铁酸铋可见光催化过一硫酸盐去除金橙Ⅱ

采用共沉淀法制备新型可见光催化剂铁酸铋,采用X射线衍射、扫描电子显微镜、FTIR对其进行表征,并研究铁酸铋激活过一硫酸盐(PMS)去除金橙Ⅱ的影响因素与金橙Ⅱ的降解规律。实验结果表明:初始pH值越低,金橙Ⅱ降解速率越高;随PMS浓度的增加,金橙Ⅱ去除率先增大后降低;随着铁酸铋用量增加,金橙Ⅱ去除率增大,当铁酸铋用量超过0.2g时,去除率趋于恒定;金橙Ⅱ初始浓度增加,去除率降低,但随时间增加,最终去除效果仍趋于一致;当金橙Ⅱ浓度为10 mg·L~(-1),PMS浓度为0.3 mmol·L~(-1),铁酸铋用量为0.2 g,反应时间为70 min时,金橙Ⅱ去除率可达到99.58%;金橙Ⅱ稳定降解时,符合拟一级动力学方程。     

锰铝层状双金属氢氧化物活化过一硫酸盐降解橙黄Ⅱ

通过水热法制备MnAl层状双金属氢氧化物(MA),采用扫描电镜(SEM)、傅里叶红外光谱仪(FTIR)、X射线衍射仪(XRD)和比表面积分析仪(BET)对其进行表征,并用其活化过一硫酸盐(PMS)降解偶氮染料橙黄Ⅱ。实验结果表明,当温度为25℃,溶液初始pH为7,0.1 g/LMA,1 mmol/LPMS,反应90分钟后20mg/L橙黄Ⅱ降解率为85.2%。橙黄Ⅱ的降解率随着PMS浓度、溶液初始pH值和温度升高而增大。MA投加量有最优值。水中常见离子Cl^-、NO₃^-、HCO₃^-、HPO₄^-、HA都对降解有一定的抑制。自由基猝灭实验结果表明体系中的主要氧化物种为¹O₂。经过5次循环使用后,橙黄Ⅱ的降解率还可达到38.2%。在实际水体应用中,橙黄Ⅱ的降解率可达53.8%。     

活化过硫酸盐降解染料实验的设计与实施

设计了活化过硫酸盐降解模拟染料废水的实验,通过直观的实验现象和过硫酸钠不同活化方式的应用,发挥学生学习的主动性,引导学生查阅相关文献,对实验进行开放式设计及探索。针对不同层次学生采取分层次引导,循序渐进地培养学生的动手能力、解决实际问题的能力和创新能力。     

铈盐－过硫酸盐复合引发体系的研究

铈盐－过硫酸盐复合引发体系的研究李朝阳，丘坤元（北京大学化学系，北京，１００８７１）关键词复合引发体系，铈盐，过硫酸盐，氧化还原引发本文研究了一种新的复合引发体系，即在传统的单独钟盐引发体系中引人过硫酸盐这一本身具有强氧化性的新组分，提高原体系的引发...     

表面改性活性炭活化过硫酸盐降解苯酚

采用硝酸氧化联合高温处理法对活性炭(AC)进行表面改性(样品记为ACNH),并将其用于活化过硫酸盐(PS)降解苯酚.通过氮气等温吸附、元素分析、X射线光电子能谱和扫描电子显微镜等手段对改性前后活性炭的表面性质进行了表征分析.考察了活性炭投加量、PS/苯酚摩尔比、苯酚初始浓度和初始p H等条件对苯酚降解率的影响.结果表明,改性后活性炭活化PS能力显著提高,在ACNH/PS体系中苯酚的降解速率是AC0/PS体系中的5倍;ACNH的pH值适用范围宽;活性炭表面醌基、吡喃酮结构和碳原子平面层上的离域π电子(Cπ)在活化PS过程中起主要作用,而羧基起抑制作用.     

过硫酸盐激活协同可见光催化降解四环素的机理和降解路径

为了提升微污染水体中抗生素的降解效率,利用过硫酸钠(PDS)激活协同手性介孔TiO₂可见光催化(PDS/vis-TiO₂)对四环素(TC)进行降解。详细对比研究了以手性TiO₂作为催化剂的PDS激活(PDS/TiO₂)、可见光催化(vis-TiO₂)和PDS/vis-TiO₂三种体系中,降解污染物的活性物种和污染物降解路径等的差异。结果表明,不对称的螺旋堆积结构在手性介孔TiO₂中引入了丰富的Ti³⁺,不仅提升了其可见光响应,同时能够激活PDS生成自由基。PDS/vis-TiO₂体系中光生空穴h⁺和·OH等多种自由基可以同时参与TC的降解,5 h内其对TC去除率可达到95%以上,远超PDS/TiO₂体系(TC去除率为48.9%)和vis-TiO₂体系(TC去除率为71.1%)。PDS加入到光催化体系中,会受到光生电子的激活而产生自由基,从而消耗光生电子,提升光生空穴和电子的分离率,达到协同增强污染物的降解能力。另外PDS激活后产生自由基也会大大增加体系对TC的降解性能。密度泛函理论计算和中间产物分析结果表明,TC在PDS/vis-TiO₂体系中的降解路径包含了光生空穴h⁺攻击TC的降解路径,同时也包括自由基攻击TC的降解路径。     

过硫酸盐激活协同可见光催化降解四环素的机理和降解路径

为了提升微污染水体中抗生素的降解效率,利用过硫酸钠（PDS）激活协同手性介孔TiO₂可见光催化（PDS/vis-TiO₂）对四环素（TC）进行降解。详细对比研究了以手性TiO₂作为催化剂的PDS激活（PDS/TiO₂）、可见光催化（vis-TiO₂）和PDS/vis-TiO₂三种体系中,降解污染物的活性物种和污染物降解路径等的差异。结果表明,不对称的螺旋堆积结构在手性介孔TiO₂中引入了丰富的Ti³⁺,不仅提升了其可见光响应,同时能够激活PDS生成自由基。PDS/vis-TiO₂体系中光生空穴h⁺和·OH等多种自由基可以同时参与TC的降解,5 h内其对TC去除率可达到95%以上,远超PDS/TiO₂体系（TC去除率为48.9%）和vis-TiO₂体系（TC去除率为71.1%）。PDS加入到光催化体系中,会受到光生电子的激活而产生自由基,从而消耗光生电子,提升光生空穴和电子的分离率,达到协同增强污染物的降解能力。另外PDS激活后产生自由基也会大大增加体系对TC的降解性能。密度泛函理论计算和中间产物分析结果表明,TC在PDS/vis-TiO₂体系中的降解路径包含了光生空穴h+攻击TC的降解路径,同时也包括自由基攻击TC的降解路径。     

石墨相氮化碳可见光下活化过一硫酸盐氧化降解光惰性邻苯二甲酸二甲酯的机理研究（英文）

近几年过一硫酸盐(PMS)活化技术备受关注,其中利用太阳能活化PMS具有可持续和环保的优势,但PMS本身不吸收可见光.因此,本文提出利用具有可见光响应的石墨相氮化碳(g-C3N4)激发产生光电子进而活化PMS.首先利用三聚氰胺前驱体通过热缩聚法制备g-C3N4,通过X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)、紫外-可见光漫反射(UV-Vis)、荧光光谱(PL)、透射电镜(TEM)、N2吸附脱附测试(BET)、电化学等一系列方法对g-C3N4进行表征,研究其表面性质及光学性能.结果显示, g-C3N4具有典型的片层结构和可见光活性,禁带宽度为2.7 e V.本文选取光惰性的内分泌干扰物邻苯二甲酸二甲酯(DMP)为目标污染物,系统地研究了其降解动力学和降解机理.研究发现,在短波紫外光(254和300nm)照射下,直接光解和·OH参与的反应机理能实现DMP的光降解,而在可见光照射下g-C3N4介导的光催化过程不能使DMP分解;但当添加PMS时,体系主导自由基由·O2–转化为SO4·–和·OH,从而实现DMP的有效降解和矿化.研究还发现,高浓度的PMS和高剂量的g-C3N4均可以提高PMS的活化量和相应的DMP降解效率,但提高催化剂剂量的方式能更充分的利用PMS.尽管高浓度的DMP阻碍了PMS和光催化剂g-C3N4的有效接触,但可以提高PMS的利用率.当p H低于零电荷点(5.4)时, DMP的降解效率较高.此外,使用两种淬灭剂(乙醇和叔丁醇)与DMP进行竞争性实验,结合电子自旋共振检测,表明SO4·–和·OH都是体系主要的自由基.此外,还对g-C3N4的可持续性能进行考察,四次循环实验结果显示,该催化剂具有良好的可重复利用性.对DMP降解进行总有机碳测定,发现降低了19%.最后,利用液相色谱质谱联用对DMP降解产物进行定性定量分析,发现DMP主要通过SO4·–和·OH对苯环的攻击以及脂肪族链的氧化断键这两种途径进行降解.综上可见,利用可见光激发g-C3N4产生的光电子能有效活化PMS降解顽固型有机污染物,可为实现太阳能活化PMS技术提供有力的技术参考.     

Ni-N-C单原子催化剂活化过硫酸盐降解苯酚

采用煅烧法制备了以木质素生物炭为载体的单原子催化剂(Ni-N-C-10), 用于高效活化过硫酸盐(PMS)降解苯酚. 利用扫描电子显微镜(SEM)、 透射电子显微镜(TEM)、 经球差校正的高角度环形暗场扫描透射电子显微镜(AC-HAADF-STEM)、 X射线粉末衍射仪(XRD)以及X射线光电子能谱仪(XPS)等对材料进行了表征分析, 证明合成了原子分散的催化剂Ni-N-C-10. 探究了制备过程中双氰胺的投加量和降解实验中催化剂投加量、 PMS投加量、 pH值以及温度对苯酚降解的影响. 结果表明, 在催化剂制备过程中, 加入10倍质量比的双氰胺更有利于实现原子分散. Ni-N-C-10/PMS体系在较低的催化剂和PMS投加量、 以及较宽的pH值范围(3~9)内都能有效活化PMS降解苯酚. 此外, 该体系的稳定性好且应用范围广, 除了能高效降解苯酚外还能快速降解双酚A、 四环素和亚甲基蓝. 电子顺磁共振检测和自由基淬灭实验结果表明, Ni-N-C-10/PMS体系降解苯酚为SO₄^?-、 ·OH和¹O₂ 3种主要活性物种共同作用的结果, 其中¹O₂起主导作用. 反应前后Ni-N-C-10催化剂的XPS分析结果表明, 催化降解苯酚的效率与Ni位点呈正相关.     

Synthesis,insecticidal activity and molecular docking study of clothianidin analogues with hydrazide group

A series of novel neonicotinoid analogues were designed and synthesized by introducing a hydrazide group into clothianidin. Their structures were confirmed by IR, 1H NMR, and HRMS （ESI）. Preliminary bioassay showed that some compounds, Sb and Sg, exhibited good activity against soybean aphids （Aphis glycines） at 100 mg L ^-1. In addition, molecular docking with receptor was carried out to explain their different activity from clothianidin.     

Visible light induced photocatalytic degradation of phenol by polymer-modified semiconductors: Study of the influencing factors and the kinetics

To investigate the influencing factors and the kinetics of photocatalytic degradation of phenol, experiments were carried out using conjugated polymer poly(fluorene-co-thiophene) (PFT) sensitized TiO₂ and ZnO under LED (light-emitting diode) lights of the wavelength of 450–475 nm. Influencing factors, such as initial phenol concentration, photocatalyst dosage and pH value on the photocatalytic degradation of phenol were studied in detail. The reaction kinetics was found to follow pseudo first-order law.     

掺氮二氧化钛可见光照射降解微囊藻毒素-LR

采用溶胶凝胶法制备了N掺杂TiO2(N-TiO2)纳米粉体光催化剂,利用X射线光电子能谱(XPS)、X射线衍射(XRD)、紫外可见反射光谱及透射电镜(TEM)分析测定,对光催化剂N/TiO2进行了结构表征.发现N掺杂TiO2相对纯TiO2禁带宽度变窄,可见光区有明显吸收.在可见光照射下,利用纳米N/TiO2作为光催化剂降解微囊藻毒素(Microcystin-LR,MC-LR),通过高效液相色谱仪(HPLC)跟踪检测降解过程MC-LR浓度变化,液质联用仪(LC-MS)检测MC-LR降解中间产物变化.利用电子自旋共振法(ESR)及过氧化物酶催化氧化方法跟踪定性定量测定光催化过程中氧化物种的种类变化.采用总有机碳(TOC)测定仪测定了MC-LR光催化深度氧化矿化效果.结果表明,可见光(λ420nm)照射可有效激发光催化剂N-TiO2活化分子氧降解MC-LR,在反应条件下,光催化反应14h,MC-LR降解率达到100%,20h矿化率达到59%.其光催化反应体系中氧化物种主要为羟基自由基(·OH).质谱检测到13种降解产物,主要反应机理为光催化反应产生·OH进攻MC-LR结构四个易氧化部位,以及一些氨基酸之间的肽键的水解.     

Visible light induced catalytic water reduction without an electron relay

Protons from water are reduced by a catalytic system composed of a heteroleptic iridium(III) photosensitizer [Ir(ppy)2(bpy)]+, platinum catalyst, and sacrificial reductant. The hydrogen quantum yield reaches 0.26 in this study, which proceeds via reductive quenching of the excited photosensitizer by triethanolamine. This simplified approach allows the characterization of degradation products that are otherwise obscured in more complex systems. A novel 16-well setup for parallel kinetic analysis of H2 evolution enables high-throughput screening of reaction conditions and quantization of the decaying reaction rate. DFT calculations rationalize the differences between this and previous studies on tris-diimine ruthenium(II) photosensitizers.     

Vanadium supported on spinel cobalt ferrite nanoparticles as an efficient and magnetically recoverable catalyst for oxidative degradation of methylene blue

Vanadium supported on spinel cobalt ferrite nanoparticles was synthesized and characterized using Fourier transform infrared spectroscopy, X‐ray diffraction, energy‐dispersive X‐ray analysis and transmission electron microscopy. For the first time, the prepared material was used for the catalytic degradation of methylene blue as an organic dye in the presence of hydrogen peroxide as a green oxidant and NaHCO₃ as a co‐reagent at room temperature. The dependency of removal percentage on various parameters such as amount of catalyst, pH, reaction time and temperature and the effect of radical scavenging agents were studied. Finally, recoverability and reusability of the vanadium supported on spinel cobalt ferrite nanoparticles were investigated.     

A2BO4尖晶石类催化剂在紫外可见光水氧化的研究

采用溶胶-凝胶法制备La_xSr_(2-x)MnO_4尖晶石类光催化剂,确定了适用于La_xSr_(2-x)MnO_4的制备方法和条件,通过改变结构和组分实现光催化水氧化反应。实验表明,晶体的缺陷和晶格的变形影响光催化性能且x为0.3~0.6时都表现良好的催化活性,Na_2S_2O_8浓度过高不利于催化性能,可能发生其它的副反应。利用X-射线衍射(XRD)法,气相色谱(GC)法、电化学循环伏安法、极化曲线法、X射线光电子能谱分析(XPS)法对结构和其催化性能进行表征。     

Visible light photocatalysis with benzophenone for radical thiol-ene reactions

We report herein a simple, metal- and oxidant-free visible light promoted strategy for an anti-Markovnikov hydrothiolation of unactivated olefins using benzophenone as an inexpensive photocatalyst at room temperature. Anti-Markovnikov adducts of a wide variety of olefins and thiols are formed in highly regioselective manner and good to excellent yields. The present radical thiol-ene reaction is operationally simple and well tolerates a variety of functional groups.     

Visible light induced photocatalytic reaction of rhodamine B dye via 12-tungstosilicic acid in water

Using 12-tungstosilicic acid (SiW124-) as the catalyst, rhodamine B (RhB) dye in an aerated aqueous solution can undergo an effective photocatalytic stepwise N-deethylation process under visible light irradiation, and dioxygen is reduced to hydrogen peroxide by the reducedSiW12 4-. This provides the potential for moving polyoxometalate-based photocatalytic processes from the near-UV into the visible region of the spectrum.     

Visible light degradation of ibuprofen using PANI coated WO3@TiO2 photocatalyst

A PANI-coated heterojunction of WO₃@TiO₂ nanocomposite was fabricated in three stages. The performance evaluation of the prepared photocatalyst for the degradation of ibuprofen was performed under visible light. Characterization of the photocatalyst using X-ray diffraction (XRD) analysis showed that the TiO₂ prepared constituted of the anatase phase. Furthermore, results from in situ XRD analysis of WO₃ show that it consisted of monoclinic and orthorhombic crystalline structures. These phases were not affected by the incorporation of PANI as revealed by XRD analysis. Results from Transmission electron microscopy (TEM) examination showed that sphere-like WO₃ and TiO₂ nanorods of different sizes were prepared In addition, fabrication of a heterojunction of WO₃@TiO₂ wrapped in PANI was shown by TEM analysis. Results from photoluminescence studies indicate that coupling TiO₂ with WO₃ enhanced the charge separation and the degradation performance of the nanocomposite. Supporting the heterojunction on PANI enhanced the degradation efficiency as indicated during the performance evaluation process. Diffuse reflectance spectra (DRS) calculations of the PANI/WO₃@TiO₂ catalysts showed that they can be used under visible light. The experimental results of X-ray Photon Spectroscopy (XPS) analysis showed the presence of elements W, C, O, Ti, and N. Solution pH influenced the degradation process and the maximum degradation efficiency was attained at pH 9. The degradation followed the Langmuir-Hinshelwood kinetic model with a Kinetic constant of 3.5 × 10^?2. The rate of degradation increased in the presence of bicarbonate/carbonate ions and persulfate ions.