基于过氧化物处理木材活性染料染色废水的工艺及其机理研究

发布时间：2018-05-05 07:14

  本文选题：木材 + 染色废水　； 参考：《中南林业科技大学》2017年硕士论文

【摘要】：木材染色是低质木材增值有效方法之一。木材染色属于木材化学加工范畴,生产过程中产生大量的废水已经成为木材加工工业的污染源头之一,废水中含有大量的有机污染物,致使化学需氧量高,色度大,成分复杂且具有致癌、致畸、致基因突变等危害,严重威胁人类健康和生态环境。因此木材染色废水必须经过处理使其达标排放是迫切解决的问题。基于过氧化物处理的高级氧化技术具有氧化能力强、无选择性、反应速度快、处理效果好等优点,Fe~(2+)催化H_2O_2产生·OH以及以热活化Na_2S_2O_8产生SO_4~(-·)都能够快速的氧化降解废水中的难降解有机污染物,是印染工业废水处理常用的氧化处理方法之一,但目前应用于木材加工工业废水的深度处理鲜有报道。因此,本研究以木材活性染料染色废水为研究对象,探讨两种不同自由基的氧化降解工艺。并借助UV-Vis,HPLC,FTIR and Raman spectra等手段,深入分析研究热活化Na_2S_2O_8产生SO_4~(-·)氧化木材活性染料染色废水的降解机理。主要研究内容如下:(1)以Fe~(2+)催化H_2O_2产生羟基自由基处理木材活性染料染色废水,研究结果表明,各影响因素从大到小的影响顺序为pH值氧化剂H_2O_2投加量反应温度反应时间硫酸亚铁浓度。优化工艺条件为30%H_2O_2投加浓度为7.5ml/L、FeSO_4·7H_2O为0.9g/L、处理液初始pH值为2.5、反应温度为50℃、反应时间为80min。在此优化条件下化学需氧量和色度去除率分别达90.5%和99.99%。(2)以热活化Na_2S_2O_8产生SO_4~(-·)处理木材活性染料染色废水,结果表明,化学需氧量去除率都是先随温度的升高、Na_2S_2O_8投加量的增大、反应时间的延长而升高,分别到达90℃、50g/L、150min后CODCr去除率保持不变;初始pH值对CODCr去除率影响不明显。得到优化工艺条件为反应温度90℃,Na_2S_2O_8投加量50g/L,反应时间150min,初始pH不调,在此处理工艺条件下,CODCr去除率达到91.06%。(3)利用响应面分析进一步优化热活化Na_2S_2O_8产生SO_4~(-·)处理工艺,得到的最优工艺参数为反应温度为90℃,Na_2S_2O_8投加入量为51.3g/L,反应时间为2.00h,初始pH不调,处理后染色废水CODCr平均去除率为98.36%,TN平均去除率为89.33%,苯胺类平均去除率为95.64%。(4)基于热活化Na_2S_2O_8产生SO_4~(-·)深度氧化木材活性染料染色废水,采用UV-Vis,HPLC,FTIR and Raman spectra探讨氧化机理。结果表明,热活化Na_2S_2O_8产生SO_4~(-·)可以使废水中染料分子结构中的共轭发色基团-N=N-键发生断裂,同时使苯环和萘环发生开环反应,从而使废水脱色,且萘环的降解速率比苯环的降解速率要高,并且-N=N-键氧化降解速率符合一级反应动力学方程,速率常数为0.033 min-1,反应活化能Ea为29.22 kJ/mol。
[Abstract]:Wood dyeing is one of the effective methods to increase the value of low quality wood. Wood dyeing belongs to the category of wood chemical processing. A large amount of wastewater produced in the production process has become one of the sources of pollution in the wood processing industry. The waste water contains a large number of organic pollutants, resulting in high chemical oxygen demand and large chroma. The composition is complex and has the hazard of carcinogenesis, teratogenicity and gene mutation, which is a serious threat to human health and ecological environment. Therefore, it is urgent to solve the problem that wood dyeing wastewater must be treated to meet the discharge standards. The advanced oxidation technology based on peroxide treatment has the advantages of strong oxidation ability, non-selectivity and fast reaction rate. It is one of the commonly used oxidation treatment methods for printing and dyeing wastewater to catalyze the production of OH from H_2O_2 and from thermal activated Na_2S_2O_8 to produce so _ 4 / C _ 4), which can rapidly oxidize and degrade the refractory organic pollutants in the wastewater. However, there are few reports on advanced treatment of wastewater from wood processing industry. Therefore, in this study, two kinds of free radical oxidation and degradation processes were studied with wood reactive dyestuff wastewater as the research object. By means of UV-Vis-HPLCX FTIR and Raman spectra, the degradation mechanism of oxidized wood dyeing wastewater produced by heat-activated Na_2S_2O_8 was studied. The main research contents are as follows: (1) Fe~(2) H_2O_2 was used to produce hydroxyl radical to treat wood dyeing wastewater. The order of influencing factors from big to small is pH value oxidant H_2O_2 dosage, reaction temperature, reaction time, ferrous sulfate concentration. The optimum conditions were as follows: the concentration of 30%H_2O_2 was 7.5 ml / L, the concentration of FeSOs was 0.9g / L, the initial pH value was 2.5, the reaction temperature was 50 鈩，

本文编号：1846749