Pyrene In Water Research Articles

Different sorption behaviours of pyrene onto polyethylene microplastics in a binary system with water and a ternary system with water and sediment

Microplastics (MPs) and polycyclic aromatic hydrocarbons (PAHs) are two ubiquitous coexisting pollutants that pose potential threats to the environment and organisms and have attracted increasing attention in recent years. However, the interaction between these two pollutants in water, with and without sediment, and the associated mechanisms have not been fully understood. This study aims to explore differences in the sorption behaviours of pyrene at environmentally realistic concentrations by polyethylene MPs (PE-MPs) in binary (water-MPs) and ternary (water-MPs-sediment) systems and to elucidate the role of sediment in the sorption process. Kinetic and isothermal studies show that sediment acted as a “sponge” to adsorb the vast majority of pyrene at the beginning of the sorption experiment in the ternary system, which behaved differently than in the binary system. The sediment-sorbed pyrene was then gradually released but re-adsorbed by PE-MPs, while the concentration of pyrene in water remained at a steady low level. These findings reveal that PE-MPs exhibited a higher pyrene affinity than sediment and being potential pyrene carriers in aqueous systems. Through sorption kinetics and isotherm models study, it was found that pseudo-second-order (PSO) kinetics (0.9773), Elovich (0.9314) and Henry’s (0.9850) models has the highest R2 value, indicating that chemisorption and hydrophobic interactions were attributed to the sorption process. The present study also demonstrates the competition between sediment and MPs in adsorption of pyrene, and highlights the impact of sediment and MPs in the partitioning of PAHs in aquatic environments, which may change the fate of pollution carried by MPs.

Cooperative adsorption-degradation of benzo[a]pyrene by extracellular enzymes of white rot fungi immobilized on macroporous adsorption resin

Adsorption technology has been widely used in water purification, but its removal mechanism mainly depends on the enrichment and transformation of pollutants, and it cannot be completely degraded. Based on the adsorption properties of macroporous adsorbent resins and the biodegradation of extracellular enzymes of white rot fungi, a synergic study on the adsorption and degradation of benzo[a]pyrene in water was conducted in this paper. The results of the eight-resin screening exhibited that the resin AB-8 exhibited the best immobilization effect of enzymes and removal rate of benzo[a]pyrene. The removal of benzo[a]pyrene by immobilized enzymes and adsorption resin followed pseudo-secondary kinetics, while the degradation of benzo[a]pyrene by free enzymes followed first-order kinetics. Immobilized enzymes can achieve the adsorption-degradation of benzo[a]pyrene, its removal rate reached 92.78% after 6h, which is higher than the degradation rate of free enzymes and faster than the resin adsorption. After that, molecular docking indicated that van der Waals forces and Pi-Alkyl attributed to the binding of laccase and benzo[a]pyrene. Physical adsorption synergistic biodegradation technology is of great practical significance and theoretical value for the sustainable treatment of polluted water.

Feasibility of SERS-Active Porous Ag Substrates for the Effective Detection of Pyrene in Water

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants that are typically released into the environment during the incomplete combustion of fossil fuels. Due to their relevant carcinogenicity, mutagenicity, and teratogenicity, it is urgent to develop sensitive and cost-effective strategies for monitoring them, especially in aqueous environments. Surface-enhanced Raman spectroscopy (SERS) can potentially be used as a reliable approach for this purpose, as it constitutes a valid alternative to traditional techniques, such as liquid and gas chromatography. Nevertheless, the development of an SERS-based platform for detection PAHs has so far been hindered by the poor adsorption of PAHs onto silver- and gold-based SERS-active substrates. To overcome this limitation, several research efforts have been directed towards the development of functionalized SERS substrates for the improvement of PAH adsorption. However, these strategies suffer from the interference that functionalizing molecules can produce in SERS detection. Herein, we demonstrate the feasibility of label-free detection of pyrene by using a highly porous 3D-SERS substrate produced by an inductively coupled plasma (ICP). Thanks to the coral-like nanopattern exhibited by our substrate, clear signals ascribable to pyrene molecules can be observed with a limit of detection of 23 nM. The observed performance can be attributed to the nanoporous character of our substrate, which combines a high density of hotspots and a certain capability of trapping molecules and favoring their adhesion to the Ag nanopattern. The obtained results demonstrate the potential of our substrates as a large-area, label-free SERS-based platform for chemical sensing and environmental control applications.

A Simple Route for the Preparation of Gold Nanofilms and Their Application in SERS Detection of Pyrene in Water

Design and preparation of various rational gold nanostructures has been recognized as a promising solution for the surface-enhanced Raman scattering (SERS) signal amplification. Here, a simple fabrication method was reported for the synthesis of highly sensitive gold nanofilms for SERS detection through covering ginger-liked gold nanoparticles on the stainless steel sheet. The prepared gold nanofilms were then tested by a dip-SPME-SERS method for detecting pyrene. The limit of detection for pyrene standard solution was 0.1ppb, while the limit of detection for pyrene in tap water and lake water without any pretreatment was 5 ppb, respectively. The whole analysis process takes less than 15 minutes. Our method may be a potential alternative way to the chromatography method. The fabricated gold nanfilms are expected to be used for the rapid and sensitive detection of other pollutants such as organic pesticides and polycyclic aromatic hydrocarbon.

Highly selective fluorescence sensor sensing benzo[a]pyrene in water utilizing carbon dots derived from 4-carboxyphenylboronic acid

4-Carboxyphenylboronic acid was used as the single precursor to facilely prepare fluorescent carbon quantum dots by one-step solvothermal method. The as-obtained carbon dots (CDs) exhibited highly selective and sensitive for benzo[a]pyrene (BaP), and may be a splendid sensor for sensing BaP. The principle was that the as-prepared CDs could form a complex with BaP through hydrophobic interaction which causes the decrease of fluorescence intensity of CDs by static quenching principle. The constructed fluorescent sensor exhibited excellent linearity ranged from 0.002 to 0.06 μg mL−1 and provided a low limit of detection of 0.16 ng mL−1. The experimental results showed that this fluorescent sensor resulted in simplicity, rapidness, low cost, short analytical time, and high sensitivity and stability. Validation with real water samples endowed the sensor high reliability and feasibility for BaP determination in practical application in various samples.

Moisture-sensitive metal-organic framework constructed from cobalt and 4-(4-pyridyl) benzoic acid for dispersive solid-phase extraction of polycyclic aromatic hydrocarbons in apple.

A moisture-sensitive metal-organic framework CoII (pybz)2 ·2DMF was synthesized and applied as the adsorbent of dispersive solid-phase extraction. The structure changed after water treatment due to the fact that two chelate carboxylate groups on the skeleton were transformed to monodentate because of the coordination of water molecules. The material showed good adsorption for fluorene, phenanthrene, fluoranthene, and pyrene in water because of the π-π conjugation and π-complexation effects. Coupled with high-performance liquid chromatography, a dispersive solid-phase extraction method of determining the content of fluorene, phenanthrene, fluoranthene, and pyrene in apple samples was established after optimizing the extraction conditions. Methanol containing 4% acetic acid was used as the effective eluent. The linearities were 0.5-1000μg/kg for fluorene, phenanthrene and 5-1000μg/kg for fluoranthene, pyrene. The limits of detection were 0.06-0.6μg/kg, and the recoveries were 94.4-116.4%. The method has a high sensitivity for the determination of four polycyclic aromatic hydrocarbons in apple samples.

Controlling the sign of Excimer‐Origin Circularly Polarised Luminescence by Balancing Hydrophilicity/Hydrophobicity in Bipyrenyl Arginine Peptides

In this paper, the circularly polarised luminescence (CPL) properties of peptides with pyrene in water is described. To consider new ways to control CPL in water, we synthesized a chiral LL-oligopeptide luminophores with two fluorescent pyrenyl and some hydrophilic arginine units. CPL from a transparent pyrenyl excimer was shown at 480 to 510 nm in water. Their CPL signs can be adjusted by changing the number and position of arginine units at the ends of the chiral peptide backbone. More information can be found in the Communication by Mizuki Kitamatsu, Yoshitane Imai et al.

Degradation of pyrene in contaminated water and soil by Fe2+-activated persulfate oxidation: Performance, kinetics, and background electrolytes (Cl-, HCO3- and humic acid) effects

SO4−-based oxidation technologies have been considered as key solution in polycyclic aromatic hydrocarbons (PAHs) degradation. This study constructed Fe2+-activated persulfate oxidation to degrade pyrene in water and soil by using batch and column experiments. Pyrene degradation kinetic in polluted water and effects of soil background electrolytes (Cl−, HCO3− and humic acid) on pyrene degradation were both investigated. The variation of soil properties during pyrene degradation in soil was evaluated. Polluted water remediation results showed that approximately 93.2 % of pyrene was degraded by 65 mM of persulfate with Fe2+/persulfate molar ratio of 0.25. In soil, 88.5 % of pyrene was degraded under the same persulfate concentration and Fe2+/persulfate molar ratio, and there was a slight decrease of soil pH (from 6.7 to 5.4). Cl−, HCO3− and humic acid in soil brought an adverse effect to pyrene degradation through scavenging SO4−. Column study of soil remediation proved the superiority of Fe2+ in activating persulfate, whose application in soil remediation can finally reduce soil pollution and simultaneously avoid the excessive soil acidification in in-situ remediation. In addition, by evaluating the soil organic matter and total organic carbon during the remediation process, it was found that the soil properties have been improved. Therefore, Fe2+-activated persulfate oxidation would be a feasible way to remediate pyrene polluted water/soil.

Treatment of Polycyclic Aromatic Hydrocarbons in Oil Sands Process-Affected Water with a Surface Flow Treatment Wetland

This study applied a passive sampling approach using low-density polyethylene passive samplers to determine the treatment efficiency of the Kearl surface flow treatment wetland for polycyclic aromatic hydrocarbons (PAHs) in Oil Sands Process-affected Waters (OSPW). Treatment efficiency was measured as concentration-reduction and mass-removal from the OSPW. The results show that the wetland’s ability to remove individual PAHs from the influent varied substantially among the PAHs investigated. Treatment efficiencies of individual PAHs ranged between essentially 0% for certain methylated PAHs (e.g., 2,6-dimethylnaphthalene) to 95% for fluoranthene. Treatment in the Kearl wetland reduced the combined total mass of all detected PAHs by 54 to 83%. This corresponded to a reduction in the concentration of total PAHs in OSPW of 56 to 82% with inflow concentrations of total PAHs ranging from 7.5 to 19.4 ng/L. The concentration of pyrene in water fell below water quality targets in the Muskeg River Interim Management Framework as a result of wetland treatment. The application of the passive samplers for toxicity assessment showed that in this study PAHs in both the influent and effluent were not expected to cause acute toxicity. Passive sampling appeared to be a useful and cost-effective method for monitoring contaminants and for determining the treatment efficiency of contaminants in the treatment wetland.

Differential responses in the biotransformation systems of the oyster Crassostrea gigas (Thunberg, 1789) elicited by pyrene and fluorene: Molecular, biochemical and histological approach – Part II

Pyrene (PYR) and fluorene (FLU) are among the sixteen priority Polycyclic Aromatic Hydrocarbons (PAH) of the United States Environmental Protection Agency and are both frequently detected in contaminated sites. Due to the importance of bivalve mollusks in biomonitoring programs and the scarce information on the biotransformation system in these organisms, the aim of this study was to investigate the effect of PYR and FLU at the transcriptional level and the enzymatic activities of some biotransformation systems in the Pacific oyster Crassostrea gigas, and to evaluate the histological effects in their soft tissues. Oysters C. gigas were exposed for 24 h and 96 h to PYR (0.25 and 0.5 μM) and FLU (0.6 and 1.2 μM). After exposure, transcript levels of cytochrome P450 coding genes (CYP1-like, CYP2-like, CYP2AU2, CYP356A1, CYP17α-like), glutathione S tranferase genes (omega GSTO-like and microsomal, MGST-like) and sulfotransferase gene (SULT-like), and the activity of ethoxyresorufin O-deethylase (EROD), Glutathione S-transferase (GST) and microssomal GST (MGST) were evaluated in gills. Histologic changes were also evaluated after the exposure period. PYR and FLU bioconcentrated in oyster soft tissues. The half-life time of PYR in water was lower than fluorene, which is in accordance to the higher lipophilicity and bioconcentration of the former. EROD activity was below the limit of detection in all oysters exposed for 96 h to PYR and FLU. The reproductive stage of the oysters exposed to PYR was post-spawn. Exposure to PYR caused tubular atrophy in digestive diverticula, but had no effect on transcript levels of biotransformation genes. However, the organisms exposed for 96 h to PYR 0.5 μM showed higher MGST activity, suggesting a protective role against oxidative stress in gills of oysters under higher levels of PYR in the tissues. Increased number of mucous cells in mantle were observed in oysters exposed to the higher FLU concentration, suggesting a defense mechanisms. Oysters exposed for 24 h to FLU 1.2 μM were in the ripe stage of gonadal development and showed higher transcript levels of CYP2AU2, GSTO-like and SULT-like genes, suggesting a role in the FLU biotransformation. In addition, after 96 h of exposure to FLU there was a significant increase of mucous cells in the mantle of oysters but no effect was observed on the EROD, total GST and MGST activities. These results suggest that PAH have different effects on transcript levels of biotransformation genes and enzyme activities, however these differences could also be related to the reproductive stage.

Characterization of a new biosurfactant produced by an effective pyrene-degrading Achromobacter species strain AC15

An Achromobacter species strain AC15 was isolated from mangrove soil and identified as a potent producer of biosurfactant. It could utilize high concentrations of pyrene as the sole source of carbon and energy. Results showed that AC15 degraded about 40% of the pyrene, which was provided at an initial concentration of 300 mg L−1, and reduced surface tension of the culture medium from 67.2 to 33.2 mN m−1 after 14 d of incubation using its good emulsification property on the culture medium. The main chemical component of partially purified biosurfactant, namely BS15, was analyzed by gas chromatography-mass spectrometry, amino acid analysis, and LTQ Orbitrap Elite mass spectrometry. Results showed that BS15 was a novel linear lipopeptide with a long-chain C16 fatty acid and peptide comprised of four amino acid residues. The molecular structure was determined as CH3-(CH2)14–CO–O-Leu-Asp-Lys-Ser. The solubility of pyrene in water improved 1.5–1.9 times in the presence of 40–60 mg L−1 of BS15. This work demonstrated that strain AC15 and its biosurfactant BS15 could be potential candidates in further applications of bioremediation of high-molecular weight polycyclic aromatic hydrocarbons.

Dissolved organic matter-mediated photodegradation of anthracene and pyrene in water

Toxicity and transformation process of polycyclic aromatic hydrocarbons (PAHs) is strongly depended on the interaction between PAHs and dissolved organic matters (DOM). In this study, a 125W high-pressure mercury lamp was used to simulate the sunlight experiment to explore the inhibition mechanism of four dissolved organic matters (SRFA, LHA, ESHA, UMRN) on the degradation of anthracene and pyrene in water environment. Results indicated that the photodegradation was the main degradation approach of PAHs, which accorded with the first-order reaction kinetics equation. The extent of degradation of anthracene and pyrene was 36% and 24%, respectively. DOM influence mechanism on PAHs varies depending upon its source. SRFA, LHA and ESHA inhibit the photolysis of anthracene, however, except for SRFA, the other three DOM inhibit the photolysis of pyrene. Fluorescence quenching mechanism is the main inhibiting mechanism, and the binding ability of DOM and PAHs is dominantly correlated with its inhibiting effect. FTIR spectroscopies and UV–Visible were used to analyze the main structural changes of DOM binding PAHs. Generally, the stretching vibration of N–H and C–O of polysaccharide carboxylic acid was the key to affect its binding with anthracene and C–O–C in aliphatic ring participated in the complexation of DOM and pyrene.

Development of a turn-on graphene quantum dot-based fluorescent probe for sensing of pyrene in water.

Polycyclic aromatic hydrocarbons (PAHs) are potentially harmful pollutants that are emitted into the environment from a range of sources largely due to incomplete combustion. The potential toxicity and carcinogenic effects of these compounds warrants the development of rapid and cost-effective methods for their detection. This work reports on the synthesis and use of graphene quantum dots (GQDs) as rapid fluorescence sensors for detecting PAHs in water. The GQDs were prepared from two sources, i.e. graphene oxide (GO) and citric acid (CA) – denoted GO-GQDs and CA-GQDs, respectively. Structural and optical properties of the GQDs were studied using TEM, Raman, and fluorescence and UV-vis spectroscopy. The GQDs were then applied for detection of pyrene in environmental water samples based on a “turn-off-on” mechanism where ferric ions were used for turn-off and pyrene for turn-on of fluorescence emission. The fluorescence intensity of both GQDs was switched on linearly within the 2–10 × 10−6 mol L−1 range and the limits of detection were found to be 0.325 × 10−6 mol L−1 and 0.242 × 10−6 mol L−1 for GO-GQDs and CA-GQDs, respectively. Finally, the potential application of the sensor for environmental water samples was investigated using lake water and satisfactory recoveries (97–107%) were obtained. The promising results from this work demonstrate the feasibility of pursuing cheaper and greener environmental monitoring techniques.

Matrix Type Effect on Sorption Concentration Process and Luminescent Determination of Pyrene

The influence of the type of the matrix on the process of sorption concentration of pyrene (one of the best-known ecotoxicants of the series of polycyclic aromatic hydrocarbons (PAHs)) in homogeneous and heterogeneous solutions (distilled water, an R-12 solvent (a mixture of toluene, butyl acetate, and xylene), and an aqueous micellar solution of an anionic surface-active substance, sodium dodecyl sulfate) as well as on its further determination via solid-phase luminescence is studied. The sorption properties of the following matrices are compared: a cellulose sorbent (filter paper) and filter materials based on polypropylene, viscose, and polyester. It is found experimentally that, upon studying solutions of pyrene in water and an R-12 solvent for sorption and further recording of solid-phase luminescence, a hydrophobic polypropylene matrix is more suitable; however, in the case of the use of aqueous micellar solutions of sodium dodecyl sulfate, it is preferable to execute the sorption and observe the solid-phase luminescence of pyrene on a viscose matrix. The obtained results can be used for developing a highly sensitive method for the monitoring of the concentration of pyrene in various environments.

AuAg alloy film-based colorful SPR imaging sensor for highly sensitive immunodetection of benzo[a]pyrene in water.

A colorful surface plasmon resonance imaging (SPRi) sensor with the hue-based enhanced sensitivity has been developed by using sputtered AuAg alloy thin film as the sensing layer. The condition for optimizing the hue-based sensitivity of the SPRi sensor was achieved, that is, the initial resonance wavelength is in the range from 595 to 610nm. Under this condition, the hue-based refractive index sensitivity of the SPRi sensor was measured as high as Δhue/Δnc=29879/RIU. This sensitivity is 8 times higher than that obtained with a gold-layer SPRi sensor (Δhue/Δnc=3658/RIU) and 7.7 times as high in magnitude as the spectral sensitivity of the same sensor (ΔλR/Δnc=3897.6 nm/RIU). After functionalization of the AuAg alloy film with the monoclonal antibody, the sensor was used for quantitative immunodetection of highly carcinogenic benzo[a]pyrene (BaP) in water. According to the experimental results, the average hue of the SPR color image (300 pixels×300 pixels) experiences an initial rapid increase and then stabilizes 15min after exposure of the functionalized AuAg alloy film to an aqueous BaP solution sample. The variation of average hue obtained at the equilibrium of surface immunoreaction is a linear function of BaP concentration with the slope being Δhue/Δc=132.2/(μg·L-1). A cooled CCD camera is able to distinguish a change of Δhue=1, offering the colorful SPRi sensor the BaP detection limit of 0.01 μg·L-1. The comparative measurements of the sensor's responses indicate that the hue variation obtained with 0.1 μg·L-1 of BaP is equal to that obtained either with 5 μg·L-1 of benzanthracene or with 5 μg·L-1 of benzofluoranthene, revealing the sensor's excellent specificity to BaP. The work demonstrated that the AuAg alloy film-based colorful SPRi sensor can be used not only for visualized analysis of molecular interaction at the surface but also for quantitative trace detection of small-molecule analytes.

Capacitive sensor for detection of benzo(a)pyrene in water

An affinity sensor based on capacitive transduction was developed to detect benzo(a)pyrene (BaP) in river water. Two types of recognition elements, the synthetic receptor analogues molecularly imprinted polymers (MIPs) and natural monoclonal antibody (mAb) were tested for this type of biosensor. Different polymerization strategies to obtain MIPs were compared. One approach comprised a preliminary batch synthesis of beads that were subsequently coupled covalently to an electrode surface. Another approach consisted of the in-situ synthesis of MIPs directly onto the electrode surface using electropolymerization. The latter approach provided the best results. To choose the optimal recognition element mAb and MIP-modified electrodes different sets were evaluated with regards to their sensitivity, selectivity, linear range and re-usability. The mAb-modified electrodes were considerably more sensitive toward BaP (ng L−1 range vs µg L−1 range for the MIP-modified one), and showed a broader linear working range than the MIP-modified electrodes. The latter revealed more suitable for group-selective determination of PAHs. The developed capacitive sensor was tested for the detection of BaP in naturally-contaminated water samples collected in different places of Ghent, Belgium. The results obtained with the sensor were coherent and reproducible, and were in a good agreement with the confirmation technique, HPLC-FlD.

A peptoid supramolecular host for benzo[a]pyrene in water

Studies that identify a new supramolecular host for the highly toxic and prevalent carcinogen benzo[a]pyrene (BP) are reported here. By monitoring changes to absorption and fluorescence spectra, the interaction between BP and two peptoids (N-substituted glycine oligomers) of different length and self-association propensities were compared. Peptoid length and solvent choice influence spectral features. Observed trends support that peptoid self-association in aqueous solution generates a hydrophobic core to which BP can associate.

A luminescence immunoassay test method for determining benzo[a]pyrene in natural water

A test method is developed for determining benzo[a]pyrene in natural water, based on the use of a polyethylene filter (frit) with adsorbed specific antibodies, placed within a transparent column. In passing a test solution, the analyte is adsorbed on the frit similarly to the process implemented in immunoaffinity preconcentration. The added conjugate of a labeled analyte takes the remained vacant binding sites of antibodies. Luminescent semiconductor nanoparticles (quantum dots) CdSe/ZnS, used as labels, enable visual determination under irradiation with UV light. The limit of detection for benzo[a]pyrene in water is similar to 0.5 ng/mL.

Influence of sodium dodecyl sulfate on the phase transition of thermoresponsive hyperbranched polymer in water

The influence of sodium dodecyl sulfate (SDS) on the cloud point temperature (Tcp) of the aqueous solution of thermoresponsive hyperbranched polyethylenimine derivative HPEI-IBAm was studied systematically. When pH was below 8.5, HPEI-IBAm was positively-charged. Initially, the Tcp of HPEI-IBAm decreased significantly, followed by an obvious increase with the increase of SDS concentration. The lower the pH was, the higher the SDS concentration was required to achieve the minimum Tcp. When pH was above 8.5, HPEI-IBAm was neutral and raising the SDS concentration led to the gradual increase of Tcp. Compared to linear poly(N-isopropyl acrylamide) (PNIPAm), the Tcp of the current hyperbranched HPEI-IBAm was more sensitive to SDS. The thermoresponsive HPEI-IBAm/SDS complex was used as host to accommodate the non-polar pyrene in water. The lowest SDS concentration for effectively enhancing the solubility of pyrene in water was around 6.4 mmol·L-1. When HPEI-IBAm was present, the SDS concentration threshhold was decreased to about 0.31 mmol·L-1. Fluorescence technique with pyrene as the hydrophobic probe demonstrated that the SDS concentration of 7.2 mmol·L-1 was required to form the hydrophobic domain to accommodate pyrene guests without HPEI-IBAm, while only 0.2 mmol·L-1 of SDS was required in the presence of HPEI-IBAm.

Chlorophyll catalyse the photo-transformation of carcinogenic benzo[a]pyrene in water.

Algal blooms cause great damage to water quality and aquaculture. However, this study showed that dead algal cells and chlorophyll could accelerate the photo-transformation of benzo[a]pyrene (BaP), a ubiquitous and persistent pollutant with potently mutagenic and carcinogenic toxicities, under visible light irradiation. Chlorophyll was found to be the major active substance in dead algal cells, and generated a high level of singlet oxygen to catalyse the photo-transformation of BaP. According to various BaP metabolites formed, the degradation mechanism was proposed as that chlorophyll in dead algal cells photo-oxidized BaP to quinones via photocatalytic generation of singlet oxygen. The results provided a good insight into the role of chlorophyll in the photo-transformation of organic contaminants and could be a possible remediation strategy of organic pollutants in natural environment.