Coking and decoking chemistry for resource utilization of polycyclic aromatic hydrocarbons(PAHs)and low-carbon process

Low-carbon process for resource utilization of polycyclic aromatic hydrocarbons(PAHs)in zeolitecatalyzed processes,geared to carbon neutrality-a prominent trend throughout human activities,has been bottlenecked by the lack of a complete mechanistic understanding of coking and decoking chemistry,involving the speciation and molecular evolution of PAHs,the plethora of which causes catalyst deactivation and forces regeneration,rendering significant CO_(2) emission.Herein,by exploiting the high-resolution matrix-assisted laser desorption/ionization Fourier-transform ion cyclotron resonance mass spectrometry(MALDI FT-ICR MS),we unveil the missing fingerprints of the mechanistic pathways for both formation and decomposition of cross-linked cage-passing PAHs for SAPO-34-catalyzed,industrially relevant methanol-to-olefins(MTO)as a model reaction.Notable is the molecule-resolved symmetrical signature:their speciation originates exclusively from the direct coupling of in-cage hydrocarbon pool(HCP)species,whereas water-promoted decomposition of cage-passing PAHs initiates with selective cracking of inter-cage local structures at 8-rings followed by deep aromatic steam reforming.Molecular deciphering the reversibly dynamic evolution trajectory(fate)of full-spectrum aromatic hydrocarbons and fulfilling the real-time quantitative carbon resource footprints advance the fundamental knowledge of deactivation and regeneration phenomena(decay and recovery motifs of autocatalysis)and disclose the underlying mechanisms of especially the chemistry of coking and decoking in zeolite catalysis.The positive yet divergent roles of water in these two processes are disentangled.These unprecedented insights ultimately lead us to a steam regeneration strategy with valuable CO and H_(2) as main products,negligible CO_(2) emission in steam reforming and full catalyst activity recovery,which further proves feasible in other important chemical processes,promising to be a sustainable and potent approach that contributes to carbon-neutral chemical industry.

Study on polycyclic aromatic hydrocarbons (PAHs) contents and sources in the surface soil of Huizhou City, South China, based on multivariate statistics analysis

Studies of polycyclic aromatic hydrocarbons (PAHs) in the surface soil were conducted in Huizhou City, which is located in the Pearl River Delta, South China. Sixteen PAHs in 42 soil samples were detected. The results showed that 4 components of PAHs were detectable in all soil samples, and other 12 components were also detect- able to some extent. The total PAHs contents range from 35.40 to 534.5 μg/kg with the mean value of 123.09 μg/kg. Soil in Huizhou was slightly polluted by PAHs according to Maliszewska-Kordybach’s study. It can be confirmed that the increase of PAHs contents in the surface soil of Huizhou City is closely connected to human activities. Mul- tivariate analysis was also made in this study. Principal component analysis was used to constrain their origins, and 3 principal components (PCs) were extracted. The results showed that coal combustion and oil spilling made the major contributions to PAHs. Cluster analysis was made and 16 priority PAHs were classified as 4 sorts, and the result revealed the differences in environmental behavior, chemical properties and sources of PAHs.

Transport and behavior of marine oil spill containing polycyclic aromatic hydrocarbons in mesocosm experiments

Polycyclic aromatic hydrocarbons(PAHs)are one of the most important groups in oil,and re sponsible for major toxic and/or carcinogenic impact on humans and wildlife.It is important to understand the behavior of PAHs in marine environment after an oil-spill incident.However,interaction between petroleum PAHs and microbial communities in a marine environment remains unclear.Therefore,a series of mesocosm experiments were conducted.in which water-accommodated fraction(WAF)of oil was generated to simulate an oil-spill scenario and to analyze the transport and behavior of marine oil spill containing PAHs with and without dispersants.Results indicate that the application of dispersant could increase the concentration of total PAHs in water column due mainly to significant increase in the concentration of highmolecular weight(HMW)PAHs at a lower removal rate.At the end of the 7-day experiment,significant amount of HMW PAHs were accumulated in sediment.In general,the application of dispersant did not increase the sediment uptake of PAHs but increased the PAHs concentration in water column.

Development of analytical methods for polycyclic aromatic hydrocarbons (PAHs) in airborne particulates: A review

In the present work, the different sample collection, pretreatment and analytical methods for polycyclic aromatic hydrocarbons （PAHs） in airborne particulates is systematacially reviewed, and the applications of these pretreatment and analytical methods for PAHs are compared in detail. Some comments on the future expectation are also presented.

Ultrasensitive Detection of Polycyclic Aromatic Hydrocarbons(PAHs) in Water Using Three-Dimensional SERS Substrate Based on Porous Material and pH 13 Gold Nanoparticles

Sensitivity is crucially important for surface-enhanced Raman spectroscopy(SERS)application to detect trace-level polycyclic aromatic hydrocarbons(PAHs)in the seawater.In this study,a high sensitivity three-dimensional(3-D)SERS substrate composed with syringe filter,glycidyl methacrylate-ethylene dimethacrylate(GMA-EDMA)porous material and optimal parameters(57 nm,pH 13)gold nanoparticles(Au NPs)was developed for the detection of PAHs in water.The enhancement effect and repeatability of this 3-D substrate were also explored.The Raman intensity of pyrene using 3-D SERS substrate is about 8 times higher than that of substrate only using p H 13 gold colloid solution and about 12 times higher than that of substrate using natural Au NPs and GMA-EDMA porous material,which means both the pH 13 AuN Ps and the GMA-EDMA porous material are important factors for the sensitivity of this 3-D SERS substrate.Good repeatability of this optimal 3-D substrate was obtained.The relative standard deviation(RSD)is less than 8.66% on the same substrate and less than 3.69% on other different substrates.Four kinds of PAHs,i.e.,phenanthrene,pyrene,benzo(a)pyrene,benzo(k)fluoranthene and their mixture,were detected at the different concentrations.Their limits of detection(LODs)are 8.3×10^-10(phenanthrene),2.1×10^-10(pyrene),3.8×10^-10(benzo(a)pyrene)and 1.7×10^-10 mol L^-1(benzo(k)fluoranthene),respectively.In addition,these four PAHs were also detected by fluorescence spectroscopy to evaluate the sensitivity of SERS technology using this optimal 3-D SERS substrate.The results showed that the sensitivity of SERS based on the 3-D SERS substrate even using the portable Raman system was closed to that of fluorescence spectroscopy.Therefore,the SERS technology using this optimal 3-D substrate is expected to be an in-situ method for the detection of environmental PAHs.

The Pollution Characteristic of Polycyclic Aromatic Hydrocarbons (PAHs) in Typical Sewage Irrigation Area in North of China

This research aims to investigate the pollution characteristic of PAHs in Xiaodian sewage irrigation area. The result shows that the concentrations ofPAHs range from 47.94 to 46432.85ng/g while that of the total components of the 16 kinds of PAHs are 5969.81ng/g. PAHs with for rings and more than 4 rings are the main and important pollutants in topsoils of Xiaodian District. The main input of PAHs is combustion source, and the main pollution source in this area is fired coal. The topsoils in Xiaodian District are polluted by human activity in varying degrees. 23 of all 31 topsoil samples have been heavily polluted, especially those located nearby developed industrial townships and irrigation channels.

Bioremediation of Total Polycyclic Aromatic Hydrocarbon Contaminated Soil Using Nitrified Sawdust and Pseudomonas auriginosa

Bioremediation involving bioaugmentation and biostimulation are eco-friendly existing methods for degrading polycyclic aromatic hydrocarbons (PAHs) in contaminated soils. This study investigates the efficiency of Pseudomonas auriginosa and nutrient-enriched sawdust (SD) in biodegrading ∑PAHs in contaminated soil (CS). Four compost mixtures of CS/SD (1:0, 3:1, 1:1, 1:3) were applied for 2, 4, 6, 8-week bio-cleanup after inoculation. Results show ∑PAHs concentrations decreased with increasing time of treatment for all four compost in experimental and control setups. The removal efficiency of ∑PAHs was clearly associated with nutrient-enriched sawdust and Pseudomonas auriginosa, especially for 3:1, 1:1, and 1:3 ratios. Both factors had a significant effect (p = 0.05) on removal efficiency compared to the control setup. The highest (78.5%) and lowest (37.8%) ∑PAHs removal efficiency were observed for CS/SD ratios of 1:3 and 1:0 respectively after 8-week treatment. In this instance, this study recommends a CS/SD ratio of 1:3 at 8-week treatment to achieve maximum removal efficiency of ∑PAHs in contaminated soils.

CARBONIZED FIBROUS RESIN AS A NEW SORBENT FOR SAMPLING POLYCYCLIC AROMATIC HYDROCARBONS (PAHS) IN AMBIENT AIR

A new sampling method of ambient air analysis using carbonized fibrous resin as asorbent for polycyclic aromatic hydrocarbons (PAHs) was reported.The physical and chemical properties of the carbonized fibrous resins were measured. Thesample pretreatment with ultrasonic extraction and subsequent clean-up ehition through a silica gelcolumn was optimized. The suitable ultrasonic extraction conditions were selected as follows: resinweight was 1.5 g, ultrasonic extraction time 20 min, volume of extraction solvent 100 mi andextraction operation times 2～3. The concentrated extractable organic matter was submitted to nextstep of clean-up procedure of adsorption chromatography on silica gel column/n-hexane and amixture of dichloromethene:n-hexane solution 2:3 (v/v). The PAHs fractions in the real samplesfrom Changzhou, China were particularly analyzed using GC-MS data system and the data of massspectra, retention times and scan numbers of the real samples were compared with that of thestandards of 16 PAHs listed by the US EPA as 'priority pollutants' of the environment. Theanalysis of the real samples indicates that the carbonized fibrous resin is a good sorbent. Thepretreatment of samples of ambient air with carbonized fibrous resin as a sorbent for P,AHs isproved to be reliable and might be used for the procedure of the determination of PAHs inatmospheric environment.

Polycyclic aromatic hydrocarbons in soils of Beijing and Tianjin region: Vertical distribution, correlation with TOC and transport mechanism

The contents and distribution of 20 polycyclic aromatic hydrocarbons （PAHs） and heterocyclic aromatic hydrocarbons （HAHs） were investigated in 16 soil profiles of Beijing and Tianjin region. Transport of high molecular weight PAHs （HMWPAHs） and the correlation between total organic carbon （TOC） and their concentrations were also discussed. The results indicated that highly contaminated sites were located at urban or wastewater irrigation areas and pollutants mainly accumulated in topsoil （〈 40 cm）, with a sharp content decrease at the vertical boundary of 30-40 cm. Total PAHs/HAHs concentrations in soils from Tianjin were markedly greater than those from Beijing. Even the contents at bottoms of soil profiles in Tianjin were higher than those in topsoils of Beijing soil profile. HMWPAHs dominated the PAH profiles, exhibiting a uniform distribution of pyrogenic origin between topsoils and deep layers. Furthermore, the percentages of HMWPAHs remained relative constant with the depth of soil profiles, which were consistent with the distribution of particulate matter-associated PAHs in the local atmospheric environments. Therefore, HMWPAHs transport with particulates might be the predominant source found in soil profiles.

Polycyclic Aromatic Hydrocarbons in Agricultural Soils of the Southern Subtropics,China

从到全球环境的污染的中国的副热带的区域的坚持的有机污染物(流行音乐) 的贡献被付了大注意；然而，很少在中国的这些区域以内在农业生态系统对流行音乐的国家被知道。这研究首先揭示了污染的国家和多不的芳族烃的分发(哼) 在在副热带的区域的农业土壤。115 表土(0 20 厘米) 在这些区域的胃被取样。集中和类型哼坚定的使用气体色层法被连接到质谱法(GCMS ) 。总数哼集中从 22.1 ～ 1 256.9 ng g ? 1，与 318.2 ±的一个平均数 148.2 ng g ? 1。措辞笼统地，水流哼集中比大多数哼低层次从不同国家和区域在很多调查报导了。哼异构体比率显示了那焦性没食子酸 lysin 的起源例如与车辆尾巴气体和工业排出物有关的石块燃料燃烧，是主导的来源在中国的南部的副热带的区域哼。尽管哼集中与减少的污染，人口，和交通密度减少了，在很大程度上哼作文在整个副热带的土壤是类似的与萘，菲， fluoranthene，和是主导的 benzo (b) fluoranthene。

Uptake, accumulation and translocation of polycyclic aromatic hydrocarbons by winter wheat cultured on oily sludge-amended soil

The purpose of this study is to comparatively investigate the plant uptake, accumulation and translocation behaviors of polycyclic aromatic hydrocarbons (PAHs) as priority pollutants in soil contaminated with oily sludge. The influence of different oily sludge application doses on the uptake of contaminants was studied together with the profile of individual PAH in roots, straws and leaves of winter wheat. Pot experiments were conducted using oily sludge application doses of 0, 5, 10, 15 and 20 percent, respectively. The total PAHs contents of control soil and oily sludge were 16.96 and 3504.66 μg/g, respectively. Analysis for the contents of the 16 PAHs was carried out with a HPLC-UV using plant tissue samples obtained at the 265th day of growth. The total PAHs contents in treated winter wheat were 9.02-334.81 ng/g for roots, 8.45-336.52 ng/g for straws and 10.70-406.32 ng/g for leaves. In addition to 5% of oily sludge dose, the total PAHs content in leaves was always highest under other doses of oily sludge application. With respect to individual PAH, the content did not show a significant plant tissue related trend. However, both the total content and individual content of PAHs in treated winter wheat tissues did increase with increasing oily sludge application dose. Another analysis for the control soil indicates that the degradation rate of PAHs was significantly enhanced by winter wheat after 265 days of growth based on the residual concentrations of PAHs in planted and unplanted soils.

Characterization of the parent and hydroxylated polycyclic aromatic hydrocarbons in the soil of the Fildes Peninsula,Antarctica

Polycyclic aromatic hydrocarbons(PAHs)and hydroxylated polycyclic aromatic hydrocarbons(OH-PAHs)were investigated in the soil of the Fildes Peninsula,Antarctica.Various analytes were detected,and the concentration of OH-PAHs was 0.3001.847 ng g 1 dry weight,with the dominant components being danthron and 1-hydroxy-phenanthrene.The relationship between soil total organic matter(TOM),OH-PAHs,and the parent PAHs in the soil was studied.No significant correlation was detected between the spatial distribution of OH-PAHs and the occurrence of PAHs,whereas a positive correlation with TOM was found.

Dissipation of polycyclic aromatic hydrocarbons in crop soils amended with oily sludge

Oil fields present a potential ecological risk to nearby farmland soil. Here we present a new method designed to evaluate the ability of winter wheat(Triticum aestivum) to contribute to the dissipation of polycyclic aromatic hydrocarbons(PAHs), which are priority pollutants in soils contaminated by oily sludge. The influence of different doses of oily sludge on the dissipation of PAHs was studied along with individual PAH profiles in soils after different periods of plant growth. Five soil samples were artificially contaminated with different percentages of oily sludge(0 %, 5 %, 10 %, 15 % and 20 %). Winter wheat grew in the oily sludge–amended soils for 265 days.PAH content in the soils was monitored over the course of the study. The rate of PAH dissipation is related to the properties of different PAHs, period of winter wheat growth, and oily sludge application dose. Analysis for treated soils indicates that the dissipation of PAHs increased significantly over the first 212 days, followed by minimal changes over the final 53 days of treatment. In contrast, PAH dissipation slowed with increasing oily sludge application. For each PAH, the experimental results showed a significant compound-dependent trend. Winter wheat in the present study significantly enhanced the dissipation of PAHs in oily sludge–contaminated soil.

A 200-Year Record of Polycyclic Aromatic Hydrocarbons Contamination in an Ombrotrophic Peatland in Great Hinggan Mountain, Northeast China

Peat bogs are regarded as one of the faithful archives of atmospheric polycyclic aromatic hydrocarbons(PAHs) deposition, and a large number of studies on PAHs accumulation in peatlands have been reported in Europe and North America. Comparatively little information is available on peat chronological records of atmospheric PAHs flux in China. We investigated the concentrations and historical accumulation rates of PAHs(AR PAHs) through geochemical analysis of three 210Pb-dated ombrotrophic peat cores from Great Hinggan Mountain, northeast China. Eight USEPA priority PAHs were detected and they are naphthalene(Nap), acenaphthylene(Acl), acenaphthene(Ace), fluorence(Flu), phenanthrene(Phe), anthracene(Ant), fluoranthene(Fla) and pyrene(Pyr), respectively. The average total eight PAHs(tPAHs) concentrations are 135.98- 262.43 μg kg-1 and the average AR tPAHs over the last two centuries are 96.45- 135.98 μg m-2 yr-1. The Ace, Acl and Phe account for 30.93- 54.04%, 25.29- 35.81%, and 9.14- 19.84% of the tPAHs, respectively, and have significant positive correlations with the tPAH. As a result, they are regarded as the iconic compounds of PAHs pollution in this area. A ca.200-yr atmospheric PAHs contamination history was reconstructed from the temporal sequences of bothconcentration and AR tPAHs, suggesting the variation of local environmental pollution. The main sources of the PAHs are identified by two isomer ratios as petrogenic origin including oil extraction and refining process as well as their combustions for industrial development. In addition, the contribution of coal combustion for industrial activities and resident heating could not be ignored. But prior to 1860, the undeveloped industry and most of agricultural activities might mainly account for the low level of PAHs, although it could infer a long-range input of atmospheric PAHs from other industrial areas. Therefore, there is a global implication to study longterm PAHs pollution records and all the results will provide practical significance in formulating policies to achieve sustainable and healthy development.

Emission characteristics of dioxins,furans and polycyclic aromatic hydrocarbons during fluidized-bed combustion of sewage sludge

Pre-dried sewage sludge with high sulfur content was combusted in an electrically heated lab-scale fluidized-bed incinerator. The emission characteristics of polychlorinated dibenzo-p-dioxins （PCDDs）, polychlorinated dibenzofurans （PCDFs） and polycyclic aromatic hydrocarbons （PAHs） were studied. Coal and calcium oxide （CaO） were added during the sewage sludge combustion tests to optimize combustion conditions and control SO2 emission. The results indicated that the flue gases emitted during mono-combustion of sewage sludge were characterized by relatively high concentrations of SO2, NOx and organic pollutants, due to the high sulfur, nitrogen, and volatile matter content of sewage sludge. The total 16 USEPA priority PAHs and 2,3,7,8-substituted PCDD/Fs produced from sewage sludge combustion were found to be 106.14 μg/m^3 and 8955.93 pg/m^3 in the flue gas, respectively. In the case of cocombustion with coal （msludge/mcoal =1：1）, the 16 PAHs and 2,3,7,8-substituted PCDD/Fs concentrations were markedly lower than those found during mono-combustion of sewage sludge. During co-combustion, a suppressant effect of CaO on PCDD/Fs formation was observed.

Distribution and Source Apportionment of Polycyclic Aromatic Hydrocarbons from Atmospheric Particulate Matter PM2.5 in Beijing

A total of 11 PM2.5 samples were collected from October 2003 to October 2004 at 8 sampling sites in Beijing city. The PM2.5 concentrations are all above the PM2.5 pollution standard （65 μg m^-3） established by Environmental Protection Agency, USA （USEPA） in 1997 except for the Ming Tombs site. PM2.5 concentrations in winter are much higher than in summer. The 16 Polycyclic aromatic hydrocarbons （PAHs） listed as priority pollutants by USEPA in PM2.5 were completely identified and quantified by high performance liquid chromatography （HPLC） with variable wavelength detector （VWD） and fluorescence detector （FLD） employed. The PM2.5 concentrations indicate that the pollution situation is still serious in Beijing. The sum of 16 PAHs concentrations ranged from 22.17 to 5366 ng m^-3. The concentrations of the heavier molecular weight PAHs have a different pollution trend from the lower PAHs. Seasonal variations were mainly attributed to the difference in coal combustion emission and meteorological conditions. The source apportionment analysis suggests that PAHs from PM2.5 in Beijing city mainly come from coal combustion and vehicle exhaust emission. New measures about restricting coal combustion and vehicle exhaust must be established as soon as possible to improve the air pollution situation in Beijing city.

Organochlorine pesticides and polycyclic aromatic hydrocarbons in water and sediment of the Bosten Lake,Northwest China

We evaluated organic pollution in Bosten Lake, Xinjiang, China, by measuring the concentrations and distributions of organochlorine pesticides （OCPs） and polycyclic aromatic hydrocarbons （PAHs）. Water and sediment samples were collected from 19 sites 031-1319） in the lake for analysis. Our analytical results show that the concentrations of total OCPs in water ranges from 30.3 to 91.6 ng/L and the concentrations of PAHs ranges from undetectable （ND） to 368.7 ng/L. The concentrations of total OCPs in surface （i.e., lake bottom） sediment ranges from 6.9 to 16.7 ng/g and the concentrations of PAHs ranges from 25.2 to 491.0 ng/g. Hexachlorocyclohexanes （HCHs） and dichlorodiphenyltrichloroethanes （DDTs） account for large proportions of the OCPs. Low α- to γ-HCH ratios in both water and sediment samples indicate possible contributions from both industrial products and lindane. DDTs in water are probably from historical input, whereas DDTs in sediments are from both historical and recent inputs. Moreover, DDT products in both water and sediments were from multiple sources in the northwestern part of the lake（B11, B12, B13, and B14）. Fugacity ratios for DDT isomers （p,p＇-DDE and p,p＇-DDT） at these sites were generally higher than equilibrium values. These results suggest that the input from the Kaidu River and diffusion of DDTs from the sediment to the water are responsible for DDT pollution in the water. Lower-molecular-weight PAHs, which originate primarily from wood and coal combustion and petroleum sources, represent the major fraction of the PAHs in both water and sediment samples. Our findings indicate that OCPs and PAHs in Bosten Lake can be attributed primarily to human activities. A risk assessment of OCPs and PAHs in water and sediment from Bosten Lake, however, suggests that concentrations are not yet high enough to cause adverse biological effects on the aquatic ecosystem.

Influence of rice straw burning on the levels of polycyclic aromatic hydrocarbons in agricultural county of Taiwan

Atmospheric particulate and polycyclic aromatic hydrocarbons （PAHs） size distribution were measured at Jhu-Shan （a rural site） and Sin-Gang （a town site） in central Taiwan during the rice straw burning and non-burning periods. The concentrations of total PAHs accounting for a roughly 58% （34%） increment in the concentrations of total PAHs due to rice-straw burning. Combustion-related PAHs during burning periods were 1.54-2.57 times higher than those during non-burning periods. The mass median diameter （MMD） of 0.88-1.21 μm in the particulate phase suggested that rice-straw burning generated the increase in coarse particle number. Chemical mass balance （CMB） receptor model analyses showed that the primary pollution sources at the two sites were similar. However, ricestraw burning emission was specifically identified as a significant source of PAH during burning periods at the two sites. Open burning of rice straws was estimated to contribute approximately 6.3%-24.6% to total atmospheric PAHs at the two sites.

Treatment of tunnel wash waters-experiments with organic sorbent materials.PartⅠ:Removal of polycyclic aromatic hydrocarbons and nonpolar oil

Tunnel wash waters characterize all waters that run off after washing procedures of tunnels are performed.These waters represent a wide spectrum of organic and inorganic pollutants,such as polycyclic aromatic hydrocarbons(PAHs)and toxic metals.Removal of such contaminants from water runoff was investigated using laboratory tests after washing procedure was performed on two road tunnels in eastern Norway(Hanekleiv and Bragernes).Due to diverse character of both,treatment media and treated wash waters, the wh...