【作者】 宋宝华；

【导师】 邹东雷；

【作者基本信息】 吉林大学 ， 环境工程， 2005， 硕士

【摘要】 本文正是在湿式过氧化氢催化氧化技术的基础上,对低温常压非均相催化氧化技术进行应用研究。相比于其它催化氧化技术,本试验将催化剂活性组分固载到多孔催化剂载体上,制备成非均相催化氧化剂,利用自制高效非均相催化剂催化加入的氧化剂产生具有高氧化性的自由基,同时在低温常压、较温和的反应条件下,高氧化活性的自由基开始对有机污染物进行氧化降解,最终将有机污染物降解为二氧化碳和水。通过实验,发现载铜型催化剂对CODcr 和NH₃-N 的去除率均好于载钴型催化剂,铜作为催化剂活性组分,能够更好、更多地催化氧化剂产生具有高氧化活性的氧化自由基;通过正交实验确定了在低温常压条件下,Cu/C 催化剂催化氧化反应的最适反应条件,因素组合为:温度=80℃、pH 值=4、H₂O₂ 用量=100ml/L、催化剂用量=120g/L,此时CODcr去除率较高,达92.24%,反应温度是影响实验结果的主要因素;其次为氧化剂H₂O₂用量以及催化剂用量、pH 值,按照由正交试验确定的反应条件进行Cu/C 动态试验,发现催化剂在连续使用后,对污染物的去除率降低较快,易失活;确定了制备Cu-Al₂O₃ 催化剂时浸渍液浓度为8%制得的催化剂综合评价最好;同时确定了在低温常压条件下,Cu-Al₂O₃ 催化剂催化氧化反应的最佳反应条件:温度为75℃,pH 值为3,催化剂使用量为0.1kg/L,氧化剂使用量为80ml/L,反应时间为0.5h;对比催化剂与载体的衍射图可知,有些γ-Al₂O₃的特征峰消失,很可能是在催化剂制备过程中各形态铜的融入使有些孔道发生了晶体构型的改变,对比单纯γ-Al₂O3、新鲜催化剂和使用后的催化剂的衍射图可知,铜在催化剂中主要以Cu₂O 和CuO 形态存在,固载效果最好,不易流失,也有Cu 存在,固载效果不好,易流失;最后通过连续动态反应,认为自制催化剂具有优秀的催化性能,低温常压催化氧化技术在实践中具有有效性和可行性。更多还原

【Abstract】 With the development of the modern industry, people have paid moreattention on the treatment of the industrial wastewater. To treat the industrialwastewater which is poisonous, harmful, nonbiodegradable and has highorganic content and complex composition, the biochemical method is hardto reach the demand of effluent.The advanced oxidation processes (AOPs) based on producing theradical utilize the radical to attack the giant molecule of hard degradedorganic and remove the contaminant and treating high concentrations ofhard degraded organic waste water.But AOPs often have difficulty topopularize and application in practice, due to the cost very expensive.Because some oxidant have more strong selectivity, then more and moreoxidant have been needed for get some better oxidation effects.Catalytic oxidation technology is the advanced and enforcedtechnology of AOPs. The catalysis of the catalyst can lower the temperatureand pressure of reaction, shorten the time of reaction and prevent the erosionon equipment, so the rate of oxidation reaction have increased and the costhave reduced. The disadvantages of the homogeneous catalyst are as follow:(1) the catalyst is dissoluble to the water, it can not be reused, (2) the cost ofthe reagent is higher, (3) other impurities are brought into the wastewaterduring the treatment process, etc. The separation of catalyst and wastewateris simpler in the heterogeneous catalytic oxidation. Beside this, theheterogeneous catalyst also has high activity and good stability. All of theseadvantages simplify the treatment process greatly. However, theheterogeneous catalytic oxidation technology still has some problems, forexample the high reaction temperature and pressure, the hardness of treatingthe large flux wastewater and expensive reagent etc.However the technology of heterogeneous catalytic oxidation at lowtemperature and atmospheric pressure can catalyzed the oxidant to degradedthe hard degraded organic pollutant at low temperature (T<100℃) andatmospheric pressure.Heterogeneous catalytic oxidation processes base on the Langmuirkinetics of the adsorption and desorption of single molecule layer, theHougen and Watson theory of the control and analysis of velocity, the theorywhich concluded by Carberry of Langmuir-Hinshelwood-Hougen-Watson(LHHW) and the modern surface science theory. The theory of reaction isthe pollutants and oxidant molecule permeate to around the activity centerand be absorbed by the activity center, then catalytic oxidation reactionbetween pollutant and oxidant occurs on/at the surface of the catalyst., atlast the products of reaction desorbed to solution.The reaction process can be conclude as followed,Adsorption: A(the oxidant molecule) + σ(the active center) Aσ B(the pollutant molecule) + σ(the active center) Bσ Catalysis: Aσ+ BσPσ(the products on surface)+ σDesorption:PσP(the products in liquid) + σThe velocity of reaction be controlled by the slowest reaction of theabove.This trial make the active component loaded on the multiaperturecatalyst carrier to prepare the heterogeneous catalyst and utilize the catalystto catalyzed the oxidant degrading the organic pollutants to CO2 and H2O atlow temperature and atmospheric pressure. There are some results havebeen found after the experiments as followed:(ⅰ) The adsorption performance of catalyst has been studied. It isfound that the CODcr removal ratio of C-catalyst is higher than 20% and theratio of others catalyst are between 15~17%. The NH3-N removal ratio ofF-catalyst is higher than the others catalyst , and the ratio of Cu/F and Co/Fare 47.57% and 35.08%. The ratio of C-catalyst and Al-catalyst are lowerthan 20%. The data are useful to study the catalytic performance of catalyst.(ⅱ)The cuprum loaded catalyst has a better remove ratio of CODcrand NH3-N than the cobalt loaded catalyst. The CODcr removal ratio ofCu/Al reach 88.7% and is 34.73% higher than Co/Al; the removal ratio ofCu/C reach 77.14% and is 10.59% higher than Co/C; the removal ratio ofCu/F and Co/F are 51.76% and 45.88%. The NH3-N removal ratio of Cu/Alreach 70.67% and is 14.57% higher than Co/Al; the removal ratio of Cu/Creach 63.59% and is 3.93% higher than Co/C; the removal ratio of Cu/F andCo/F are 50.65% and 49.96%.As the data has shown, we choice Cu/C 和Cu/Al2O3 as the catalyst of the catalytic oxidation at low temperature andatmospheric pressure.(ⅲ) The study found that when the concentration of impregnant is 8%,the catalyst prepared in this solution has excellent catalytic activity. Theremove ratio of CODcr and NH3-N reach 84.97% and 64.39%.(ⅳ) The optimal reaction conditions of Cu/Al2O3 catalytic oxidation atlow temperature and atmospheric pressure has been ascertained. Whentemperature is 75℃, the pH value is 3, the dosage of catalyst is 0.1kg/L, thedosage of oxidant is 80ml/L and the reaction time is 0.5 hour, the removal ofcatalytic oxidation is optimum. The remove ratio of CODcr and NH3-N are92.4% and 67.82%.(ⅴ) The optimal reaction conditions of Cu/ Al2O3catalytic oxidationat low temperature and atmospheric pressure has been ascertained also.When temperature is 80℃, the pH value is 4, the dosage of catalyst is120g/L, the dosage of oxidant is 100ml/L, the removal of catalytic oxidationis optimum. The remove ratio of CODcr is 92.24%.The reaction temperature is the most important factor of the removal.The dosage of oxidant is secondary. The dosage of catalyst and the pH valuehave litter impact on the removal. In dynamic experiment, it is found thatthe catalyst’s catalytic performance decreased fast. So Cu/C catalyst hasbeen eliminate through selection.(ⅵ) The catalyst activity in dynamic reaction has also been studied byusing Cu-Al2O3 catalyst as filling of the catalytic oxidation reactor. Whenthe reaction time added, he remove ratio of CODcr and NH3-N increased.The CODcr of wastewater decreased from 4540 mg/L to1206.49mg/L, thento 409.17mg/L, and the NH3-N of wastewater decreased from 552.28 mg/L更多还原