【作者】 邹海平；

【导师】 邱祖民；

【作者基本信息】 南昌大学 ， 工业催化， 2007， 硕士

【摘要】 近年来，半导体光催化降解高浓度难生化的有机废水已得到了很大的发展，但仍存在不足，亟待完善。例如单纯TiO₂光生载流子的复合率高且能量利用率低。为了提高光催化过程的量子效率和能量利用率，加速光生载流子的界面迁移率、降低复合率，本文提出以顺磁性半导体微晶Fe₂O₃为活性组分，外加磁场与一定波长的普通白炽灯光协同催化降解酸性蓝染料废水。本文以浓度为1000 mg／L，COD为1640 mg／L的酸性蓝染料废水为研究对象，采用H₂O₂催化氧化处理工艺研究了催化剂的制备、废水降解条件、光-磁组合协同效应以及染料降解机理等。在催化剂的制备研究过程中，主要探讨了载体的选择、浸渍液浓度、浸渍时间和次数、焙烧条件和催化剂的使用寿命。结果表明：以超细非晶态SiO₂为载体制得的催化剂活性较高；该载体在浓度为0.4 mol／L的硝酸铁溶液中浸渍5小时1次，在焙烧温度为500℃，焙烧时间为3小时的条件下，所制备的催化剂处理酸性蓝染料废水，COD去除率达81.71％。催化剂连续使用5次后仍具有较高的催化活性，废水COD去除率仍达80.98％，该催化剂具有较高的催化活性和较长的使用寿命。通过IR和XRD图谱分析可知，该催化剂的晶相为γ-Fe₂O₃／SiO₂。在废水降解工艺条件的研究中，主要探讨了pH值、催化剂用量、H₂O₂用量、反应时间、反应温度等因素对酸性蓝染料废水处理效果的影响。实验结果表明：在pH等于3，催化剂用量为1.6g／L，H₂O₂用量为6 mL／L，70℃条件下反应120 min时，COD去除率达81.71％。在光-磁组合协同效应的研究中，探讨了外加单一白炽灯、磁场以及光-磁协同作用对酸性蓝染料废水处理影响。结果表明：单一白炽灯、磁场以及光-磁协同作用都对光催化处理酸性蓝染料废水的COD去除率有一定的影响。光强度为11W，光照距离为15 cm，光照时间为120 min，COD去除率由81.71％提高到86.83％。外加磁场强度为2.2mT，作用时间为100 min，COD去除率由81.59％提高到85.12％。在上述条件都不变的情况下，光-磁协同作用100 min，COD去除率达到87.71％。为了更好的控制反应工艺条件和掌握反应规律，本文初步对染料降解机理进行了探讨。光催化氧化降解酸性蓝时，·OH先攻击偶氮键，同时又和-SO₃Na发生部分取代。偶氮键脱落后，生成一系列不稳定的中间产物，随着反应的进行，这些中间产物在·OH和O₂的作用下，最后生成一些小分子酸，甚至被矿化为CO₂和H₂O。更多还原

【Abstract】 In recent years, photocatalytic degradation of high concentration and difficultbiochemical organic wastewater with semiconductor has got very great development,but still it is insufficient to exist, for example, pured TiO₂ photo-generating carrierrecombination rate is high and energy efficiency is low. In order to improving thequantum efficiency of photocatalysis and energy utilization, accelerating the interfacemobility of photo-generating carrier and reducing its recombination rates, we tookparamagnetic semiconductor microcrystalline Fe₂O₃ as active component, appliedmagnetic field and a certain wavelength common incandescent lamp light cooperativephotocatalytic degradation of acid blue dye wastewater in this paper.Based on the concentration of acid blue dye wastewater, 1000 mg/L, COD1640 mg/L and used the process of H₂O₂ catalytic oxidation, preparation of catalyst,conditions of treating wastewater, the combined cooperative effect of magneto-opticaland mechanism of dye degradation were studied in this paper.In the process of catalyst development, the selection of supports, concentrationof soaked liquid, impregnating time and frequency, calcination conditions and theservice life of catalyst were discussed. The results showed the catalyst suppored onultrafine amorphous SiO₂ had high catalytic activity. The support was impregnated inferric nitrate solution, the concentration of 0.4 mol/L, for once 5 hours and calcined at500℃for 3h COD removal of 81.71% were obtained over the catalyst in thetreatment of acid blue dye wastewater. The COD removal still kept 80.98% and thecatalyst remained high catalytic activity after reuse of 5 times. The results showed thecatalyst represented a better activity and longer service life. The crystal phase ofcatalyst isγ-Fe₂O₃/SiO₂ by analysis of IR and XRD.In the research of wastewater treatment technology, the effects of pH, catalystdosage, H₂O₂ amount, reaction time and reaction temperature on the efficiency oftreating acid blue dye wastewater were discussed. The experimental results showedthat the COD removal rate can reach 81.71% under the conditions of pH 3, catalyst dosage 1.6 g/L, H₂O₂ amount 6 mL/L, reaction temperature 70℃and reaction time120 min.In the research of the combined cooperative effect of magneto-optical, theeffects of applied single incandescent lamp, magnetic field and cooperative effect ofmagneto-optical on the efficiency of treating acid blue dye wastewater were discussed.The results showed that all of the three factors had influence on the COD removalrate of photocatalytic treating acid blue dye wastewater. The COD removal rateincreased from 81.71% to 86.83% under the conditions of illumination intensity 11w,light source distance 15 cm and illumination time 120 min. The COD removal rateincreased from 81.59% to 85.12% under the conditions of intense of magnetic field2.2 mT and imposing time 100 min. The COD removal rate could reach 87.71%under the constant above conditions and magneto-optical cooperative acting time 100min.In order to better control reaction process conditions and master the reactionrules, the mechanism of dye degradation was preliminarily studied in this paper. Inthe process of photocatalytic oxidation acid blue, First·OH attacked the azo bond andsimultaneous partially substituted for -SO₃Na. After the abscission of azo bond, aseries of unstable intermediates were generated. With the reaction progressing, thoseintermediates were became some of small molecular acid and even mineralized toCO₂ and H₂O in the presence of·OH and O₂.更多还原