可达95%,硝基苯类物质、on试剂消耗量小,处理成本低。     

铁碳内电解-SBR生化法处理硝基苯废水试验与研究

铁碳在水中发生的内电解过程可有效去除硝基苯废水的色度 ,提高污水的可生化性 ,并对CODCr具有良好的去除效果。试验结果表明 :进水CODCr为 34 0 0mg/L的硝基苯废水 ,经内电解法预处理后 ,脱色率可达 75 %,CODCr去除率也可达 6 0 %左右 ;后续处理采用SBR工艺 ,其去除CODCr效果较好 ,处理后的出水水质可达到国家有关标准排放要求的指标。     

Electroreduction of nitrobenzene to p-aminophenol using voltammetric and semipilot scale preparative electrolysis techniques

This paper describes an investigation of the reduction of nitrobenzene to p-aminophenol by the use of CV, RDE and preparative electrolysis with Cu and Cu(Hg) electrodes. The preparative electrolyses of nitrobenzene were carried out at controlled current and controlled potential conditions using copper and amalgamated copper using a new semipilot (laboratory) scale system in the absence of an organic cosolvent. The effects of redox reagents and the concentration of nitrobenzene in catholyte added to the medium were also examined. The best results were obtained with 2.3% BiCl₃ at nitrobenzene concentration of 0.144 g cm^–3 catholyte. The most suitable electrode material was found to be amalgamated copper and the reduction of nitrobenzene to p-aminophenol was found to follow an ECE mechanism.     

硝基苯在离子液体BPyBF4/H2O中的电化学行为

在离子液体1-丁基吡啶四氟硼酸盐(BPyBF₄)的水溶液中,采用循环伏安法(CV)、计时电流法(CA)、恒电位电解及原位红外光谱法(in-situ FTIRS)等研究了硝基苯在铂电极上的电化学还原行为。研究结果表明:硝基苯在离子液体BPyBF₄/H₂O体系中的还原过程是受扩散控制的,其还原产物主要是偶氮苯,经估算得到硝基苯在该体系中的扩散系数为3.1×10^-7 cm²·s^-1,提高温度和加入一定浓度的水均有利于硝基苯在该体系中的电化学还原。