无机矿物黏土负载纳米零价铁技术研究进展

概述了采用无机矿物黏土负载纳米零价铁的原理.对目前国内外6种重要的负载零价铁的无机矿物黏土材料进行了对比分析,包括蒙脱石、累托石、坡缕石、高岭土、膨润土、沸石,并阐述了其中几种矿物黏土负载纳米铁后的形态以及去除污染物的效果.最后对一些最新的矿物在负载纳米铁的应用创新及其应用前景和发展趋势方面进行了展望.     

地下水修复中纳米零价铁材料制备及应用综述

纳米零价铁（nZVI）具有较强的还原和吸附能力,能有效去除多种类型的污染物质,在地下水环境修复领域一直备受关注。但由于其易团聚和易钝化等缺陷,在实际应用过程中还存在着许多问题。本文综述了nZVI的常用制备方法,并对nZVI的常用改性方法进行归纳,分析各种改性方法起到的具体作用,指出改性过后的复合材料依然存在着的问题。在此基础上,阐述了改性nZVI在去除地下水中有机污染物和无机污染物的应用进展,总结了改性nZVI材料在去除过程中起到的具体作用和反应机制,并进一步归纳现阶段nZVI在地下水修复中的传输手段。根据已有研究成果,指出应改进现有制备方法实现nZVI的量产,在考虑nZVI生物毒性和材料再回收的前提下,合理使用多种改性方式实现nZVI的材料制备,选择符合污染场地实际情况的传输手段,从而提高nZVI在地下水污染修复中的使用寿命和对目标污染物的处理效果。     

Removal of organic load and phenolic compounds from olive mill wastewater by Fenton oxidation with zero-valent iron

Pre-treatment of olive mill wastewater (OMW) by Fenton Oxidation with zero-valent iron and hydrogen peroxide was investigated to improve phenolic compounds degradation and the chemical oxygen demand (COD) removal. Experimental procedure is performed with diluted OMW with COD 19 g/L and pH 5.2. The application of zero-valent Fe/H₂O₂ procedure allows high removal efficiency of pollutants from OMW. The optimal experimental conditions were found to be continuous presence of iron metal, acidic pH (2–4) and 1 M hydrogen peroxide solution. The experimental results show that the removal of 1 g of COD need 0.06 M of H₂O₂. At pH 1, the maximum COD removal (78%) is achieved after 1 h. Therefore, with a pH value within 2 and 4 the maximum COD removal reached 92%. Phenolic compounds are identified in treated and untreated OMW by gas chromatography coupled to mass spectrometry (GC–MS). The result shows a total degradation of phenolic compounds and an increasing biodegradability of treated OMW.     

壳聚糖稳定纳米零价铁及衍生物在水处理中的应用

壳聚糖稳定纳米零价铁（CS-NZVI）是一种新型复合材料，兼具还原能力和吸附能力，可用于水中金属离子、含砷盐的去除和芳香族染料的降解。该文首先介绍了目前制备CS-NZVI的主要方法和特点，总结了利用CS-NZVI处理重金属离子、砷离子、染料废水的机理和应用研究进展；接着，综述了壳聚糖改性CS-NZVI、金属催化剂改性CS-NZVI及复合改性CS-NZVI的方法及其应用；最后，对优化CS-NZVI制备过程、拓宽应用条件、提高材料性能等方面提出了建议和展望。     

纳米零价铁活化过硫酸盐降解新兴污染物咖啡因

采用液相还原法制备纳米零价铁(nZVI),通过X射线衍射、扫描电镜?能谱、傅里叶红外光谱及X射线光电子能谱对其进行表征。考察了nZVI活化过硫酸盐(PS)降解咖啡因(CAF)的性能。实验结果表明,当PS为5 mmol/L、nZVI投加量为0.2 g/L时,50 mg/L的CAF可在15 min内降解97.6%;溶液初始pH和腐殖酸(HA)对nZVI/PS体系降解CAF无影响;Cl^-、SO₄^2-、H₂PO₄-和NO₃-对CAF的降解呈抑制效果;自由基抑制实验表明体系中存在·OH与SO₄^?-,且SO₄^?-占主导,nZVI/PS体系可有效降解多种污染物。     

Manganese ferrite nanoparticles synthesized through a nanocasting route as a highly active Fenton catalyst

Spinel ferrite MnFe₂O₄ nanoparticles were synthesized by means of a nanocasting technique using a low-cost mesoporous silica gel as a hard template. The magnetic nanoparticles, of <10 nm diameter and with a surface area of around 100 m²/g, were tested as a heterogeneous Fenton catalyst for the decomposition of hydrogen peroxide under neutral and basic conditions. This catalyst shows a much higher activity than previous heterogeneous catalysts reported in the literature, which is mainly ascribed to its small particle size. Furthermore, the magnetic catalyst can be easily separated from the reaction medium by means of an external magnetic field. The effects of residual silica and the purity of the catalyst (hematite formation) on catalytic activity have been studied and correlated. The results obtained show this catalyst to be a suitable candidate for the removal of pollutants in wastewaters by means of the Fenton heterogeneous reaction.     

颗粒活性炭载纳米零价铁去除水中的Cr(Ⅵ)

以Fe2+溶液为原料、NaBH4为还原剂,采用传统液相还原技术合成了颗粒活性炭(GAC)载纳米零价铁(nZVI)复合材料GAC-nZVI,用扫描电镜对GAC-nZVI进行表征,通过间歇实验考察了其对去除Cr(VI)的影响。结果表明,GAC能阻止nZVI颗粒聚集,合成的GAC-nZVI能有效去除水中的Cr(VI)。在Cr(VI)初始浓度50 mg/L、温度40℃和pH=2.0、投加GAC-nZVI 3.0 g/L的条件下反应5 min,Cr(VI)去除率为99.4%。pH=2.0?4.0时,处理后水中总铬浓度均低于1 mg/L,表明残留少量Cr(III)。随pH值和Cr(VI)浓度增加,Cr(VI)去除率降低;随反应温度和GAC-nZVI投加量增加,Cr(VI)去除率增加。准一级动力学模型可用于描述Cr(VI)的去除过程。相同条件下,GAC-nZVI去除Cr(VI)的反应速率常数达0.19797 min?1,为原颗粒活性炭反应速率常数0.0023 min?1的86倍。随pH值降低或反应温度和GAC-nZVI投加量增加,反应速率常数增加。     

Synthesis of clay-supported nanoscale zero-valent iron using green tea extract for the removal of phosphorus from aqueous solutions

This study addresses the synthesis of nanoscale zero-valent iron (nZVI) in the presence of natural bentonite (B-nZVI) using green tea extract.The natural bentonite and B-nZVI were then applied for the removal of phosphorus from aqueous solutions at various concentrations,pH levels and contact time.The desorption of phosphorus (P) from adsorbents was done immediately after sorption at the maximum initial concentration using the successive dilution method.The characterization of FTIR,SEM,and XRD indicated that nZVI was successfully loaded to the surface of natural bentonite.The sorption of phosphorus on B-nZVI was observed to be pH-dependent,with maximum phosphorus removal occurring at the pH range of 2 to 5.The results demonstrate that the maximum sorption capacities of natural bentonite and B-nZVI were 4.61 and 27.63 mg·g-1,respectively.Langmuir,Freundlich,and Redlich-Peterson models properly described the sorption isotherm data.For either adsorbent,desorption isotherms did not coincide with their corresponding sorption isotherms,suggesting the occurrence of irreversibility and hysteresis.The average percentages of retained phosphorus released from natural bentonite and B-nZVI were 80％ and 9％,respectively.The results indicated that sorption kinetics was best described by the pseudo-second-order model.The present study suggests that B-nZVI could be used as a suitable adsorbent for the removal of phosphorus from aqueous solutions.     

Nitrogen-doped carbon coated palygorskite as an efficient electrocatalyst support for oxygen reduction reaction

An electrocatalyst support, nitrogen-doped graphitic layer (CN_x) coated palygorskite (PLS) (donated as PLS@CN_x), is synthesized by carbonizing the polypyrrole (PPy) coated PLS and is explored for the first time as a cathode electrocatalyst support in proton exchange membrane fuel cell. The structural and chemical properties of the PLS@CN_x are investigated by Fourier-Transform infrared spectrometer, thermogravimetric analysis, X-ray diffraction and transmission electron microscopy. The electrocatalytic activity and stability of Pt/PLS@CN_x toward oxygen reduction reaction (ORR) are studied by cyclic voltammetry (CV) and steady state polarization measurements. Upon loading Pt (20 wt%), the catalysts exhibit superior catalytic performance during ORR, surpassing the conventional Pt/C (Vulcan XC-72) catalysts. High electrocatalytic activity and good stability can be attributed to the nitrogen atom incorporation and SiO₂ component in PLS.     

零价铁材料还原水中硝酸盐的研究进展

硝酸盐（NO3-）是水体中常见的污染物，进入人体后会造成多种损害。零价铁(ZVI)作为一种活性金属，因其高效、无毒、价廉和来源丰富而被广泛用于NO3-的还原。尽管ZVI对硝酸盐有较高的去除效率，但传统ZVI法还原NO3-的主要产物是NH4+，这会对水体造成二次污染。并且由于反应过程中形成的铁氧化物会抑制电子传递，ZVI难以长时间维持高反应活性，对pH有较高的依赖。通过开发或改善现有ZVI复合材料、以及耦合微生物工艺等手段，可降低pH对反应的限制以及还原产物中NH4+的比例，同时将其脱氮性能进一步优化提升，这是目前乃至今后的重点研究方向。该文重点总结了ZVI对NO3-的作用效能和去除机制，阐述了理化特性、pH、温度、溶解氧等因素对ZVI化学反硝化效能的影响，涵盖了ZVI还原硝酸盐的各项性能强化措施。最后归纳了ZVI材料在实际脱氮中需要注意的问题，对其未来发展前景作出了探讨和展望。     

Sulfonic acid functionalized periodic mesostructured organosilica as heterogeneous catalyst

Periodic mesostructured organosilicas (PMO) were first synthesized using 1,2-bis(triethoxysilyl)ethylene (BTENE) under acidic conditions using Pluronic 123 as surfactant. The ethylene bridges were then arylated with benzene using AlCl₃ as catalyst. These materials were further treated with sulfuric acid for the sulfonation of the phenyl moieties yielding a new preparation of sulfonic acid functionalized PMO. Ordered hexagonal mesostructures with surface areas up to 440 m²/g and narrow pore size distribution (around 5.3 nm) were obtained. This work thus provides a new example of chemical modification for the conception of functionalized PMO catalysts. Liquid phase self-condensation of heptanal was performed at 75 °C in the presence of these catalysts and the results were compared with those obtained with several other heterogeneous acid catalysts.

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Heterogeneous Fenton catalyst derived from hydroxide sludge as an efficient and reusable catalyst for anthraquinone dye degradation

Hydroxide sludge (HS) is the main by-product of drinking water production stations. In our work, we have promoted the valorization of these sludge, we convert it into activated carbon to serve as a support as a heterogeneous Fenton catalyst for reactive blue 19 (RB 19) degradation. The HS and Fe/HS-300 were characterized by means of SEM, EDX-ray, FTIR and XRD analysis. RB 19 and TOC removals were 92% and 41% respectively in optimal condition. More importantly, Fe/HS-300 exhibited an excellent stability and low Fe ion leaching (0.2–0.7mg/L), it was recycled 6 runs still maintaining the same efficiency.     

Microwave-assisted one-pot three-component synthesis of thiazolidinones using KSF@Ni as an efficient heterogeneous catalyst

Convenient, one-pot three-component reaction for the synthesis of thiazolidinones from aldehydes, thiosemicarbazide, and maleic anhydride in the presence of KSF@Ni as heterogeneous catalyst under microwave irradiation was developed. Products were obtained in reasonable yield in short reaction time.     

负载金作为非均相催化剂催化选择性液相加氢反应的研究进展(英文)

The great potential of gold catalysts for chemical conversions in both industrial and environmental concerns has attracted increasing interest in many fields of research. Gold nanoparticles supported by metal oxides with high surface area have been recognized as highly efficient and effective green heterogeneous catalyst even at room temperature under normal reaction conditions, in gas and liquid phase reactions. In the present review, we dis-cuss the recent development of heterogeneous, supported monometal ic gold catalysts for organic transforma-tions emphasizing mainly liquid phase hydrogenation reactions. Discussions on the catalytic synthesis procedures and the promoting effect of other noble metals are omitted since they are already worked out. Appli-cations of heterogeneous, supported monometal ic catalysts for chemoselective hydrogenations in liquid phase are studied including potential articles during the period 2000–2013.     

Recent development of supported monometallic gold as heterogeneous catalyst for selective liquid phase hydrogenation reactions

The great potential of gold catalysts for chemical conversions in both industrial and environmental concerns has attracted increasing interest in many fields of research. Gold nanoparticles supported b...     

Fe1Co0.5Ba2.5氧化物纳米颗粒芬顿催化降解亚甲基蓝的研究

采用溶胶-凝胶法制备的铁钴钡氧化物纳米颗粒作为非均相类芬顿催化剂,研究其催化降解亚甲基蓝,考察催化剂投加量,H2O2投加量,温度等对亚甲基蓝降解效率和降解速率的影响.结果表明,在最佳的实验条件下该氧化物颗粒与过氧化氢组成的芬顿试剂在20 min内,亚甲基蓝降解率达到95％.该反应符合一级动力学模型,55℃条件下,速率常数为0.10 min-1,反应活化能为54.1kJ/mol.     

Degradation of salicylic acid by photo-assisted Fenton reaction using Fe ions on strongly acidic ion exchange resin as catalyst

The photo-assisted Fenton degradation of salicylic acid (SA) was studied by using strongly acidic ion exchange resin (SAIER) exchanged with Fe ions as catalyst in the presence of UV light (254 nm) and H₂O₂. The X-ray photoelectron spectroscopy (XPS) results revealed that the Fe ions are indeed anchored by the sulfonate groups on the surface of the SAIER and are Fe³⁺. Our results also indicate that the Fe/SAIER catalyst can significantly enhance the degradation rate of SA without remarkable Fe leaching to the solution, implying that the catalyst has photo-catalytic activity. In addition, the effects of [H₂O₂]/[SA] molar ratio, UVC light power, solution pH, catalyst loading, and initial SA concentration on the degradation of SA were investigated in detail.     

Nitrogen-doped reduced graphene oxide/Fe2O3 hybrid as efficient catalyst for ammonium nitrate

In this investigation, we successfully synthesized a hybrid material, N-rGO@Fe₂O₃, via a one-step hydrothermal process, comprising nitrogen-doped reduced graphene oxide and α-Fe₂O₃. Thorough characterization using diverse analytical methods validated its structure. Employing this hybrid composite as a catalyst, we studied its efficacy in the catalytic thermal decomposition of ammonium nitrate (AN). The N-rGO@Fe₂O₃/AN composite was prepared using a recurrent spray coating method with 3 % mass of the hybrid material. Thermo-gravimetric (TG) and differential scanning calorimetric (DSC) analyses were employed to investigate the catalytic effect. Computational assessment of Arrhenius parameters was conducted through isoconversional kinetic approaches. Results from the kinetic analysis allowed the determination of the critical ignition temperature. Furthermore, calorific values for pure AN and N-rGO@Fe₂O₃/AN were measured using an oxygen calorimetric bombe, revealing a 41 % reduction in activation energy barrier and a lowering of the critical ignition temperature from 292 °C to 283 °C upon incorporation of the hybrid material. Notably, the surface modification of AN with N-rGO@Fe₂O₃ resulted in an increase of 1440 J/g in the observed calorific values. These findings highlight the potential of N-rGO@Fe₂O₃ as an effective catalyst, offering promising implications for applications in enhancing ammonium nitrate thermal decomposition.     

Fibrous material based on a combination of poly(acrylic acid‐co‐hydroxyethyl methacrylate) with iron ions as a heterogeneous Fenton catalyst for dye oxidative decomposition

The Fenton method has been used to remedy dye wastewater because hydroxyl radicals generated from the Fenton reaction can oxidize the dye into small molecules. In comparison with a homogeneous reaction, a heterogeneous reaction with a solid material as a catalyst is a more appropriate alternative for dye wastewater treatment. Because of the large specific surface area and excellent applicability, a novel fibrous material based on a combination of functional polymer with iron ions was designed in this study and used as a heterogeneous catalyst for dye wastewater treatment by the Fenton method. The fibrous material was found to have good catalytic activity for the oxidative decomposition of a variety of dyes and good reusability; additionally, the fibrous material could remove the dye to a greater extent and leave fewer iron ions in the treated wastewater than a homogeneous Fenton catalyst such as iron(II) chloride (FeCl₂). What is more, the fibrous material could adsorb the residual iron ions from the treated wastewater and make these iron ions take part in the next catalyzation. The previous results make us believe that the prepared fibrous material might be used to create a green approach for dye wastewater treatment. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44875