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Nitrates in concentrated brines can be electrochemically reduced in the cathodic chamber of a split-cell electrochemical reactor
with formation of ammonium (and small amounts of nitrite). Fortunately, ammonium may be electrochemically oxidized to nitrogen
gas in the anodic reaction chamber if a coupled sequential process is used. The presence of chloride in the brine waste is
an important consideration in oxidative electrochemical processes, however, because it cycles through oxidized and reduced
states at the electrode surfaces and in the bulk solution. Electrochemical oxidation converts chloride ions to “active chlorine”
species with additional oxidizing capability (chlorine, hypochlorous acid and hypochlorite – essentially bleach), as well
as to chlorates, depending on the reaction conditions. The production of these active species improves treatment performance
in the ammonium oxidation phase since oxidation is no longer limited to the electrode surface. However, the process must be
engineered to minimize loss of process efficiency due to parasitic side reactions (chloramines and chlorate). In this study,
two-stage batch electrolysis was conducted using a three-electrode (copper anode, platinum-coated titanium cathode, silver/silver
chloride reference) electrochemical cell, with the anodic and cathodic chambers separated by a Nafion 117 membrane. Treatment
of nitrate and ammonium was tested with and without the presence of chloride in the waste. No significant difference was observed
in cathodic nitrate reduction with chloride present or absent. However, the presence of chloride in the solution favored overall
soluble nitrogen elimination upon oxidation. Increasing applied current increased production of undesirable byproducts (especially
chlorate). 相似文献
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电化学法处理高盐苯酚废水的研究 总被引:9,自引:0,他引:9
对在氯盐电解质中用电化学方法处理含酚废水进行了研究,着重探讨了盐的种类与浓度、反应温度与溶液:pH、电流密度、苯酚初始浓度及阴阳极转换频率对苯酚去除率的影响。在Na2SO4的浓度为0.2mol/L,NaCl的浓度为0.1mol/L、苯酚初始质量浓度为200mg/L、电流密度为0.04A/cm^2、温度为35℃、pH为12.5、阴阳极转换频率为5min/次及反应时间为200min的条件下,苯酚的去除率为99.5%,COD去除率为5%,CIO^-把苯酚氧化成了其他有机化合物。 相似文献
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耦合光催化与生物处理4-氯酚废水 总被引:11,自引:0,他引:11
采用三相内循环式流化床光反应器和固定床生物反应器耦合处理4-氯酚(4-CP)废水。光反应器中采用粗孔硅胶负载的具有高活性和长寿命的TiO2为催化剂,处理效率高。废水的BOD5/COD及固定床生物反应器处理效果表明,4-CP为难生物降解物,光催化预处理能显著增强废水的可生化性。在单级耦合处理中,光催化预处理4h后进行生物处理,能达到最佳效率,但要完全矿化COD则需要延长预处理时间。光催化预处理为生物处理提供可降解性COD,后者却没有机会作用于前者。在多级耦合处理中,两者之间存在协同作用,使多级耦合处理效率大大提高。 相似文献
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超声波协同电化学氧化降解苯胺的研究 总被引:15,自引:0,他引:15
采用超声波协同电化学氧化法处理苯胺溶液,考察了超声时间、苯胺浓度、溶液pH、电解电压、电解质浓度等因素对苯胺降解率的影响。试验结果表明:在超声波与电化学联合作用下,苯胺降解率随降解时间的延长而提高,苯胺浓度无论是低还是高,声电联合作用完全去除苯胺只需30min左右,电化学单独作用完全去除苯胺约需要120min;苯胺初始浓度较低时,其降解率较高;随着pH的增大,苯胺降解率先降低后提高,pH为10左右苯胺降解率最高;电解质Na2SO4的浓度对苯胺降解率影响不大;电解电压在4~12V范围内,苯胺降解率随电压升高而提高,电压为16V时,其降解率下降。 相似文献
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电化学工艺处理有机废水的研究进展 总被引:1,自引:0,他引:1
综述了目前国内外学者在二维电极和三维电极的开发和改进方面的研究成果,指出了电化学氧化技术和电极材料的主要研究方向和发展趋势.提出为解决电化学水处理技术中提高电催化效率和延长电极寿命的问题,当前研究的主要方向应集中在阳极材料、反应器结构和处理工艺方面. 相似文献
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分别采用磁场、超声波和Fenton试剂氧化单独处理糠醛废水,在反应时间均为3h的条件下,COD去除率分别为13%、52%和55%。磁场和Fenton试剂氧化、磁场和超声波、超声波和Fenton试剂氧化耦合分别作用于糠醛废水,COD去除率有一定提高,反应3h后糠醛废水COD去除率分别达65%、57%和85%。将磁场、超声波和Fenton试剂氧化耦合作用于糠醛废水,COD去除率达到95%,为糠醛废水的治理提出了一条新的途径。 相似文献
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电化学法处理高含盐活性艳蓝KN-R废水的研究 总被引:11,自引:0,他引:11
在分隔的流经式电化学反应器中,以金属氧化物电极(DSA)为阳极、石墨为阴极,采用电化学法对活性艳蓝KN—R模拟废水进行处理研究。在恒电位模式下,测定了染料废水在最大可见吸收波长(592nm)处的吸光度及电解液的TOC质量浓度。实验结果表明,阳极电位、NaCl浓度、染料浓度、电解液pH对染料废水的脱色率有较大的影响。在阳极电位为1.13V、Na2SO4浓度为0.1mol/L、NaCl浓度为0.5mol/L、活性艳蓝KN—R浓度为0.1mmol/L、电解液pH为6.4、温度为30℃的条件下,经4h的电解,染料废水的脱色率达到100%,但TOC质量浓度的变化不明显。 相似文献
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电化学还原-中和絮凝-生化-吸附法处理分散染料生产废水 总被引:3,自引:0,他引:3
采用电化学还原-中和絮凝-生化-粉煤灰吸附法处理分散染料废水,处理效果较好。在废水初沉后COD为2800-3200mg/L、色度为2000倍的情况下,处理出水COD<200mg/L,色度低于20倍。试验结果表明,电化学还原对废水脱色有明显的效果;废水中的分散染料可生化性好,对生化过程无明显的抑制作用;粉煤灰有良好的吸附性能,对废水中COD的吸附能力可达到20mg/g。 相似文献
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采用压片-烧结法制备了Ti5O9-Ti4O7电极,采用XRD和SEM技术对Ti5O9-Ti4O7电极进行了表征。以自制的Ti5O9-Ti4O7电极为阳极,电解处理含2,4,6-三硝基苯酚(TNP)的模拟废水,考察了电流密度、电解质质量浓度、废水p H、废水温度和反应时间等因素对废水COD去除率和TNP降解率的影响。表征结果显示:该电极的主要成分为Ti5O9,并含有部分Ti4O7;该电极的比表面积较大。Ti5O9-Ti4O7电极电解处理含TNP废水的最佳实验条件为:电流密度20 m A/cm2、电解质Na2SO4质量浓度6.0 g/L、废水p H为7、废水温度30℃。在此最佳条件下电解反应180 min后,COD去除率为90.6%,TNP降解率为93.9%,表明Ti5O9-Ti4O7电极具有较高的催化能力和电流效率。 相似文献
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Papadopoulos Aristotelis Parissopoulos George Papadopoulos Frantzis Papagianopoulou Areti Karteris Apostolos 《Water, Air, & Soil Pollution: Focus》2004,4(4-5):157-167
This paper presents a test case for the effects of recirculation on stabilization pond performance. The BOD5, COD, SS and Total Coliform removal at the intermediate treatment stages and the outlet of a stabilization pond treatment line, over a 2-year operational period (January 2000-December 2001), is described in detail and the effluent at different stages of treatment is compared to that of a conventional stabilization pond treatment line operating under similar conditions. The system consisted of four ponds in line—an anaerobic pond, followed by three individual ponds (Pond 1, Pond 2 and Pond 3). The effluent of the last pond (Pond 3) was recirculated back to the inlet of the first pond (Pond 1) at a discharge ratio 2:1 (recirculation:inflow). The overall BOD5, COD, SS and Total Coliforms total reduction was 89%, 81%, 85% and 99.7%, respectively. The anaerobic pond proved to be the most efficient in removing COD and SS (57% and 68%, respectively) whereas Pond 1 achieved the most significant reduction in BOD5 and Total Coliforms (69% and 86%, respectively). Although BOD5 and COD were adequately reduced by the recirculating pond line, the SS concentration was high due to algae presence in the final effluent. Moreover, the Total Coliforms were insufficiently removed due to the reduced hydraulic retention time involved in this type of recirculation. 相似文献