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期刊论文 27

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Shape selective catalysis in methylation of toluene: Development, challenges and perspectives

Jian Zhou, Zhicheng Liu, Yangdong Wang, Dejin Kong, Zaiku Xie

《化学科学与工程前沿(英文)》 2018年 第12卷 第1期   页码 103-112 doi: 10.1007/s11705-017-1671-x

摘要: Toluene methylation with methanol offers an alternative method to produce -xylene by gathering methyl group directly from C1 chemical sources. It supplies a “molecular engineering” process to realize directional conversion of toluene/methanol molecules by selective catalysis in complicated methylation system. In this review, we introduce the synthesis method of -xylene, the development history of methylation catalysts and reaction mechanism, and the effect of reaction condition in -selective technical process. If constructing -xylene as the single target product, the major challenge to develop -selective toluene methylation is to improve the -xylene selectivity without, or as little as possible, losing the fraction of methanol for methylation. To reach higher yield of -xylene and more methanol usage in methylation, zeolite catalyst design should consider improving mass transfer and afterwards covering external acid sites by surface modification to get short “micro-tunnels” with shape selectivity. A solid understanding of mass transfer will benefit realizing the aim of converting more methanol feedstock into -methyl group.

关键词: shape selective catalysis     methylation of toluene    

Environmental pollution and DNA methylation: carcinogenesis, clinical significance, and practical applications

null

《医学前沿(英文)》 2015年 第9卷 第3期   页码 261-274 doi: 10.1007/s11684-015-0406-y

摘要:

Environmental pollution is one of the main causes of human cancer. Exposures to environmental carcinogens result in genetic and epigenetic alterations which induce cell transformation. Epigenetic changes caused by environmental pollution play important roles in the development and progression of environmental pollution-related cancers. Studies on DNA methylation are among the earliest and most conducted epigenetic research linked to cancer. In this review, the roles of DNA methylation in carcinogenesis and their significance in clinical medicine were summarized, and the effects of environmental pollutants, particularly air pollutants, on DNA methylation were introduced. Furthermore, prospective applications of DNA methylation to environmental pollution detection and cancer prevention were discussed.

关键词: environmental pollution     DNA methylation     cancer     biomarker     diagnosis     therapy     prevention    

Adsorption of benzene and toluene from waste gas using activated carbon activated by ZnCl

Leila KARIMNEZHAD,Mohammad HAGHIGHI,Esmaeil FATEHIFAR

《环境科学与工程前沿(英文)》 2014年 第8卷 第6期   页码 835-844 doi: 10.1007/s11783-014-0695-4

摘要: A series of activated carbons with high surface area were prepared from walnut shell using chemical activation with ZnCl . In this research the carbonization stage was carried out at 500°C. The performance of the synthesized carbons evaluated in adsorption of benzene and toluene from waste gas. The influence of impregnation ratio on the characteristics of synthesized activated carbons as well as their adsorption capacity was investigated. The ratio of activation agent to walnut shell was selected in the range of 0.5–2.0 wt/wt. The synthesized activated carbons were characterized using XRD, SEM, BET and FTIR techniques. The highest activated carbon production yield was obtained at impregnation ratio of 1.5 wt/wt. The XRD analysis illustrated that peaks intensity decreased with increasing impregnation ratio showing that amorphous property of samples was increased. The SEM analysis revealed successful pore development in synthesized activated carbons obtained at high impregnation ratios. The surface area of the activated carbons increased with increasing impregnation ratio and its maximum value reached 2643 m ?g at impregnation ratio of 2/1. FTIR analysis indicated that the relative amount of different acidic surface groups on synthesized carbons was a function of impregnation ratio. Experimental results for benzene and toluene adsorption showed a high potential of employing synthesized impregnated activated carbon for treatment of waste gas. Generally, the amount of VOC adsorbed on the surface was affected by physicochemical properties of synthesized activated carbons.

关键词: Chemical activation     activated carbon     textural characterization     adsorption     benzene     toluene    

Microwave-assisted catalytic oxidation of gaseous toluene with a Cu-Mn-Ce/cordierite honeycomb catalyst

Longli Bo, Shaoyuan Sun

《化学科学与工程前沿(英文)》 2019年 第13卷 第2期   页码 385-392 doi: 10.1007/s11705-018-1738-3

摘要: A novel Cu-Mn-Ce/cordierite honeycomb catalyst was prepared by an incipient wetness method and the catalyst was characterized. The active ingredients were present as various spinel species of Cu, Mn and Ce oxides with different valences and they were unevenly dispersed over the surface of the catalyst. The catalytic oxidation of gaseous toluene was primarily investigated using a fixed bed reactor under microwave heating in the continuous flow mode. Under the optimal conditions of 6.7 wt-% loading of the active component, a bed temperature of 200°C, a flow rate of 0.12 m ·h and an initial concentration of toluene of 1000 mg·m , the removal and mineralization efficiencies of toluene were 98% and 70%, respectively. Thus the use of the microwave effectively improved the oxidation of toluene and this is attributed to dipole polarization and hotspot effects. After four consecutive cycles (a total of 1980 min), the Cu-Mn-Ce/cordierite catalyst still exhibited excellent catalytic activity and structural stability, and the toluene removal was higher than 90%. This work demonstrates the possibility of treating volatile organic compounds in exhaust gases by microwave-assisted catalytic oxidation.

关键词: microwave     catalytic oxidation     toluene     Cu-Mn-Ce/cordierite     mineralization    

and characterization of novel carbon molecular sieve membrane/PSSF composite by pyrolysis method for toluene

Ying Yan, Peng Huang, Huiping Zhang

《化学科学与工程前沿(英文)》 2019年 第13卷 第4期   页码 772-783 doi: 10.1007/s11705-019-1827-y

摘要: Carbon molecular sieve membrane (CMSM)/paper-like stainless steel fibers (PSSF) has been manufactured by pyrolyzing poly (furfuryl alcohol) (PFA) coated on the metal fibers. PFA was synthesized using oxalic acid dihydrate as a catalyst and coated on microfibers by dip coating method. For the purpose of investigating the effects of final carbonization temperature, the composites were carbonized between 400°C and 800°C under flowing nitrogen. The morphology and microstructure were examined by X-ray diffraction, Fourier transforms infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, N adsorption and desorption, Raman spectra and X-ray photoelectron spectra. The consequences of characterization showed that the CMSM containing mesopores of 3.9 nm were manufactured. The specific surface area of the CMSM/PSSF fabricated in different pyrolysis temperature varies from 26.5 to 169.1 m ∙g and pore volume varies from 0.06 to 0.23 cm ∙g . When pyrolysis temperature exceeds 600°C, the specific surface, pore diameter and pore volume decreased as carbonization temperature increased. Besides, the degree of graphitization in carbon matrix increased with rising pyrolysis temperature. Toluene adsorption experiments on different structured fixed bed that was padded by CMSM/PSSF and granular activated carbon (GAC) were conducted. For the sake of comparison, adsorption test was also performed on fixed bed packed with GAC. The experimental results indicated that the rate constant ′ was dramatically increased as the proportion of CMCM/PSSF composites increased on the basis of Yoon-Nelson model, which suggested that structured fixed bed padded with CMSM/PSSF composite offered higher adsorption rate and mass transfer efficiency.

关键词: carbon molecular sieve membrane     stainless steel fibers     pyrolysis     structured fixed bed     toluene    

Effects of two transition metal sulfate salts on secondary organic aerosol formation in toluene/NO

Biwu CHU, Jiming HAO, Junhua LI, Hideto TAKEKAWA, Kun WANG, Jingkun JIANG

《环境科学与工程前沿(英文)》 2013年 第7卷 第1期   页码 1-9 doi: 10.1007/s11783-012-0476-x

摘要: Aerosol phase reactions play a very important role on secondary organic aerosol (SOA) formation, and metal-containing aerosols are important components in the atmosphere. In this study, we tested the effects of two transition metal sulfate salts, manganese sulfate (MnSO ) and zinc sulfate (ZnSO ), on the photochemical reactions of a toluene/NO photooxidation system in a 2 m smog chamber. By comparing photochemical reaction products of experiments with and without transition metal sulfate seed aerosols, we evaluated the effects of transition metal sulfate seed aerosols on toluene consumption, NO conversion and the formation of ozone and SOA. MnSO and ZnSO seed aerosols were found to have similar effects on photochemical reactions, both enhance the SOA production, while showing negligible effects on the gas phase compounds. These observations are consistent when varying metal sulfate aerosol concentrations. This is attributed to the catalytic effects of MnSO and ZnSO seed aerosols which may enhance the formation of condensable semivolatile compounds. Their subsequent partitioning into the aerosol phase leads to the observed SOA formation enhancement.

关键词: manganese sulfate     zinc sulfate     seed aerosols     toluene photooxidation     secondary organic aerosol    

CuO/zeolite catalyzed oxidation of gaseous toluene under microwave heating

Longli BO, Jianbo LIAO, Yucai ZHANG, Xiaohui WANG, Quan YANG

《环境科学与工程前沿(英文)》 2013年 第7卷 第3期   页码 395-402 doi: 10.1007/s11783-012-0417-8

摘要: The development of a combined process of catalytic oxidation and microwave heating for treatment of toluene waste gas was described in this work. Toluene, a typical toxic volatile organic compound, was oxidized through a fixed bed reaction chamber containing zeolite-supported copper oxide (CuO/zeolite) catalyst mixed with silicon carbide (SiC), an excellent microwave-absorbing material. The target compound was efficiently degraded on the surface of the catalyst at high reaction temperature achieved by microwave-heated SiC. A set of experimental parameters, such as microwave power, air flow and the loading size of CuO etc., were investigated, respectively. The study demonstrated these parameters had critical impact on toluene degradation. Under optimal condition, 92% toluene was removed by this combined process, corresponding to an 80%–90% TOC removal rate. Furthermore, the catalyst was highly stable even after eight consecutive 6-h runs. At last, a hypothetical degradation pathway of toluene was proposed based on the experimental data obtained from gas chromatography-mass spectrum and Fourier transform infrared spectroscopy analyses.

关键词: microwave     catalytic oxidation     CuO/zeolite catalyst     silicon carbide (SiC)     toluene    

Optimized porous clay heterostructure for removal of acetaldehyde and toluene from indoor air

Pu ZHAO,Lizhong ZHU

《环境科学与工程前沿(英文)》 2016年 第10卷 第2期   页码 219-228 doi: 10.1007/s11783-014-0760-z

摘要: Adsorption is the most widely used technology for the removal of indoor volatile organic compounds (VOCs). However, existing adsorbent-based technologies are inadequate to meet the regulatory requirement, due to their limited adsorption capacity and efficiency, especially under high relative humidity (RH) conditions. In this study, a series of new porous clay heterostructure (PCH) adsorbents with various ratios of micropores to mesopores were synthesized, characterized and tested for the adsorption of acetaldehyde and toluene. Two of them, PCH25 and PCH50, exhibited markedly improved adsorption capability, especially for hydrophilic acetaldehyde. The improved adsorption was attributed to their large micropore areas and high micropore-to-mesopore volume ratios. The amount of acetaldehyde adsorbed onto PCH25 at equilibrium reached 62.7 mg·g , eight times as much as the amount adsorbed onto conventional activated carbon (AC). Even at a high RH of 80%, PCH25 removed seven and four times more of the acetaldehyde than AC and the unmodified raw PCHs did, respectively. This new PCH optimized for their high adsorption and resistance to humidity has promising applications as a cost-effective adsorbent for indoor air purification.

关键词: porous clay heterostructure     volatile organic compounds     adsorption     adsorbent     indoor air    

Effects of exogenous acylated homoserine lactones on biofilms in biofilters for gaseous toluene treatment

《环境科学与工程前沿(英文)》 2023年 第17卷 第2期 doi: 10.1007/s11783-023-1617-0

摘要:

● Biofilm formation was enhanced by exogenous AHLs.

关键词: Quorum sensing     AHLs     Biofilter     Biofilm formation    

Adsorption of toluene, ethylbenzene and xylene isomers on multi-walled carbon nanotubes oxidized by different

Fei YU, Jie MA, Yanqing WU

《环境科学与工程前沿(英文)》 2012年 第6卷 第3期   页码 320-329 doi: 10.1007/s11783-011-0340-4

摘要: Multi-walled carbon nanotubes (MWCNTs) were fabricated and oxidized by different concentrations of sodium hypochlorite (NaOCl) solutions. The untreated MWCNTs and modified MWCNTs were employed as adsorbents to study their characterizations and adsorption performance of toluene, ethylbenzene and xylene isomers (TEX) in an aqueous solution. The physicochemical properties of MWCNTs were greatly affected after oxidation, which influences TEX adsorption capacity. The 3% NaOCl-oxidized MWCNTs shows the greatest enhancement in TEX adsorption, followed by the 30% NaOCl. More interestingly, the 15% NaOCl-oxidized MWCNTs has lower adsorption capacities than untreated MWCNTs. The adsorption mechanism of TEX on treated MWCNTs is attributed to the combined action of hydrophobic interaction, π-π bonding interaction between the aromatic ring of TEX and the oxygen-containing functional groups of MWCNTs and electrostatic interaction. 3% NaOCl solution could not only introduce much oxygen-containing functional groups on MWCNTs, but also lead to less damage for the pore structure. This suggests that the CNTs-3% NaOCl is efficient adsorbent for TEX and that they may possess good potential for TEX removal in wastewater treatment.

关键词: adsorption     toluene     ethylbenzene and xylene isomers (TEX)     multi-walled carbon nanotube     surface oxidation    

DNA methylation-based subclassification of psoriasis in the Chinese Han population

Fusheng Zhou, Changbing Shen, Yi-Hsiang Hsu, Jing Gao, Jinfa Dou, Randy Ko, Xiaodong Zheng, Liangdan Sun, Yong Cui, Xuejun Zhang

《医学前沿(英文)》 2018年 第12卷 第6期   页码 717-725 doi: 10.1007/s11684-017-0588-6

摘要: Psoriasis (Ps) is an inflammatory skin disease caused by genetic and environmental factors. Previous studies on DNA methylation (DNAm) found genetic markers that are closely associated with Ps, and evidence has shown that DNAm mediates genetic risk in Ps. In this study, Consensus Clustering was used to analyze DNAm data, and 114 Ps patients were divided into three subclassifications. Investigation of the clinical characteristics and copy number variations (CNVs) of , , and in the three subclassifications revealed no significant differences in gender ratio and in Ps area and severity index (PASI) score. The proportion of late-onset (≥40 years) Ps patients was significantly higher in type I than in types II and III ( = 0.035). Type III contained the smallest proportion of smokers and the largest proportion of non-smoking Ps patients ( = 0.086). The CNVs of and showed no significant differences but the CNV of significantly differed among the three subclassifications ( = 0.044). This study is the first to profile Ps subclassifications based on DNAm data in the Chinese Han population. These results are useful in the treatment and management of Ps from the molecular and genetic perspectives.

关键词: psoriasis     DNA methylation     subclassification    

Influence of environmental temperature and relative humidity on photocatalytic oxidation of toluene on

GUO Ting, BAI Zhipeng, WU Can, ZHU Tan

《环境科学与工程前沿(英文)》 2008年 第2卷 第2期   页码 224-229 doi: 10.1007/s11783-008-0039-3

摘要: TiO supported on active carbon fiber (TiO/ACF), an absorbable photocatalyst, is a new kind of material applied in air purification. In this paper, the influence of environmental temperature (T) and relative humidity (RH) on the gas-solid adsorption of toluene and the photocatalytic oxidation (PCO) efficiency of adsorbed toluene on TiO/ACF were studied, and then, the purification capability of TiO/ACF was estimated. PCO results showed that although the PCO efficiency increased under high RH and T levels, the amount of adsorption of toluene decreased. Moreover, quantitative analysis results of intermediates indicated that more environmental risk emerged when PCO of toluene was carried out at higher environmental T and RH levels because more toxic intermediates would be accumulated on the TiO/ACF. So, it is significant to control the environmental T and RH conditions in the application of the PCO technique. T = 25°C and RH = 30% is the optimal condition for purifying toluene in our experimental system.

关键词: application     gas-solid adsorption     technique     TiO/ACF     experimental    

A biofilter model for simultaneous simulation of toluene removal and bed pressure drop under varied inlet

Jinying XI,Insun KANG,Hongying HU,Xian ZHANG

《环境科学与工程前沿(英文)》 2015年 第9卷 第3期   页码 554-562 doi: 10.1007/s11783-014-0671-z

摘要: In this study, a biofiltration model including the effect of biomass accumulation and inert biomass growth is developed to simultaneously predict the Volatile Organic Compounds (VOCs) removal and filter bed pressure drop under varied inlet loadings. A laboratory-scale experimental biofilter for gaseous toluene removal was set up and operated for 100 days with inlet toluene concentration ranging from 250 to 2500 mg?m . According to sensitivity analysis based on the model, the VOCs removal efficiency of the biofilter is more sensitive to Henry’s constant, the specific surface area of the filter bed and the thickness of water layer, while the filter bed pressure drop is more sensitive to biomass yield coefficient and original void fraction. The calculated toluene removal efficiency and bed pressure drop satisfactorily fit the experimental data under varied inlet toluene loadings, which indicates the model in this study can be used to predict VOCs removal and bed pressure drop simultaneously. Based on the model, the effect of mass-transfer parameters on VOCs removal and the stable-run time of a biofilter are analyzed. The results demonstrate that the model can function as a good tool to evaluate the effect of biomass accumulation and optimize the design and operation of biofilters.

关键词: Volatile Organic Compounds (VOCs)     biofilters     modelling     biomass accumulation     pressure drop    

Mutant DNA methylation regulators endow hematopoietic stem cells with the preleukemic stem cell property

null

《医学前沿(英文)》 2015年 第9卷 第4期   页码 412-420 doi: 10.1007/s11684-015-0423-x

摘要:

Genetic mutations are considered to drive the development of acute myeloid leukemia (AML). With the rapid progress in sequencing technologies, many newly reported genes that are recurrently mutated in AML have been found to govern the initiation and relapse of AML. These findings suggest the need to distinguish the driver mutations, especially the most primitive single mutation, from the subsequent passenger mutations. Recent research on DNA methyltransferase 3A (DNMT3A) mutations provides the first proof-of-principle investigation on the identification of preleukemic stem cells (pre-LSCs) in AML patients. Although DNMT3A mutations alone may only transform hematopoietic stem cells into pre-LSCs without causing the full-blown leukemia, the function of this driver mutation appear to persist from AML initiation up to relapse. Therefore, identifying and targeting preleukemic mutations, such as DNMT3A mutations, in AML is a promising strategy for treatment and reduction of relapse risk.

关键词: preleukemic stem cell     acute myeloid leukemia     relapse     DNMT3A    

Steam reforming of toluene as a tar model compound with modified nickel-based catalyst

Omeralfaroug KHALIFA, Mingxin XU, Rongjun ZHANG, Tahir IQBAL, Mingfeng LI, Qiang LU

《能源前沿(英文)》 2022年 第16卷 第3期   页码 492-501 doi: 10.1007/s11708-021-0721-8

摘要: Catalytic steam reforming is a promising route for tar conversion to high energy syngas in the process of biomass gasification. However, the catalyst deactivation caused by the deposition of residual carbon is still a major challenge. In this paper, a modified Ni-based Ni-Co/Al O -CaO (Ni-Co/AC) catalyst and a conventional Ni/Al O (Ni/A) catalyst were prepared and tested for tar catalytic removal in which toluene was selected as the model component. Experiments were conducted to reveal the influences of the reaction temperature and the ratio between steam to carbon on the toluene conversion and the hydrogen yield. The physicochemical properties of the modified Ni-based catalyst were determined by a series of characterization methods. The results indicated that the Ni-Co alloy was determined over the Ni-Co/AC catalyst. The doping of CaO and the presence of Ni-Co alloy promoted the performance of toluene catalytic dissociation over Ni-Co/AC catalyst compared with that over Ni/A catalyst. After testing in steam for 40 h, the carbon conversion over Ni-Co/AC maintained above 86% and its resistance to carbon deposition was superior to Ni/A catalyst.

关键词: catalytic steam reforming     tar model compound     Ni-based catalyst     carbon resistance    

标题 作者 时间 类型 操作

Shape selective catalysis in methylation of toluene: Development, challenges and perspectives

Jian Zhou, Zhicheng Liu, Yangdong Wang, Dejin Kong, Zaiku Xie

期刊论文

Environmental pollution and DNA methylation: carcinogenesis, clinical significance, and practical applications

null

期刊论文

Adsorption of benzene and toluene from waste gas using activated carbon activated by ZnCl

Leila KARIMNEZHAD,Mohammad HAGHIGHI,Esmaeil FATEHIFAR

期刊论文

Microwave-assisted catalytic oxidation of gaseous toluene with a Cu-Mn-Ce/cordierite honeycomb catalyst

Longli Bo, Shaoyuan Sun

期刊论文

and characterization of novel carbon molecular sieve membrane/PSSF composite by pyrolysis method for toluene

Ying Yan, Peng Huang, Huiping Zhang

期刊论文

Effects of two transition metal sulfate salts on secondary organic aerosol formation in toluene/NO

Biwu CHU, Jiming HAO, Junhua LI, Hideto TAKEKAWA, Kun WANG, Jingkun JIANG

期刊论文

CuO/zeolite catalyzed oxidation of gaseous toluene under microwave heating

Longli BO, Jianbo LIAO, Yucai ZHANG, Xiaohui WANG, Quan YANG

期刊论文

Optimized porous clay heterostructure for removal of acetaldehyde and toluene from indoor air

Pu ZHAO,Lizhong ZHU

期刊论文

Effects of exogenous acylated homoserine lactones on biofilms in biofilters for gaseous toluene treatment

期刊论文

Adsorption of toluene, ethylbenzene and xylene isomers on multi-walled carbon nanotubes oxidized by different

Fei YU, Jie MA, Yanqing WU

期刊论文

DNA methylation-based subclassification of psoriasis in the Chinese Han population

Fusheng Zhou, Changbing Shen, Yi-Hsiang Hsu, Jing Gao, Jinfa Dou, Randy Ko, Xiaodong Zheng, Liangdan Sun, Yong Cui, Xuejun Zhang

期刊论文

Influence of environmental temperature and relative humidity on photocatalytic oxidation of toluene on

GUO Ting, BAI Zhipeng, WU Can, ZHU Tan

期刊论文

A biofilter model for simultaneous simulation of toluene removal and bed pressure drop under varied inlet

Jinying XI,Insun KANG,Hongying HU,Xian ZHANG

期刊论文

Mutant DNA methylation regulators endow hematopoietic stem cells with the preleukemic stem cell property

null

期刊论文

Steam reforming of toluene as a tar model compound with modified nickel-based catalyst

Omeralfaroug KHALIFA, Mingxin XU, Rongjun ZHANG, Tahir IQBAL, Mingfeng LI, Qiang LU

期刊论文