Polycyclic Aromatic Hydrocarbons In Solution Research Articles

Source apportionment and toxicity of atmospheric polycyclic aromatic hydrocarbons by PMF: Quantifying the influence of coal usage in Taiyuan, China

Atmospheric polycyclic aromatic hydrocarbons (PAHs) were analyzed in the gas phase and total suspended particulate (TSP) from summer 2014 to spring 2015 in Taiyuan, northern China. Taiyuan is an area with some of the highest atmospheric PAH levels in the world, and the total PAHs was highest in winter, followed by autumn, spring and summer. Low air temperature and a southern wind with low speed often led to higher PAH levels in Taiyuan. Although less than a half fraction, the benzo[a]pyrene equivalent concentration (BEQ) of particulate PAHs was almost equal to that of the total PAHs. Four sources, coal combustion, vehicle emissions, coke processing and biomass burning, were determined by positive matrix factorization (PMF), with contributions of 41.36%, 24.74%, 19.71% and 14.18% to the total PAHs in Taiyuan, respectively. Compared with the total PAHs, the particulate PAH solution underestimated the contribution of the coke processing, especially in winter, and overestimated vehicle emissions. The coke processing had a greater contribution to atmospheric PAHs with a southern wind at low speeds in winter in Taiyuan. Ultimately, the coke plants distributed in the Taiyuan-Linfen-Yuncheng basin should receive greater attention for air quality improvement in Taiyuan.

Efficient simultaneous removal of petroleum hydrocarbon pollutants by a hydrophobic silica aerogel-like material

The biodegradation of polycyclic aromatic hydrocarbons (PAHs) and monoaromatic hydrocarbons (MAHs), comprised in the petroleum, is slow and is associated with mutagenic, teratogenic and carcinogenic effects in humans. Aerogels are nanoporous, high surface area materials with easy recovery and high sorption capacities. In this work, the interaction between the aerogel-like material prepared with methyltrimethoxyslane (MTMS) and mix solutions containing MAHs (e.g., benzene, toluene and xylenes (BTXs)) and PAHs (e.g., pyrene, benzo(b)fluoranthene and benzo(a)pyrene) has been assessed. We found that the simultaneous sorption of all aromatic hydrocarbons occurs following a multilayer mechanism, highlighting the role of hydrophobic adsorbent-adsorbate and adsorbate-adsorbate interactions. We have also found that the removal efficiency is similar for all adsorbates and are equal to 16–18%, which leads to a total removal efficiency of around 100%. Desorption experiments show desorption efficiency of ca. 100% for PAHs; however, BTXs show higher interaction with the aerogel and lower desorption rates (below 50%). The silica aerogel-like adsorbent was characterized, before and after equilibrium with BTXs and PAHs solutions, by thermogravimetry (TG), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The ability of this aerogel for removing all these pollutants from a real gasoline sample has also been tested.

Separation of polycyclic aromatic hydrocarbons from rhamnolipid solution by activated carbon adsorption

Separating hydrophobic organic contaminants from a surfactant solution facilitates the reuse of surfactants and reduces waste disposal costs. This study presented an investigation of selective adsorption of hydrophobic organic compounds in rhamnolipid solution by activated carbon as a means of recovering biosurfactants. Three polycyclic aromatic hydrocarbons (PAHs) were used as examples of hydrophobic organic compounds, along with rhamnolipid as biosurfactants. PAH solubility in the micelles increased linearly with increasing concentrations of rhamnolipid. Batch adsorption experiments on containing rhamnolipid and PAH solutions were performed using activated carbon. The adsorption behavior of rhamnolipid and PAH fitted the Freundlich isotherm model and pseudo-second-order kinetics model well. The selectivity value for PAH removal from the surfactant solution decreased with decreasing PAH hydrophobicity and increased with decreasing surfactant concentration. The sorption process was divided into four steps, and sorption schematics were proposed to elucidate the mechanism of sorption. Micelle adsorption was followed by surface solubilization. The findings demonstrate that activated carbon adsorption is an effective method for recovering biosurfactants.

A novel and cost-effective method for the determination of fifteen polycyclic aromatic hydrocarbons in low volume rainwater samples

A novel single-step method was developed for the determination of 15 polycyclic aromatic hydrocarbons (PAHs) at ultratrace levels in rainwater by on-line in-tube solid-phase microextraction (IT-SPME) coupled to high-performance liquid chromatography-photodiode array-fluorescence detection. This paper is focused on a study of the IT-SPME coupling and optimization, its application to rainwater and other environmental waters and the stability of PAH rainwater solutions. In order to solve the different extractive behavior of PAHs, several IT-SPME parameters were optimized, with the type and percentage of organic modifier playing a decisive role. In the kinetic study on stability of PAH solutions, the organic modifier has proven to be effective as a preservative, avoiding the loss of the higher-molecular weight PAHs. The proposed method presents a wide interval of linearity (10–1500ngL−1) and a good relative standard deviation between 3.4% and 14.6% for the PAHs analyzed. Detection and quantification limits between 2.3 and 28ngL−1 and 5.7 and 65ngL−1 were obtained respectively, taking into account the values of the procedure blanks. Recoveries for different kinds of real water samples were within the range of 72–110%. Low and medium-molecular weight PAHs predominate in daily and monthly rainwater samples analyzed. In comparison with other methods reported, the proposed method achieves a significant reduction of the sample volume, the organic solvent consumption and time of sample treatment, allowing a cost-effective analysis of environmental waters. The method is especially suitable for samples from the precipitation events of low intensity or short duration for which sample volume is limiting.

AN INNOVATIVE APPROACH TO ENVIRONMENTAL SAMPLE PREPARATION FOR DETERMINATION OF POLYCYCLIC AROMATIC HYDROCARBONS BY GC-MS USING NEW SORBENTS IN QUECHERS TECHNIQUE

Polycyclic aromatic hydrocarbons (PAHs) have been considered as environmental pollutants of a great concern. Regardless of the method of quantitative analysis to be applyied, sample preparation is essential for the accurate determination of PAHs. Due to the extreme complexity of the soil samples, caused primarily by the presence of hundreds of compounds, many of them have similar physical and / or chemical properties as well as the analyzed compounds, and preparation of environmental samples for analysis is crucial for validity of the PAHs analysis. No matter which method will be applied for later analysis, sample preparation has to fulfill a number of conditions such as, adequate selectivity, efficiency, availability, easy to perform, short duration of the procedure. QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method of sample preparation is a relatively new method that uses different sorbents and solvent systems. In this paper, the possibility of application of sorbents (diatomaceous earth, clinoptilolite and carbon black), which are not usually used in QuEChERS clean-up step of sample preparation, using 3 different solvent mixtures hexane / acetone (1:1, v / v) cyclohexane / acetone (1: 1, v / v) and acetonitrile / methanol (2:1, v / v) was investigated. Standard solutions of PAHs were treated with selected sorbents and solvent systems in all combinations, and then analyzed by GC-MS method. The overall accuracy of the method varied depending of compound and used sorbent/solvent system, while precision of the method was constantly good. Highest mean recovery for all PAHs (49.22%) was recorded for clinoptilolite, hexane / acetone combination. Diatomaceous earth showed lower recoveries in comparison with clinoptilolite, with all solvent systems, while recoveries for carbon black were almost zero. Among tested sorbents, clinoptilolite was identified as good starting sorbent which characteristics could be modified with aim to achieve higher accuracy, precision and selectivity of the method, and enable its new application in analytical chemistry. Key words: PAHs, QuEChERS, sorbents, GC-MC.

Anionic-nonionic mixed-surfactant-enhanced remediation of PAH-contaminated soil.

Soil washing is an efficient remediation technique that enhances the solubility of polycyclic aromatic hydrocarbons (PAHs) in specific surfactant to remediate PAH-contaminated soil. This study evaluated the remediation efficiency of PAH-contaminated soil from a coke oven plant by comparing sodium dodecyl sulfate (SDS), sodium dodecylbenzene sulfonate (SDBS), and Triton X-100 (TX100), as well as TX100-SDS and TX100-SDBS mixed surfactants. Results showed that SDS-TX100 and SDBS-TX100 had synergistic effects on PAH solubilization when surfactant concentrations were above their critical micelle concentration. Competitive effects of the three solubilized PAHs (phenanthrene with three rings, fluoranthene with four rings, and benzo[a]pyrene with five rings) with a particular anionic-nonionic mixed surfactant were investigated. PAHs with more rings were found to slightly decrease the solubility in surfactant solution of PAHs with fewer rings, whereas PAHs with fewer rings promoted the solubility in surfactant solution of PAHs with more rings. The removal ratios of PAHs during the remediation of actual PAH-contaminated soil were best improved by the anionic-nonionic mixed surfactant TX100-SDS (9:1), followed by TX100-SDS (8:2), TX100-SDS (7:3), TX100-SDBS (7:3), TX100, SDBS, and SDS. Therefore, anionic-nonionic mixed surfactants can help improve the remediation performance of PAHs based on their application in tests of cleaning actual PAH-contaminated soil from a coke oven plant.

ChemInform Abstract: IUPAC‐NIST Solubility Data Series. 98. Solubility of Polycyclic Aromatic Hydrocarbons in Pure and Organic Solvent Mixtures‐Revised and Updated. Part 3. Neat Organic Solvents

AbstractReview: 77 refs.

ChemInform Abstract: IUPAC‐NIST Solubility Data Series. 98. Solubility of Polycyclic Aromatic Hydrocarbons in Pure and Organic Solvent Mixtures: Revised and Updated. Part 1. Binary Solvent Mixtures

AbstractReview: 89 refs.

Use of nitrogen to remove solvent from through oven transfer adsorption desorption interface during analysis of polycyclic aromatic hydrocarbons by large volume injection in gas chromatography

The through oven transfer adsorption desorption (TOTAD) interface allows large volume injection (LVI) in gas chromatography and the on-line coupling of liquid chromatography and gas chromatography (LC–GC), enabling the LC step to be carried out in normal as well as in reversed phase. However, large amounts of helium, which is both expensive and scarce, are necessary for solvent elimination. We describe how slight modification of the interface and the operating mode allows nitrogen to be used during the solvent elimination steps. In order to evaluate the performance of the new system, volumes ranging from 20 to 100μL of methanolic solutions of four polycyclic aromatic hydrocarbons (PAHs) were sampled. No significant differences were found in the repeatability and sensitivity of the analyses of standard PAH solutions when using nitrogen or helium. The performance using the proposed modification was similar and equally satisfactory when using nitrogen or helium for solvent elimination in the TOTAD interface. In conclusion, the use of nitrogen will make analyses less expensive.

Methodology of the determination of polycyclic aromatic hydrocarbons in foods

The known methods of determining polycyclic aromatic hydrocarbons (PAHs) in foods used in the current practice of analytical laboratories in Russia are revised. Instrumental methods of high performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GCMS), and liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the quantification of PAHs in solutions and food items are considered. Methodological recommendations for the analytical sample pretreatment of 15 top priority PAHs in foods are formulated.

Surface Characteristics of Ti/IrO2 Anode Material and its Electrocatalytic Properties for Polycyclic Aromatic Hydrocarbons (PAHs) Degradation in Aqueous Solution

In this study, electrochemical degradation of 16 priority PAHs was examined using Ti/IrO2 anode. Iridium dioxide (IrO2) was coated by thermal decomposition of appropriate precursor solution on surface of titanium plate. Surface morphology of coated surface was observed by FESEM and XRD analysis. All electrochemical experiments were conducted using synthetic solution of PAHs in a batch cell under galvanostatic condition. GC-MS was used to quantify PAHs concentration. Electrochemical oxidation results reveal significant degradation of PAHs at Ti/IrO2 surface. Total PAHs removal was about 97 % at all studied initial pH values 3, 6 and 9 in the presence of electrolyte. Crystalline surface of Ti/IrO2 anode exhibited good electrocatalytic properties towards PAHs degradation.

IUPAC-NIST Solubility Data Series. 98. Solubility of Polycyclic Aromatic Hydrocarbons in Pure and Organic Solvent Mixtures—Revised and Updated. Part 3. Neat Organic Solvents

This work updates Vols. 54, 58, and 59 in the IUPAC Solubility Data Series and presents solubility data for polycyclic aromatic hydrocarbon solutes dissolved in neat organic solvents. Published solubility data for acenaphthene, anthracene, biphenyl, carbazole, dibenzofuran, dibenzothiophene, fluoranthene, fluorene, naphthalene, phenanthrene, phenothiazine, pyrene, thianthrene, and xanthene that appeared in the primary literature from 1995 to the end of 2011 are compiled and critically evaluated. Experimental solubility data for more than 550 different solute-organic solvent systems are included. Solubility data published prior to 1995 were contained in three earlier volumes (Vols. 54, 58, and 59) and are not repeated in this volume.

IUPAC-NIST Solubility Data Series. 98. Solubility of Polycyclic Aromatic Hydrocarbons in Pure and Organic Solvent Mixtures: Revised and Updated. Part 1. Binary Solvent Mixtures

This work updates Vols. 54, 58, and 59 in the IUPAC Solubility Data Series and presents solubility data for polycyclic aromatic hydrocarbon solutes dissolved in binary organic solvent mixtures. Published solubility data for anthracene, naphthalene, phenanthrene, phenothiazine, and pyrene that appeared in the primary literature between 1995 to the end of 2011 are compiled and critically evaluated. Experimental solubility data for 360 different solute-binary solvent systems are included in the volume. Solubility data published prior to 1995 were contained in three earlier volumes (Vols. 54, 58, and 59) and are not repeated in this volume.

IUPAC-NIST Solubility Data Series. 98. Solubility of Polycyclic Aromatic Hydrocarbons in Pure and Organic Solvent Mixtures: Revised and Updated. Part 2. Ternary Solvent Mixtures

This work updates Vols. 54, 58, and 59 in the IUPAC Solubility Data Series and presents solubility data for polycyclic aromatic hydrocarbon solutes dissolved in ternary organic solvent mixtures. Published solubility data for anthracene, phenanthrene, and pyrene that appeared in the primary literature between 1995 to the end of 2011 are compiled and critically evaluated. Experimental solubility data for 119 different solute-ternary solvent systems are included in the volume. Solubility data published prior to 1995 were contained in three earlier volumes (Vols. 54, 58, and 59) and are not repeated here.

DETERMINATION OF POLYCYCLIC AROMATIC HYDROCARBONS IN CIGARETTE FILTER TAR BY MEANS OF HOLLOW-FIBER LIQUID PHASE MICROEXTRACTION-HPLC-UV SYSTEM

A high-pressure liquid chromatographic method was developed to determine polycyclic aromatic hydrocarbons (PAHs) in cigarette filter tar using hollow fiber-liquid-phase microextraction (HF-LPME) for the clean-up and enrichment steps. The donor phase for HF-LPME is a mixture of acetonitrile and water. Before analyzing real cigarette samples, some preliminary experiments were necessary to find the optimum starting HF-LPME conditions, including donor phase composition (acetonitrile/water), pH, acceptor phase type, mixing rate, and extraction time. These experiments were performed with model PAH solutions. The chromatographic analysis of the acceptor solution was performed using a C18 reversed-phase column and a UV detector system. Under optimum conditions, percent recoveries and enrichment factors ranged from 63 to 97% and from 208 to 320, respectively, for model PAH solutions. The recoveries from real samples were between 8 and 71%, whereas the enrichment factors ranged from 27 to 234. The limit of detection (LOD) of the six PAHs was found to be between 0.040 and 0.136 ng mL−1. The concentrations of the six PAHs in real samples (various brands of cigarettes) were determined. The total amounts of PAHs (six) found in the filter tar of the three brands filter tar were 165.49, 50.49, and 51.04 ng/cigarette, respectively.

Micellar Enhanced Ultrafiltration for the Removal of Polycyclic Aromatic Hydrocarbons (PAHs) Mixtures in Underground Contaminated Water in Oman

In an attempt to analyze polycyclic aromatic hydrocarbons (PAHs) in diesel contaminated underground water in Oman (Rustaq), Gas chromatography-Mass spectrometry was first used to determine the different concentrations in a standard mixture containing 16 PAHs. Retention time and calibration curves were obtained for all aromatic compounds and were used to identify a given analyte as well as its concentration in the contaminated underground water. Micellar enhanced ultrafiltration (MEUF) was then used to treat standard aqueous solution of PAHs at low concentration (~ 1 ppb) using an edible nonionic surfactant (Tween 80). The totality of the mixture components was completely rejected. Within the experimental detection limit (± 0.01 ppb), the residual PAH concentrations were less than 0.01 ppb in accord with the allowed concentrations in drinking water. Likewise, excellent rejections of PAHs in MEUF treatment of diesel contaminated underground water at an Omani site (Rustaq) were observed. The concentration of PAHs was reduced to less than 0.01 ppb, the accepted limit for the most toxic member of the PAH group (benzo(a)pyrene).

Efficiency of butyl rubber sorbent to remove the PAH toxicity

Large amounts of polycyclic aromatic hydrocarbons (PAHs) have been released to the marine environment as a result of oil spills and from other sources including wastewaters, surface runoff, industrial processes, atmospheric deposition, biosynthesis, and natural events such as forest fires. PAHs have been known to affect a variety of biological processes and can be potent cell mutagens/carcinogens and toxic. In this study, PAH toxicity removal was investigated by using a novel macroporous butyl rubber (BR) sorbent. To find out the toxicity removal efficiency of the sorbents, the toxicity tests with Vibrio fisheri (luminescence bacteria) and Phaeodactylum tricornutum (marine algae) were applied to the acenaphthene (Ace) and phenanthrene (Phen) solutions in seawater (Ace: 500– 1000 μg/L; Phen; 100–1000 μg/L) before and after sorbent applications. Additionally, lysosomal stability and filtration rate biomarker techniques were applied to the mussels (Mytilus galloprovincialis) exposed to 1000 μg/L Phen solution and bioaccumulation was measured. The results showed that the toxicity of the PAH solutions decreased 50–100 percent depending on the concentration of the solutions and organisms. Phaeodactylum was found as the most sensitive organism to Phen and Ace. Since the application of BR sorbent removed the Phen from the solution, the bioaccumulated Phen amount in the mussels decreased accordingly.

The fate of the aqueous phase polycyclic aromatic hydrocarbon fraction in a detention pond system

The concentration of dissolved polycyclic aromatic hydrocarbons (PAH) in influent, effluent, and within a detention pond system was measured. The "soluble fraction" was operationally defined as the PAHs in solution that passed through a 1.2 μm filter. The results show that influent and effluent PAH concentrations were similar, indicating that dissolved PAH moved essentially unhindered through the detention pond system. In general, low molecular weight PAH were present at the highest concentrations and the highest PAH concentrations were measured in Summer. Also, year-to-year variations in PAH concentration were observed. At the end of sufficiently large storms, the pond was comparably unpolluted. During dry periods, the dissolved PAH concentration rose, possibly due to evapoconcentration and by partitioning of PAH from trapped contaminated sediment in the detention pond system. This study provides evidence that aqueous-phase PAH concentrations in runoff water were relatively unaffected by the passage through a conventional detention pond system.

Development of Molecular Imprinted Polymer for Selective Adsorption of Benz[a]pyrene Among Airborne Polycyclic Aromatic Hydrocarbon Compounds

This study combined molecular imprinted polymers (MIPs) and solid-phase extraction (SPE) to create a novel sample pretreatment technique for chemical analysis of polycyclic aromatic hydrocarbons (PAHs) in cigarette smoke. Experimental results demonstrated that MIPs have good selectivity for benz[a]pyrene (BaP) among mixtures of 16 PAH solutions. Molecular imprinted SPE (MISPE) cartridges were applied to a sample taken from mainstream smoke from a cigarette. Based on functional monomer and crosslinker, this study investigated four groups of MIPs. After each template was removed, tests on capacity, selectivity, recovery, scanning electron microscope observations, and real environmental sample tests were conducted. Experimental results showed that MIP-3 (methacrylic acid-co-trimethylolpropane trimethacrylate) is the best MIP, with a capacity of 7.80 ± 0.8 (μg/g), BaP selectivity exceeding 84%, and recovery exceeding 80%. In the environmental sample tests, that is, mainstream smoke from reference cigarettes 3R4F, 87% of BaP was adsorbed by the MISPE cartridge compared with that adsorbed by the filters. All experimental results suggested that MISPE can more effectively adsorb BaP among the 16 different PAHs in mixtures, reduce background interferences, and increase signal resolution as compared with traditional extraction techniques. Additionally, using MISPE cartridges in sample pretreatment reduced both the analysis time and the amount of organic solvent used. In addition, using MISPE may also extract toxic target analytes from a complex sample selectively and more effectively than traditional Soxhlet extraction. Combination of MIP-3 and SPE for environmental sample pretreatment offers a useful tool for selective isolation of the mutagenic PAHs. This study is also the first to apply an MISPE cartridge in the analysis of trace-level BaP in cigarette smoke.

Adsorption of polycyclic aromatic hydrocarbons from aqueous solutions by modified periodic mesoporous organosilica

A novel procedure was developed for the synthesis of a periodic mesoporous organosilica (PMO), which was used to remove polycyclic aromatic hydrocarbons (PAHs) from aqueous solutions. Adsorption equilibrium isotherms and adsorption kinetics experiments were carried out in solutions of PAHs (2–60mgL−1), using the PMO as adsorbent. Adsorption models were used to predict the mechanisms involved. The adsorption kinetics data best fitted the pseudo-first-order kinetic model for naphthalene, and to the pseudo-second-order model for fluorene, fluoranthene, pyrene, and acenaphtene. The intraparticle model was also tested and pointed to the occurrence of such processes in all cases. The isotherm models which best represented the data obtained were the Freundlich model for fluoranthene, pyrene, and fluorene, the Temkin model for naphthalene, and the Redlich–Peterson model for acenaphtene. PAHs showed similar behavior regarding kinetics after 24h of contact between adsorbent and PAHs. FTIR, XRD, BET, and SEM techniques were used for the characterization of the adsorbent material.