Facile Preparation of PVA-AA/TiO2 Composite Gel Particles and Their Tunable Photo-catalytic Property for the Degradation of Methyl Orange

In the presence of titanium dioxide powder, cross-linking reaction between commercial polyvinyl alcohol(PVA)-based macromonomer and acrylic acid(AA) was initiated with potassium persulfate in an emulsifying system. As a result, PVA-AA/TiO2 composite gel particles were obtained. The morphology and composition of the particles were analyzed with scanning electron microscopy(SEM), energy scattering x-ray spectroscopy(EDS), Fourier infrared spectroscopy(FTIR), and thermogravimetric analysis(TGA). The analysis results confirmed that the particles were the expected ones. TiO2 was dispersed homogeneously within the spheroidal particles. Compared to the control gel, the composite gel particles not only contained Ti element but also showed higher thermal stability. In addition, the photo-catalytic behavior of the particles for the degradation of methyl orange contained in aqueous solution was examined. The particles exhibited photocatalytic characteristic for the degradation of the model dye, which could be modulated by simply varying the amount of cross-linking agent or TiO2. The photo-catalytic degradation percentage of methyl orange maintained at 91%-96% after using the particles three times, which indicated that TiO2 could played its role repeatedly via being fixated within polyvinyl alcohol-based gel.

Degradation of Residual Formaldehyde in Fabric by Photo-catalysis

The residual formaldehyde （HCHO） in fabric was degraded using photo-catalysis assisted by the compound catalyst of nano-TiO2 and nano-ZnO. The effects of several factors on the degradation, such as the composing of catalyst, irradiation time, pH value and the H2CHO concentration of the immersed solution were investigated. Results showed that H2CHO of the immersed solution had degraded 93% after 5 h irradiation, and the degradation ratio of formaldehyde could be improved and the aging of the fabric can be avoided with the addition of ZnO nanoparticles and pH value of the immersed-fibric solution. The fabric with residual formaldehyde about 1 800 μg/g can be efficiently treated to satisfy the China National Standard （GB/2912.1-1998） with the photo-catalytic degradation.

Effects of Cu(Ⅱ) or Zn(Ⅱ) on photodegradation of some toxic organic compounds in wastewater by using TiO_2 as catalyst

The effects of Cu (Ⅱ) or Zn (Ⅱ) on the photo-catalytic degradation of some organic chemicals in water, such as acetone, phenol, dyes, and tea saponin were studied. Dyes in wastewater from a textile factory can be effectively degraded by photo-catalysis with TiO 2 and ultraviolet light or sunshine, but the reaction rate could be slowed down if copper or zinc salt exists in the solution.

Iron–doped bismuth oxybromides as visible-light-responsive Fenton catalysts for the degradation of atrazine in aqueous phases

Pesticides and its degradation products,being well–known residues in soil,have recently been detected in many water bodies as pollutants of emerging concerns,and thus there is a contemporary demand to develop viable and cost–effective techniques for the removal of related organic pollutants in aqueous phases.Herein,a visible-light-responsive Fenton system was constructed with iron–doped bismuth oxybromides(Fe–BiOBr)as the catalysts.Taking the advantage of sustainable Fe(Ⅲ)/Fe(Ⅱ)conversion and optimized H_(2)O_(2)utilization,the optimal Fe–BiOBr–2 catalyst showed an excellent atrazine removal efficiency of 97.61%in 120 min,which is superior than the traditional homogeneous Fenton and the majority of heterogeneous processes documented in the literature.In this photo–Fenton system,hydroxyl(·OH)and superoxide(·O_(2)^(-))radicals were dominant active species contributed to the oxidative degradation of atrazine.Due to the production of various active radicals,five degradation pathways were proposed based on the identification of intermediates and degradation products.Overall,this work not only demonstrates a fundamental insight into creating highly efficient and atom economic photo-Fenton systems,but also provides a complementary strategy for the treatment of organic pollutants in water.

Photocatalytic degradation of pesticide residues with RE^(3+)-doped nano-TiO_2

The photocatalytic degradation effects of carbofuran solution under concentration of 0.2,0.4,0.8 g/L Re3+-doped nano-TiO2 were studied.The highest degradation rate of 54.89% was obtained after 4 h degradation when the concentration of nano-TiO2 was 0.4 g/L.Then field trials of photocatalytic degradation with suspension nano-TiO2 were conducted.The photocatalytic degradation effect of organic phosphorus and carbamate pesticides in tomato leaves and soil with different concentratio catalyst(0,0.2,0.4,0.6,0.8 g/L) were studied.The results showed that nano-TiO2 could significantly increase photocatalytic degradation rate of pesticide residues in tomato leaves and soil.Pesticide residues degradation rate could be increased by 20%-30% on the tomato leaves and 15%-20% in soil,and the best concentration of photocatalytic degradation was 0.2-0.4 g/L.

掺(氟)A-TiO_(2)制备及其光催化反应动力学研究

通过水热法制备了氟掺杂A-TiO_(2)粉末,以甲基橙溶液为污染物,探讨甲基橙的初始浓度C_0、掺氟A-TiO_(2)用量m、掺氟量χ(摩尔分数)等因素在可见光照下对甲基橙催化降解反应的动力学影响。结果表明:在最佳条件(60 W白炽灯照射、C_(0 )=0.02 g/L、pH=6、m=0.3 g/L,χ=5%、21℃、t=40 min)下,光催化降解甲基橙的过程为动力学一级反应。

改性掺Fe^(3+)A-TiO_(2)的水热制备及其紫外光催化降解甲酚红

用水热法制备了Fe^(3+)摩尔掺量分别为0、2%、4%、5%、6%、8%的TiO_(2)粉末,并对其进行了XRD表征。以甲酚红为降解对象,探索紫外光催化降解的最佳条件。结果表明:TiO_(2)晶体为单一锐钛矿型,即为A-TiO_(2);在最佳条件下(甲酚红溶液初始浓度10mg/L,溶液pH=6,Fe^(3+)摩尔掺量为5%的A-TiO_(2)的用量为4g/L,16℃254nm的紫外光照射50min),甲酚红溶液的降解率最大。

Pd-MnO_2 nanoparticles/TiO_2 nanotube arrays(NTAs) photo-electrodes photo-catalytic properties and their ability of degrading Rhodamine B under visible light

Pd-MnO2/TiO2 nanotube arrays（NTAs） photo-electrodes were successfully fabricated via anodization and electro deposition subsequently; the obtained Pd-MnO2/TiO2 NTAs photo electrodes were analyzed by scanning electron microscopy（SEM）, X-ray diffraction（XRD） and characterized accordingly. Moreover, the light harvesting and absorption properties were investigated via ultraviolet–visible diffuse reflectance spectrum（DRS）; photo degradation efficiency was investigated via analyzing the photo catalytic degradation of Rhodamine B under visible illumination（xenon light）. The performed analyses illustrated that Pd-MnO2 codoped particles were successfully deposited onto the surface of the TiO2 nanotube arrays;DRS results showed significant improvement in visible light absorption which was between400 and 700 nm. Finally, the photo catalytic degradation efficiency results of the designated organic pollutant（Rhodamine B） illustrated a superior photocatalytic（PC） efficiency of approximately 95% compared to the bare TiO2 NTAs, which only exhibited a photo catalytic degradation efficiency of approximately 61%, thus it indicated the significant enhancement of the light absorption properties of fabricated photo electrodes and their yield of UOH radicals.

木质素还原制备金纳米颗粒及其催化性能

自然界中的木质素来源广泛,其含量仅次于纤维素,是一种具有还原性的可再生芳香聚合物。本研究利用木质素在太阳光激发下还原Au(Ⅲ)制备金纳米颗粒(Au NPs),并将其用于催化还原废水中的有机污染物。主要探究了不同木质素质量浓度、HAuCl_(4)浓度、光照时间等条件对Au NPs粒径及形貌的影响;利用紫外-可见光谱仪、纳米粒度仪、透射电子显微镜(TEM)、X射线光电子能谱分析(XPS)对Au NPs理化性质进行了表征。结果表明,木质素作还原剂成功制备了Au NPs,最佳制备工艺如下:木质素质量浓度为0.1 mg/mL,HAuCl_(4)浓度为1.00 mmol/L,HAuCl_(4)溶液与木质素溶液体积比为4∶1,光照时间为60 min,此条件下制得的Au NPs平均粒径为32.14 nm。此外,以亚甲基蓝(MB)和对硝基苯酚(4-NP)为污染物模型物探究了Au NPs的催化性能,结果表明,Au NPs对MB和4-NP具有良好的光催化还原性能,反应速率常数分别为0.765 8和0.316 6 min^(-1)。木质素还原Au(Ⅲ)制备得到的Au NPs/木质素用于废水中染料和硝基芳香族污染物的光催化还原,不仅实现了木质素的高值化利用,而且实现了废水中有机污染物的高效去除。

TiO_2溶胶对水中1,2-二氯乙烷脱氯的光催化作用

以TiOSO_4为前驱体,制备出澄清、稳定的橙黄色透明TiO_2溶胶,平均粒径26nm.利用该水性TiO_2溶胶作为光催化剂对水中微量1,2-二氯乙烷进行紫外光催化研究,实验所用紫外灯主波长365nm,平均照射功率密度0·3mW/cm2,降解过程中产生的氯离子和氢离子浓度的变化用电导率仪实施监测.结果表明,二氧化钛溶胶的浓度对光催化反应有一个最佳范围,在本实验条件下,二氯乙烷降解的最佳光催化剂浓度为5×10-6;在一定范围内,当固定入射光强和光催化剂浓度时,随二氯乙烷溶液浓度的提高,其降解效率也相应增大.

T-ZnO_w-TiO_2/PMMA复合半导体膜的制备及其光催化性能的研究

将经去离子水处理陈化后的锌粉与沸石混合后在950℃下煅烧制备了四针状氧化锌晶须(T-ZnOw)。以SEM、TEM、SRD、UV-Vis等对T-ZnOw的形貌、可见-紫外光特性进行了表征;将其掺杂于锐钛矿型的TiO2中,负载于聚甲基丙烯酸甲酯(PMMA)薄膜上,测试其光催化性能。结果表明:T-ZnOw-TiO2/PMMA纳米复合材料较单一的ZnO/PMMA和TiO2/PMMA显示出更高的光催化降解亚甲基蓝的活性,紫外光照60min后降解率高达98%。

掺Fe^(3+) A-TiO_2的合成及其对酸性红B的光催化降解性能

以硫酸氧钛和FeCl_3·6H_2O为主要原料,采用水热法合成了掺Fe^(3+)的纯锐钛矿型A-TiO_2催化剂,其结构经FT-IR和X-射线衍射表征。以波长365nm紫外灯为光源,酸性红B为降解对象,研究了其光催化降解性能。实验结果表明:掺Fe^(3+)有利于提高TiO_2的催化性能,当掺Fe^(3+)量为0.2mol%时,A-TiO_2的光催化性能最强;当掺Fe^(3+)A-TiO_2投放量为400mg·L^(-1),于20℃降解时间40min,对10mg·L^(-1)酸性红B溶液(pH=5)的降解率最大(95.11%)。

Fe(Ⅲ)-EDTA/H_2O_2催化光降解苯酚模拟废水

研究UV254光照下,Fe（Ⅲ）-EDTA/H2O2对苯酚的催化光降解效能。首先考察反应时间、溶液初始pH值、Fe（Ⅲ）与EDTA的浓度比值对UV/Fe（Ⅲ）-EDTA催化光降解苯酚的影响,进而考察UV/Fe（Ⅲ）-EDTA/H2O2体系对苯酚的降解效能。结果表明：当溶液pH为7,Fe（Ⅲ）/EDTA浓度比值为1：1时,经过1h反应,UV/Fe（Ⅲ）-EDTA体系对苯酚的催化光降解效率达61.13%。在溶液初始pH为3~7时,UV/Fe（Ⅲ）-EDTA对苯酚的降解率均可达60%以上。在中性条件下,UV/Fe（Ⅲ）-EDTA体系添加H2O2后可把苯酚的降解率从61.13%提高到91.30%。反应前后溶液的紫外扫描光谱表明光降解过程中苯酚的苯环共轭结构被破坏。最后对UV/Fe（Ⅲ）-EDTA/H2O2体系催化光降解机理进行了初步探讨。

铁基金属有机框架的制备及其催化降解性能

铁基金属有机框架化合物(Fe-MOFs)具有超高的比表面积、良好的生物相容性和出色的光芬顿催化性能,在处理染料废水方面具有广阔的应用前景。采用不同的有机羧酸配体,通过溶剂热法和水热法合成了3种Fe-MOFs(MIL-53、MIL-88A和MIL-100)。采用SEM、XRD、FTIR和UV-vis等方法对Fe-MOFs的形貌与结构进行表征,探究了其在可见光下对染料的催化降解性能。此外,通过电化学测试、自由基捕获试验和电子自旋共振波谱(ESR)探究了Fe-MOFs的催化机理。结果表明,MIL-88A(Fe)的光催化活性最高,在60 min内对染料的降解率高达99.5%。在光芬顿反应中,·OH是降解染料的主要活性物质,同时·O_(2)^(-)和^(1)O_(2)也参与了染料降解过程。

NH2-nFe3O4@ZnO@Ce磁性复合材料的制备及其对三氯酚污染物的光催化降解

采用溶剂热法制备了氨基功能化纳米nFe3O4(NH2-nFe3O4),进一步得到纳米ZnO修饰的NH2-nFe3O4@ZnO和Ce掺杂的磁性复合材料NH2-nFe3O4@ZnO@Ce.通过X-射线衍射(XRD)、傅里叶变换红外光谱(FTIR)、洛伦兹透射电镜(TEM)、扫描电镜(SEM)、振动样品磁强计(VSM)、紫外-可见漫反射(UV-DRS)等手段对其进行了组成、结构、形貌、磁性等表征,并研究了其光催化降解三氯酚(2,4,6-TCP)的性能.系统考察了Ce掺杂量、TCP的初始浓度、溶液pH值等因素对材料的降解性能的影响,初步探讨了降解机理.结果表明,NH2-nFe3O4@ZnO@Ce平均粒径约为50 nm,饱和磁化强度为11.98 emu·g-1.在pH 4.0—7.0,NH2-nFe3O4@ZnO@Ce磁性复合材料可以实现对浓度<20.0 mg·L-1的TCP溶液在60 min内近100%降解.Ce的掺杂和NH2-nFe3O4复合有利于形成掺杂能级、加快光生电子的迁移能力,降低光生电子-空穴对复合率,有效提高材料对TCP的降解性能.NH2-nFe3O4@ZnO@Ce循环使用5次后,该催化体系对TCP的降解率仍能保持95%以上,是有优异潜力的TCP降解的绿色催化剂.

Fe3O4@生物炭磁性材料光-类Fenton降解水中盐酸四环素

以玉米秸秆为生物炭原料,在600℃高温缺氧条件下煅烧成炭,并利用共沉淀法在其上负载Fe3O4,制得Fe3O4@玉米秸秆炭磁性非均相芬顿催化剂。运用XRD、SEM、EDS和TEM技术对材料进行表征,研究其在不同条件下光-类Fenton协同催化降解水中盐酸四环素的性能,考察材料的磁性回收能力和催化稳定性。结果表明,Fe3O4纳米颗粒均匀覆盖在炭载体表面,整体形貌上保持玉米秸秆通道状多孔结构。初始pH=7条件下降解盐酸四环素的最佳参数为:溶液初始过氧化氢量为10 mmol/L、Fe3O4@玉米秸秆炭催化剂投加量为0.3 g/L、反应时间为60 min。材料具有pH为3~7的适用范围和磁性回收能力。催化剂稳定性强,进行5次重复实验后仍可保持98%的降解率。

泥质活性炭-铁酸镍磁性光催化剂对亚甲基蓝的降解

采用水热反应法制备了易于固液分离的泥质活性炭(SAC)负载磁性光催化剂铁酸镍(NiFe2O4),样品通过在可见光照射下降解亚甲基蓝评价其光催化降解能力。结果表明:以NiSO4·6H2O和FeCl3·6H2O为主要原料,加入10%(约0.2344 g)的泥质活性炭,在180℃水热条件下反应8 h,制备的SAC-NiFe2O4光催化活性最强。光催化反应时在草酸存在条件下,14 h时亚甲基蓝的去除率达到97%。以此为依据,研究了泥质活性炭制备的SAC-NiFe2O4磁性光催化剂并在可见光辐射条件下降解亚甲基蓝。结果表明,SAC-NiFe2O4磁性光催化剂在催化反应14h平衡后的去除率达到98%以上。催化剂循环使用3次以上,其催化活性基本不变。可见以泥质活性炭制备SAC-NiFe2O4磁性光催化剂有望用于光催化降解有机污染物。

纤锌矿型β-CuGa_(1−x)ZnxO_(2)的Zn^(2+)取代Ga^(3+)不等价掺杂对其结构及光催化性质的影响

采用离子交换法制备了Zn^(2+)在Ga-位不等价掺杂的功能陶瓷材料(β-CuGa_(1−x)ZnxO_(2)).通过X射线衍射(XRD)和透射电子显微镜(TEM)对材料的晶体结构进行表征,通过原位高温X射线衍射(HT-XRD)和同步热分析仪(TG-DSC)对材料的热稳定性进行表征,通过紫外-可见漫散射光谱(UV-Vis DRS)以及第一性原理计算对材料的光学性质进行研究,并通过甲基橙(MO)的降解反应评价了Zn^(2+)在Ga-位的引入对该功能陶瓷光催化性能的影响.结果显示,Zn^(2+)的引入引起带隙变宽,吸光范围变窄,自发极化变小,进而导致单位时间内生成的高活性物质减少,不利于降解反应.通过光致发光光谱(PL)对降解机理进行了初步探究.根据实验结果提出了改进β-CuGaO_(2)性质的可能方法.

磁性MOF制备及对阳离子翠蓝X-GB的吸附和光催化降解

选用Cu(NO_3)_2·3H_2O、双(3,5-二羧基苯基)对苯二甲酰胺(H_4L_1)以及纳米Fe_3O_4,采用混合法制备了一种磁性有机骨架材料Fe_3O_4/Cu-H_4L_1,并将其用于阳离子翠蓝X-GB的吸附和可见光催化降解。结果表明:30 mg的吸附材料在180 min内对10 mL质量浓度为15 mg/L的阳离子翠蓝X-GB吸附率可达到85.25%,吸附速率为4.08×10~(-2)mg/(g·min);在可见光照射下,150 min内5 mg的材料对40 mL质量浓度为15 mg/L的阳离子翠蓝X-GB的光降解效率高达99.44%;分别经过5次循环吸附和光催化降解,Fe_3O_4/Cu-H_4L_1不仅保留了较高的染料去除率和光催化降解效率,而且还保留了其优良的磁性;使用后的Fe_3O_4/Cu-H_4L_1能通过外加磁场简易收集和重复使用。

自制掺Fe^(3+)锐钛矿型-TiO_2复合材料的光催化反应动力学研究

以自制的掺Fe^(3+)锐钛矿型TiO_2(A-TiO_2)为光催化剂,以酸性刚果红为降解对象,研究酸性刚果红的初始浓度C0、催化剂用量m和掺铁量χ等因素对自制A-TiO_2可见光催化降解反应动力学方程的影响和光催化剂对酸性刚果红的吸附性能。结果表明:在40W白炽灯照射下,当C0=20mg/L、m=0.6g/L(pH=6)、χ=1.2%(摩尔分数)、室温(18℃)下反应t=56min时,酸性刚果红的降解率最大D=92.7%。酸性刚果红的光催化降解过程符合一级反应动力学方程,于上述最佳条件下其表观反应速率常数k达到最大,为0.0404min-1。自制的光催化剂对C0分别为20、30和40mg/L的酸性刚果红吸附率E随C0增大而减小,110min达到吸附平衡,对20mg/L酸性刚果红的吸附率E达94.6%。D和E成正比。