Monoaromatic Hydrocarbons Research Articles

Occurrence and exposure risk of mono-aromatic hydrocarbons in selected petroleum product jetty impacted soils from the Niger Delta, Nigeria

This study evaluated the occurrence and human exposure risk of mono-aromatic hydrocarbons (MAHs) such as benzene, toluene, ethylbenzene, and o,p-xylene (BTEX) in soils from petroleum product jetty from the Niger Delta, Nigeria. Samples were collected from the top (0-15 cm), sub (15-30 cm), and bottom (30-45 cm) soil depths. The MAHs components were determined using Headspace gas chromatography-mass spectrometer (HS-GCMS). The individual and ƩMAHs concentrations ranged from not detected (ND) to 1528 µg kg-1 and ND to 2512 µg kg-1 respectively. The total cancer risks were within the low category. The source identification indicated that the origin MAHs species are attributed to solvent, paints, and gasoline-diesel spill and particulate emission from gasoline/diesel combustion exhaust in the vicinity of the petroleum product jetty. This depicts the presence of low molecular weight petroleum fractions such as gasoline and kerosene that could exhibit toxicological and carcinogenic effects to organisms in soils within the jetty. Clean-up actions should be carried out to prevent the accumulation of MAHs in soil-plant uptake and the potential ecological and human exposure risks of MAHs in the surrounding soil and aquatic ecosystem

Selective hydrogenation of light cycle oil for BTX and gasoline production purposes

Abstract The study of the best experimental conditions and catalyst for the hydrogenation (HYD) of light cycle oil (LCO) for upgrading purposes was carried out. The objective was to examine the ability of two commercial hydrotreatment (HDT) catalysts for selective aromatic saturation. The effect of the hydrotreatment operation parameters (temperature, pressure, liquid hourly space velocity, H2/HC ratio) on the sulfur and nitrogen contents and in the saturation of aromatic hydrocarbons was also investigated. The goal was to obtain the highest conversion to mono-aromatic hydrocarbons from this di-aromatic (naphthalene derivatives) type feedstock, and at the same time to get reasonable hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) performance to avoid contaminant hydrocarbons for the next step (usually hydrocracking, HCK). An appropriate hydrotreated product with the highest concentration of mono-aromatic derivatives, a minimum reduction on the total aromatic content, and suitable decrements of sulfur and nitrogen compounds, was achieved using a cobalt-molybdenum supported on alumina catalyst, at 330 °C, 5.5 MPa, and a liquid hourly space velocity of 1.1 h−1. Additionally, the kinetics of the HDA was studied, assuming a lump characterization into tri-, di- and mono-aromatic and aliphatic hydrocarbons, pseudo-first-order reaction rates between these conversions, and thermal losses and diffusional resistances to be undetectable.

High-quality oil production via the catalytic conversion of printed circuit boards

The catalytic pyrolysis (CP) of phenolic printed circuit boards over red mud and acid catalysts, HZSM-5, HBeta, HY, and desilicated HZSM-5 (HDeZSM-5), was performed using a microreactor. Compared to the non-CP, the in-situ CP led to high-quality debrominated oil production containing large quantities of aromatic and phenol compounds. Among the catalysts used, HBeta showed the highest debromination (DeBr) efficiency, followed in order by HY, red mud, HDeZSM-5, and HZSM-5. HDeZSM-5 produced the largest amount of mono-aromatic hydrocarbons (MAHs), followed by HZSM-5, HBeta, HY, and red mud. Two-stage CP over in-situ red mud and ex-situ zeolites (HBeta and HDeZSM-5) was also evaluated. Although the two-stage CP produced smaller amounts of MAHs than in-situ CP over zeolites, it achieved the maximum DeBr efficiency. Between the two catalyst configurations, 1) in-situ red mud/ex-situ HBeta and 2) in-situ red mud/ex-situ HDeZSM-5, the latter produced larger amounts of MAHs with minimal brominated oil formation. Two-stage CP over in-situ red mud/ex-situ zeolites also showed that HDeZSM-5 achieved a longer catalyst lifetime in the production of debrominated MAHs owing to the smaller amount of coke formation than HBeta. This paper will provide a guideline for accelerating the commercialization of the CP process of PCB to maximize the clean fuel production efficiency with the minimized pollution.

Applicability of ground source heat pumps as a bioremediation-enhancing technology for monoaromatic hydrocarbon contaminants

Geothermal or ground source heat pumps (GSHPs) are among the highest growing renewable energy technologies used for heating and cooling of buildings. However, despite being a well-established technology, their geo-environmental effects such as impact of the heat on the biosphere is still not thoroughly understood. This study uses FEFLOW software, to simulate heat and mass transport of a vertical closed-loop GSHP system. Transient flow and heat transport results for a multiple borehole system are presented which indicate long-term effects on subsurface temperature. Moreover, the impact of temperature change in a contaminated granular porous subsurface during remediation applications is examined. In particular, as subsurface temperatures are elevated due to geothermal heating, sorption will decrease and biodegradation rates will increase. These effects are examined in the context of contaminant transport, to evaluate the possibility of utilizing geothermal heating as a remediation strategy. The results revealed that temperature changes caused by GSHP operation can significantly enhance biodegradation of hydrocarbon contaminants. For instance, elevated subsurface temperature resulted in 97% reduction in benzene total mass, after one year of GSHP operation for a typical office building in Toronto.

Five-Year Enhanced Natural Attenuation of Historically Coal-Tar-Contaminated Soil: Analysis of Polycyclic Aromatic Hydrocarbon and Phenol Contents.

The objective of this study was to assess the soil pollution on an industrial wasteland, where coal-tar was processed in the period between 1880 and 1997, and subsequent to assess the decline in the content of phenols and polycyclic aromatic hydrocarbons (PAHs) during enhanced natural attenuation. The soil of the investigated area was formed from a layer of uncompacted fill. Twelve sampling points were established in the investigated area for collecting soil samples. A study conducted in 2015 did not reveal any increase in the content of heavy metals, monoaromatic hydrocarbons (BTEX), and cyanides. However, the content of PAHs and phenols was higher than the content permitted by Polish norms in force until 2016. In the case of PAHs, it was observed for individual compounds and their total contents. Among the various methods, enhanced natural attenuation was chosen for the remediation of investigated area. Repeated analyses of the contents of phenols and PAHs were conducted in 2020. The results of the analyses showed that enhanced natural attenuation has led to efficient degradation of the simplest substances—phenol and naphthalene. The content of these compounds in 2020 was not elevated compared to the standards for industrial wastelands. The three- and four-ring hydrocarbons were degraded at a lower intensity. Based on the mean decrease in content after 5-year enhanced natural attenuation, the compounds can be arranged in the following order: phenols > naphthalene > phenanthrene > fluoranthene > benzo(a)anthracene > chrysene > anthracene.

Green Nanosilicas for Monoaromatic Hydrocarbons Removal from Air

We demonstrate a novel application of green nanosilicas (GN), prepared via an environmentally friendly route, in removing volatile organic compounds (VOCs). Herein, we aim to establish GN as viable alternatives to traditional mesoporous silicas for the removal of monoaromatic hydrocarbons (MAHC). The results show that the GN have high extraction efficiencies comparable to those previously reported for mesoporous silicas. It was demonstrated that bespoke GN can be syntheised readily with the ability to tailor their physical properties and MAHC adsorption. In order to understand the MAHC adsorption by GN, their porosity, morphology and pore structure were characterised. It was observed that the combination of broad pore size distribution and, in particular, the presence of meso- and micro-porosity in GN contributed to high MAHC extraction efficiencies and selectivity. Although from a commercial viewpoint, further optimisation of GN is desirable in order to replace traditional sorbents, this work clearly highlights a new family of “green” sorbents, which can be prepared with a substantial reduction in secondary pollution with potential applications in selective gas separation.Graphical New green nanoparticles (GN) have been developed as VOC adsorbents; GN preparation is rapid and under neutral pH and room temperature conditions, leading to a substantial reduction in secondary pollution. Their successful performance is related to their unique physical properties, which can be easily tailored.

Emissions and toxic units of solvent, monomer and additive residues released to gaseous phase from latex balloons

This study describes the VOCs emissions from commercially available latex balloons. Nine compounds are determined to be emitted from 13 types of balloons of different colors and imprints in 30 and 60 °C. The average values of total volatile organic compounds (TVOCs) emitted from studied samples ranged from 0.054 up to 7.18 μg g−1 and from 0.27 up to 36.11 μg g−1 for 30 °C and 60 °C, respectively. The dataset is treated with principal component analysis (PCA) and multiple curve resolution (MCR) to characterize its internal patterns. Here two groups on compounds are recognized – the first one related to balloon material, the second one being emissions of compounds previously adsorbed on balloon material. The toxicity assessment of MCR modeled balloons’ emissions was performed by toxic unit (TU) approach. The obtained TUs were summed to give toxicity emission assessment. The incorporation of TUs allows to identify the balloons with the most toxic emissions– imprinted ones in 60 °C. The compounds of the highest TUs are hexanal and benzene. FTIR analysis shows that all balloons are made of the same polymeric material – isoprene, so all differences in emissions are related to different additives like pigments, imprints or these responsible for opaqueness. Analyzing the obtained research results it was noticed that latex balloons might be considered as an important source of emission of aliphatic and monoaromatic hydrocarbons to the gaseous phase.

Pyrolysis technology for Cortaderia selloana invasive species. Prospects in the biomass energy sector

Cortaderia selloana (CS), is an invasive and exotic species that is generating significant invasive problems in the Iberian Peninsula ecosystems. The objective of this research was to study this plant potential thorough a pyrolytic process helping to reduce its expansion. Stems and leaves were subjected to conventional and flash pyrolysis. These processes were carried out in an original design oven using a 25 °C/min heating ramp at a 750 °C temperature and during 60 min at the pyrolysis temperature for conventional pyrolysis and with 750 °C and 850 °C pyrolysis temperatures for flash. Gas-fraction obtained by flash pyrolysis had higher HHV data when compared with conventional ones (∼17 MJ/kg vs ∼5 MJ/kg) due to their less CO2 and higher CO, CH4 and H2. The greater bio-oil yield was obtained for CSS-P (33.58%). The composition of conventional pyrolysis bio-oils had an overbearing of nonaromatic and monoaromatic hydrocarbons nature whereas bio-oils from flash pyrolysis were composed mainly of polycyclic aromatic hydrocarbons. Bio-char fraction was higher in CSL than CSS with HHV similar to lignite and bituminous coals (22.74–29.12 MJ/kg). After done the quantification and characterization of the fractions, it was concluded that a possible energetic valorization of Cortaderia selloana biomass was possible.

Assessing toxicity of hydrophobic aliphatic and monoaromatic hydrocarbons at the solubility limit using novel dosing methods

Reliable delineation of aquatic toxicity cut-offs for poorly soluble hydrocarbons is lacking. In this study, vapor and passive dosing methods were applied in limit tests with algae and daphnids to evaluate the presence or absence of chronic effects at exposures corresponding to the water solubility for representative hydrocarbons from five structural classes: branched alkanes, mono, di, and polynaphthenic (cyclic) alkanes and monoaromatic naphthenic hydrocarbons (MANHs). Algal growth rate and daphnid immobilization, growth and reproduction served as the chronic endpoints investigated. Results indicated that the dosing methods applied were effective for maintaining mean measured exposure concentrations within a factor of two or higher of the measured water solubility of the substances investigated. Chronic effects were not observed for hydrocarbons with an aqueous solubility below approximately 5 μg/L. This solubility cut-off corresponds to structures consisting of 13–14 carbons for branched and cyclic alkanes and 16–18 carbons for MANHs. These data support reliable hazard and risk evaluation of hydrocarbon classes that comprise petroleum substances and the methods described have broad applicability for establishing empirical solubility cut-offs for other classes of hydrophobic substances. Future work is needed to understand the role of biotransformation on the observed presence or absence of toxicity in chronic tests.

Uptake of monoaromatic hydrocarbons during biodegradation by FadL channel-mediated lateral diffusion

In modern societies, biodegradation of hydrophobic pollutants generated by industry is important for environmental and human health. In Gram-negative bacteria, biodegradation depends on facilitated diffusion of the pollutant substrates into the cell, mediated by specialised outer membrane (OM) channels. Here we show, via a combined experimental and computational approach, that the uptake of monoaromatic hydrocarbons such as toluene in Pseudomonas putida F1 (PpF1) occurs via lateral diffusion through FadL channels. Contrary to classical diffusion channels via which polar substrates move directly into the periplasmic space, PpF1 TodX and CymD direct their hydrophobic substrates into the OM via a lateral opening in the channel wall, bypassing the polar barrier formed by the lipopolysaccharide leaflet on the cell surface. Our study suggests that lateral diffusion of hydrophobic molecules is the modus operandi of all FadL channels, with potential implications for diverse areas such as biodegradation, quorum sensing and gut biology.

ZSM-5 catalyzed copyrolysis of sugarcane bagasse with LDPE: Influence of microwave-assisted acid pretreatment of sugarcane bagasse on yield and composition of gasoline range oil

In the present study, microwave-assisted acid pretreatment (MAAP) was employed to reduce the recalcitrance of sugarcane bagasse (SCB). The pretreated SCB was subjected to catalytic copyrolysis with LDPE in a lab-scale pyrolysis reactor using ZSM-5 catalyst. The influence of operating parameters affecting the effectiveness of MAAP (pretreatment time, pretreatment temperature, level of microwave power, and sulfuric acid concentration) on (i) yields of copyrolysis products, (ii) compositions of crude bio-oil, and gasoline range oil (GRO) (a cut obtained by simple distillation of crude bio-oil having boiling point range of 25 to 230 °C) was optimized. Under optimum operating conditions of pretreatment (microwave power, 600 W; sulfuric acid concentration, 1.5 M; pretreatment time, 15 min; pretreatment temperature, 130 °C), the highest crude bio-oil yield of 43.84% and least biochar yield of 17.65% were observed. The crude bio-oil obtained by pretreated SCB (PT SCB) contained 25.63% gasoline range fraction compounds (GRF), which was 1.96 times higher than the corresponding value for untreated SCB (UT SCB). GC HRMS analysis of GRO showed that it contains 33.14% monoaromatic hydrocarbons, 28.87% C5–C12 alkanes, 11.24% C5–C12 olefins, 25.64% oxygenated compounds (including phenols, furans, esters, and other oxygenated compounds), and 1.14% naphthalenes and indanes. The fuel properties of GRO were estimated and found to be reasonably closer to properties of commercial gasoline.

Moniliella spathulata, an oil-degrading yeast, which promotes growth of barley in oil-polluted soil

The yeast strain Moniliella spathulata SBUG-Y 2180 was isolated from oil-contaminated soil at the Tengiz oil field in the Atyrau region of Kazakhstan on the basis of its unique ability to use crude oil and its components as the sole carbon and energy source. This yeast used a large number of hydrocarbons as substrates (more than 150), including n-alkanes with chain lengths ranging from C10 to C32, monomethyl- and monoethyl-substituted alkanes (C9–C23), and n-alkylcyclo alkanes with alkyl chain lengths from 3 to 24 carbon atoms as well as substituted monoaromatic and diaromatic hydrocarbons. Metabolism of this huge range of hydrocarbon substrates produced a very large number of aliphatic, alicyclic, and aromatic acids. Fifty-one of these were identified by GC/MS analyses. This is the first report of the degradation and formation of such a large number of compounds by a yeast. Inoculation of barley seeds with M. spathulata SBUG-Y 2180 had a positive effect on shoot and root development of plants grown in oil-contaminated sand, pointing toward potential applications of the yeast in bioremediation of polluted soils.Key points• Moniliella spathulata an oil-degrading yeast• Increase of the growth of barley

Numerical and experimental investigation of soot precursor and primary particle size of aviation fuel (RP-3) and n-dodecane in laminar flame

RP-3 is the most popular aviation fuel in China and its soot emission raises serious concern. The current study analyzed the soot precursors of RP-3 and n-dodecane in laminar flame, and integrated the corresponding poly-aromatic hydrocarbons (PAHs) growth mechanisms with popular RP-3 and n-dodecane oxidation mechanisms to improve the soot formation prediction for both fuels. The sizes of soot precursors were determined by the fringe lengths of soot particles. At dimensionless height DH = 0.25 of RP-3 and DH = 0.50 of n-dodecane, the geometric mean fringe lengths of RP-3 and n-dodecane are measured to be 0.67 nm and 0.64 nm respectively, which approximate to the size of the five-ringed (A5) poly-aromatic hydrocarbon. An A5 growth mechanism was then added on both popular RP-3 and n-dodecane oxidation mechanisms respectively. The base oxidation mechanisms for both fuels only contain the mono-aromatic hydrocarbons formation and benzene was treated as soot precursors in simulation. After validation by the ignition delay time and flame speed in literature, the combined mechanisms were then used to simulate the soot property and validated by the measured primary particle diameter. The simulation results suggested that the computed soot precursor concentrations of the combined mechanisms are smaller than that of the base mechanism. The combined mechanisms enhance the soot nucleation process which increases the primary particle number density prediction, and weaken the soot growth process which decreases the soot volume fraction prediction for both fuels. Eventually, the proposed combined mechanisms including the large PAHs growth provide a better agreement with the measured primary particle diameter.

Equilibrated TodX and CymD united-atom models with and without membrane for article: Uptake of monoaromatic hydrocarbons during biodegradation by FadL channel-mediated lateral diffusion.

Equilibrated TodX and CymD united-atom models with and without membrane for article: Uptake of monoaromatic hydrocarbons during biodegradation by FadL channel-mediated lateral diffusion.

Renewable aromatic hydrocarbons production from catalytic pyrolysis of lignin with Al-SBA-15 and HZSM-5: Synergistic effect and coke behaviour

With a focus on converting waste to energy, this study integrated the macromolecular reaction ability of Al-SBA-15 and the shape selectivity of HZSM-5 for the production of renewable aromatic hydrocarbons. Results demonstrated that the catalytic pyrolysis of lignin with both Al-SBA-15 and HZSM-5 was able to improve the mono-aromatic hydrocarbons (MAHs) production while inhibiting the formation of undesirable poly-aromatic hydrocarbons (PAHs), thus controlling the MAHs and PAHs content in the bio-oil. At optimal operation conditions (pyrolysis temperature: 550 °C, Al-SBA-15/HZSM-5 ratio: 1:3), the MAHs content was 42.57% higher than that catalyzed by HZSM-5 only (28.30%). The PAHs content was only 27.13%. Typical MAHs (benzene, toluene and xylene, denoted as BTX) and PAHs selectivities were determined as 55.91% and 38.92%, respectively. Thermogravimetry-differential thermogravimetric (TG-DTG) analysis indicated that the used HZSM-5 was principally composed of graphite-like coke and a negligible content of fibrous-like coke. The coke content was observed as 5.65% compared to 10.52% in the HZSM-5 only. Furthermore, the efficient synergistic effect of Al-SBA-15 and HZSM-5 resulted in the deep conversion and directional reforming of the lignin pyrolysis vapors. This study can promote the high-grade utilization of lignin through the application of feasible fixed-bed catalytic pyrolysis technology.

Catalytic co-pyrolysis of torrefied poplar wood and high-density polyethylene over hierarchical HZSM-5 for mono-aromatics production

The catalytic co-pyrolysis of torrefied poplar wood sawdust (TPW) and high-density polyethylene (HDPE) was investigated over hierarchical HZSM-5. Compared with raw PW/HDPE, the bio-oil yield from co-pyrolysis of TPW/HDPE decreased gradually while the quality of bio-oil was upgraded. With increasing torrefaction temperature from 220 to 280 °C, the amounts of acids, furans, and anhydrosugars in bio-oil were significantly reduced due to the removal of hemicellulose, whereas the production of phenols and alkenes were improved due to the enhanced hydrogen transfer reaction. In the catalytic co-pyrolysis, increasing torrefaction temperature caused an enhanced production of mono-aromatics as well as the selectivity of BTX (benzene, toluene, and xylene). Nevertheless, severe torrefaction (280 °C) lead to a rapid reduction of aromatic yield and selectivity due to the loss of cellulose. Compared to parent HZSM-5, hierarchical HZSM-5 treated with alkaline concentration (0.2–0.3 mol/L) favored the formation of mono-aromatics at the expense of polyaromatics. The maximum mono-aromatics yield of 71.75% was obtained during catalytic co-pyrolysis of 260-TPW/HDPE over 0.3-HZSM-5. The present work suggests that torrefaction pretreatment followed by the catalysis of hierarchical HZSM-5 is an efficient way to promote the production of valuable mono-aromatic hydrocarbons from biomass and plastic wastes.

Sulfate as a terminal electron acceptor in toluene oxidation in anaerobic conditions

In aerobic conditions, many of microorganisms cause decomposition of saturated hydrocarbons. Little publications are available relative to anaerobic transformation of these compounds, which provides substantial сapiltal saving for waste water treatment. At the same time, cultures found among aerobic decomposers of petroleum products are characterized by the ability to use elements with variable valence as terminal electron acceptors in oxidation of organic substances. Their ability to decompose aliphatic hydrocarbons helps to identify some of them.Purpose: studying the ability of a selected association of immobilized bacteria on a fibrous carrier to utilize sulfate as a terminal electron acceptor for toluene oxidation.Methodology/approach: Analytical summarizing of results, literature review, laboratory research based on standard and modern up-to-date methodologies with the use of modern analytical equipment.Findings: The availability of using microorganism selection is shown for expanding the range of polluting strippants in biological purification; the main directions are determined for the process intensification by immobilization of active sludge on a fibrous carrier. The ability of microorganisms to oxidize toluene under oxygen-free (anaerobic) conditions is studied in the laboratory conditions.Research implications: monoaromatic hydrocarbons, toluene, in particular, can be changed by selected associations of decomposers using terminal electron acceptors in oxidation of nitrates and sulfates.

Biodegradation Studies of Benzene, Toluene, Ethylbenzene and Xylene (BTEX) Compounds by <i>Gliocladium sp.</i> and <i>Aspergillus terreus</i>

Benzene, toluene, ethylbenzene and xylene (BTEX) are monoaromatic hydrocarbons found frequently in petroleum and its derivatives; and they are among the most important pollutants of soil and groundwater. This study focused on harnessing the enzymatic capabilities of filamentous fungi Gliocladium sp. and Aspergillus terreus, dwelling in a petroleum-contaminated soil to degrade benzene, toluene, ethylbenzene and xylene (BTEX) compounds. The biodegradation experiment was carried out using the fungi individually and in consortium in a batch culture containing mineral salts medium supplemented with 1% v/v BTEX. The experiments were carried out in triplicates at room temperature on a rotary shaker (180rpm) for twenty five days and aliquots were taken on a five day interval to determine the hydrocarbon utilizing fungal (HUF) count and residual BTEX in order to monitor the rate of biodegradation. The hydrocarbon utilizing fungal counts were determined by direct counting using a Neubauer Haemocytometer while, the residual BTEX was determined using absorbance values measured using a spectrophotometer and the corresponding concentrations determined from a standard curve. The highest percentage degradation of BTEX was observed with Aspergillus terreus (89.1%) while, the least was observed with Gliocladium sp. (84.4%). The growth peak was attained on the 15th day in all treatments after which the HUF counts declined. Statistical analysis showed no significant difference (P>0.05) in the mean amounts of BTEX degraded and hydrocarbon-utilizing fungal counts between the treatments. The strains of Gliocladium sp. and Aspergillus terreus used in this study showed high ability for BTEX degradation thus, they are potential candidates for bioremediation of soils contaminated with monoaromatic hydrocarbons.
 Keywords: Biodegradation, BTEX, Gliocladium sp., Aspergillus terreus, Monoaromatic hydrocarbons

Nitrated monoaromatic hydrocarbons (nitrophenols, nitrocatechols, nitrosalicylic acids) in ambient air: levels, mass size distributions and inhalation bioaccessibility

Nitrated monoaromatic hydrocarbons (NMAHs) are ubiquitous in the environment and an important part of atmospheric humic-like substances (HULIS) and brown carbon. They are ecotoxic and with underresearched toxic potential for humans. NMAHs were determined in size-segregated ambient particulate matter collected at two urban sites in central Europe, Ostrava and Kladno, Czech Republic. The average sums of 12 NMAHs (Σ12NMAH) measured in winter PM10 samples from Ostrava and Kladno were 102 and 93 ng m−3, respectively, and 8.8 ng m−3 in summer PM10 samples from Ostrava. The concentrations in winter corresponded to 6.3–7.3% and 2.6–3.1% of HULIS-C and water-soluble organic carbon (WSOC), respectively. Nitrocatechols represented 67–93%, 61–73% and 28–96% of NMAHs in PM10 samples collected in winter and summer at Ostrava and in winter at Kladno, respectively. The mass size distribution of the targeted substance classes peaked in the submicrometre size fractions (PM1), often in the PM0.5 size fraction especially in summer. The bioaccessible fraction of NMAHs was determined by leaching PM3 samples in two simulated lung fluids, Gamble’s solution and artificial lysosomal fluid (ALF). More than half of NMAH mass is found bioaccessible, almost complete for nitrosalicylic acids. The bioaccessible fraction was generally higher when using ALF (mimics the chemical environment created by macrophage activity, pH 4.5) than Gamble’s solution (pH 7.4). Bioaccessibility may be negligible for lipophilic substances (i.e. log KOW > 4.5).

Upgrading of bio-oil by ex-situ catalytic pyrolysis and in-line esterification in fluidized bed reactor

Ex-situ catalytic pyrolysis of Quercus mongolica over HZSM-5 and in-line esterification of pyrolysis/catalytic pyrolysis vapors with liquid phase n-butyl alcohol were carried out in a fluidized bed reactor. The ex-situ catalytic pyrolysis over HZSM-5 beads was performed to produce bio-oil containing aromatic hydrocarbons. The temperature of the ex-situ catalytic upgrading reaction was varied from 450 °C to 600 °C, and the maximum aromatic hydrocarbons yield was obtained at 450 °C. The selectivity for aromatic hydrocarbons as a function of catalytic reaction temperature varied depending on aromatic ring number, as the selectivity for mono-aromatic hydrocarbons decreased and that for poly-aromatic hydrocarbons increased with temperature. In-line esterification of the pyrolysis/catalytic pyrolysis vapors with liquid n-butyl alcohol was also carried out, and the GC/MS analysis results showed that the acids, aldehydes and ketones in the bio-oil were converted to esters and acetals.