Ni／Fe／Al2O3·PVDF催化还原剂的表征及制备过程优化

在PVDF基体改性的基础上，采用浸渍法制备出Ni／Fe／Al2O3PVDF催化还原剂。通过对一氯乙酸的脱氯效果研究，对交联液配比及交联时间、不同浓度硫酸镍浸渍时间、镍铁比等因素进行优化，实验优化结果表明，Ni／Fe／Al2O3PVDF催化还原剂对一氯乙酸脱氯60min脱氯率达到64％。经SEM表征，制备出的双金属在膜载体表面及断面分布均匀，呈球状和片状结构且双金属未发生团聚。     

Mn的氧化价态对Mn/γ-Al2O3催化剂催化臭氧氧化气相低浓度甲苯的影响

采用共沉淀法，以Al₂O₃为载体制备Mn/γ-Al₂O₃和Mn-Ce/γ-Al₂O₃催化剂，并分别在N₂气氛和O₂气氛下焙烧。采用固定床连续流动反应器，研究所制备催化剂在室温条件下催化臭氧氧化甲苯的性能。通过XRD、XPS和FTIR等手段对催化剂的结构和组成进行表征。结果表明，Mn/γ-Al₂O₃催化剂具有良好的催化臭氧氧化甲苯和催化臭氧自身分解的性能，共沉淀法制备催化剂的最佳Mn负载量为20%。O₂气氛焙烧和Ce的加入，可以有效提高催化剂的活性和寿命。原因是O₂气氛焙烧和Ce的加入可以提高Mn的氧化价态。催化剂失活的主要原因是有机副产物在催化剂表面吸附堆积，失活催化剂在550℃、空气气氛下焙烧可恢复催化性能。     

光助Ce-Fe/Al2O3催化H2O2降解阳离子红GTL模拟废水

利用Ce-Fe/Al₂O₃为催化剂的非均相光Fenton体系降解阳离子红GTL模拟废水，考察了H₂O₂浓度、催化剂用量、初始pH值及不同工艺过程对降解效果的影响，通过紫外-可见漫反射光谱、红外光谱、XPS手段研究铁在反应中的价态变化。结果表明，在11 W低压汞灯照射下，非均相光Fenton体系能够有效地降解结构稳定的阳离子红GTL，在pH 6，反应温度20℃，时间90 min，Ce-Fe/Al₂O₃ 2 g/L，H₂O₂浓度340 mg/L，含50 mg/L阳离子红GTL模拟废水TOC去除率为92.40%；光Fenton反应中Fe(Ⅲ)转化为Fe(Ⅱ)。     

CuO/γ-Al2O3的制备及其湿式催化氧化性能研究

针对常温常压的废水双氧水催化氧化，采用浸渍法制备CuO/γ-Al₂O₃催化剂，利用比表面积、XRD手段表征了制备工艺对催化剂的影响，以模拟苯酚废水为研究对象考察催化剂的催化性能。研究表明，焙烧温度和活性组分含量等显著影响催化剂的性能，催化剂对双氧水催化氧化苯酚溶液具有较高的催化活性。     

Co3O4/介孔分子筛催化剂对苯催化完全氧化的研究

分别以介孔分子筛MCM-41、MCM-48、SBA-15为载体，采用等体积浸渍法制备了氧化钴/介孔分子筛催化剂，利用N₂吸附、X射线衍射、程序升温还原等技术对催化剂进行了表征，考察了Co₃O₄的负载量及载体的孔结构对催化剂完全催化氧化苯的性能的影响。结果表明，Co₃O₄的负载量为20%时，催化剂的催化活性最好；载体的孔径和催化剂的可还原性能是影响催化活性的主要因素，催化剂活性顺序为Co₃O₄ /SBA-15> Co₃O₄ /MCM41> Co₃O₄ /MCM-48。     

铈改性Al2O3担载Pd催化剂的CO氧化性能研究

浸渍法制备了Al₂O₃+CeO₂为载体的Pd催化剂，对制备中各因素对催化剂效果的影响作了初步研究。考察了活性组分含量与催化剂性能的关系以及焙烧温度、水蒸气对催化剂活性的影响。结果表明，稀土Ce元素的存在使催化剂的性能得到明显改善。制备过程中焙烧步骤对催化剂的活性影响很大，催化剂制备必须高于600℃焙烧。     

低频超声协同Fe-Ni-Mn/Al2O3催化降解酸性绿B的研究

采用低频超声与Fe-Ni-Mn/Al₂O₃催化剂协同降解偶氮染料酸性绿B模拟废水，考察染料初始浓度和pH值、催化剂、饱和气体及H₂O₂等因素对酸性绿B降解效果的影响， 结果表明：催化剂Fe-Ni-Mn/Al₂O₃与低频超声存在协同效应，催化剂的最佳投加量为6 g/L；酸性条件有利于染料的超声降解，当pH=3.8时， 可取得最佳的降解效果； 酸性绿B降解率随初始浓度的增大而降低，其优化初始浓度为100 mg/L，此外，在反应体系中鼓入饱和气体也可促进酸性B的降解，且影响顺序为混合气体(air+Ar)＞氧气＞氩气；在反应过程中投加H₂O₂有利于染料降解率的提高。在优化实验条件下降解150 min，酸性绿B色度去除率达到91.4%。     

Fe3O4/Ag磁性纳米颗粒去除水中的铅离子

采用水相共沉淀法制备小尺寸磁性Fe₃O₄纳米颗粒,以没食子酸作为还原剂和表面修饰剂,还原Ag[(NH₃)₂]⁺制备出Fe₃O₄/Ag磁性纳米颗粒。研究该磁性纳米颗粒对水溶液中铅离子的吸附行为,研究结果表明,pH为7.0,吸附温度30℃时可得到最好的处理效果,铅的去除率可达99.7%以上,Fe₃O₄/Ag颗粒吸附行为符合二级动力学模型(R² > 0.99)。该磁性纳米颗粒经过多次再生处理后,仍具有很好的吸附效果,表明Fe₃O₄/Ag在水处理方面拥有良好的应用前景。     

Ni/Fe双金属降解四氯化碳和四氯乙烯的对比试验

以四氯化碳(CT)和四氯乙烯(PCE)为目标污染物,以批试验方法研究Ni/Fe双金属对CT和PCE的还原性脱氯.结果表明:Ni/Fe双金属可有效去除水中的CT和PCE;Ni/Fe双金属对CT和PCE的降解反应均符合准一级反应动力学方程;在相似的反应条件下,Ni/Fe双金属对CT和PCE脱氯的反应速率常数(kobs)之比为1.48和1.67,说明Ni/Fe双金属对CT的脱氯速率要快于对PCE的脱氯速率;Ni/Fe双金属可对PCE完全脱氯,但对CT脱氯过程中产生少量三氯甲烷(TCM).     

H4SiW12O40/TiO2/beads光催化降解亚甲基蓝的研究

以钛酸四丁酯为原料，空心微珠为载体，采用溶胶凝胶法制备TiO₂/beads光催化剂载体，然后浸渍法制备出H₄SiW₁₂O₄₀/TiO₂/beads表面负载修饰型复合光催化剂，并运用SEM、XRD、FT-IR和DRS对催化剂进行表征和分析。研究了H₄SiW₁₂O₄₀/TiO₂/beads对亚甲基蓝降解的光催化活性，考察了光强度、pH值、曝气量、底物浓度和催化剂用量等对催化效率的影响。实验结果表明，在中性条件下，H₄SiW₁₂O₄₀/TiO₂/beads催化剂的投加量为0.25 g/L，浓度为7.5 mg/L的亚甲基蓝溶液在250 W的紫外灯和600 W的可见光灯下光照60 min降解率分别可达到94.5%和55%。     

Catalytic dechlorination of monochlorobenzene with a new type of nanoscale Ni(B)/Fe(B) bimetallic catalytic reductant

A unique type of nanoscale Ni(B)/Fe(B) bimetallic catalytic reductant was prepared and used for dechlorination of monochlorobenzene (MCB). The sample Ni(B)/Fe(B) was synthesized by an electroless plating method, in which nanoscale Ni(B) was deposited on the surface of nanoscale Fe(B) synthesized by chemical reduction. The results suggest that the nanoscale Ni(B)/Fe(B) bimetallic catalytic reductant has higher dechlorination efficiency than Ni/Fe(B) catalytic reductant prepared by replacing Fe(B) with Ni(2+) in aqueous solution. The Ni content was found to be an important factor in catalytic dechlorination, with the dechlorination rate increasing with Ni content. The electroless plating method improve the efficiency of the Ni(2+) in the solution. Dechlorination takes place with the existence of nanoscale Ni(B)/Fe(B) bimetallic catalytic reductant via a pseudo-first-order reaction.     

臭氧辅助UV/Fenton法处理电镀添加剂生产废水

采用臭氧辅助光芬顿法处理电镀添加剂生产废水，考察双氧水、FeSO₄·7H₂O、pH和反应时间等因素对废水COD和UV₂₅₄去除的影响。实验结果表明，pH=4，臭氧通入量为0.25 g，双氧水的投加量93.3 mL/L，FeSO₄·7H₂O投加量为5.3 g/L，最佳反应时间为30 min，COD和UV₂₅₄去除率分别达到92.64%和87.95%。这表明，臭氧辅助光芬顿法对电镀添加剂生产废水处理效果显著，处理时间大大减少。     

V2O5-TiO2-AlF3/Al2O3催化臭氧化2,4-滴丙酸的氧化效能

为了提高有机物的臭氧化降解效率,工作中利用浸渍法制备了一种新型的三组分催化剂(记为V2O5-TiO2-AlF3/Al2O3)。催化臭氧化降解2,4-滴丙酸的实验结果表明,该催化剂能有效提高臭氧化的效率,体系可能遵循羟基自由基的作用机理。利用相对法计算结果表明,与单独臭氧化相比,V2O5-TiO2-AlF3/Al2O3催化臭氧化体系具有更大的Rct值。重复实验结果表明,该催化剂具有相对较好的稳定性。以上研究结果对推广催化臭氧化技术在实际废水处理中的应用具有重要的实际意义。     

微波辐射Bi2O3/沸石-H2O2体系降解废水中的硝基苯

研究了微波辐射下，以负载于沸石上的三氧化二铋为催化剂，以双氧水为氧化剂的催化氧化体系处理硝基苯工艺。通过单因素实验法，从反应催化剂负载量、pH、双氧水用量、微波功率、反应时间、催化剂用量等方面初步考察了硝基苯在该体系中的催化氧化效果。在氧化铋负载量3%（质量比），pH=2，2 mL 30%双氧水，火力为中火，催化剂投加量为0.7 g，反应2 min，对降解过程所得的中间产物和终产物进行了分析。结果表明，该体系对硝基苯的去除率能够达到99.2%，COD去除率为73.91%。     

Degradation of paracetamol by advance oxidation processes using modified reticulated vitreous carbon electrodes with TiO2 and CuO/TiO2/Al2O3

The degradation of paracetamol in aqueous solutions in the presence of hydrogen peroxide was carried out by photochemistry, electrolysis and photoelectrolysis using modified 100 pores per inch reticulated vitreous carbon electrodes. The electrodes were coated with catalysts such as TiO₂ and CuO/TiO₂/Al₂O₃ by electrophoresis followed by heat treatment. The results of the electrolysis with bare reticulated vitreous carbon electrodes show that 90% paracetamol degradation occurs in 4 h at 1.3 V vs. SCE, forming intermediates such as benzoquinone and carboxylic acids followed by their complete mineralisation. When the electrolysis was carried out with the modified electrodes such as TiO₂/RVC, 90% degradation was achieved in 2 h while with CuO/TiO₂/Al₂O₃/RVC, 98% degradation took only 1 h. The degradation was also carried out in the presence of UV reaching 95% degradation with TiO₂/RVC/UV and 99% with CuO/TiO₂/Al₂O₃/RVC/UV in 1 h. The reactions were followed by spectroscopy UV-Vis, HPLC and total organic carbon analysis. These studies show that the degradation of paracetamol follows a pseudo-first order reaction kinetics.     

铁氧化物复合氧化铝催化臭氧化过程中溴酸盐的生成控制简

以市售活性炭、硅藻土和氧化铝小球为载体，考察了负载铁基活性组分对催化臭氧化过程中溴酸盐的控制情况，其中，铁基复合氧化铝小球体现出更好的溴酸盐还原特性和催化剂稳定性，证实催化剂中铁氧化物是溴酸盐得到有效控制的主要活性组分。进一步考察了铁基复合氧化铝小球催化臭氧化处理实际原水过程中对溴酸盐的生成控制，以及反应过程中溶解性有机碳（DOC）的去除情况。结果表明，与单独臭氧化相比，该催化剂既能有效去除水中的溶解性有机物，又能明显抑制溴酸盐的生成，反应50 h，其活性并没有明显下降。催化剂失活主要归因于吸附位点数量的下降，可以通过负载铁氧化物来实现催化剂的再生。     

Dechlorination of chlorinated hydrocarbons by bimetallic Ni/Fe immobilized on polyethylene glycol-grafted microfiltration membranes under anoxic conditions

In this study, the dechlorination of chlorinated hydrocarbons including trichloroethylene (TCE), tetrachloroethylene (PCE) and carbon tetrachloride (CT) by bimetallic Ni/Fe nanoparticles immobilized on four different membranes was investigated under anoxic conditions. Effects of several parameters including the nature of membrane, initial concentration, pH value, and reaction temperature on the dechlorination efficiency were examined. The scanning electron microscopic images showed that the Ni/Fe nanoparticles were successfully immobilized inside the four membranes using polyethylene glycol as the cross-linker. The agglomeration of Ni/Fe were observed in poly(vinylidene fluoride), Millex GS and mixed cellulose ester membranes, while a relatively uniform distribution of Ni/Fe was found in nylon-66 membrane because of its hydrophilic nature. The immobilized Ni/Fe nanoparticles exhibited good reactivity towards the dechlorination of chlorinated hydrocarbons, and the pseudo-first-order rate constant for TCE dechlorination by Ni/Fe in nylon-66 were 3.7-11.7 times higher than those in other membranes. In addition, the dechlorination efficiency of chlorinated hydrocarbons followed the order TCE > PCE > CT. Ethane was the only end product for TCE and PCE dechlorination, while dichloromethane and methane were found to be the major products for CT dechlorination, clearly indicating the involvement of reactive hydrogen species in dechlorination. In addition, the initial rate constant for TCE dechlorination increased upon increasing initial TCE concentrations and the activation energy for TCE dechlorination by immobilized Ni/Fe was 34.9 kJ mol⁻¹, showing that the dechlorination of TCE by membrane-supported Ni/Fe nanoparticles is a surface-mediated reaction.     

Toxicity of nanoparticulate and bulk ZnO, Al2O3 and TiO2 to the nematode Caenorhabditis elegans

Limited information is available on the environmental behavior and associated potential risk of manufactured oxide nanoparticles (NPs). In this research, toxicity of nanoparticulate and bulk ZnO, Al₂O₃ and TiO₂ were examined to the nematode Caenorhabditis elegans with Escherichia coli as a food source. Parallel experiments with dissolved metal ions from NPs were also conducted. The 24-h median lethal concentration (LC₅₀) and sublethal endpoints were assessed. Both NPs and their bulk counterparts were toxic, inhibiting growth and especially the reproductive capability of the nematode. The 24-h LC₅₀ for ZnO NPs (2.3 mg L⁻¹) and bulk ZnO was not significantly different, but significantly different between Al₂O₃ NPs (82 mg L⁻¹) and bulk Al₂O₃ (153 mg L⁻¹), and between TiO₂ NPs (80 mg L⁻¹) and bulk TiO₂ (136 mg L⁻¹). Oxide solubility influenced the toxicity of ZnO and Al₂O₃ NPs, but nanoparticle-dependent toxicity was indeed observed for the investigated NPs.     

Electrospun and functionalized PVDF/PAN nanocatalyst-loaded composite for dechlorination and photodegradation of pesticides in contaminated water

A novel approach for the electrospinning and functionalization of nanocatalyst-loaded polyvinylidene fluoride/polyacrylonitrile (PVDF/PAN) composite grafted with acrylic acid (AA; which form polyacrylic acid (PAA) brush) and decorated with silver (Ag/PAN/PVDF-g-PAA-TiO₂/Fe–Pd) designed for the dechlorination and photodegradation of pesticides was carried out. PAN was used both as a nitrogen dopant as well as a co-polymer. Smooth nanofibers were obtained by electrospinning a solution of 12:2 wt.% PVDF/PAN blend using dimethylformamide (DMF) as solvent. The nanofibers were grafted with AA by free-radical polymerization using 2,2′azobis(2-methylpropionitrile) (AIBN) as initiator. Both bimetallic iron–palladium (Fe–Pd) and titania (TiO₂) nanoparticles (NP) were anchored on the grafted nanofibers via the carboxylate groups by in situ and ex situ synthesis. The Fe–Pd and nitrogen-doped TiO₂ nanoparticles were subsequently used for dechlorination and oxidation of target pollutants (dieldrin, chlorpyrifos, diuron, and fipronil) to benign products. Structural and chemical characterizations of the composites were done using various techniques. These include surface area and porosity analyzer (ASAP) using the technique by Brunner Emmett Teller (BET), Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscope (TEM) analyses were done. After dechlorination, the transformation products (TPs) for dieldrin, chlorpyrifos, diuron, and fipronil were obtained and identified using two-dimensional gas chromatography (time-of-flight) with a mass spectrometer detector (GCxGC-TOFMS). Analysis of total organic carbon (TOC) was carried out and used to extrapolate percentage mineralization. Experimental results showed that dechlorination efficiencies of 96, 93, 96, and 90 % for 1, 2, 2, and 3 h treatment period were respectively achieved for 5 ppm solutions of dieldrin, chlorpyrifos, diuron, and fipronil. The dechlorination of dieldrin, diuron, and fipronil follows first-order kinetics while that of chlorpyrifos followed pseudo-first order. Mineralization performance of 34 to 45 % were recorded when Fe–Pd was used, however upon electrospinning, doping, and grafting (Ag/PAN/PVDF-g-PAA-TiO₂/Fe–Pd composite); it significantly increased to 99.9999 %. This composite reveals great potential for dechlorination and mineralization of pesticides in contaminated water.