Kinds Of Sorbents Research Articles

Nanoparticle Assisted Fabric Phase Sorptive Extraction for Azo Dye Determination in the Industrial Sewage.

Currently, one of the significant environmental problems is the presence of azo dye materials in water sources. In this study, for the first time, a fast and sensitive sample preparation approach using nanoparticle-assisted fabric phase sorptive extraction (NFPSE) followed by high-performance liquid chromatography was examined to remove some azo dyes such as methyl red and sunset yellow from aqueous solutions. Primarily, the significance of several parameters affecting NFPSE, such as fabric type, the kind of sorbent, the number of contacts with sol-gel and the time of contact, was investigated. In addition, experiments were performed to determine the effect of different adsorption parameters, such as sample volume, adsorption time, adsorbent value, desorption time, ionic strength and pH. It was found that the calibration curve was linear within two ranges of concentrations (0.05-0.1 and 0.5-15ng/L for methyl red; 0.05-0.5 and 0.5-15ng/L for sunset yellow) with correlation coefficients better than 0.9683. The limit of detection was 0.014ng/L for methyl red and 0.015ng/L for sunset yellow. Repeatability Relative Standard Deviation (RSD) with three replicated experiments was 1.5-10% for methyl red and 2.5-5.8% for sunset yellow. Relative recovery percentages of 88-96% for methyl red and 62-92% for sunset yellow were obtained in the samples. Moreover, the results have shown that acceptable accuracy, precision and linearity make the "fabric phase sorptive extraction" a proper method for the determination of dyes from industrial sewage samples.

Использование пеностекла (гранулированного) в очистке городских поверхностных сточных вод

Introduction. When purifying natural objects from heavy metals a decisive role is played by sorption technologies, for the development of which new kinds of sorbents are required. The aim of the study is to evaluate the sorption capacity of granulated foam glass in the treatment of surface wastewater (SW) from urbanized areas from heavy metals (on the example of Co, Cr, Cu, Fe, Ni, Pb and Zn). Materials and methods. Granulated foam glass was used as a sorbent. The sorbate was urban surface wastewater from the city of Chelyabinsk. The interaction in the sorbent-sorbate system was studied in laboratory conditions by the limited volume method of static sorption when the pollutants were in the liquid phase and brought into contact with a stationary sorbent. The contact time of the sorbent with the sorbate was varied from 3 to 168 hours and the ambient temperature from 0 to 20 °C. The structure and surface composition of the sorbents were studied using a JEOL JSM-6460LV scanning electron microscope with an attachment for micro X-ray spectral analysis. Changes in the sorbate composition during interaction with the sorbents were determined by atomic emission spectrometry on an OPTIMA 2100 DV spectrometer (Perkin Elmer). Hydrogen index was determined on a pH-meter microprocessor рН-150МИ. Results. The structure and surface composition of granulated cellular glass has been studied. The efficiency of sorption of granulated foam glass of heavy metals from urban surface wastewater has been revealed. Conclusions. The results show that the investigated granulated foam glass is an effective sorption material and allows the extraction of heavy metals (cobalt, chromium, copper, iron, nickel, lead, zinc) from urban surface wastewater.

New boron selective sorbents for sorption – membrane hybrid system

The synthesis and properties of core-shell sorbents dedicated to the removal of borates from aqueous solutions were described. By modification of polymer matrices with vinylbenzyl chloride followed by its derivatization with N-methyl glucamine a new kind of sorbents were obtained. The testing of boron sorption reviled that the process efficiency was related to the pore diameter and the content of ligand in the sorbent. The best material for use in a hybrid system, where boron is absorbed by fine particles and removed in microfiltration, was Poropak Q with a specific surface area of 300 m2/g.

Determination of trace organic contaminants by a novel mixed-mode online solid-phase extraction coupled to liquid chromatography–tandem mass spectrometry

In this study, a novel mixed-mode online solid-phase extraction (SPE) method was developed to recover miscellaneous trace organic contaminants (TrOCs) from environmental water samples. Six kinds of sorbents, including C18 substances, hypercross-linked polymers (2), cation-exchange resins, anion-exchange resins, and graphitized nonporous carbons, were packed into a single online SPE cartridge. Furthermore, a fully automated analytic method was established by coupling this mixed-mode online SPE with liquid chromatography tandem mass spectrometry (online SPE-LC-MS/MS). Sixty-nine TrOCs with diverse properties were selected to examine the performance of this mixed-mode SPE cartridge in comparison with solo-mode online SPE cartridges. The method quantification limit (MQL) and the relative recovery coefficient of TrOCs in diverse water matrices, including groundwater, surface water and sewage effluent were evaluated. The MQL of most TrOCs was lower than 10 ng L−1. The relative recovery coefficients for most TrOCs in the groundwater (50/69) and surface water (38/69) matrix fit in the satisfactory range. Moreover, mixed-mode online SPE coupled with LC-high-resolution MS was applied for a suspect screening of TrOCs in sewage effluents. A series of highly polar TrOCs that had scarcely been reported by previous studies were identified by this practical and easily accessible method. Finally, this novel mixed-mode online SPE with LC-MS/MS method was applied to quantify the TrOCs in the environmental water samples.

Molecular Simulation of Adsorption in Deep Marine Shale Gas Reservoirs

Deep marine shale gas reservoirs are extremely rich in the Sichuan basin in China. However, due to the in situ conditions with high temperature and high pressure (HTHP), in particular reservoir pressure being usually much higher than the test pressure, it is difficult to accurately clarify the adsorption behavior, as seepage theory plays an important role in shale gas reserves evaluation. Therefore, three kinds of sorbent, including illite, quartz and kerogen, and two simulation methods, containing the grand canonical ensemble Monte Carlo method and molecular dynamics method, are synthetically used to determine the methane adsorption behavior under HTHP. The results show that both absolute adsorption and excess adsorption decrease with the increase of temperature. When the pressure increases, the absolute adsorption increases quickly and then slowly, and the excess adsorption first increases and then decreases. The superposition of wall potential energy is strongest in a circular hole, second in a square hole, and weakest in a narrow slit. The effect of pore size increases with the decrease of the pore diameter. Under HTHP, multi-layer adsorption can occur in shale, but the timing and number of layers are related to the sorbent type.

Removal of Mercury from Acidic Solutions of Mercury Chloride by Means of Sorbents Prepared by Catalyzed Vulcanization of Vegetable Oils

Mercury is a metallic element, dangerous and toxic for the environment. Presently, the incineration of municipal solid waste (MSW) belongs to important sources of Hg emissions. Methods of conversion of metallic mercury and mercury compounds from soluble and toxic forms into water insoluble/non-toxic form (HgS) are sought after. Gaseous HCl and a significant part of HgCl2 vapors present in flue gas from incineration of MSW can be removed there by absorption in hot water. Efficiencies of Hg2+ removal from acidic water solutions by means of sorbents prepared by catalyzed reaction of sulfur with vegetable oils (inverse vulcanization) were studied. These kinds of sorbents were tested and found to be exploitable for selective removal of mercury ions from aqueous solutions, particularly from acidic solutions containing HCl at higher temperatures (50–75 °C). Presence of relatively high concentrations of salts of some other metallic elements (Fe, Zn, Ca) had only very small effects on Hg-sorption. Mercury adsorbed on such sorbents converts relatively quickly into a non-toxic form (HgS). Reactive sulfides and SH‑groups present on the surface of the sorbent particles contribute to a faster sorption of mercury and its conversion to HgS. Leaching of zinc from the catalyst (Zn‑diethyldithiocarbamate) present in the vulcanized sorbents is negligible at neutral conditions and small (about 10 %) at acidic conditions (pH = 1.5).

RESEARCH ON THE PROPERTIES OF SORBENTS AND DECONTAMINANTS IN THE PROCESSES WITH SMALL ISOTOPE EFFECTS

The low values of isotope effects in the sorption/decontamination processes make it possible to investigate the properties of the sorbing and decontaminating agents with the use of stable isotope simulators. In the work present-ed here the element content was determined from the characteristic X-ray emission induced by the proton beam (PIXE), by gamma-ray emission from the radioactive source, and by emission from the X-ray tube. Based on the results of efficiency determination for different kinds of sorbents and decontaminants, recommendations have been given for the choice of materials having the wanted performance characteristics.

Carbon dioxide capture from a real coal-fired flue gas using K-based solid sorbents in a 0.5 MWe-scale test-bed facility

Three kinds of K2CO3-based solid sorbents was tested in a 0.5 MWe-scale test-bed, integrated with a real coal fired power plant. The test-bed, consisting of a fast fluidized-bed carbonator, a bubbling fluidized-bed regenerator and a bubbling fluidized-bed sorbent cooler, was installed beside a Unit #3 in a Hadong coal-fired power plant. The components of K2CO3-based solid sorbents were an active reaction component of K2CO3 for CO2 sorption with the supports including Al2O3 for mechanical strength. Three different solid sorbents were differentiated depending on the amount of an active component (35 wt.% or 40 wt.%) and the different composition of Al2O3 (alpha alumina or gamma alumina). CO2 capture performance was evaluated in a test-bed at the same operating conditions for three kinds of solid sorbents, which showed better CO2 capture performance with the solid sorbent with 40 wt.% than that with 35 wt.% one. Better performance with alpha alumina as a support was obtained as compared to that with gamma alumina. Additionally, the effect of water vapor to CO2 mole ratio in a flue gas, solid hold-up in a mixing zone of a carbonator and the regeneration temperature on the CO2 capture performance was analyzed. The experimental results in a test-bed was confirmed by analyzing the solid samples of after-carbonation and after-regeneration. The CO2 capture efficiency in the carbonator was varied from 60 to 90% whereas the dynamic sorption capacity of the sorbents from 3–7 wt.% in relation with the kinds of sorbents and the operating conditions. All the experimental data was used to design the 10 MWe-scale pilot plant beside a Unit #8 in a Hadong coal-fired power plant.

Effect of Sodium Bromide on CaO-Based Sorbents Derived from Three Kinds of Sources for CO2 Capture.

The calcium looping (CaL), which applies carbonation/calcination cyclic reactions of a CaO sorbent, has received extensive attention for postcombustion CO2 capture. However, as the number of cyclic reactions increased, the capture efficiency of regenerated CaO decreased rapidly. Sodium doping was proposed for modification of a CaO sorbent, but there was little research on whether sodium doping had a good effect on different kinds of sorbents. In this paper, three different kinds of calcium-based sorbents, i.e., CaCO3, dolomite, and SG-CaO, were modified by NaBr to explore the effect of sodium on CO2 capture performance. The results showed that the modification effects of sodium on three kinds of precursors were different. For CaCO3, the modification effect of sodium doping was the best. After 50 cycles, the sorption capacity of CaO/NaBr was over 3.5 times that of an unmodified sorbent; for dolomite, sodium had a moderate effect during initial cycles and then showed obvious improvement in the stability of the sorbent, the sorption capacity of the modified dolomite increased by over 30% after 50 cycles; for the SG-CaO, sodium had a negative effect, the sorption capacity of the modified sorbent decreased by about 30% after 50 cycles. When the atmosphere contained SO2, the doping of an alkali metal also showed a certain effect.

Effect of impregnation sequence of Pd/Ce/γ-Al2O3 sorbents on Hg0 removal from coal derived fuel gas

This study attempted to investigate the effect of impregnation sequence of the Pd/Ce/γ-Al2O3 sorbents on Hg0 removal. To this end, five kinds of sorbents were prepared and tested in simulated coal derived fuel gas (N2–H2–CO–H2S–Hg), including Pd/γ-Al2O3, Ce/γ-Al2O3 and three kinds of Pd-based sorbents with Ce impregnation on γ-Al2O3 substrate. The tests were conducted at 250 and 300 °C respectively. According to the results, bimetallic Ce–Pd/γ-Al2O3 sorbent prepared by simultaneously impregnating Pd and Ce showed much higher and more stable removal efficiency of Hg0 than the other three kinds of sorbents. The Hg0 removal efficiency of Ce–Pd/γ-Al2O3 sorbent reached above 98% within 480 min at 250 °C and 91% within 200 min at 300 °C. Characterization results indicated that the sorbent Ce–Pd/γ-Al2O3 prepared by the co-impregnation method had bigger specific surface area (216.6 m2/g) than the other three kinds of Pd-based sorbents. The content Pd and Ce on the sorbent Ce–Pd/γ-Al2O3 surface is 0.21% and 0.61%, which proved higher than that of the other three kinds of Pd-based sorbents, and observation from STEM-XEDS maps showed it demonstrated the highest dispersion. It is found that Ce is likely to promote the dispersion of Pd on the support surface during the preparation of the sorbent under the co-impregnation method. Meanwhile, Ce enhanced the H2S resistance of the sorbent. Thereby, Ce–Pd/γ-Al2O3 sorbent is found to have the optimal performance of mercury removal. In this study, the Hg0 removal mechanism of the Pd/Ce/γ-Al2O3 sorbents in the simulated coal derived fuel gas was also elaborated.

Simultaneous extraction and preconcentration of monomethylmercury and inorganic mercury using magnetic cellulose nanoparticles.

Magnetite (Fe3O4) nanoparticles were modified with nanocellulose and are showed to be a useful sorbent for magnetic solid-phase extraction of mercury species. Speciation analysis was performed by using gas chromatography coupled to atomic fluorescence detection (GC-pyro-AFS). The magnetic properties of the sorbent make this approach simple and rapid, and the use of a renewable and biodegradable nanomaterial (nanocellulose) makes it environmentally friendly. The factors that affect adsorption (pH value, amount of nanomaterial, time, volume of sample) and desorption (solvent, time) have been optimized. Both desorption and derivatization of mercury species were performed in a single step. This reduces considerably the sample preparation time. Under the optimized conditions, the limits of detection are 4.0pgmL-1 for monomethylmercury and 5.6pgmL-1 for inorganic mercury. The repeatability and reproducibility are satisfactory. The method enables inorganic mercury and monomethylmercury to be simultaneously extracted, with preconcentration factors up to 300. The potential interferences of organic matter and/or co-existing ions were also investigated using synthetic waters. The procedure was applied to the analysis of tap water and river water samples with different characteristics from a mercury polluted area (Almadén, Spain). The extraction recoveries ranged from 81 to 98% regardless of the type of water, which demonstrates the applicability of the method. This is the first time that this kind of sorbent is used for trace metal speciation. Graphical abstract Schematic representation of the new composite material (made of Fe3O4 magnetic nanoparticles and cellulose fibers, MCNPs) for the simultaneous extraction and preconcentration of mercury species taking advantage of the magnetic properties of this eco-friendly sorbent.

A lean method for determination of dynamic capacity of a sorbent at multiple sorption of cations

A lean method for calculation of the dynamic capacity of a sorbent as the time function has been suggested that employs a limited amount of experimental data for a sorption process of any duration and allows to obtain an analytical solution by quadrature. To its input parameters belongs a linear flow rate in an adsorber (column) rather than a volume flow rate. This simplifies a reproduction of the sorption process with the target kinetic characteristics at constructively different devices. The method applicability is independent of a kind of sorbent as well as of a number of sorbates in a multicomponent solution. The present paper represents both a theory of the method and its application to a particular case of the concurrent sorption of cations of three heavy metals, Cu(II), Ni(II) and Zn(II), on a natural multifunctional clay-like sorbent glauconite.

A magnetic knitting aromatic polymer as a new sorbent for use in solid-phase extraction of organics.

Magnetic knitting aromatic polymers (Fe3O4/KAPs) are introduced here as a new kind of sorbents. KAPs are hyper-cross-linked-polymers that were prepared via a Friedl-Crafts reaction from triphenylphosphine and benzene as building blocks. The Fe3O4/KAP composite was obtained by coprecipitation of KAP with magnetite nanoparticles. The resulting Fe3O4/KAP is shown to be a viable magnetic sorbent for various organic materials such as the phenylurea herbicides (PUHs), including metoxuron, monuron, chlortoluron, monolinuron and buturon, and also for various phthalates, polycyclic aromatic hydrocarbons and chlorophenols. The Fe3O4/KAP was characterized by means of Brunauer-Emmett-Teller surface area measurements, Fourier-transform infrared spectroscopy, thermogravimetry, X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Following desorption with acetonitrile, the analytes were quantified by using HPLC with UV detection. The effects of adsorbent dosage, extraction time, sample pH, ionic strength, desorption solvent and desorption time were optimized for the PUHs. Under optimal conditions, response is linear from 0.5-1.0 up to 50ng·mL-1 for the five PUHs. Lower limits of detection range between 0.05 and 0.30ng·mL-1. Other figures of merit include (a) high enrichment factors (60-297), (b) good recoveries (91.8-106.5%), and (c) relative standard deviations of <8.4%. The method was successfully applied to analysis of the PUHs in real samples (bottled mixed juice, milk and soymilk). The results indicate that such Fe3O4/KAPs have a wide application scope as an adsorbent for use in magnetic solid phase extraction. Graphical abstract A magnetic knitting aromatic polymer based nanocomposite (Fe3O4/KAP) was prepared by a one-pot method and explored as an absorbent for magnetic solid-phase extraction (MSPE) of phenylurea herbicides (PUHs) from bottled mixed juice, milk and soymilk samples before quantitation byHPLCwithUV detection.

Determination of five pyrethroid pesticides residue in liquid milk by gas chromatography using multi-walled carbon nanotubes as dispersion solid phase extraction sorbent

A novel multi-walled carbon nanotubes (MWCNTs) dispersive solid phase extraction (d-SPE) method which combined with gas chromatography (GC) coupled with electron capture detector (ECD) was developed for the determination of five pyrethroid pesticides in liquid milk for the first time. The effect of d-SPE conditions on the kinds of sorbent, MWCNTs and magnesium sulfate anhydro mass ratio, and extraction condition were researched, and then, the suitable method was found. Under the optimal conditions, the linear range was from 20 to 500 μg kg−1. The recoveries were from 81.8% to 112.1%, with the corresponding relative standard deviations (RSDs) less than 6%, correlation coefficients from 0.9978 to 0.9990, and limits of detection and quantification from 2.62 to 4.86 μg kg−1 and 8.73 to 16.2 μg kg−1. The proposed method is simple, fast, safe, and has high recovery and sensitivity applicable to analyze pyrethroid pesticides in liquid milk sample.

Synthesis of sulfur nanoparticles-loaded alumina as a low-cost sorbent for the preconcentration of nickel from real samples

ABSTRACTThis study reports a simple method for the synthesis of α-sulfur-nanoparticles-loaded alumina as a reliable kind of sorbents in solid-phase extraction (SPE) methods for the preconcentration and determination of trace levels of Ni(II) from real samples. The most important advantage of this technique is not using the ligand as a complexing agent and hence the disadvantages of other SPE methods have been avoided. The calibration graph was linear over the range of 0.66–100 µg/L and the relative standard deviation (RSD) of 1.98% at 50 µg/L was obtained. The limit of detection (LOD) and preconcentration factor (PF) were obtained as 0.22 µg/L and 250, respectively. The maximum adsorption capacity of the adsorbent was found to be 18 mg/g for Ni(II).

Characteristics and Properties of Absorption Materials for Mercury Removal at High Temperature

In this study, some metal-M/aluminum carbonate absorption materials with molar ratio of M:Al=3:1 were manufactured. There was Cu–Al, Mn–Al, Fe–Al three kinds of sorbents synthesized by co-precipitate method. The physicochemical structures during mercury removal were analyzed by a surface area and pore structure analyzer (BET), an X-ray diffraction (XRD), a scanning electron microscope coupled with an electron detection scanning (SEM/EDS), and X-ray fluorescence (XRF). The results showed that surface areas for metal-M/aluminum carbonate sorbents were only about 11~12 m2/g and the metal ratio loaded was more than 80%. Lab-scale tests mercury removal efficiency in the temperature range of 200–300 oC indicated that there was an improvement in the performance of mercury removal by increasing reaction temperature. Cu–Al, Fe–Al and Mn–Al all three sorbents reached their absorption equivalent of 256.6, 253.3 and 247.0 μg/g under 300 oC operating temperature and 19736 h-1 gas hourly space velocity. Additionally, the presence of transition metals can significantly improve the efficiency of mercury removal of the absorption materials.

Simultaneous determination of chlorantraniliprole and cyantraniliprole in fruits, vegetables and cereals using ultra-high-performance liquid chromatography-tandem mass spectrometry with the isotope-labelled internal standard method.

A reliable and sensitive isotope-labelled internal standard method for simultaneous determination of chlorantraniliprole and cyantraniliprole in fruits (apple and grape), vegetables (cucumber and tomato) and cereals (rice and wheat) using ultra-high-performance liquid chromatography-tandem mass spectrometry was developed. Isotope-labelled internal standards were effective in compensating for the loss in the pretreatment and overcoming the matrix effect. The analytes were extracted with acetonitrile and cleaned up with different kinds of sorbents. The determination of the target compounds was achieved in less than 4 min using a T3 column combined with an electrospray ionization source in positive mode. The overall average relative recoveries in all matrices at three spiking levels (10, 20 and 50 μg kg(-1)) ranged from 95.5 to 106.2 %, with all relative standard deviations being less than 14.4 % for all analytes. The limits of detection did not exceed 0.085 μg kg(-1) and the limits of quantification were below 0.28 μg kg(-1) in all matrices. The method was demonstrated to be convenient and accurate for the routine monitoring of chlorantraniliprole and cyantraniliprole in fruits, vegetables and cereals.

Preparation of metal ions impregnated polystyrene resins for adsorption of antibiotics contaminants in aquatic environment

ABSTRACTIn this study, the strong‐acid polystyrene resin D001 was modified by impregnation with metal ions Fe3+, Cu2+, and Zn2+to prepare new kinds of sorbents. The modified D001 was characterized by N2sorption–desorption isotherms, X‐ray powder diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The sorption performance of the metal modified resins for removal of antibiotics tetracycline (TC) and doxycycline (DC) from aquatic environment was investigated and excellent sorption capability with more than 98% removal ratio was observed for these resins after modification. Although these modified resins also presented pH‐dependent sorption, they showed much better flexibility with pH fluctuation than those of the unmodified original D001, and extremely strong sorption capability was exhibited in a wide range of pH 2–8 for both TC and DC. Pseudo‐second‐order kinetic equation described the sorption process more reasonably than pseudo‐first‐order equation. Langmuir isotherm model provided the best match to the equilibrium data with monolayer maximum sorption capacity of 417–625 mg g−1under 288–318 K. The sorption capacity decreased with the increase of ionic strength of NaCl. The main sorption mechanism was proposed to be surface complexation, cation bridge interaction and electrostatic attraction/competition between antibiotics and metal modified resins. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2015,132, 41803.

P.4.f.001 The cumulative effect of childhood trauma on adult mental and physical health: results from the Marine Resiliency Study

In this work, we interestingly happened to observe the adsorption of stainless steel sample loop of HPLC. The adsorptive behaviors of the stainless steel loop toward different kinds of compounds were studied, including polycyclic aromatic hydrocarbons (PAHs), halogeno benzenes, aniline derivatives, benzoic acid derivatives, phenols, benzoic acid ethyl ester, benzaldehyde, 1-phenyl-ethanone and phenethyl alcohol. The adsorptive mechanism was probably related to hydrophobic interaction, electron-rich element–metal interaction and hydrogen bond. Universal adsorption of stainless steels was also testified. Inspired by its strong adsorptive capability, bare stainless steel loop was developed as a modification-free in-tube device for solid-phase microextraction (SPME), which served as both the substrate and sorbent and possessed ultra-high strength and stability. Great extraction efficiency toward PAHs was obtained by stainless steel loop without any modification, with enrichment factors of 651–834. By connecting the stainless steel loop onto a six-port valve, an online SPME–HPLC system was set up and an SPME–HPLC method has been validated for determination of PAHs. The method has exceptionally low limits of detection of 0.2–2 pg/mL, which is significantly lower than that of reported methods with different kinds of sorbents. Wide linear range (0.5–500 and 2–1000 pg/mL), good linearity (R2 ≥ 0.9987) and good reproducibility (RSD ≤ 2.9%) were also obtained. The proposed method has been applied to determine PAHs in environmental samples. Good recoveries were obtained, ranging from 88.5% to 93.8%.

Adsorptive behavior and solid-phase microextraction of bare stainless steel sample loop in high performance liquid chromatography

In this work, we interestingly happened to observe the adsorption of stainless steel sample loop of HPLC. The adsorptive behaviors of the stainless steel loop toward different kinds of compounds were studied, including polycyclic aromatic hydrocarbons (PAHs), halogeno benzenes, aniline derivatives, benzoic acid derivatives, phenols, benzoic acid ethyl ester, benzaldehyde, 1-phenyl-ethanone and phenethyl alcohol. The adsorptive mechanism was probably related to hydrophobic interaction, electron-rich element–metal interaction and hydrogen bond. Universal adsorption of stainless steels was also testified. Inspired by its strong adsorptive capability, bare stainless steel loop was developed as a modification-free in-tube device for solid-phase microextraction (SPME), which served as both the substrate and sorbent and possessed ultra-high strength and stability. Great extraction efficiency toward PAHs was obtained by stainless steel loop without any modification, with enrichment factors of 651–834. By connecting the stainless steel loop onto a six-port valve, an online SPME–HPLC system was set up and an SPME–HPLC method has been validated for determination of PAHs. The method has exceptionally low limits of detection of 0.2–2pg/mL, which is significantly lower than that of reported methods with different kinds of sorbents. Wide linear range (0.5–500 and 2–1000pg/mL), good linearity (R2≥0.9987) and good reproducibility (RSD≤2.9%) were also obtained. The proposed method has been applied to determine PAHs in environmental samples. Good recoveries were obtained, ranging from 88.5% to 93.8%.