三维电解处理孔雀石绿染料废水的研究

发布时间：2018-05-19 09:51

本文选题：孔雀石绿 + 三维电解　；参考：《青岛科技大学》2015年硕士论文

【摘要】：三苯甲烷类染料是目前市场上一种应用十分广泛的一类染料；此类染料具有相当复杂的结构,同时也是一种有毒物质,对人类和环境的危害极大。染料在其生产、运输、使用等各个过程中都会产生大量废弃物和废水。三苯甲烷类染料废水的色度极大,COD很高,降解难度大,严重危害环境和人类健康。鉴于这种现状,本论文以一种典型的三苯甲烷类染料孔雀石绿为实验对象,采用三维电极反应器,以DAS电极为阳极,石墨板为阴极,活性炭为粒子电极,对其进行降解实验。由于活性炭具有吸附性,在每次实验前活性炭都要用待降解废水进行饱和,以避免其对三维电解效果的影响。本研究考察了电解过程中整个体系的pH值、外加电场的电压、电解质的种类以及浓度、曝气量、电解时间等各因素对降解实验影响。并通过正交试验探寻降解实验的最合适的反应条件和参数。从实验结果可以看出,考察的各个参数对试验的影响程度从大到小的顺序依次为：电解时间体系pH值电极电压电解质浓度曝气量。结合实验结果和运行成本来考虑,本实验最后选定的电解条件为：外加电场的电极电压为8v,初始pH值为6,曝气量为0,电解质Na2SO4浓度为0.1 mol/L,电解时间为120 mmin,在此反应条件下得到的孔雀石绿的最终降解率为92%,COD的最终降解率达到86%。本论文还研究了在电解过程的机理和其他参数。通过测定电解反应器中的电场分布和氧化还原电位可得知,随着反应的进行,越靠近阳极氧化位置的还原电位会升高,而靠近阴极的位置氧化还原电位则会逐渐下降。通过缩小取样时间间隔,增加取样次数,测定样品的孔雀石绿(Malachite Green,简称MG)浓度和COD浓度,紫外可见扫描对电解溶液进行分析,初步探寻降解反应的机理和动力学公式。粒子电极一直是三维电极法的关键点之一,也是目前研究者正在攻克的难点之一。活性炭颗粒由于其良好的导电性和吸附性被广大研究者青睐,但是也正因为其良好的导电性导致实验过程中短路电流和旁路电流较大,而有效电流就相对总电流非常小,导致电流效率过低,造成电力资源的浪费。因此,为了提高电流效率,研究者更多情况下会往活性炭中掺入石英砂颗粒,这种颗粒不导电,能在一定程度上减小短路电流。由于两种颗粒的粒径和密度都不一样,因此在电解过程中会出现两种材料分层的现象。本实验选择在活性炭颗粒上负载其他物质,包括金属氧化物,导电高分子材料和不导电的高分子物质,来考察其电解效果。结果显示,随着不导电颗粒的加入,同样电解条件下,电流减小,电流效率也明显提高,孔雀石绿和COD的降解率都达到了70%以上,其中以负载绝缘材料PTFE的活性炭的电流效率最佳。
[Abstract]:Triphenylmethane dyes are widely used in the market at present. These dyes have a very complex structure and are also a kind of toxic substances, which do great harm to human beings and the environment. A large amount of waste and wastewater will be produced in the production, transportation and use of dyes. Triphenylmethane dyestuff wastewater has a great chrominance and high COD, which is difficult to degrade, and seriously endangers the environment and human health. In view of this situation, a typical triphenylmethane dye malachite green was used as the experimental object in this paper. A three-dimensional electrode reactor was used, with DAS electrode as anode, graphite plate as cathode, activated carbon as particle electrode, and its degradation experiment was carried out. Because the activated carbon is adsorptive, the activated carbon must be saturated with the wastewater to be degraded before each experiment to avoid its influence on the effect of three-dimensional electrolysis. The effects of pH value of the whole system, voltage of applied electric field, type and concentration of electrolyte, aeration rate and electrolytic time on the degradation experiment were investigated. The optimum reaction conditions and parameters of the degradation experiment were investigated by orthogonal test. It can be seen from the experimental results that the order of influence of each parameter on the test is as follows: electrolytic time system pH value electrode voltage electrolyte concentration aeration. Considering the results of the experiment and the running cost, The electrolysis conditions are as follows: the electrode voltage of applied electric field is 8 v, the initial pH is 6, the aeration is 0, the concentration of electrolyte Na2SO4 is 0.1 mol / L, and the electrolysis time is 120mmin. under these conditions, the final drop of malachite green is obtained. The final degradation rate of COD was 86%. The mechanism and other parameters of electrolysis process are also studied in this paper. By measuring the electric field distribution and the redox potential in the electrolysis reactor, it can be seen that the reduction potential near the anodic oxidation position will increase with the reaction, but the redox potential near the cathode will decrease gradually. By reducing the sampling time interval and increasing the sampling times, the concentration of malachite Malachite Green (MGG) and the concentration of COD were determined. The electrolysis solution was analyzed by UV-Vis scanning, and the mechanism and kinetic formula of degradation reaction were preliminarily explored. Particle electrode is always one of the key points of three-dimensional electrode method, and it is also one of the difficulties that researchers are trying to solve. Activated carbon particles are favored by many researchers because of their good conductivity and adsorbability, but it is also due to their good conductivity that the short-circuit current and bypass current are larger in the experimental process, while the effective current is very small relative to the total current. The current efficiency is too low, resulting in the waste of power resources. Therefore, in order to improve the current efficiency, the researchers often add quartz sand particles to the activated carbon, which is non-conductive and can reduce the short-circuit current to a certain extent. Because the particle size and density of the two kinds of particles are different, there are two kinds of material delamination in the electrolysis process. In this experiment, the electrolysis effect of activated carbon particles was investigated by loading other substances, including metal oxide, conductive polymer material and non-conductive polymer material. The results show that with the addition of non-conductive particles, the current decreases and the current efficiency increases obviously under the same electrolysis conditions. The degradation rates of malachite green and COD are over 70%. The active carbon loaded with the insulating material PTFE has the best current efficiency.
【学位授予单位】：青岛科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X788

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