高效环保型凹凸棒土-SnO2-TiO2复合光触媒剂的制备及其性能研究

论文总字数：13391字

摘 要

以凹凸棒黏土(Att)为基体，通过溶胶-凝胶浸渍工艺，将一系列不同比例的SnO₂-TiO₂ (m_Att/m_(SnO2-TiO2) = 1; r = n_Sn/(n_Sn n_Ti)=1, 1/5, 1/6, 1/7, 1/8, 1/9, 1/10, 1/11 , 0 )复合氧化物负载于凹凸棒土表面，制备凹凸棒黏土复合型光触媒剂(Att-SnO₂-TiO₂)。采用XRD、BET、TEM等分析技术对产物进行了表征。研究结果表明，SnO₂-TiO₂复合氧化物均匀地负载于凹凸棒土表面；经过复合氧化物负载改性后，凹凸棒土的表面形貌得到明显改善，产物的负载效果好、比表面大。以光触媒降解对硝基苯胺为对象，研究了凹凸棒土复合光触媒的光催化性能。结果表明，凹凸棒土复合光触媒显示出优异的光催化性能，其光催化活性顺序为Att-SnO₂-TiO₂gt;Att-TiO₂gt;Att-SnO₂gt;Att；而且比例对凹土复合光触媒剂的性能有明显的影响：在紫外光条件下，当r = 1/8时，Att-SnO₂-TiO₂显示出优异的光催化性能，90min内对30mg/L对硝基苯胺的降解率达99.8%。且实验证实Att-SnO₂-TiO₂复合光触媒剂的重复利用率也相当高，在五次回收后对30mg/L对硝基苯胺的降解率达98.7%。

关键词：凹凸棒，光触媒，溶胶-凝胶浸渍，Att-SnO₂-TiO₂，对硝基苯胺

Abstract: Photocatalytic removal of Nitroaniline under ultraviolet radiation has been studied using attapulgite (Att) composites, which were synthesized by depositing SnO₂-TiO₂ hybrid oxides on the surface of Att to form a composite photocatalyst (denoted Att-SnO₂-TiO₂) using sol-gel dipping process. The obtained products were marked as Att-SnO₂-TiO₂ and were characterized by X-Ray diffraction (XRD), BET surface area and Transmission electron microscope (TEM) methods. Results showed that Att-SnO₂-TiO₂ nanocomposite particles with high dispersibility were successfully loaded onto the surface of Att fibers. Correspondingly, the photocatalytic activity of Att was improved significantly by loading Att-SnO₂-TiO₂.The photoactivity of the composite photocatalyst decreased in the sequence Att -SnO₂-TiO₂gt;Att-TiO₂gt;Att- SnO₂gt;Att. In order to achieve the best photocatalyst, Att is always the total quality 50%, but the molar ratio of SnO₂ and TiO₂ in the Att-SnO₂-TiO₂ composites was adjusted to give a series proportions r = nSn/(nSn nTi)=1, 1/5, 1/6, 1/7, 1/8, 1/9, 1/10, 1/11 , 0 . Results indicated that the proportion of SnO₂ and TiO₂ had a critical effect on the photocatalytic activity. Under ultraviolet light irradiation, the highest degradation rate of 30mg/L p-nitroaniline was 99.8% within 90 min by using Att-SnO₂-TiO₂ r = 1/8 as photacatalyst. The repeated use of the composite photocatalyst was also confirmed and degradation rate 30mg/L p-nitroaniline maintained 98.7% after 5 times usage.

Key words: Attapulgite, Photocatalyst, Sol - gel dip, Att-SnO₂-TiO_2, p-nitroaniline

目 录

1 引 言 4

2 实验部分 5

2.1复合光触媒剂的制备 5

2.2 材料表征 5

2.3 材料的光催化性能 6

3 结果与讨论 6

3.1触媒剂的表征 6

3.2 紫外光触媒性能研究 9

3.2.1 触媒剂工作条件的选择 9

3.2.1.1对硝基苯胺浓度的选择 9

3.2.1.2触媒剂的投入量 10

3.2.1.3对硝基苯胺初始溶液的pH值 11

3.2.2 凹凸棒土复合光触媒材料的光触媒性能研究 11

3.2.2.1对硝基苯胺降解产物 11

3.2.2.2对硝基苯胺溶液的COD测试 12

3.2.2.2复合光触媒材料的配比 12

3.2.2.3复合光触媒材料催化反应的动力学 14

3.2.3复合光触媒剂的重复利用 15

结 论 17

参 考 文 献 18

致 谢 20

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