Catalytic removal of volatile organic compounds using ordered porous transition metal oxide and supported noble metal catalysts

Most of volatile organic compounds （VOCs） are harmful to the atmosphere and human health. Cata‐lytic combustion is an effective way to eliminate VOCs. The key issue is the availability of high per‐formance catalysts. Many catalysts including transition metal oxides, mixed metal oxides, and sup‐ported noble metals have been developed. Among these catalysts, the porous ones attract much attention. In this review, we focus on recent advances in the synthesis of ordered mesoporous and macroporous transition metal oxides, perovskites, and supported noble metal catalysts and their catalytic oxidation of VOCs. The porous catalysts outperformed their bulk counterparts. This excel‐lent catalytic performance was due to their high surface areas, high concentration of adsorbed oxy‐gen species, low temperature reducibility, strong interaction between noble metal and support and highly dispersed noble metal nanoparticles and unique porous structures. Catalytic oxidation of carbon monoxide over typical catalysts was also discussed. We made conclusive remarks and pro‐posed future work for the removal of VOCs.

STUDY ON DEGRADATION OF LDPE CATALYZED BY MULTI-VALENCE METALLIC ORGANIC COMPOUNDS AT COMPOST TEMPERATURE

The catalytic effects of the organic compounds of iron,tin and manganese on the degradation of low density polyethylene (LDPE) at compost temperature are discussed.A series of samples were aged in a simulating compost environment.The mechanical properties,viscosity average molecular weight (M η) of PE and hydroperoxide (POOH) concentration in the samples were measured.FT IR and DSC were also applied to characterize some samples.It was shown that the above mentioned metallic organic compounds can catalyze the degradation of LDPE efficiently.After 2 months aging,all samples with catalysts became fragile and the M η of the material decreased dramatically.Furthermore,the concentration of carbonyl and the degree of crystallinity of the material increased with the aging time.

Toxicity assessment of heavy metals and organic compounds using CellSense biosensor with E.coli

A new strategy using an arnperometric biosensor with Escherichia coli （E. coli） that provides a rapid toxicity determination of chemical compounds is described. The CellSense biosensor system comprises a biological component immobilized in intimate contact with a transducer which converts the biochemical signal into a quantifiable electrical signal. Toxicity assessment of heavy metals using E.coli biosensors could be finished within 30 min and the 50% effective concentrations （ECso） values of four heavy metals were determined. The results shows that inhibitory effects of four heavy metals to E.coli can be ranked in a decreasing order of Hg^2＋ 〉 Cu^2＋ 〉 Zn^2＋ 〉 Ni^2＋, which accords to the results of conventional bacterial counting method. The toxicity test of organic compounds by using CellSense biosensor was also demonstrated. The CellSense biosensor with E. coli shows a good, reproducible behavior and can be used for reproducible measurements.

Pollution of organic compounds and heavy metals in a coal gangue dump of the Gequan Coal Mine, China

Samples around a coal gangue dump of the Gequan Coal Mine were collected in April 2009. GC (gas chromatography) and GC/MS (gas chromatography/mass spectrometry) were employed to analyze the composition of organic matter in the samples. ICP-MS (inductively coupled plasma mass spectrometry) was used to determine the concentrations of heavy metals. The contents of organic extracts are within the range of 140-750 mg/kg. Alkand aro-ratios are relatively high. Compared to those of the background sample (GQ13 ), the contents of saturated hydrocarbon compounds in all the samples are relatively high. The contents of polycyclic aromatic hydrocarbons (PAHs) are relatively high with the distance getting closer to the coal gangue dump. These indicate that organic matter in the samples is from coal particles of the coal gangue dump. The distributions of heavy metals are very similar: the contents decrease with distance from the dump, which indicates that the harmful heavy metals from the coal gangue dump have polluted as thick as at least 500 m.

Adsorptive removal of nitrogen-containing compounds from fuel by metal-organic frameworks

The adsorptive denitrogenation from fuels over three metal-organic frameworks(MIL-96(Al),MIL-53(Al)and MIL-101(Cr))was studied by batch adsorption experiments.Four nitrogen-containing compounds(NCCs)pyridine,pyrrole,quinoline and indole were used as model NCCs in fuels to study the adsorption mechanism.The physicochemical properties of the adsorbents were characterized by XRD,N2physical adsorption,FT-IR spectrum and Hammett indicator method.The metal-organic frameworks(MOFs),especially the MIL-101(Cr)containing Lewis acid sites as well as high specific surface area,can adsorb large quantities of NCCs from fuels.In addition,the adsorptive capacity over MIL-101(Cr)will be different for NCCs with different basicity.The stronger basicity of the NCC is,the more it can be absorbed over MIL-101(Cr).Furthermore,pore size and shape also affect the adsorption capacity for a given adsorbate,which can be proved by the adsorption over MIL-53(Al)and MIL-96(Al).The pseudo-second-order kinetic model and Langmuir equation can be used to describe kinetics and thermodynamics of the adsorption process,respectively.Finally,the regeneration of the used adsorbent has been conducted successfully by just washing it with ethanol.

Nonmetallic modified zero-valent iron for remediating halogenated organic compounds and heavy metals: A comprehensive review

Zero-valent iron(ZVI),an ideal reductant treating persistent pollutants,is hampered by issues like corrosion,passivation,and suboptimal utilization.Recent advancements in nonmetallic modified ZVI(NM-ZVI)show promising potential in circumventing these challenges by modifying ZVI's surface and internal physicochemical properties.Despite its promise,a thorough synthesis of research advancements in this domain remains elusive.Here we review the innovative methodologies,regulatory principles,and reduction-centric mechanisms underpinning NM-ZVI's effectiveness against two prevalent persistent pollutants:halogenated organic compounds and heavy metals.We start by evaluating different nonmetallic modification techniques,such as liquid-phase reduction,mechanical ball milling,and pyrolysis,and their respective advantages.The discussion progresses towards a critical analysis of current strategies and mechanisms used for NM-ZVI to enhance its reactivity,electron selectivity,and electron utilization efficiency.This is achieved by optimizing the elemental compositions,content ratios,lattice constants,hydrophobicity,and conductivity.Furthermore,we propose novel approaches for augmenting NM-ZVI's capability to address complex pollution challenges.This review highlights NM-ZVI's potential as an alternative to remediate water environments contaminated with halogenated organic compounds or heavy metals,contributing to the broader discourse on green remediation technologies.

Metal–organic compounds as promising anode materials for potassium ion batteries: A mini review

Potassium-ion batteries(PIBs)represent one of the most promising alternatives to lithium-ion batteries(LIBs),owing to their exceptional attributes such as high voltages,potent power capabilities,and cost-effectiveness.Nonetheless,challenges arise from the sluggish kinetics and significant volume expansion observed during the insertion/extraction of large-radii potassium ions,leading to subpar rate performance and considerable capacity degradation in potassium-ion batteries.Consequently,it becomes imperative to explore advanced anode materials exhibiting high electrochemical activity and robust structural stability.In this regard,the present review focuses on recent progress in metal-organic compounds(MOCs)as anode materials for potassium-ion batteries,systematically discussing their outstanding merits from the perspective of metal speciation.Additionally,the principal mechanism of K ion storage within relevant MOCs is presented.Furthermore,a comprehensive summary of existing drawbacks that hinder the broader application of MOCs-based materials is provided,along with proposed guidelines and strategies for addressing the inferior performance characteristics.This review serves to illuminate the development of MOCs-based anode materials for potassium-ion batteries and offers a valuable reference for future research endeavors.

Ligand controlled structure of cadmium(Ⅱ) metal-organic frameworks for fluorescence sensing of Fe^(3+) ion and nitroaromatic compounds

Three cadmium(II) metal-organic frameworks(MOFs) based on tetracarboxylate ligands, namely[Cd_2(TTTA)(DMF)_3]·2 DMF(1),[Cd_2(TB)(H_2O)_4]·3DMF·H_2O(2)and [Cd(TEB)_(0.5)].2 DMF.4 H_2O(3) have been designed and synthesized. Complex 1 is a 2-dimensional(2 D) 3,4-connected network with 3,4 L13 topology, complex 2 features a 3-dimensional(3D) 3,4-connected tfa topology with a 2-fold interpenetrating structure and complex 3 has a 3D 4-connected dia topology with a 4-fold interpenetrating structure. Interestingly, 2 exhibits permanent pores and selective adsorption of CO_2 over CH_4. In addition, 2 shows fluorescence sensing of Fe^(3+) ion and rapid detection of nitroaromatic compounds(NACs) through fluorescence quenching.

Nafion-Induced Metal-Metal Interactions in a Platinum(II) Terpyridyl Acetylide Complex:a Luminescent Sensor for Detection of Volatile Organic Compounds

The platinum(II) terpyridyl acetylide complex [Pt(terpy)(C≡CR)]ClO4 (terpy=2,2'∶6'2''-terpyridine, R=CH2CH2CH3) (1) was incorporated into Nafion membranes. At high loading the dry membranes exhibit intense photoluminescence with max at 707 nm from the 3MMLCT state, which was not observed in fluid solution. Upon exposure to the vapor of polar volatile organic compounds (VOC), this photoluminescence was significantly red-shifed. This process was fully reversible when the VOC-incorporated membrane was dried in air. The dramatic and reversible changes in the emission spectra made the Nafion-supported complex as an interesting sensor candi-date for polar VOC.

手性金属-有机框架二维材料的液相色谱拆分性能研究

二维金属-有机框架材(2D-MOFs)具有大比表面积、厚度小、活性位点充分暴露、传质阻力小等优点,将其用作高效液相色谱(HPLC)固定相理论上可以增加色谱柱的塔板数,进而提高其分离效能,在手性分离领域展现出独特的应用价值。将手性分子L-羟基脯氨酸和D-(+)-葡萄糖分别修饰到NH_(2)-Ni/Co MOFs和Zn-NH_(2)-BDC MOFs两种2D-MOFs上,制备二维手性金属-有机框架纳米片(2D-CMOFs),再将Zn-NH_(2)-BDC-D-(+)-葡萄糖和NH_(2)-Ni/Co-L-羟基脯氨酸通过“网包法”固载在硅胶表面制备手性固定相。实验表明:19种手性药物和5种位置异构体被NH_(2)-Ni/Co-L-羟基脯氨酸手性色谱柱拆分开,基线分离了6种手性药物和3种位置异构体;10种手性药物和3种位置异构体被Zn-NH_(2)-BDC-D-(+)-葡萄糖色手性谱柱拆分开;且两个手性柱都具有良好的重复性。

金属-有机框架传感器检测水环境中全氟和多氟化合物研究进展

全氟和多氟化合物(Perfluorinated and Polyfluorinated Compounds,PFASs)作为环境中普遍存在的持久性污染物,已对水体和人们的健康造成威胁。为了减少和控制PFASs污染,保障饮用水安全,需要建立简单有效的分析方法对水环境中的PFASs进行及时监测。而基于金属有机框架(Metal-Organic Frameworks,MOFs)及其衍生物的传感器可以快速灵敏地检测水中痕量PFASs,其制备过程简单、成本低,并具有现场应用的潜力。本文主要综述MOFs光学传感器、MOFs电化学传感器和MOFs固相微萃取传感器在水环境PFASs检测中的研究进展,并讨论MOFs传感器面临的挑战以及未来发展趋势,以期为传感器技术的发展和环境中污染物的快速检测提供参考。

Coordination polymers： Challenges and future scenarios for capture and degradation of volatile organic compounds

Over the past few decades, coordination polymers/metal organic frameworks （CPs/MOFs） have drawn a great deal of attention for diverse applications due to their advantages of intrinsically ttLnable chemical structure, flexible architecture, high pore volume, high surface area, multifunctional properties, etc. To date, numerous CPs/MOFs have been developed and employed for the treatment and control of gaseous pollutants, such as volatile organic compounds （VOCs）, through capture, sorptive removal, and catalytic degradation. Nevertheless, there are also some key drawbacks and challenges for the practical application of these systems （e.g., poor selectivity, high energy （and fiscal） cost, high synthesis cost, low capacity, and difficulties in regeneration and recycling）. In this review, recent developments in CPs/MOFs research are described with their associated mechanisms for capture, sorptive removal, and catalytic degradation of VOCs. To this end, we discuss the key variables and challenges for afforded abatement of VOCs through CPs/MOFs technologies. Hopefully, this review will help the scientific community set future directions for the advancement of CPs/MOFs techniques for the effective management of diverse environmental issues.

Recent advance on VOCs oxidation over layered double hydroxides derived mixed metal oxides

Catalytic oxidation is regarded as one of the most promising strategies for volatile organic compounds(VOCs)purification.Mixed metal oxides(MMOs),after topological transformation using layered double hydroxides(LDHs)as precursors,are extensively used as catalysts for VOCs oxidation due to their uniformity advantage.This review summarizes the developments in the LDH-derived VOCs heterogeneous catalytic oxidation over the last 10 years.Particularly,it addresses the VOCs abatement performance over MMO,noble metal/MMO,core-shell structured MMO,and integral MMO film catalysts originating from LDHs.Moreover,it highlights the water vapor effect and oxidation mechanism.This review indicates that LDH-based catalysts are a category of important VOCs oxidation materials.

Sodium-treated sepiolite-supported transition metal(Cu,Fe,Ni,Mn,or Co)catalysts for HCHO oxidation

Sodium-treated sepiolite(Na Sep)-supported transition metal catalysts(TM/Na Sep;TM = Cu, Fe, Ni, Mn, and Co) were synthesized via a rotary evaporation method. Physicochemical properties of the as-synthesized samples were characterized by means of various techniques, and their catalytic activities for HCHO(0.2%) oxidation were evaluated. Among the samples, Cu/Na Sep exhibited superior performance, and complete HCHO conversion was achieved at 100 ℃(GHSV = 240000 m L/(g·h)). Additionally, the sample retained good catalytic activity during a 42 h stability test. A number of factors, including elevated acidity, the abundance of oxygen species, and favorable low-temperature reducibility, were responsible for the excellent catalytic activity of Cu/Na Sep. According to the results of the in-situ DRIFTS characterization, the HCHO oxidation mechanism was as follows:(i) HCHO was rapidly decomposed into dioxymethylene(DOM) species on the Cu/Na Sep surface;(ii) DOM was then immediately converted to formate species;(iii) the resultant formate species were further oxidized to carbonates;(iv) the carbonate species were eventually converted to CO2 and H2O.

Hierarchically-structured metal oxide-based gas sensors for volatile organic compound detection

Metal oxide-based gas sensors have been widely used in portable systems for conventional gas or volatile organic compound(VOC)vapor detection because of their fascinating advantages such as low cost,easy production,compact size and convenient measuring integration.For improving gas sensing properties including sensitivity,selectivity and response speed,many novel nanostructured metal oxides have been investigated as the sensitive materials.Among them,hierarchical structures are promising because of their sufficient inter-spaces which enable gases diffusion through the inner position of the entire sensing film.Here,we provide a summary focusing on the synthesis,gas sensing properties to VOCs and sensing mechanisms of the meso-macroporous SnO_2 hierarchical structures,and a flower-like hierarchical ZnO structure consisting of porous single-crystalline nanosheets.Our review would be able to provide an understanding on the evolution and the challenges of hierarchically structured metal oxide-based gas sensors,and create some new opportunities for the development of gas-sensing techniques.

Synthesis and DFT Calculation of a Four- coordinated Manganese Compound Mn_2(BPTC)

A new four-coordinated manganese compound Mn2（BPTC） （BPTC =- biphenyl- 2,4,4＇,6-tetracarboxylate） with flu topology net was synthesized under hydrothermal conditions. Single-crystal X-ray diffraction analysis confirms its crystal belongs to the monoclinic system, space group C2/c with a = 12.2092（11）, b = 14.6932（9）, c = 8.9998（10） A, t= 108.256（12）°, Z= 4, V= 1533.2（2） A3, Dc = 1.889 mg/m3,μ = 1.69, F（O00） = 864, the final R = 0.063 and wR = 0.201 for 1407 observed reflections （I 〉 20（/））. UV-Vis absorption spectrum shows the title compound has a strong absorption at 326 and 238 nm and the optical diffuse reflectance determination shows the band gap of the title compound is 3.15 eV. The theory calculation elucidated that the UV absorptions of the title compound mainly arise from the electron transition from bonding orbitals of BPTC4- ligand to the empty orbitals of BPTC4- and Mn（II） ions.

氧化钙活化过硫酸盐修复重金属-有机物复合污染土壤

采用氧化钙活化过硫酸盐氧化法修复重金属-有机物复合污染土壤,考察了过硫酸钠投加量、过硫酸钠与氧化钙投加比、水土比等对修复效果的影响,探讨了机理。结果表明,在过硫酸钠投加量2.5 mmol/g,氧化钙与过硫酸钠投加比2∶5,水土比3∶1的条件下,汞、砷的钝化率分别为81%和83%,存在形态由弱酸提取态转化为更为稳定的残渣态,氯仿、苯、总石油烃和1,2,3-三氯丙烷的去除率分别为99%,98%,82%,80%。氧化钙一方面,催化过硫酸盐,产生硫酸根自由基和羟基自由基氧化重金属、降解有机污染物。另一方面,通过物理固封和吸附、络合、沉淀作用钝化汞、砷。研究为重金属-有机物复合污染土壤修复技术的实际应用奠定基础。

金属有机框架材料在橡胶密封条除味性能中的应用

将金属有机框架材料(MOFs)作为三元乙丙橡胶(EPDM)密封条的除味剂,研究了MOFs对EPDM的硫化行为和力学性能的影响,考察了MOFs对EPDM释放出挥发性有机化合物气味的抑制效果。结果显示,MOFs的加入可促进EPDM的硫化且其力学性能基本不变;MOFs对有机胺和二硫化碳等气味分子具有较好的吸附效果,EPDM的气味等级从4.5降至2.0。

进口再生塑料颗粒中特征污染物的筛选及污染特征研究

为了掌握进口再生塑料颗粒中污染物的污染特性,选取5种不同类型的进口再生塑料颗粒,基于来源及再生利用过程分析其可能含有的污染物类型,筛选出重金属、双酚类化合物〔包括四溴双酚A(BPA)与四溴双酚S(BPS)〕和挥发性有机物(VOCs)3种特征污染物进行污染特征分析。结果发现,5种再生塑料颗粒中检测出6种重金属,包括Cr、Mn、Pb、Cd、Cu、Hg,其中Cr、Mn、Pb的浓度相对较高;5种再生塑料颗粒中BPS的检出率达100%,BPA的检出率为20%~100%,且BPS浓度大于BPA,这可能与实际生产中使用BPS等代替BPA有关;5种再生塑料颗粒中检测出的VOCs中,除二氯甲烷外均为苯的同系物。研究结果可为塑料颗粒后续的再生利用提供基础数据支持,并有助于相关部门进一步规范进口再生塑料颗粒的管控。

金属-有机框架化合物在制备5-羟甲基糠醛中的应用进展

5-羟甲基糠醛(5-HMF)被认为是可由生物质原料制备、最具价值和潜力替代石化工业中基础化学品的生物基化合物,可用来制备诸多高附加值的化学品。金属-有机框架化合物(MOFs)具有独特的孔结构和极高的催化性能,在生物质催化转化领域拥有潜在应用价值。介绍了5-HMF的性质、用途及MOFs的合成和应用,综述了生物质制备5-HMF的主要途径以及MOFs在制备5-HMF中的应用进展,并展望了未来的研究方向。