Treatment of naphthalene derivatives with iron-carbon micro-electrolysis

The degradation of five naphthalene derivatives in the simulated wastewater was investigated using the iron-carbon micro-electrolysis method.The optimal initial pH of solution and adsorption of iron-carbon and removal efficiency of the total organic carbon(TOC)were investigated.The results show that the removal efficiency of the naphthalene derivatives can reach 48.9%?92.6% and the removal efficiency of TOC is 42.8%?78.0% for the simulated wastewater with 200 mg/L naphthalene derivatives at optimal pH of 2.0?2.5 after 120 min treatment.The degradation of five naphthalene derivatives with the micro-electrolysis shows the apparent first-order kinetics and the order of removal efficiency of the naphthalene derivatives is sodium 2-naphthalenesulfonate,2-naphthol,2,7-dihydroxynaphthalene,1-naphthamine,1-naphthol-8-sulfonic acid in turn.It is illustrated that the substituents of the naphthalene ring can affect the removal efficiency of naphthalene due to their electron-withdrawing or electron-donating ability.

Study on Micro Electrolysis Treatment for Decolorizing Dyed Water

Method for decolrizing dyed wastewater was researched and the affecting factors dicussed. The result shows that the conditions for getting an optimum decolorization effect are: a reaction time of 60 min, a coke size of 5～10 mm, a solid/liquid ratio of 1∶10, an air blast volume of 4 m3/h, and proper Fe/coke ratio determined by the type of dye material. The system acidity influences dyed wastewater in different ways, i.e., acid condition is good for the decolorization of scarlet 3R and methyl orange simulated wastewater but bad for that of alkali violet 5BN simulated wastewater, while the decolorization of dispersed yellow E-RGFL simulated wastewater has nothing to do with pH.

Micro-electrolysis technology for industrial wastewater treatment

Experiments were conducted to study the role of micro-electrolysis in removing chromaticity and COD and improving the biodegradability of wastewater from pharmaceutical, dye-printing and papermaking plants. Results showed that the use of micro-electrolysis technology could remove more than 90% of chromaticity and more than 50% of COD and greatly improved the biodegradability of pharmaceutical wastewater. Lower initial pH could be advantageous to the removal of chromaticity. A retention time of 30 minutes was recommended for the process design of micro-electrolysis. For the use of micro-electrolysis in treatment of dye-printing wastewater, the removal rates of both chromaticity and COD were increased from neutral condition to acid condition for disperse blue wastewater; more than 90% of chromaticity and more than 50% of COD could be removed in neutral condition for vital red wastewater.

Optimization of the N2 generation selectivity in aqueous nitrate reduction using internal circulation micro-electrolysis

The reduction of nitrate using internal circulation micro-electrolysis te chnology(ICE)was investigated.The effect of the reaction time,initial pH,Fe/C ratio,and aeration rate on the nitrate reduction was investigated using a single factor experiment.Based on the results of the single factor experiment,a response surface methodology(RSM)was applied to optimize the N2 generation selectivity.The effects and interactions of three independent variables were estimated using a Box-Behnken design.Using the RSM analysis,a quadratic polynomial model with optimal conditions at pH=8.8,Fe/C=1:1,and an aeration rate of 30 L·min-1 was developed by means of the regre ssion analysis of the experimental data.Using the RSM optimization,the optimal conditions yielded a N2 generation selectivity of 72.0%,which is in good agreement with experimental result(73.2%±0.5%)and falls within the 95%confidence interval(IC:66.8%-77.3%)of the model results.This indicates that the model obtained in this study effectively predicts the N2 generation selectivity for nitrate reduction by the ICE process,thus providing a theoretical basis for process design.

Structural parameter optimization for novel internal-loop iron–carbon micro-electrolysis reactors using computational fluid dynamics

It is generally recognized that internal-loop reactors are well-developed mass and heat-transfer multiphase flow reactors. However, the internal flow field in the internal-loop reactor is influenced by the structure parameter of the reactor, which has a great effect on the reaction efficiency. In this study, the computational fluid dynamics simulation method was used to determine the influence of reactor structure on flow field, and a volume-offluid model was employed to simulate the gas–liquid, two-phase flow of the internal-loop micro-electrolysis reactor. Hydrodynamic factors were optimized when the height-to-diameter ratio was 4:1, diameter ratio was9:1, draft-tube axial height was 90 mm. Three-dimensional simulations for the water distributor were carried out, and the results suggested that the optimal conditions are as follows: the number of water distribution pipes was four, and an inhomogeneous water distribution was used. According to the results of the simulation,the suitable structure can be used to achieve good fluid mechanical properties, such as the good liquid circulation velocity and gas holdup, which provides a good theoretical foundation for the application of the reactor.

Nitrogen removal efficiency of iron-carbon micro-electrolysis system treating high nitrate nitrogen organic pharmaceutical wastewater

The nitrate nitrogen removal efficiency of iron-carbon micro-electrolysis system was discussed in treating pharmaceutical wastewater with high nitrogen and refractory organic concentration. The results show that the granularity of fillings,pH,volume ratios of iron-carbon and gas-water,and HRT. have significant effects on the nitrogen removal efficiency of iron-carbon micro-electrolysis system. The iron-carbon micro-electrolysis system has a good removal efficiency of pharmaceutical wastewater with high nitrogen and refractory organic concentration when the influent TN,NH4+-N,NO3--N and BOD5/CODCr are 823 mg/L,30 mg/L,793 mg/L and 0.1,respectively,at the granularity of iron and carbon 0.425 mm,pH 3,iron-carbon ratio 3,gas-water ratio 5,HRT 1.5 h,and the removal rates of TN,NH4+-N and NO3--N achieve 51.5%,70% and 50.94%,respectively.

Degradation of Nitrobenzene Wastewater via Iron/Carbon Micro-electrolysis Enhanced by Ultrasound Coupled with Hydrogen Peroxide

The zero valent iron/granular active carbon(ZVI/GAC) micro-electrolysis enhanced by ultrasound(US) coupled with hydrogen peroxide(H_2O_2) was investigated for the deep degradation of nitrobenzene-containing wastewater. The results of scanning electron microscopy-energy dispersive X-rays analysis(SEM-EDS) demonstrated that continuously accelerated regeneration of ZVI and GAC in situ by US could improve the process for converting nitrobenzene(NB) to aniline(AN). H_2O_2 was decomposed catalytically by the byproduct Fe^(2+) ions generated in the micro-electrolysis process to hydroxyl radicals and the organic pollutants in the wastewater were finally mineralized to CO2 and H2O. Effects of the ZVI dosage, the ZVI/GAC mass ratio, the initial pH value and the H_2O_2 dosage on the efficiency for degradation of NB were studied in these experiments. The optimal operating conditions covered a ZVI dosage of 15 g/L, a ZVI/GAC mass ratio of 1:2,an initial pH value of 3 and a H_2O_2 dosage of 4 mL. In this case, the NB removal efficiency reached 97.72% and the total organic carbon(TOC) removal efficiency reached 73.42% at a NB concentration of 300 mg/L. The reduction of NB by USZVI/GAC followed the pseudo-first-order kinetics model, and the pseudo-first-order rate constants were given at different initial pH values. The reaction intermediates such as AN, benzoquinonimine, p-benzoquinone, p-nitrophenol and other organic acids were detected and a probable pathway for NB degradation has been proposed.

STUDY ON TREATING ALKALI EXTRACTION-STAGE EFFLUENT FOR COLOR REMOVAL BY MICRO-ELECTROLYSIS METHOD

The micro-electrolysis technology was applied in the decolorizing treatment of bleaching E-stage effluent and the influencing factors were discussed in this paper. The initial pH and the retention time were main factors influencing the color removal rate, in addition, adding air and enough pH for neutralization were necessary for the treatment. The test showed that the decolorizing result was efficient by micro-electrolysis treatment when adding air, initial pH was 3, 20 minutes of reaction time, the final pH 10 for neutralization. The color removal rate was up to 90%. The chance of ultraviolet absorption spectrum also demonstrated the mechanism of color removal in the wastewater treatment.

基于响应面法的微电解活化过硫酸盐降解苯酚研究

目的优化微电解活化过硫酸盐氧化处理苯酚废水体系的工艺条件,提高废水处理效果。方法构建微电解活化过硫酸盐氧化降解体系,采用响应面法分析过硫酸盐浓度、初始pH值和反应温度对苯酚废水降解效果的影响,使用模型确定最佳工艺参数。结果三个因素对苯酚降解率均有较显著影响,显著性由大到小依次为反应温度、过硫酸盐浓度、初始pH值;模拟得出的最佳工艺条件:过硫酸盐浓度为15.98 mmol/L、初始pH值为2.78、反应温度为74.73℃,并且模拟预测结果与试验数据非常接近。结论该模型可以较为准确地预测微电解活化过硫酸盐降解苯酚废水的最佳反应条件与降解率。

铜强化铁碳微电解陶粒阴极对硝基苯废水的降解研究

采用电镀法,考察Cu 2+浓度、电流密度、电镀时间对镀层形貌及电镀速率的影响,以SEM-EDS、XRD、CV等分析方法对所获得的铜电镀污泥碳进行表征;并进一步制备三元微电解陶粒,考察不同加铜方式对陶粒性能的影响。结果表明:在Cu 2+浓度为0.15 mol/L、电流密度为12.5 mA/cm 2时镀层均匀、致密;铜电镀掺杂制备的三元微电解陶粒对硝基苯废水的降解有更高的去除效果,在初始pH为3且废水中的硝基苯浓度为100 mg/L时,反应180 min即可达到90.61%的硝基苯去除率,且对硝基苯的降解符合伪一级动力学反应,反应速率常数可达到0.01058 min-1。

Fenton耦合铁碳微电解技术处理电镀废水的工艺优化

以福建某电镀厂镀镍废水为研究对象,采用Fenton耦合铁碳微电解技术对其进行处理,考察了铁投加量、铁碳质量比、初始pH值及H_(2)O_(2)投加量对COD_(Cr)去除率的影响,通过响应面法优化工艺条件,建立二次多项式预测模型,分析各因素间的交互作用,并检验模型的准确性。结果表明,各因素对COD_(Cr)去除率的影响显著性排序为:初始pH值>H_(2)O_(2)投加量>铁碳质量比>铁投加量;当铁投加量为40 g·L^(-1)、铁碳质量比为0.8、初始pH值为4.0、H_(2)O_(2)投加量为30 mmol·L^(-1)时,COD_(Cr)去除率为78.2%,与预测值(78.9%)基本吻合,说明采用响应面法优化得到的工艺条件准确可靠。

微电解-絮凝沉淀协同处理氰化提金废水的研究

采用微电解-絮凝沉淀技术处理高浓度氰化提金废水,主要研究了电压、电解时间、极板间距、温度、聚合氯化铁(PFC)添加量对CNT、CN-、Cu和Zn离子去除率的影响及过程反应机制。结果表明:室温条件下,以钛板为阴极、石墨板为阳极,采用一阴两阳电解体系处理氰化提金废水,当PFC添加量为750mg·L^(-1),电压4.5V,时间3h,极板间距10mm时,废水中CNT、CN-、Cu和Zn离子的去除率分别为97.29%、97.83%、99.36%和98.74%,处理后废水可直接返回浸出系统。电场作用下废水中原有的Cl-及PFC解离产生的Cl-定向迁移至阳极发生氧化反应,产生的Cl2及ClO-将阳极附近的游离氰、金属氰络合离子间接氧化生成N2和CO_(2),释放出的重金属离子部分在阴极电沉积析出,部分Cu^(2+)会以Cu(OH)2沉淀形式被去除,Zn^(2+)与Cu(CN)32-发生共沉淀以Zn(CN)2及CuCN沉淀形式被去除。同时,微电解-絮凝与PFC水解互相促进,水解产生的氢氧化物与多核羟基络合物通过吸附、絮凝作用有助于沉淀物的快速沉降。采用该技术可达到快速高效去除氰化物及综合利用有价金属的目的,为氰化提金废水的无害化处理与资源综合利用提供了新的途径。

氯化钠对铁碳微电解工艺处理硝基苯废水的影响研究

为了探究铁碳微电解工艺在含盐环境下对水中污染物的去除效率和稳定性,以硝基苯作为处理对象,以氯化钠为盐分来源,构建模拟废水的连续处理装置,通过单因素试验获得反应最佳条件。研究结果表明,铁碳微电解处理硝基苯废水的最佳条件为:废水初始pH值为3,水力停留时间为2 h,曝气量为1 L/min;此条件下氯化钠对铁碳微电解降解硝基苯具有明显的强化作用,在氯化钠质量分数为0.5%~1.5%时,硝基苯去除率可提高20%~30%。

铁铜碳三元微电解填料制备及性能的研究

为制备更高效的微电解填料材料,在铁碳微电解体系中加入Cu,通过高温焙烧制成铁铜碳多孔微电解填料。实验表明:通过铁铜碳正交实验得出最佳铁铜碳质量比为2∶2∶5,其甲基橙及COD去除率较铁碳微电解技术分别提高11%和7.02%。利用单因素及正交实验考察造孔剂含量、膨润土含量、填料粒径、焙烧温度、焙烧时间对去除效果的影响确定最佳制备条件。结果表明:在甲基橙初始质量浓度为100 mg·L^(-1)、填料投加量为50 g·L^(-1)、曝气量为300 mL·min^(-1)、初始pH为4、反应时间为2 h时,甲基橙去除率最高。最佳制备条件为羧甲基纤维素钠质量分数为4.5%、膨润土质量分数为30%、填料直径为10 mm,焙烧温度为850℃、焙烧时间为2.5 h。对甲基橙及COD去除率达到77.27%、46.60%,表明铁铜碳三元微电解填料具有更高效的性能。

高浓度有机废水处理及回用工程实践研究

本文以某化工企业为例,采用“微电解-高级芬顿氧化-生物处理-砂滤-炭滤-反渗透-三效蒸发”的组合工艺,对其排放的高浓度有机废水进行处理。工程实践表明,系统维持相对稳定时,出水指标均可满足企业内部生产用水的水质要求,实现废水零排放。

铁碳微电解-Fenton氧化法处理石化工业有机废水

为探讨用铁碳微电解-芬顿氧化工艺处理石化工业的有机废水的最适处理效果。通过单因素实验与正交实验分别研究铁碳微电解法和Fenton氧化法的最适反应条件,基于此进行平行实验,根据实验结果分析选择采用铁碳微电解-Fenton氧化一体式联用工艺,再通过正交实验得出最佳反应条件:初始pH为2.5、铁碳投加量140 g/L、铁碳反应时间1 h、Fe^(2+)/H_(2)O_(2)投加比为1∶2.72,芬顿反应时间2 h,出水COD_(Cr)为307~327 mg/L,COD_(Cr)去除率为51%以上。影响联用工艺反应处理效果的大小顺序为:初始pH>铁碳反应时间>铁碳投加量>Fe^(2+)/H_(2)O_(2)投加比>反应时间。联用工艺相较单一实验处理废水,处理后COD_(Cr)浓度均未可达到水污染物排放标准限值中石油化工工业第二时段二级标准,处理效果仅于物理现象上有所提升,但COD_(Cr)去除率并无明显提升,处理效果不够彻底,适宜作为有机废水的预处理方法。

铁炭微电解催化氧化处理高浓度有机废水处理试验研究

采用铁炭微电解催化氧化预处理工艺处理高浓度有机废水能显著提高废水的可生化性,为后续废水生化处理提供有利条件。某一化工废水经该工艺处理,出水能稳定达到排放标准。

一种用于铝电解区域浓度跟踪控制系统中的微电压采集单元的设计及应用

本文针对用于铝电解区域浓度跟踪控制系统中的微电压采集单元的设计进行了阐述,其中详细描述了系统的整体设计构架以及微电压采集单元采集、隔离、放大、调零等各部分的设计原理及相关参数。同时,对其在铝电解区域浓度跟踪控制系统中的关键作用进行了阐述,其作为铝电解区域浓度跟踪控制系统的重要信号感知终端,是系统的整体精准性、稳定性的基石。

酸化-微电解-Fenton组合工艺处理PCB显影废水中有机物的研究

印制电路板(PCB)行业产生的显影废水是一种成分复杂、难以生化降解的高浓度有机废水。本文首先采用单因素实验确定酸化、铁碳微电解、Fenton氧化反应的最佳反应条件,其中酸化pH值为2;铁碳微电解条件:铁碳质量比取2,百毫升废水药剂投加量为3 g,pH值为2,反应时间为30 min;Fenton氧化条件:初始pH值为3,H_(2)O_(2)与Fe^(2+)的摩尔比为6,百毫升废水需加入H_(2)O_(2)0.6 m L,反应时间为90 min。其次,通过酸化-铁碳微电解-Fenton氧化组合工艺处理该废水,经组合工艺处理后,废水中的COD_(Cr)浓度从原来的5 320 mg/L降至432 mg/L左右,去除率达91%左右,为工厂废水预处理提供了依据。

Ce掺杂海绵Fe/Cu-C复合微电解填料制备及己内酰胺废水降解研究

己内酰胺废水COD高,可生化性较差。为了提高微电解降解己内酰胺的效率,制备掺杂铈的复合微电解填料,并对其使用条件、降解效果和作用机理进行研究。复合微电解填料的制备方法为利用化学置换法向海绵铁(s-Fe)表面负载铜,形成的双金属还原颗粒与活性炭、碳酸锰、氧化铈等组分混合,随后高温焙烧。使用BET,SEM及XRD等方法,分析不同组分配比填料的物理化学性质,探究各组分所发挥的作用及其机理。研究结果表明,铈掺杂的复合微电解填料对己内酰胺的降解效果显著提升。在双金属颗粒(s-Fe/Cu)、碳酸锰、活性炭按照m(s-Fe)∶m(Cu)∶m(Mn)∶m(C)为15∶5∶1∶6.3、铈含量为9%、膨润土含量为30%的最佳制备条件下,复合微电解填料对己内酰胺废水的降解率达到74.68%,COD的去除率达到90.43%。与市售填料相比,自制填料对己内酰胺废水的去除率比市售填料高55.65%,B/C由原水的0.25提高到0.81,高于市售填料0.43,可生化性显著提高。XPS分析和淬灭实验表明,该填料通过微电解反应过程产生·OH,·O-2和1O2三种自由基团,促进了有机物的降解。