Acenaphthylene Research Articles

Volatility and chemical composition of secondary organic aerosol derived from acenaphthylene and acenaphthene under various oxidant conditions

Acenaphthene (ACE) and acenaphthylene (ACY), distinguished by their unique structures, exhibit high reactivity among polycyclic aromatic hydrocarbons (PAHs). Particularly, the rapid ozonolysis of the carbon-carbon double bond in ACY and the swift oxidation of the fused cyclopenta ring in both ACE and ACY by NO3 underscore their distinct atmospheric fate. Through the utilization of a thermo denuder and high-resolution mass spectrometry, the chemical composition and volatility of four types of secondary organic aerosols (SOA) derived from ACE and ACY are investigated. The chemical composition of SOA formed by ACY ozonolysis is characterized by low O: C ratios and high unsaturation, suggesting the retention of aromatic structures. This leads to measured high SOA volatility and is consistent with the low reactivity of O3 with aromatic compounds. In contrast to ozonolysis, the reaction of NO3 with ACY could yield SOA with very low volatility, characterized by abundant dimers and highly oxidized products. Furthermore, the prevalence of compounds with 11 carbon atoms suggests the presence of complex mechanisms in the ACY oxidation process initiated by NO3, where dealkylation reactions and cleavage reactions may be pivotal. The diverse chemical composition and volatility of SOA from ACE and ACY reacting with NO3 radicals highlight the substantial impact of precursor structure on SOA chemical composition, particularly concerning the presence of active carbon-carbon double bonds. The higher O: C ratio of SOA from OH-initiated oxidation of ACE indicates the significant role of OH in the oxidation of PAHs. These findings offer valuable insights into the atmospheric fate of these PAHs, underscoring the necessity for a comprehensive understanding of their degradation processes and the formation of SOA.

Exploration and comparison of the relationship between PAHs and ROS in PM2.5 emitted from multiple anthropogenic sources in the Guanzhong Plain, China

Anthropogenic emissions have emerged as an important source of urban atmospheric PM2.5, exacerbating air pollution and the associated health implications. This study analyses PM2.5, originating from major anthropogenic sources (industries, motor vehicles, and solid-fuel combustion for domestic applications) in the Guanzhong Plain in China, along with the parent- (p-), alkylated- (a-), and oxygenated- (o-) polycyclic aromatic hydrocarbons (PAHs) and reactive oxygen species (ROS) levels in PM2.5. Industrial emissions are mainly characterised by high abundances of benzo[b]fluoranthene (BbF), benzo[k]fluoranthene (BkF), and benz[a]fluoranthene (BaF). The 4-ring p-PAHs, such as fluoranthene (FLA), pyrene (PYR), benzo[a]anthracene (BaA), and chrysene (CHR) proportions and the diagnostic ratios of indeno[1,2,3-cd]pyrene (IcdP)/[IcdP + benzo[ghi]perylene (BghiP)] and 1-acenaphthenone (1ACO)/[1ACO + 9-fluorenone (9FO)] in motor vehicle emission PM2.5 were higher than the other sources. Household solid fuel combustion features high proportions of methylnaphthalene (M-NAP), i.e., 2 M-NAP and 1 M-NAP and 3-ring p-PAHs. Acenaphthylene (ACY), acenaphthene (ACE), anthracene (ANT), 1,4-chrysenequinone (1,4CHRQ), and reactive oxygen species (ROS) were positively correlated among the three anthropogenic sources. Moreover, the correlations between other PAHs and ROS varied significantly among the three sources. As mixed and compound organic pollutants, 2- and 3-ring p-PAHs were more positively correlated with the ROS activity of household solid fuel combustion sources compared with industrial and motor vehicle sources. Based on the relative contribution of these three sources to PAHs in PM2.5, we estimated the cancer risks of males and females in the Guanzhong area to be 2.95 × 10−6 and 2.87 × 10−6, respectively, exceeding the safety threshold of 1 × 10−6. This study provides a basic dataset for conducting a refined source apportionment of PM2.5 and a scientific basis for further understanding the relationship between PM2.5, PAHs, and ROS in northern China.

Smoked and Fermented Bushmeat (Mpunam) Products: Risk Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) Resulting From Processing.

The polycyclic aromatic hydrocarbons (PAHs) congener concentrations and risk upon human exposure to smoked bushmeat products were analyzed. GC/MS MRM and QuEChERS methods were used for the analysis. This work has become necessary due to the need for more information concerning the quantitative determination of these compounds and their health risk assessment. The 16 PAH congeners identified were acenaphthylene (ACA), naphthalene (NAP), acenaphthene (ACE), fluorene (FLU), anthracene (ANT), phenanthrene (PHE), fluoranthene (FLT), pyrene (PYR), benzo[b]fluoranthene (BBF), benzo[k]fluoranthene (BKF), benzo[a]anthracene (BAA), chrysene (CHR), indeno(1,2,3-cd)pyrene (IND), dibenzo(a,h)anthracene (DAA), benzo(g,h,i)pyrene (BGP), and benzo[a]pyrene (BAP). At the 5% and 95% daily intake levels, BAP was at 3.34 and 17.39 μg/kg(bw)/day, ΣPAH4 was at 25.11 and 109.15 μg/kg(bw)/day, and ΣPAH8 was at 55.76 and 236.68 μg/kg(bw)/day, respectively. BAP, ΣPAH4, and ΣPAH8 concentration exceeded the European Union limits, as BAP concentration was as low as 6.09 μg/kg and as high as 34.19. The exposure values were significantly high. Specifically, the margin of exposure for BAP was as low as 2.09 × 10-2; for ΣPAH4, it was 1.36 × 10--2; and for ΣPAH8, it was 1.95 × 10-2 all at the 95% level. These figures are substantially lower than the benchmark of 10,000, indicating a higher ILTCR. Furthermore, the ILTCR ranged from a minimum of 47.77 to a maximum of 248.53 at the 5% and 95% levels, respectively. This study makes smoked bushmeat a public health concern because the higher figures obtained indicate higher carcinogenicity upon consumption.

Quantification and risk assessment of polycyclic aromatic hydrocarbons in street dust from functional areas of Khamis-Mushait, Saudi Arabia

The aim of present work is focused on determination of the residual concentrations of 16 PAHs and their health risk assessment in selected sectors of the street dust along Khamis-Mushait, Asir area. Objectives/backgrounds: With the recent rapid development of urbanization, polycyclic aromatic hydrocarbons (PAHs) in street dust pose serious problems to human health and ecological environment. Method: HPLC system (HPLC Nexera-i LC 2040 C 3D Plus Shimadzu Integrated) was used to perform the measurements following well-established USEPA 3550B method . Results: The average value of PAHs in Khamis-Mushait street dust was 2809.46 ng/g, ranging from 1250.41 to 4249.29 ng/g. Incinerator and industrial locations had the highest concentration of fossil PAHs, accounting for 69.62% of PAHs. The King Fahd Garden and Al-Hayat National Hospital regions had the highest concentrations of carcinogenic PAHs and combustion PAHs, which accounted for 41.70 and 27.46% of all PAHs, respectively. Naphthalene (NAP), acenaphthylene (ACY), and acenaphthene (ACE) were more effective range low. However, ACE was more effective range medium, and ACY, ACE, and DBA (dibenzo-anthracene) were more probable effect level. Furthermore, the effects of NAP, fluoranthene (FLT), pyrene (PYR), and benzo(a)pyren (BaP) were greater than the threshold effect level (TEL). For both kids and adults, the hazardous index (HI) was in the following order: ACE>ACY>NAP>PYR>fluorene (FLR)>FLT> benzo(ghi)perylene (BghiP)>phenanthrene (PHN)>ANT. However, total HI for noncancer risks for PAHs varied between 9.91´10-5 and 2.69´10-2 and from 9.22´10-4 to 2.50´10-1 for adults and children, respectively. Conclusion: Various approaches (geochemical indices, statistical analysis, and health risk assessment) were exploited to evaluate the levels of 16 PAHs in street dust from Abha and Khamis-Mushait City, Saudi Arabia. These values are considered safe level and insignificant to adults and children. In addition, ACE may pose risk based on acute and intermediate oral exposure. The following order from several sources was reported by the cluster analysis of dust samples: commercial>industrial>traffic.

Selective photodimerization of acenaphthylene in polymersome nanoreactors.

PEG-b-PLA polymersomes are used as nanoreactors for the photodimerization of acenaphthylene (ACE), increasing reaction rate significantly. The reaction steered towards almost exclusive formation of anti product (94 : 6). This selectivity is remarkable, as other known systems commonly mediate formation of the syn product.

Treatment of Hydrophobic Polycyclic Aromatic Hydrocarbons and Toxicity Using GO-TiO2-Sr(OH)2/SrCO3 Nanocomposite via Photocatalytic Degradation

In this study, the effects of increasing sun light irradiation time (30 min, 120 min, 240 min and 360 min), increasing photocatalytic power (10 W, 50 W and 100 W), increasing graphene oxide (GO) nanoparticle concentrations (2 mg/l, 4 mg/l and 8 mg/l), increasing titanium dioxide (TiO2) nanoparticle concentrations (1 mg/l, 3 mg/l, 6 mg/l and 9 mg/l), increasing GO-TiO2-Sr(OH)2/SrCO3 nanocomposite concentrations (1 mg/l, 2 mg/l and 4 mg/l) on the destructions of four hydrophobic polycyclic aromatic hydrocarbons (PAHs) in a real petrochemical industry wastewater in Izmir (Turkey) were investigated. The yields in more hydrophobic PAHs with high benzene rings [benzo[a]pyrene (BaP) and benzo[k]fluoranthene (BkF)] were as high as the less hydrophobic PAHs with lower benzene rings [acenaphthylene (ACL) and carbazole (CRB)]; at pH=7.0, at 22oC after 360 min sun light irradiation time, respectively. Maximum 97%ACL, 98%CRB, 98%BaP and 99%BkF PAHs removals was detected at 4 mg/l GO-TiO2-Sr(OH)2/SrCO3 nanocomposite concentration, under 100 mW/cm2 sun light intensity, at 100 W photocatalytic power, at 360 min sun light irradiation time, at pH=7.0 and at 22oC, respectively. The effective PAHs concentrations caused 50% mortality in Daphnia magna cells increased from initial EC50=342.56 mg/l to EC50=631.05 mg/l, at pH=7.0 and at 22oC after 360 min photocatalytic degradation time resulting in a maximum acute toxicity removal of 99.99%, at 4 mg/l GO-TiO2- Sr(OH)2/SrCO3 nanocomposite concentration. The Daphnia magna acute toxicity was significantly reduced.

Quantification and Risk Assessment of PAHs in Street Dust from Functional Areas of Khamis-Mushait, Saudi Arabia

The average value of polycyclic aromatic hydrocarbons (PAHs) in Khamis-Mushait street dust was 2809.46 ng/g, ranging from 1250.41-4249.29 ng/g. Incinerator and industrial locations had the highest concentration of fossil PAHs (∑FPAHs), accounting for 69.62% of PAHs. The highest concentrations of carcinogenic PAHs (∑CARC) and combustion PAHs (∑COMB) were found in the King Fahd Garden and Al-Hayat National Hospital regions, accounting for 41.70 % and 27.46 % of PAHs, respectively. Naphthalene (NAP), Acenaphthylene (ACY) and Acenaphthene (ACE) were > effective range low (ERL). However, ACE was > effective range medium (ERM), and ACY, ACE, and DBA (dibenzo anthracene) were > Probable Effect Level (PEL). Furthermore, the effects of NAP, fluoranthene (FLT), pyrene (PYR), and benzo (a)pyren (BaP) were greater than the threshold effect level (TEL). The order of Hazardous indices (HI) for both children and adults were ACE > ACY > NAP > PYR > fluorene (FLR) > FLT > benzo (ghi) perylene (BghiP) > phenanthrene (PHN) > ANT. However, total HI for non-cancer risks for PAHs were 2.69×10-2 -9.91×10-5 and 2.50x10-2 - 9.22×10-4 to adults and children, respectively. These values considered safe level and insignificant to adults and children. In addition, ACE may pose risk based on acute and intermediate oral exposure. The cluster analysis of dust samples declared the following order from different sources: traffic > industrial > commercial.

Photodegradation of acenaphthylene over plasmonic Ag/Ag3PO4 nanopolyhedrons synthesized via in-situ reduction

We report a simple strategy to synthesize the Ag3PO4 nanopolyhedrons with regular morphology and uniform size under mild conditions. The photocatalytic properties of the composite were optimized by adjusting the content of Ag nanoparticles. The as-prepared photocatalysts were characterized and the photocatalytic performances were evaluated by the degradation of acenaphthylene (ANY) under visible-light illumination. The surface plasmon resonance (SPR) of appropriate Ag nanoparticles was generated on surface under visible light irradiation, which enhanced the absorption and utilization of visible light. At the same time, the conductivity of Ag promoted the separation and transfer of photogenerated carriers, provided active sites for the reaction, and enhanced the photocatalytic degradation efficiency through the generation of active species. As a result, the optimized composite exhibited enhanced visible-light photocatalytic activity of 0.03512 min−1 and higher removal rate of 97.3% for ANY (4 times and 1.8 times higher than that of pristine Ag3PO4, respectively), more photogenerated active species (h+ and •O2–) and relatively high stability (4 times of cycle experiments). In addition, the possible degradation pathway of ANY was proposed. The work of this paper has a crucial guiding significance for the working principle and design direction of silver semiconductor composite photocatalysts with surface plasmon effect.

Health risks of PM2.5-bound polycyclic aromatic hydrocarbon (PAH) and heavy metals (PPAH&HM) during the replacement of central heating with urban natural gas in Tianjin, China.

To investigate the health effects of fine particulate matter (≤ 2.5μm in aerodynamic diameter; PM2.5)-bound heavy metals and polycyclic aromatic hydrocarbons (PAHs) before and after the implementation of the Urban Natural Gas Heating Project (UNGHP), the lifetime cancer risks, hazard quotients (HQs) of heavy metals and PAHs were calculated. Seven kinds of heavy metals (Al, As, Cd, Cr, Mn, Ni and Se) and 12 kinds of PAHs including acenaphthylene (ANY), acenaphthene (ANA), fluoranthene (FLT), pyrene (PYR), chrysene (CHR), benz[a]anthracene (BaA), benzo[b]fluoranthene (BbF), benzo[k]fluoranthene (BkF), benzo[a]pyrene (BaP), dibenz[a,h]anthracene (DBA), benzo[ghi]perylene (BPE) and indeno[1,2,3-cd]pyrene (IPY) were analyzed and used for the health risk assessments. It was found that HQ of Mn fell from 1.09 in the coal-burning period to 0.72 in the gas-burning period in the suburban area. And lifetime cancer risks of PAHs fell from 35.7 × 10-6 in the coal-burning period to 17.22 × 10-6 in the gas-burning period in the urban area. It could be concluded that, during the gas-burning period, downward trends were observed for the lifetime cancer risks and HQs of most kinds of heavy metals and PAHs in all regions of Tianjin compared to those during the coal-burning period. The UNGHP was effective, and we should also take other measures to control the pollution.

Simultaneous removal of multiple polycyclic aromatic hydrocarbons (PAHs) from urban stormwater using low-cost agricultural/industrial byproducts as sorbents

The potential of five low-cost and globally available sorbents, including three raw waste products – waste tire crumb rubber (WTCR), coconut coir fiber (CCF) and blast furnace slag (BFS) – and two modified materials – biochar (BC) and iron coated biochar (FeBC) – were evaluated for removing a mixture of polycyclic aromatic hydrocarbons (PAHs): pyrene (PYR), phenanthrene (PHE), acenaphthylene (ACY) and naphthalene (NAP) from simulated stormwater. The physicochemical characteristics of the sorbents were assessed by BET-N2 surface area, CHN elemental analysis, FTIR and scanning electron microscope (SEM-EDS). The experimental data were well described by both linear and Freundlich isotherm and pseudo-second order kinetic models. The adsorption rate was mainly controlled by the film diffusion mass transfer mechanism. The magnitude of PAHs partition coefficients (Kd) followed the order of BC > FeBC > WTCR > CCF ≫ BFS, ranging from 80 to 390,000 L/kg. The sorption Kd values were positively correlated with both aromaticity of sorbents and octanol-water partition coefficients (Kow) of PAHs. Solution ionic strength and pH did not have significant effects on the sorption of PAHs by all sorbents. In contrast, humic acid, as dissolved organic carbon, decreased sorption capacities of WTCR and CCF, and increased sorption efficiency of BFS, which was confirmed with field-collected real stormwater. The hydrophobic π–π interactions were the main mechanism for the sorption of PAHs by various sorbents. These findings are promising for future development of cost-effective sorption filters for removal of hydrophobic organic pollutants from urban stormwater runoff.

Visible-Light Photocatalysis of Asymmetric [2+2] Cycloaddition in Cage-Confined Nanospace Merging Chirality with Triplet-State Photosensitization.

Although the photodimerization of acenaphthylene (ACE) has been known for 100 years, the asymmetric cycloaddition of its 1-substituted derivatives is unknown. Herein, we report a supramolecular photochirogenic approach in which a homochiral and photoactive Δ/Λ-[Pd6 (RuL3 )8 ]28+ metal-organic cage (Δ/Λ-MOC-16) is used as a supramolecular reactor for the enantioselective exited-state photocatalysis of 1-Br-ACE. Owing to preorganization of the substrates by the supramolecular cage, stereochemical control of the triplet state, and nanospace transfer of energy and chirality, the cycloaddition of ACE proceeded with high selectivity for the formation of anti over syn stereoisomers, whereas the regio-, stereo-, and enantioselective cycloaddition of unsymmetrical 1-Br-ACE showed effective enantiodifferentiation of a pair of anti head-to-head stereoisomers. The enzyme-mimicking photocatalysis was verified by catalytic turnover, rate enhancement, and competing-guest inhibition experiments.

Visible‐Light Photocatalysis of Asymmetric [2+2] Cycloaddition in Cage‐Confined Nanospace Merging Chirality with Triplet‐State Photosensitization

AbstractAlthough the photodimerization of acenaphthylene (ACE) has been known for 100 years, the asymmetric cycloaddition of its 1‐substituted derivatives is unknown. Herein, we report a supramolecular photochirogenic approach in which a homochiral and photoactive Δ/Λ‐[Pd6(RuL3)8]28+ metal–organic cage (Δ/Λ‐MOC‐16) is used as a supramolecular reactor for the enantioselective exited‐state photocatalysis of 1‐Br‐ACE. Owing to preorganization of the substrates by the supramolecular cage, stereochemical control of the triplet state, and nanospace transfer of energy and chirality, the cycloaddition of ACE proceeded with high selectivity for the formation of anti over syn stereoisomers, whereas the regio‐, stereo‐, and enantioselective cycloaddition of unsymmetrical 1‐Br‐ACE showed effective enantiodifferentiation of a pair of anti head‐to‐head stereoisomers. The enzyme‐mimicking photocatalysis was verified by catalytic turnover, rate enhancement, and competing‐guest inhibition experiments.

Alternated biodegradation of naphthalene (NAP), acenaphthylene (ACY) and acenaphthene (ACE) in an aerobic granular sludge reactor (GSBR)

The paper presents quantitative changes of selected 2- and 3-ring PAHs after process phases of GSBR reactor. The studies have been carried out for 264 cycles of GSBR reactor, during which concentration of naphthalene was increased in the range of 3.00–710.00 μg/L, acenaphthylene 1.00–160.00 μg/L, acenaphthene 3.00–440.00 μg/L. GSBR operating cycle consisted of filling (30 min), mixing (90 min), aeration (540 min), sedimentation (10 min), decanting (30 min) and downtime (20 min) phases. Activated sludge dry mass concentration was 4.00 kg/m3. Conducted studies showed that in GSBR reactor naphthalene was degraded with the highest intensity. Results of the statistical analysis confirmed that naphthalene concentrations were statistically significantly different (α = 0.05) after each individual GSBR process phase, while in case of acenaphthene and acenaphthylene, the differences were observed only between mixing and aeration phases. Additionally, equations estimating concentrations of PAHs in treated wastewater were developed. Selected activated sludge technological parameters (sludge volume index, sludge and hydraulic retention time) and concentration of PAHs were used for equations. The R2 coefficients of equations were above 0.99, which indicates a good adjustment of estimation to observed values.

Levels and human health risk assessment of persistent organics, metalloid and heavy metals in fish

Concentrations of Polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and heavy metals (Fe, Zn, Mn, Cu, Ni, Cd. V, Cr, Pb, Hg, As) were measured in fish (Clarias gariepinus) samples collected from selected stations (S1, S2 and S3) along the stretch of Ovia River, Southern Nigeria, to assess the potential risks to humans consuming fish from the river. Acenaphthylene (AcPY), 2,2',5-Trichlorobiphenyl (PCB 18) and iron (Fe) were the most dominant residues with mean concentrations ranging from 0.002 to 0.128, 0.001 to 0.003 and 175.97 to 255.52 mg/kg respectively. The most carcinogenic PAH, Benzo(a)pyrene (BaP) in S3, all the PCB congeners, cadmium (Cd), and lead (Pb) concentrations in the three stations were observed to be above EU recommended guideline values for food safety which calls for concern. Concentrations of dioxin‐like PCB congeners, 77, 105, 114 and the sum of carcinogenic PAHs also contributed to the toxic burden of these contaminants in fish. Estimation of the daily intake of PAHs, PCBs, and heavy metals showed values below the reference dose proposed by WHO for all the toxicants investigated, indicating that consumption of fish from Ovia River generally does not subject consumers to significant health risk. In contrast, the estimated cumulative THQ for the assessed heavy metals, however, indicate health risks from exposure to Heavy metals through fish consumption. Continuous surveillance and monitoring of the Ovia River are therefore imperative to mitigate further pollution.

Coated direct inlet probe coupled with atmospheric-pressure chemical ionization and high-resolution mass spectrometry for fast quantitation of target analytes

The coated direct inlet probe (CDIP) is a new laboratory-made low-cost technology developed from a direct inlet probe (DIP), which has the advantage of quick enrichment/cleanup of an analyte from liquid samples. A capillary probe is coated with hydroxy-terminated polydimethylsiloxane (OH-PDMS), divinylbenzene (DVB), and β-cyclodextrin (β-CD) by a sol-gel method. This probe can be directly coupled with a commercialized atmospheric-pressure chemical ionization (APCI) ion source and high-resolution mass spectrometry, which are widely applicable, reliable, and durable. The ability to perform quantitative analyses with the use of a stable-isotope-labeled internal standard (SIL-IS) was tested by using different concentrations of acenaphthylene (ACY), acenaphthene (ACP), fluorene (FLR), fluoranthene (FLT), phenanthrene (PHE), and benzo[a]pyrene (B[a]P). Calibration curves with a coefficient of determination of R2 ≥ 0.9982 for different polycyclic aromatic hydrocarbons (PAHs) were obtained. A limit of detection (LOD) of 0.008–0.04 ng mL−1 for PAHs was determined. The entire workflow is solvent-free and can be completed in less than 5 min, which demonstrates the advantages of this technique for quantitative analysis.

Fluorescence anisotropy analysis of comb‐type grafted poly(N,N‐diethylacrylamide‐co‐acrylic acid)‐g‐poly(N,N‐diethylacrylamide) microgels labeled by acenaphthylene

ABSTRACTTwo kinds of thermosensitive and pH sensitive comb‐type grafted poly(N,N‐diethylacrylamide‐co‐acrylicacid)‐g‐poly(N,N‐diethylacrylamide) [P(DEA‐co‐AA)‐g‐PDEA] microgels labeled by acenaphthylene (ACE) were prepared in water/methanol mixed solvent. Both of them were prepared through surfactant‐free emulsion polymerization: one was labeled in the main chain of the gel networks (B‐ACE) and the other was labeled in the grafted chains of the gel networks (G‐ACE). Steady state fluorescence anisotropy was used to study the mobility of the chains in different buffers at their lower critical solution temperature. It was found that the grafted chains moved more freely than the main chain, and the pH dependence of the mobility of the grafted chain was more pronounced. With the results obtained in the present study, we can better understand why the microgels with grafted chains have faster response rates than the ones of normal types. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46742.

Functionalization of Graphene Oxide with 9-aminoanthracene for the Adsorptive Removal of Persistent Aromatic Pollutants from Aqueous Solution.

A novel modified graphene oxide nanocomposite was fabricated via a facial procedure, aiming to removal of the aromatic pollutants from aqueous solution. The graphene oxide (GO) was functionalized with 9-aminoanthracene and produced graphene oxide-9-aminoanthracene (GO-9-AA). FTIR, XRD, TGA, TEM and Raman spectroscopy techniques were used for characterization of the adsorbents. Adsorption of naphthalene (NAP), acenaphthylene (ACN), and phenanthrene (PHN) as a model of polycyclic aromatic hydrocarbons (PAHs) was investigated by GO-9-AA. The adsorbent showed excellent removal efficiency towards PAHs from aqueous solution. Equilibrium data of the adsorption process were successfully fitted with Freundlich model from single solute system, and the maximum adsorption capacities followed the order of NAP > ACN >PHN. The kinetic analysis revealed that the overall adsorption process was fast and successfully fitted with the pseudo-second-order kinetic model. The anthracene ring makes GO-9-AA π-electron rich, thus facilitating π-π EDA interaction between NAP, ACN and PHN with GO-9-AA.

The growth of phenanthrene from naphthalene by C2H2 additions

Two paths are investigated for the growth of phenanthrene from naphthalene by the addition of C2H2 groups. The first series of steps leads to acenaphthylene (ACN), which is consistent with the path found previously. The addition of C2H2 to ACN can yield a product with two adjacent five-membered rings. Opening one five-membered ring produces a five-membered ring with CH2 side group. This can be converted to a six-membered ring in a manner analogous to the hydrogen atom catalysed fulvene to benzene conversion. A second path, with a somewhat higher barrier, can also lead to the phenanthrene product. The transition state for the second path is essentially isoenergetic with the stating material of ACN + C2H2 + H.

Adsorption of polycyclic aromatic hydrocarbons from wastewater by using silica-based organic–inorganic nanohybrid material

Polycyclic aromatic hydrocarbons (PAHs) are a group of priority pollutants, which are classified as persistent hazardous contaminants. Herein, the adsorption of three PAHs, naphthalene (NAP), acenaphthylene (ACN), and phenanthrene (PHN), from wastewater onto NH2-SBA-15 organic–inorganic nanohybrid material as a function of pH of the media (2–10), sorbent dosage (0.5–3.5 g L−1), PAH concentration (1–18 mg g−1), and temperature (25–45 °C) were elucidated. The prepared adsorbents were characterized by scanning electron microscope, transmission electron microscopy, X-ray diffractions, and thermogravimetric analysis. Among Langmuir, Freundlich, and Temkin isotherms models, it was found that the Langmuir model gave an excellent overall fit (R2 > 0.97). The maximum adsorption capacity of 1.92, 1.41, and 0.76 mg g−1 was obtained for NAP, ACN, and PHN, respectively. Adsorption kinetics of PAHs onto NH2-SBA-15 was in accordance with the pseudo-second-order model, providing evidence that pore mass transferring was involved. PAHs' adsorption was strongly dependent on temperature, and confirmed the spontaneous and endothermic nature of the process. The optimized sorption condition was successfully applied to the real petroleum refinery wastewater samples and the adsorption capacity of NH2-SBA-15 was satisfactory for PAHs' studies as 1.67, 1.06, and 0.24 mg g−1 for NAP, ACN and PHN, respectively. Furthermore, reusability was successfully tested by five sequential recoveries.

Determination of Polyaromatic Hydrocarbons in Domestic, Commercial and Industrial soot samples

Abstract Polycyclic aromatic hydrocarbons (PAHs) were determined in domestic, commercial and industrial soot samples via HPLC. The study showed that benzo[a]pyrene (bap) was not present in most of the samples. The highest quantity of BaP was found in Pakistan Particle Board where its concentration was 259.12 mg/kg. The high quantity of other PAHs such as chrysene (CHR), anthracene (ANT), fluorene (FL), naphthalene (NAP), phenanthrene (PHE), acenaphthylene (ACP) and flouranthene (FTH) were found in tandoor, kabab karayi, tabakhee, brick kiln and motor car soot samples. The low concentration of most of the PAH compounds in most of the samples might be due to their photooxidative, biological and microbial degradation.