Adsorption Of Polycyclic Aromatic Hydrocarbons Research Articles

Employing a magnetic chitosan/molybdenum disulfide nanocomposite for efficiently removing polycyclic aromatic hydrocarbons from milk samples

This study aimed to develop a highly efficient nanocomposite composed of magnetic chitosan/molybdenum disulfide (CS/MoS2/Fe3O4) for the removal of three polycyclic aromatic hydrocarbons (PAHs)—pyrene, anthracene, and phenanthrene. Novelty was introduced through the innovative synthesis procedure and the utilization of magnetic properties for enhanced adsorption capabilities. Additionally, the greenness of chitosan as a sorbent component was emphasized, highlighting its biodegradability and low environmental impact compared to traditional sorbents. Factors influencing PAH adsorption, such as nanocomposite dosage, initial PAH concentration, pH, and contact time, were systematically investigated and optimized. The results revealed that optimal removal efficiencies were attained at an initial PAH concentration of 150 mg/L, a sorbent dose of 0.045 g, pH 6.0, and a contact time of 150 min. The pseudo-second-order kinetic model exhibited superior fitting to the experimental data, indicating an equilibrium time of approximately 150 min. Moreover, the equilibrium adsorption process followed the Freundlich isotherm model, with kf and n values exceeding 7.91 mg/g and 1.20, respectively. Remarkably, the maximum absorption capacities for phenanthrene, anthracene, and pyrene on the sorbent were determined as 217 mg/g, 204 mg/g, and 222 mg/g, respectively. These findings underscore the significant potential of the CS/MoS2/Fe3O4 nanocomposite for efficiently removing PAHs from milk and other dairy products, thereby contributing to improved food safety and public health.

Amplified adsorption and photocatalytic degradation of polycyclic aromatic hydrocarbons using biocompatible nanocrystalline reduced graphene oxide quantum dots

Carcinogenic polycyclic aromatic hydrocarbons (PAHs) have been broadly recognized as significant organic pollutants in the environment, which pose a serious threat to both humans and animals. Therefore, there is an urgent need to develop a solution that effectively removes and reduces PAHs present in the environment. In the present work, we synthesized biocompatible nanocrystalline reduced graphene oxide quantum dots in powdered form (rGOQDTs) of crystallite size 2 nm through hydrothermal method and subsequently used for efficient adsorption and degradation of PAHs for the first time. We noticed that the adsorption of PAHs onto rGOQDTs was faster and more efficient as compared to adsorption on graphene oxide (GO). A 40-fold giant enhancement in the adsorption efficiency of Anthracene and Pyrene on rGOQDTs has been observed as compared to that of graphene oxide. We attribute this enormous enhancement in adsorption efficiency to the stacking of PAHs with rGOQDTs and stronger π-π interactions between rGOQDTs and PAHs. Interestingly, rGOQDTs also exhibit efficient photo-degradation of adsorbed PAHs under visible light irradiation and it degrades almost all PAHs after 80 min of visible light illumination. The degradation efficiency of PAHs is also higher for rGOQDTs as compared to GO. Our work paves the way for efficient removal and degradation of polycyclic aromatic hydrocarbons from the environment.

Large-scale soil application of hydrochar: Reducing its polycyclic aromatic hydrocarbon content and toxicity by heating

The beneficial roles of hydrochar in carbon sequestration and soil improvement are widely accepted. Despite few available reports regarding polycyclic aromatic hydrocarbons (PAHs) generated during preparation, their potential negative impacts on ecosystems remain a concern. A heating treatment method was employed in this study for rapidly removing PAHs and reducing the toxicity of corn stover-based hydrochar (CHC). The result showed total PAHs content (∑PAH) decreased and then sharply increased within the temperature range from 150 °C to 400 °C. The ∑PAH and related toxicity in CHC decreased by more than 80% under 200 °C heating temperature, compared with those in the untreated sample, representing the lowest microbial toxicity. Benzo(a)pyrene produced a significant influence on the ecological toxicity of the hydrochar among the 16 types of PAHs. The impact of thermal treatment on the composition, content, and toxicity of PAHs was significantly influenced by the adsorption, migration, and desorption of PAHs within hydrochar pores, as well as the disintegration and aggregation of large molecular polymers. The combination of hydrochar with carbonized waste heat and exhaust gas collection could be a promising method to efficiently and affordably reduce hydrochar ecological toxicity.

Remediation of polycyclic aromatic hydrocarbons polluted soil by biochar loaded humic acid activating persulfate: performance, process and mechanisms

The remediation for polycyclic aromatic hydrocarbons contaminated soil with cost-effective method has received significant public concern, a composite material, therefore, been fabricated by loading humic acid into biochar in this study to activate persulfate for naphthalene, pyrene and benzo(a)pyrene remediation. Experimental results proved the hypothesis that biochar loaded humic acid combined both advantages of individual materials in polycyclic aromatic hydrocarbons adsorption and persulfate activation, achieved synergistic performance in naphthalene, pyrene and benzo(a)pyrene removal from aqueous solution with efficiency reached at 98.2%, 99.3% and 90.1%, respectively. In addition, degradation played a crucial role in polycyclic aromatic hydrocarbons remediation, converting polycyclic aromatic hydrocarbons into less toxic intermediates through radicals of ·SO4-, ·OH, ·O2–, and 1O2 generated from persulfate activation process. Despite pH fluctuation and interfering ions inhibited remediation efficiency in some extent, the excellent performances of composite material in two field soil samples (76.7% and 91.9%) highlighted its potential in large-scale remediation.

Single and Competitive Adsorption of Naphthalene, Phenanthrene, and Pyrene on Polystyrene Nanofibers.

In this investigation, polystyrene (PS) nanofibers were prepared by electrospinning for the adsorption of naphthalene (Nap), phenanthrene (Phe), and pyrene (Pyr) from an aqueous solution. Surface morphology and physicochemical characteristics of PS nanofibers were analyzed using Fourier transform infrared spectroscopy (FT-IR) and point-of-zero-charge calorimetry (pHpzc). The effects of pH, ion concentration, and temperature on the adsorption were also investigated. The adsorption mechanism of target pollutants on PS nanofibers was investigated by a batch adsorption method. The adsorption kinetic studies showed that the adsorption of the three polycyclic aromatic hydrocarbons (PAHs) on PS nanofibers conformed to the pseudo-second-order kinetic model in both single and ternary systems. Meanwhile, in a single system, the three PAHs adsorbed on nanofibers were controlled by both intraparticle diffusion and liquid film diffusion, whereas the adsorption of Nap in a ternary system was controlled mainly by intraparticle diffusion, and the adsorption of Phe and Pyr was controlled mainly by liquid film diffusion. The isotherm data indicated that the Freundlich model performed better than the Langmuir model for the adsorptions of Nap, Phe, and Pyr on PS nanofibers in both the single system and the ternary system. Due to competitive adsorption, the adsorption capacities of Nap and Pyr on PS nanofibers decreased from 105.816 and 19.098 mg g-1 in the single system to 23.626 and 12.126 mg g-1 in the ternary system, but the adsorption of Phe was not affected. π-π interactions and pore filling may be jointly involved in the adsorption of PAHs on PS nanofibers.

Facile construction of magnetic solid-phase extraction of polyaniline blend poly(amidoamine) dendrimers modified graphene oxide quantum dots for efficient adsorption of polycyclic aromatic hydrocarbons in environmental water

An efficient magneto–adsorbent composed of polyaniline blend poly(amidoamine) dendrimers modified graphene oxide quantum dots and magnetic Fe3O4 particles (Fe3O4@PANI–PSS/PAMAM–QGO) for magnetic solid–phase extraction (MSPE) of polycyclic aromatic hydrocarbons (PAHs) in environmental water was synthesized. Fe3O4@PANI–PSS/PAMAM–QGO exhibited exceptional adsorption property for most PAHs analytes. The nanocomposite sorbent demonstrated a ferromagnetic behavior of 17.457 emu g−1, which is adequate for subsequent use in MSPE. Key parameters affecting the processes of adsorption and desorption, including the sorbent amount, vortex adsorption time, vortex extraction time, sample volume, a solvent for desorption and the solvent volume were all examined and optimized. The performance of MSPE using Fe3O4@PANI–PSS/PAMAM–QGO as adsorbent for four PAHs, including fluoranthene, acenaphthene, phenanthrene and pyrene were studied through high performance liquid chromatography equipped with spectrofluorometer. Under the optimal conditions, Fe3O4@PANI–PSS/PAMAM–QGO showed a wide linearity of 10–1,000 ng mL−1, low detection limit (LOD) ranging from 1.92 to 4.25 ng mL -1 and high accuracy (recoveries of 93.6–96.5 %). Enrichment factors up to 185 were achieved. Furthermore, Fe3O4@PANI–PSS/PAMAM–QGO exhibited good recyclability (10 times, RSDs ≤ 5.35%), while maintaining its high efficiency in the extraction of PAHs. The proposed method was successfully applied for environmental samples. Recoveries ranging from 81.2 to 106.2 % were obtained, indicating a low matrix effect and the robustness of the optimized MSPE method. Based on these features and under the optimal extraction conditions, Fe3O4@PANI–PSS/PAMAM–QGO was demonstrated to be a successful tool for the rapid and sensitive extraction of PAHs in the samples.

Toxic effects of polystyrene nanoplastics and polycyclic aromatic hydrocarbons (chrysene and fluoranthene) on the growth and physiological characteristics of Chlamydomonas reinhardtii

While the toxicity of nano-microplastics and polycyclic aromatic hydrocarbons (PAHs) to aquatic organisms is well-studied, their joint impact on microalgae is less explored. This study focused on single and combined effects of PS-NPs (30 nm; concentrations: 2, 5, 10, and 25 mg/L) and two PAHs (chrysene and fluoranthene at 10, 100 µg/L) for 96 h on the accumulation, growth, photosynthetic parameters, and oxidative stress in the Chlamydomonas reinhardtii. The findings revealed that exposure to increasing concentrations of PS-NPs significantly reduced the growth inhibition ratio and chlorophyll-a content after 96 h. Both PAHs (100 µg/L) + PS-NPs (25 mg/L), significantly reduced the growth inhibition ratio and chlorophyll-a levels. Individual and combined exposures of PS-NPs and PAHs can prompt antioxidant responses like SOD, GPx, and GST, as well as an unaffected level of non-enzymatic antioxidant GSH and diminished CAT activity. Furthermore, both PAHs + PS-NPs triggered ROS levels, resulting in cell membrane damage. However, the reduced oxidative effect of LPO of combined exposures can be attributed to the activation of antioxidant defenses. In addition, the microscopic visualization data shows that PS-NPs adhered to the surface of microalgae. Also, PS-NPs reduced the adsorption of PAHs on the surface of C. reinhardtii. Altogether, this study implied that the influence of coexistent PS-NPs should be considered in the environmental risk assessment of PAHs in aquatic environments.

Lowering polycyclic aromatic hydrocarbon concentrations in vegetable oil deodorizer distillates and enhancing its utilization by graphene composites

Vegetable oil deodorizer distillates (VODDs), which are the main source of natural tocopherol, are easily contaminated by polycyclic aromatic hydrocarbons (PAHs), and pose health threats to human beings. To remove 16 priority-control PAHs in VODD, three graphene (GR) composites, including TiO2-GR, sepiolite-GR and Fe3O4-GR, were prepared. PAH concentrations and removal rates were determined using gas chromatography-mass spectrum (GC-MS). Additionally, density functional theory (DFT) calculation was conducted to simulate and illustrate PAH adsorption on GR composites. The results indicated that the highest BaP removal rate was given to TiO2-GR with 90.37 ± 3.23 % after 2 h in standard solution. The adsorption followed the pseudo-first order kinetic, with the constant of −0.0141. In contrast, 61.62 ± 7.88 % total PAHs were removed in VODD using TiO2-GR. Moreover, DFT calculation verified that the strongest adsorption effect occurred between TiO2-GR and PAHs, with the adsorption energy of −2.69 eV. Additionally, GR composite morphology would be changed when LPAH concentrations are higher than 30 μg kg-1. The results also indicated the retention rates tocopherol ranged from 91.91 ± 1.92 % to 99.22 ± 0.88 %. This study firstly provides a useful tool for PAH removal in VODDs while retaining tocopherol. Moreover, it will increase the understanding of adsorption process between PAHs and GR composites.

Construction of hierarchical porous carbons with Ph-POSS based polymers for highly efficient adsorption of polycyclic aromatic hydrocarbons

Fluid catalytic cracking (FCC) diesel provides most polycyclic aromatic hydrocarbons (PAHs) in diesel. The removal of PAHs by adsorption and separation method is an efficient way to obtained purified diesel. As a kind of green economy adsorbent, porous carbon materials (PCMs) have been widely used in the adsorption of gases, aromatics and organic pollutions. Here, by direct carbonization, the PCMs are prepared from the novel Ph-POSS based porous organic polymers (POPs) which possessed high BET surface areas (∼1000 m2/g). The PCMs possess abundant microporosity and O atoms in the skeleton. The PCMs exhibit high PAHs adsorption capacity because of the hierarchical micropore size, high degree of graphitization and abundant O atoms. The strategy of construction PCMs with hierarchical micropore and heteroatoms provides an effective method to remove PAHs in the FCC diesel.

Expeditious profiling of polycyclic aromatic hydrocarbons transport and obstruction mechanisms in crop xylem sap proteins via proteomics and molecular docking

Polycyclic aromatic hydrocarbons (PAHs) pose significant environmental risks due to their toxicity and carcinogenic properties. This research seeks to pinpoint protein targets in crop xylem sap related to PAH contamination and delve into their protein-ligand interactions using computational tools. Proteomic assessment revealed differentially expressed proteins (DEPs), which were subjected to virtual high-throughput screening. Notably, the phenanthrene's influence on xylem sap proteins in maize and wheat was more pronounced than in soybean, with DEPs expression peak at 24 h post-treatment. Maize DEPs were predominantly associated with lipid biosynthesis. Phenanthrene impacted cell membrane hydrophobicity, limiting PAH adsorption and decreasing its concentration in maize xylem sap. Wheat DEPs exhibited an increase in ABC transporters after 24 h of phenanthrene exposure. ABC transporters interacted with stress-responsive proteins like C6TIY1-Co-chaperone p23 and others that either facilitate or inhibit PAH transport, including Indeno[1,2,3-cd]Pyrene and C6TIY1-Co-chaperone protein p23. Both maize and wheat created high-affinity complexes between specific proteins and PAHs, influencing their transport. This study provides insights into the mechanisms of PAH regulation and movement within plant xylem.

Hierarchical porous MOFs@COFs-based molecular trap solid-phase microextraction for efficient capture of PAHs and adsorption mechanisms

In view of the serious carcinogenic, teratogenic and mutagenic properties of polycyclic aromatic hydrocarbons (PAHs), which cause significant harm to human beings and the environment. Therefore, developing rapid adsorption and efficient analytical methods are research topic with practical significance. Herein, an innovative MOFs@COFs-based molecular trap materials were prepared with hierarchical porous core–shell structure and used as solid-phase microextraction (SPME) fiber coating, which combined with high performance liquid chromatography (HPLC) to achieve the efficient separation, capture, and detection for 7 PAHs in real samples. The possible adsorption mechanism was systematically verified and explained. Under the optimized conditions, the method developed in this experiment had a wide linear range (0.005–400 µg·L−1) with a good linear correlation coefficient (R2 > 0.9984), low detection limits (0.002–0.405 µg·L−1, S/N = 3) and low quantification limits (0.005–1.351 µg·L−1, S/N = 10). The relative standard deviations of individual fibers and different batches of fibers were 0.26–3.64% and 0.40–5.91%, respectively. Besides, the fiber showed higher enrichment capacity and extraction efficiency for PAHs compared to commercial SPME fibers and other material fibers, and exhibited excellent acid-base stability and reproducibility. This work provided a favorable synthetic pathway for the preparation of MOFs@COFs composites by layer-modified assembly synthesis strategy, showed excellent practical applicability as a SPME fiber coating combined with HPLC, and could be realized to provide technical support for future studies on the separation, adsorption, and analysis of PAHs in the petrochemical industrial zone of the Yellow River Basin.

Carbazole-Based Porous Organic Polymers with Ag(I) Doping and Derived Porous Carbon for Enhanced Adsorption of Polycyclic Aromatic Hydrocarbons

Carbazole-Based Porous Organic Polymers with Ag(I) Doping and Derived Porous Carbon for Enhanced Adsorption of Polycyclic Aromatic Hydrocarbons

The adsorption of PAHs on microplastics and desorption in the simulated human digestive system

Plastic debris is widely distributed in the aquatic environment and interacts with other pollutants. Microplastics (MPs) have a stronger binding ability with pollutants and could unconsciously ingested by humans, thus becoming the carrier of pollutants into the human body and affecting human health. In this study, polycyclic aromatic hydrocarbons (PAHs) were selected as model pollutants, polyethylene (PE) and polymethyl methacrylate (PMMA) were selected as research objects. The adsorption of PAHs on different kinds of MPs and desorption behavior in a simulated human digestive system were systematically studied. The results indicated that PAHs with higher molecular weight were more easily adsorbed on MPs, and the adsorption efficiency of PAHs on PE was 1.4–3.8 times higher than PMMA. The desorption experiments were conducted in simulated gastrointestinal fluid, the activity of enzymes directly affected the desorption of PAHs, and the desorption efficiency of PAHs from the surfaces of PMMA (0.7–41.6 %) was significantly higher than PE (0.8–27.7 %). For 15 PAHs, the desorption efficiency from the surfaces of PE decreased gradually with the number of PAHs rings, which was opposite to PMMA. Molecular dynamics simulation showed that enzymes in digestive fluid attenuated the interaction energy between MPs and PAHs, resulting in substantial desorption of PAHs from the surfaces of MPs. The risk assessment demonstrated that the carcinogenic risk of PAHs desorption from PMMA was higher than PE. This study helps understand the adsorption of PAHs on MPs and the potential health risks of accidental ingestion by humans.

Effect of humic acid-modified attapulgite on polycyclic aromatic hydrocarbon adsorption and release from paddy soil into the overlying water in a rice-crab coculture paddy ecosystem and the underlying process

Phenanthrene (Phe), a typical polycyclic aromatic hydrocarbon (PAH) pollutant, poses an enormous safety risk to rice-crab coculture (RC) paddy ecosystems. In this study, humic acid-modified purified attapulgite (HA-ATP) with a composite structure was successfully fabricated to adsorb PAHs released from paddy soil to overlying water in RC paddy ecosystems in Northeast China. The maximum crab bioturbation intensities for dissolved Phe and particulate Phe were 64.83nullng/L·(cm2·d) and 214.29nullng/L·(cm2·d), respectively. The highest concentration of dissolved Phe released from paddy soil to overlying water due to crab bioturbation reached 80.89nullng/L, while the corresponding concentration of particulate Phe reached 267.36nullng/L. The dissolved organic carbon (DOC) and total suspended solid (TSS) concentrations in overlying water increased correspondingly and were strongly correlated with dissolved Phe and particulate Phe concentrations, respectively (P < 0.05). When 6% HA-ATP was added to the surface layer of paddy soil, the efficiency of the adsorption of Phe release was 24.00%–36.38% for particulate Phe and 89.99%–91.91% for dissolved Phe. Because HA-ATP has a large adsorption pore size (11.33 nm) and surface area (82.41nullm2/g) as well as many HA functional groups, it provided multiple hydrophobic adsorption sites for dissolved Phe, which was conducive to competitive adsorption with DOC in the overlying water. In contrast to that adsorbed by DOC, the average proportion of dissolved Phe adsorbed by HA-ATP reached 90.55%, which reduced the dissolved Phe concentration in the overlying water. Furthermore, even though the particulate Phe was resuspended by crab bioturbation, HA-ATP immobilized particulate Phe due to its capacity to inhibit desorption, which achieved the goal of reducing the Phe concentration in the overlying water. This result was confirmed by research on the adsorption-desorption characteristics of HA-ATP. This research provides an environmentally friendly in situ remediation method for reducing agricultural environmental risks and improving rice crop quality.

Evolution of particle size and morphology in plasma synthesis of few-layer graphene and soot

This paper examines the evolution of particle size and morphology of plasma-synthesized carbonaceous nanoparticles for various reactants, reactant concentrations, reactor temperatures, and positions within the reactor. Aerosol particles were characterized at various positions downstream from the plasma zone by spatially-resolved thermophoretic sampling and transmission electron microscopy, Raman spectroscopy, and by in situ time-resolved laser-induced incandescence. Depending on the carbon-bearing reactant (ethanol or toluene) and its concentration, either pure few-layer graphene (FLG) or soot-like particles, or a mixture of both, were generated. The initial carbon nucleation has been found to commence less than 12.4 cm downstream from the plasma nozzle. In the case of FLG formation, particles show an increasing level of crumpling with increasing distance downstream from the plasma zone. The process was numerically simulated with a 1D plug-flow reactor model employing a joint population balance model for graphitic and amorphous-like particles (FLG and soot-like, respectively). The simulation includes modified versions of inception, hydrogen-abstraction-carbon-addition (HACA), and polycyclic-aromatic hydrocarbon (PAH) adsorption models adapted from a pre-existing soot model. The simulations showed that the ratio of HACA/PAH adsorption determined by post-plasma C2H2 is the main factor that affects the soot-to-FLG ratio. This is also consistent with experimental observations as reducing the rate at which carbon precursor is supplied to the reactor leads to less C2H2 in the post-plasma zone, which results in less PAH adsorption, and consequently suppressed soot formation in favor of FLG synthesis.

Polycyclic Aromatic Hydrocarbons as Anode Materials in Lithium-Ion Batteries: A DFT Study.

The structure and energetics of the interactive behavior of Li+ and Li with polycyclic aromatic hydrocarbons (PAHs) have been studied at the wB97XD/6-311G(d,p) level of DFT. The electron distribution in the PAHs, analyzed using the topology of the molecular electrostatic potential (MESP), led to the categorization of their aromatic rings into five types, viz Rs, Rn, Rd, Rb, and Re. Among the different rings, sextet-type Rs and naphthalene-type Rn rings showed the highest interaction with Li+. The change in MESP at the nucleus of Li+ (ΔVLi+) due to the formation of the complex Li+...PAH is found to be proportional to the adsorption energy (E1). In Li...PAH, the spin density on Li is close to zero, suggesting the formation of Li+...PAH•- due to the electron transfer from Li to PAH. The adsorption energy (E2) for Li...PAH does not correlate with the change in MESP at the nucleus of Li, whereas the dissociation energy (E3) of Li+...PAH•- to yield Li+ and PAH•- correlates well with the MESP data, ΔVLi. The study confirms that the change in MESP at the nucleus of Li+ due to complex formation gives a quantitative measure of the electronic effect of the cation-π binding. The cell potential (Vcell) is predicted for the lithium ion battery (LIB) using the Li+...PAH and Li...PAH adsorption energies. On the basis of the Vcell data, "carbon nanoflake"-type systems, viz coronene, circumbiphenyl, C42H16, and C50H18 are suggested as good anode materials for LIBs.

Remediation of PAH-contaminated soil using a combined process of soil washing and adsorption by nano iron oxide/granular activated carbon composite

This study investigated the application of magnetic granular activated carbon (MGAC) in soil washing process for the removal of polycyclic aromatic hydrocarbons (PAHs) from real contaminated soil. The magnetic composite was prepared using a facile-modified co-precipitation method. The presence of the synthesized magnetite (Fe3O4) nanoparticles on the composite surface was confirmed by the SEM and XRD characterization tests. The surface area and total pore volume of MGAC were determined to be 837.9 m2/g and 0.5 cm3/g, respectively, which were approximately 10% smaller than those for the bare GAC. The Langmuir model fitted the adsorption isotherm data the best; therefore, monolayer adsorption was predominant in the treatment process with MGAC. The maximum PAH adsorption capacity of MGAC was obtained at 153.5 µg/mg for the total PAHs, which was nearly 20% lower than that of bare GAC (190.3 µg/mg). The soil washing parameters were optimized, and the results demonstrated that the total PAH removal reached a maximum of 47.4% at an MGAC dose of 2% (w/w), washing time of 24 h, a liquid-to-soil ratio of 15:1, stirring speed of 100 rpm, pH of 8.3, and a temperature of 25 °C. For low molecular weight (LMW) PAHs, the removal from soil ranged from 34.6% to 57.7%, whereas the removal percentage of high molecular weight (HMW) PAHs was determined to be between 27.9 and 67.1 %. This indicated that the optimized soil washing with MGAC had a better efficiency for some HMW PAHs than the LMW PAHs. According to the thermodynamic studies, the adsorption of PAHs onto MGAC in the soil washing process was non-spontaneous (ΔG° > 0) and endothermic (ΔH° > 0) with increased randomness at the solid/solution interface of MGAC as temperature increases. The obtained results confirmed the efficiency of the magnetized activated carbon as adsorbent in soil washing to remove the hazardous PAH compounds from soil.

Occurrence, fate and ecological risks of 90 typical emerging contaminants in full-scale textile wastewater treatment plants from a large industrial park in Guangxi, Southwest China

Recent industrial relocation in China causes lots of environment concerns including risks of emerging contaminants (ECs). Herein, the occurrence, fate, removal and ecological risks of 34 per- and polyfluoroalkyl substances (PFAS), 17 endocrine disrupting chemicals (EDCs), 16 phthalate esters (PAEs), and 23 polycyclic aromatic hydrocarbons (PAHs) were investigated in two textile WWTPs (conventional and Fenton-modified) from a large textile industrial park in Southwest China. Totally 50 ECs were identified and the levels followed the order of PAEs > EDCs > PFAS ≈ PAHs. The EDCs predominated in textile washing and rinsing wastewater whereas the PAEs did in desizing wastewater. Biphasic correlations of log Kd and log P, molecular weight, and numbers of rings (r2 = 0.63–0.66, p < 0.01) were observed for PAHs, suggesting that hydrophobicity might not facilitate adsorption of super-hydrophobic PAHs onto activated sludge. 63–69% of detected ECs were effectively removed by two textile WWTPs with removal efficiencies ≥ 80%, which were much higher than previous reports. Fenton processing enhanced the removal efficiencies for long-chain PFAS rather than short-chain PFAS. The PAEs and EDCs posed a medium-to-high risk to aquatic organisms and were screened as the priority ECs. To date, such a comprehensive investigation for ECs has not been previously conducted in textile WWTPs and this study provides basic information about regional chemical emission inventory of ECs.

Adsorption of 2-hydroxynaphthalene, naphthalene, phenanthrene, and pyrene by polyvinyl chloride microplastics in water and their bioaccessibility under in vitro human gastrointestinal system

The interaction of microplastics (MPs) and organic pollutants has recently become a focus of investigation. To understand how microplastic residues affect the migration of organic pollutants, it is necessary to examine the adsorption and desorption behavior of organic pollutants on MPs. In this study, integrated adsorption/desorption experiments and theoretical calculations were used to clarify the adsorption mechanism of 2-hydroxynaphthalene (2-OHN), naphthalene (NAP), phenanthrene (PHE), and pyrene (PYR) by polyvinyl chloride microplastics (PVC-MPs). Based on the phenomenological mathematical models, the rate-limiting step for analyte adsorption onto PVC-MPs was adsorption onto active sites (R2 = 0.865–0.995). Except for PHE, analyte adsorption isotherms were well described by the Freundlich model (R2 = 0.992–0.998), and adsorption thermodynamics showed that analyte adsorption on PVC-MPs was a spontaneous exothermic process (ΔH0 < 0; ΔG0 < 0). Based on the order of adsorption efficiency of 2-OHN < NAP < PHE < PYR, which is identical to the competitive adsorption experiment, polycyclic aromatic hydrocarbon (PAH) adsorption on PVC-MPs increased as the aromatic ring number increased and the hydroxyl content decreased. The release of 2-OHN (49 %–52 %) from PVC-MPs into the simulated gastrointestinal environment was greater than that of NAP (5.5 %–5.7 %). Theoretical calculations and adsorption tests indicated that hydrophobic interaction was the primary influence on the adsorption of PAHs and their hydroxylated derivatives by PVC-MPs. These findings improve our understanding of MPs' behavior and dangers as pollutant carriers in the aquatic environment and help us develop recommendations for the pollution control of MPs.

Fabrication and application of Zn5 functionalized copolymer monolithic column for pipette tip micro-solid phase extraction of 4 polycyclic aromatic hydrocarbons in edible oil

The contamination of polycyclic aromatic hydrocarbons (PAHs) in edible oil is a health threat. Thus, trace analysis of PAHs is of high necessity. Based on the efficient adsorption of PAHs on Zn5 metal cluster, a Zn5 functionalized copolymer monolithic column was rationally designed for pipette tip micro-solid phase extraction (μ-SPE). The modified Zn5 improved the adsorption selectivity and capacity of the monolith for naphthalene, phenanthrene, fluoranthene and pyrene. Chemical doping and copolymerization stabilized the monolith with a long life. Under optimal extraction conditions, a μ-SPE-high performance liquid chromatography with ultraviolet detector method was established for the detection of 4 PAHs in edible oils. The method yielded detection ranges of 0.15–250 μg L−1 (R2 > 0.997), detection limits of 0.050–1.5 μg L−1, satisfactory recoveries (86.3–101.5 %), and high precisions (RSDs < 7.9 %). The results indicated that the Zn5 functionalized copolymer monolithic column was an ideal separation medium for the detection of PAHs residues in edible oils.