复极性三维电极反应器预处理焦化废水的试验研究

发布时间：2018-05-27 12:09

本文选题：焦化废水 + 三维电极　；参考：《安徽工业大学》2016年硕士论文

【摘要】：焦化废水成分复杂,污染物浓度高、水质变化幅度大、色度高、毒性大,是一种典型的难降解有机工业废水。目前,焦化废水主要采用生化工艺处理废水中有机物与氮类污染物,出水水质不理想。电化学法由于无需添加过多药剂、操作灵活、便于自动化调控、处理效果好、无二次污染等优点,在有机废水治理领域得到越来越广泛的研究与应用。三维电极法因其在传统二维电极中加入了粒子电极,增加了反应面积和传质效率,在水处理中更具优势。本研究采用三维电极法对焦化废水进行预处理,通过电化学催化氧化过程去除废水中氨氮和总氮,以期实现减少生化池的占地投资成本和硝化及反硝化的停留时间,减轻后续生化处理的负荷的目的。本研究选用DSA作阳极、钛做阴极,活性炭与玻璃珠作粒子电极,优化设计复极性三维电极反应器,用该反应器分别对氨氮模拟废水和马钢煤焦化公司的焦化废水进行了降解试验研究,分析了三维电极反应体系中污染物降解的影响因素,得出最佳降解条件,并通过氨氮降解过程以及COD去除动力学的分析,初步探索了焦化废水的降解机理。反应器降解模拟氨氮废水试验中,采用单因素试验考察了电解时间、电解电压、氨氮初始浓度、导电介质(Na_2SO_4)浓度和氯化钠投加量等因素的对氨氮去除效果的影响。试验结果表明最佳降解条件如下:氨氮初始浓度为300mg/L,电解电压为20V,导电介质(Na_2SO_4)浓度0.15mol/L,氯化钠浓度为1g/L,在此条件下电解2h,模拟废水中氨氮的去除率可达81.4%。反应器预处理焦化废水试验中,发现由于粒子电极的加入,反应面积增加,废水中的氨氮和COD去除率同比二维电极分别增加了25.9%及16.4%。在单因素试验中,电解时间、投加粒子量、曝气、极间电压、NaCl投加量,初始pH都会影响焦化废水的中氨氮和COD的降解。在极间电压为25V,NaCl投加量为1.5g/L,粒子投加量为100g,初始pH=7并曝气时最优,此条件下电解3h,氨氮的去除率可达98%,COD的去除率达83.66%,总氮和色度的去除率也分别达到了88%和87.5%。通过正交试验发现考察因素中对氨氮去除效果的影响由大到小依次为:电解时间、极间电压、NaCl投加量、粒子投加量;对COD的去除影响由大到小依次为:极间电压、电解时间、粒子投加量、氯化钠投加量。综合氨氮与COD考虑,最佳的组合条件是电解时间为3h,极间电压为25V,NaCl投加量为1.5g/L,粒子投加量为100g,此条件下对焦化废水中氨氮去除率高达98.1%,COD的去除率为83.8%,与预处理焦化废水单因素试验结论基本一致。在预处理焦化废水的反应中,对氨氮氧化过程进行了分析,氨氮的去除以折点氯化间接氧化机理为主导。COD的电催化氧化降解过程符合一级反应动力学模型,随着电压的增大,反应速率常数增加,降解速度加快。
[Abstract]:Coking wastewater is a typical refractory organic industrial wastewater because of its complex composition, high pollutant concentration, large range of water quality change, high chroma and toxicity. At present, the wastewater from coking plant is mainly treated by biochemical process, and the effluent quality is not ideal. Electrochemical method has been widely studied and applied in the field of organic wastewater treatment because of its advantages such as no need to add too many reagents, flexible operation, easy automatic control, good treatment effect and no secondary pollution. Three-dimensional electrode method has more advantages in water treatment because of the addition of particle electrode to the traditional two-dimensional electrode, which increases the reaction area and mass transfer efficiency. In this paper, three dimensional electrode method was used to pretreat coking wastewater. Ammonia nitrogen and total nitrogen in wastewater were removed by electrochemical catalytic oxidation process in order to reduce the investment cost and residence time of nitrification and denitrification. The purpose of reducing the load of subsequent biochemical treatment. In this study, DSA was used as anode, titanium as cathode, activated carbon and glass beads as particle electrode, and the bipolar three-dimensional electrode reactor was optimized. The reactor was used to study the degradation of ammonia nitrogen simulated wastewater and coking wastewater of Masteel Coal Coking Company respectively. The factors affecting the degradation of pollutants in the three dimensional electrode reaction system were analyzed and the optimum degradation conditions were obtained. The degradation mechanism of coking wastewater was preliminarily explored through the analysis of ammonia nitrogen degradation process and COD removal kinetics. The effects of electrolysis time, electrolytic voltage, initial concentration of ammonia nitrogen, the concentration of conducting medium Na2SO4) and the dosage of sodium chloride on the removal of ammonia nitrogen were investigated by single factor experiment in the reactor degradation of simulated ammonia nitrogen wastewater. The results show that the optimum degradation conditions are as follows: the initial concentration of ammonia nitrogen is 300 mg / L, the electrolytic voltage is 20 V, the concentration of conducting medium Na2SO4 is 0.15 mol / L, and the concentration of sodium chloride is 1 g / L. under this condition, the removal rate of ammonia nitrogen in simulated wastewater can reach 81.4 points for 2 h. In the reactor pretreatment of coking wastewater, it was found that the removal rate of ammonia nitrogen and COD in the wastewater increased by 25. 9% and 16. 4% respectively compared with the two dimensional electrode because of the addition of particle electrode and the increase of reaction area. In the single factor experiment, the degradation of ammonia nitrogen and COD in coking wastewater can be affected by electrolysis time, amount of particles, aeration, voltage between poles and initial pH. Under the optimum conditions of initial pH=7 and aeration, the removal rate of ammonia nitrogen can reach 83.66% and the removal rate of total nitrogen and chromaticity reaches 88% and 87.5%, respectively, when electrolysis is done for 3 h. The total nitrogen and chroma removal rates are 88% and 87.5%, respectively, when the inter-pole voltage is 1.5 g / L and the particle dosage is 100 g / L, the ammonia nitrogen removal rate is up to 83.66%, and the removal rate of total nitrogen and chroma is 88% and 87.5% respectively. Through orthogonal test, it is found that the influence of the factors on the removal of ammonia nitrogen is as follows: electrolysis time, inter-pole voltage, and particle dosage, and the effect on COD removal from large to small is: interpole voltage, electrolysis time, and so on, and the influence of these factors on ammonia nitrogen removal is as follows: electrolysis time, interpole voltage, electrolysis time and so on. The amount of particles added, the amount of sodium chloride added. Comprehensive ammonia nitrogen and COD, The optimum combination condition is that the electrolysis time is 3 h, the voltage between electrodes is 1.5 g / L, and the particle dosage is 100 g. Under this condition, the removal rate of ammonia nitrogen and COD in coking wastewater is as high as 98.1% and 83.8%, which is basically consistent with the single-factor test conclusion of pretreatment coking wastewater. In the reaction of pretreatment of coking plant wastewater, the process of ammonia nitrogen oxidation was analyzed. The electrocatalytic oxidation degradation process, which is dominated by indirect oxidation mechanism of folding point chlorination, accords with the first order reaction kinetics model, and with the increase of voltage, the degradation process of ammonia nitrogen is in accordance with the first order reaction kinetics model. The rate constant of the reaction increases and the degradation rate accelerates.
【学位授予单位】：安徽工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X784

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