海泡石TiO2的制备及其对乙酰甲胺磷催化降解特性的研究

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摘要

本课题拟制备出一种海泡石/TiO2复合催化剂，以充分利用海泡石的吸附性能

和TiO2的催化特性，达到降解有机磷农药的目的。试验首先以乙酰甲胺磷为吸附

对象研究了海泡石的吸附性能；其次采用钛酸四丁酯水解法制备出 TiO2催化剂并

在超声协同的条件下对乙酰甲胺磷进行了降解；最后采用微波辅助溶胶-凝胶法制

备出海泡石/TiO2复合催化剂，并探讨了温度、pH 值、乙酰甲胺磷初始浓度、海泡

石/TiO2复合催化剂用量、通气、H2O2、Fe2+等因素对海泡石/TiO2复合催化剂光催

化降解的影响。

主要结论如下：

(1) 海泡石的主要组成成分为 SiO2和MgO，其质量分数分别为 50.7%和24.3%，

其平均颗粒直径为 0.105μm；在温度为 10℃、pH=5、乙酰甲胺磷的初始浓度为

2mg/L、海泡石的用量为 2g/L 时，60min 后，海泡石对乙酰甲胺磷的吸附率仅为

11.2%；

(2) 海泡石对乙酰甲胺磷的吸附符合 Langmuir 吸附模型，最大吸附量为

2.4362mg/g；吸附动力学分析表明：在初始的 1.5h 内，海泡石对乙酰甲胺磷的吸

附较为符合颗粒内扩散模型，而在 1.5h~3h 内则符合拟二级动力学模型，说明颗粒

内扩散模型并不是唯一的速率控制步骤，它和其它的动力学过程共同控制着海泡

石对乙酰甲胺磷的吸附过程；ΔHo=-15.867KJ/mol，说明海泡石对乙酰甲胺磷的吸

附是一个放热过程；Ea=6.034KJ/mol，说明海泡石对乙酰甲胺磷的吸附是一个物理

吸附过程；

ΔGo= 4.734 KJ/mol > 0，说明海泡石对乙酰甲胺磷的吸附是一个非自发

的过程；

(3) 超声和添加 TiO2对于乙酰甲胺磷的降解有一定的协同作用，当温度为

20℃、pH 值为 3.0、超声频率 25kHz、超声声强为 40W/cm2、TiO2投加量为 0.6g/L

时，经 50min 超声降解，乙酰甲胺磷的降解率可达 78.3%；

(4) 在微波处理时间为 20min、微波处理温度为 20℃、微波功率为 400W 时采

用微波辅助溶胶-凝胶法成功制备出海泡石/TiO2复合催化剂；

XRF 分析海泡石/TiO2

复合催化剂中 TiO2的含量 22.6%，比海泡石中 TiO2的含量多 22.1%；激光粒度仪

分析海泡石/TiO2复合催化剂的颗粒平均粒径为 0.123μm，比海泡石颗粒平均直径

(0.105μm)大0.018μm，表明负载后海泡石的粒径得到增长，同时也说明了海泡石

/TiO2复合催化剂是一个整体，而不是海泡石和 TiO2的混合物；XRD 分析海泡石

/TiO2复合催化剂中同时含有锐钛矿相和金红石相。

(5) 与添加海泡石或 TiO2相比，利用海泡石/TiO2可实现对乙酰甲胺磷的光催

化降解，且海泡石/TiO2经再生后仍具有较好的光催化性能；在温度为 25℃、pH

为5~9、乙酰甲胺磷的初始浓度为 20mg/L、海泡石/TiO2用量为 0.25g/L、添加 0.01mL

30%H2O2时，降解 60min 后，乙酰甲胺磷的降解率可达 79.9%。

关键词：乙酰甲胺磷海泡石 TiO2海泡石/TiO2光催化降解

ABSTRACT

In order to prepare sepiolite/TiO2catalyzer that can make full use of the adsorbent

abilities of sepiolite and the titanium dioxide's catalytic abilities to photocatalytically

degrade organophosphorus pesticides. In this paper, , taken acephate as the research

sample, the removal possibilty of adsorption by sepiolite, synergistic degradation by

ultrasonic wave/TiO2, or photocatalytic degradation by sepiolite/TiO2have been

systematically investigated. And the effects of temperature、pH value、acephate initial

concentration、sepiolite/TiO2concentration、Ventilation with gas、addition of H2O2or

Fe2+ , on the degradation of acephate pesticide have been examined.

Conclusion presented can be summarized as follows:

(1) The result indicated that the silica and magnesium oxide were the major

constituents of sepiolite, that is, 50.7wt.% and 24.3 wt.% respectively, the mean particle

diameter of sepiolite was 0.105μm; When the temperature is 10 ℃ 、 pH=5 、initial

concentration of acephate is 2mg/L、concentration of sepiolite is 2g/L, the adsorption

rate of acephate would only be 11.2% within 60min.

(2) Thermodynamics results indicated that the Langmuir model appears to fit the

adsorption better and the Langmuir monolayer adsorption capacity of acephate was

estimated as 2.4362mg/g; The kinetics of the adsorption of acephate onto sepiolite could

be well described by the intra-particle diffusion model within 1.5h; while during

1.5h~3h, the pseudo-second-order kinetic model was more favorable for the adsorption

process, it means that the intraparticle diffusion was not the only rate-limiting step and

other kinetic processes might control the rate of adsorption simultaneously. the enthalpy

changes (ΔHo) were calculated to be -15.867KJ/mol, which indicated that the adsorption

of acephate onto sepiolite is a exothermic process. The result of Ea(6.034KJ/mol)

demonstrated that the adsorption of acephate onto sepiolite is a physisorption, while

ΔGo, that is 4.734KJ/mol>0, indicated the adsorption of acephate onto sepiolite is not

spontaneous.

(3) There are synergistic degradation effect between ultrasonic power and the

concentration of TiO2. The degradation rate of acephate would be 78.3% within 50min

under such conditions as ultrasonic frequency of 25kHz, output power of 40W/cm2,

adding 0.6g/L TiO2catalyst, pH of 3, and temperature of 20℃.

(4)In this study, sepiolite/TiO2could be well prepared by micro-assisted sol-gel

method, provieded the microwave temperature is 20℃，microwave processing time is

20min and microwave power is 400W. The XRD analysis indicated that the percentage

compositiom of TiO2in sepiolite/TiO2is 22.6%, while that is only 0.5% in sepiolite.

The particle diameter of sepiolite/TiO2is 0.123μm，which demonstrated that after the

loading of TiO2, the particle diameter of sepiolite increased and simultaneously

indicated that sepiolite and TiO2are not a mixture but a whole material. The results of

X-ray diffraction analysis shows that both anatase and rutile are in sepiolite/TiO2.

(5) Compare with sepiolite and TiO2, sepiolite/TiO2is a better choice for

photocatalytic degradation of organophosphorus pesticide, and sepiolite/TiO2could be

reused. The degradation rate of acephate would be 79.9% within 60min under such

conditions as pH is 5~9, the initial concentration of acephate is 20mg/L, 0.25g/L

sepiolite/TiO2catalyst, adding 0.01mL 30%H2O2, and temperature of 25℃.

Key Words: Acephate, Sepiolite, TiO2, Sepiolite/TiO2, Photocatalytic

degradation

摘要

ABSTRACT

第一章绪论...................................................................................................................1

§1.1 有机磷农药去除的研究进展...........................................................................1

§1.1.1 吸附法.....................................................................................................1

§1.1.2 微生物降解.............................................................................................2

§1.1.3 超声降解.................................................................................................2

§1.1.4 化学降解.................................................................................................3

§1.1.5 半导体多相光催化降解.........................................................................4

§1.2 海泡石负载 TiO2的研究现状 ......................................................................... 4

§1.2.1 催化剂载体的选择.................................................................................4

§1.2.2 负载型 TiO2催化剂的制备方法 ........................................................... 6

§1.3 负载型 TiO2光催化剂在降解污染物中的应用 ............................................. 9

§1.3.1 空气净化.................................................................................................9

§1.3.2 有机废水处理.........................................................................................9

§1.4 光催化降解的影响因素.................................................................................10

§1.4.1 光照时间的影响...................................................................................10

§1.4.2 温度的影响............................................................................................10

§1.4.3 溶液 pH 值的影响................................................................................10

§1.4.4 被降解物初始浓度的影响...................................................................10

§1.4.5 光催化剂投加量的影响.......................................................................11

§1.4.6 通气对降解过程的影响.......................................................................11

§1.4.7 添加氧化剂对降解过程的影响...........................................................11

§1.4.8 添加金属离子对降解过程的影响.......................................................12

§1.5 本课题的研究的目的、意义和内容.............................................................12

§1.5.1 本课题的研究的目的和意义...............................................................12

§1.5.2 本课题的研究内容...............................................................................13

第二章海泡石对乙酰甲胺磷的吸附特性研究...........................................................14

§2.1 引言.................................................................................................................14

§2.2 材料和方法.....................................................................................................14

§2.2.1 试验材料...............................................................................................14

§2.2.2 试剂和仪器...........................................................................................15

§2.2.3 试验方法...............................................................................................15

§2.3 结果与分析...................................................................................................17

§2.3.1 海泡石的化学组成...............................................................................17

§2.3.2 海泡石的粒径分布...............................................................................17

§2.3.3 温度对吸附过程的影响.......................................................................18

§2.3.4 溶液 pH 值对吸附过程的影响............................................................19

§2.3.5 乙酰甲胺磷初始浓度对吸附过程的影响...........................................20

§2.3.6 海泡石用量对吸附过程的影响...........................................................20

§2.3.7 海泡石对乙酰甲胺磷的吸附动力学...................................................21

§2.3.8 海泡石对乙酰甲胺磷的吸附热力学...................................................24

§2.3.9 海泡石对乙酰甲胺磷的吸附热力学参数...........................................25

§2.4 本章小结.........................................................................................................27

第三章 TiO2的制备及其超声降解乙酰甲胺磷 .......................................................... 30

§3.1 引言.................................................................................................................30

§3.2 材料和方法.....................................................................................................31

§3.2.1 试剂和仪器...........................................................................................31

§3.2.2 试验方法...............................................................................................32

§3.3 结果与分析.....................................................................................................34

§3.3.1 磷酸根浓度-吸光度标准曲线............................................................. 34

§3.3.2 温度对乙酰甲胺磷降解率的影响.......................................................34

§3.3.3 溶液 pH 值对乙酰甲胺磷降解率的影响............................................35

§3.3.4 超声声强对乙酰甲胺磷降解率的影响...............................................36

§3.3.5 TiO2投加量对乙酰甲胺磷降解率的影响 ........................................... 37

§3.3.6 超声和 TiO2添加对乙酰甲胺磷降解率的协同作用 ......................... 38

§3.4 本章小结.........................................................................................................38

第四章海泡石/TiO2的微波辅助制备及表征 ............................................................. 40

§4.1 引言.................................................................................................................40

§4.2 材料和方法.....................................................................................................40

§4.2.1 试剂和仪器...........................................................................................40

§4.2.2 试验方法...............................................................................................42

§4.2.3 试验步骤...............................................................................................42

§4.3 结果与分析.....................................................................................................43

§4.3.1 微波处理时间对海泡石/TiO2光催化性能的影响 ............................. 43

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摘要：

摘要本课题拟制备出一种海泡石/TiO2复合催化剂，以充分利用海泡石的吸附性能和TiO2的催化特性，达到降解有机磷农药的目的。试验首先以乙酰甲胺磷为吸附对象研究了海泡石的吸附性能；其次采用钛酸四丁酯水解法制备出TiO2催化剂并在超声协同的条件下对乙酰甲胺磷进行了降解；最后采用微波辅助溶胶-凝胶法制备出海泡石/TiO2复合催化剂，并探讨了温度、pH值、乙酰甲胺磷初始浓度、海泡石/TiO2复合催化剂用量、通气、H2O2、Fe2+等因素对海泡石/TiO2复合催化剂光催化降解的影响。主要结论如下：(1)海泡石的主要组成成分为SiO2和MgO，其质量分数分别为50.7%和24.3%，其平均颗粒直径为0.1...

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