Structural and mechanical characterizations of microporous silica–boron membranes for gas separation

This paper presents structural and mechanical characterizations of microporous silica membranes for gas separation. The membrane separative layer is made of microporous silica–B₂O₃ produced via a sol–gel process. This layer of about 200 nm of thickness is deposited on the internal surface of a tubular asymmetric γ-alumina/α-alumina support. FTIR and Raman analyses indicate the presence of the boron in the silica net and the above methods in conjunction with ¹¹B MAS NMR analyses of the samples indicate that boron is located mainly in the tetrahedral framework position. Such membranes present interesting gas separation properties at temperatures up to 500 °C and transmembrane pressures lower than 8 bar. He permeance values close to 10⁻¹⁰ kmol m⁻² s⁻¹ Pa⁻¹ are obtained, associated with ideal selectivity α(He/CO₂) which can reach 55. Mechanical properties of separative silica-modified layers are measured by nanoindentation and the coefficient of thermal expansion is obtained from pure material.     

Highly permeable mesoporous silica membranes synthesized by vapor infiltration of tetraethoxysilane into non-ionic alkyl poly(oxyethylene) surfactant films

Mesoporous silica membranes were prepared on porous alumina substrates by a vapor infiltration of tetraethoxysilane (TEOS) into a non-ionic poly(oxyethylene) (Brij56) surfactant film. Periodic mesostructured silica membranes were formed on both α- and γ-alumina substrates pre-treated with polystyrene. The polystyrene polymer plugged the pores of the alumina substrates and inhibited the deposition of silica in the alumina pores, resulting in the formation of a very thin silica membrane without a silica/alumina composite layer at the interface between mesoporous silica and the alumina substrates. The calcined mesoporous silica membrane showed very high nitrogen permeance (>10⁻⁶ mol m⁻² s⁻¹ Pa⁻¹). The single gas permeation was governed by the Knudsen diffusion mechanism. The durability of the mesoporous silica membrane against moisture in air was improved by a silylation with trimethylethoxysiliane.     

Amperometric sensing of norepinephrine at picomolar concentrations using screen printed,high surface area mesoporous carbon

Norepinephrine (NE) is detected amperometrically using the enzyme Phenylethanolamine N-methyl transferase and cofactor S-(5′-Adenosyl)-l-methionine chloride dihydrochloride with disposable screen printed mesoporous carbon electrodes. The role of internal surface area and pore size of the mesoporous carbon is systematically examined using soft-templated, mesoporous silica–carbon powders with highly microporous walls obtained from etching of the silica to produce powders with surface areas ranging from 671–2339 m² g⁻¹. As the surface area increases, the sensitivity of the biosensor at very low NE concentrations (0–500 pg mL⁻¹) in phosphate buffered saline (PBS) increases just as the current signal increases with respect to the NE concentration of 81–1581 μA mL ng⁻¹ cm⁻² for the mesoporous carbons. The best performing electrode provides similar sensitivity in whole rabbit blood in comparison to PBS despite no membrane layer to filter the non-desired reactants; the small (<5 nm) pore size and large internal surface area acts to minimize non-specific events that decrease sensitivity.     

PAMAM dendrimer composite membrane for CO2 separation: Formation of a chitosan gutter layer

A poly(amidoamine) (PAMAM) dendrimer composite membrane with an excellent CO₂/N₂ separation factor was developed in-situ. The In-situ Modification (IM) method was used to modify the surface of commercial porous membranes, such as ultrafiltration membranes, to produce a gas selective layer by controlling the interface precipitation of the membrane materials in the state of a received membrane module. Using the IM method, a chitosan layer was prepared on the inner surface of a commercially available ultrafiltration membrane as a gutter layer, in order to affix PAMAM dendrimer molecules on the porous substrate. After chitosan treatment, the PAMAM dendrimer was impregnated into the gutter layer to form a PAMAM/chitosan hybrid layer. The CO₂ separation performance of the resulting composite membrane was tested at a pressure difference of 100 kPa and a temperature of 40 °C, using a mixed CO₂ (5 vol%)/N₂ (95 vol%) feed gas. The PAMAM dendrimer composite membrane, with a gutter layer prepared from ethylene glycol diglycidyl ether and a 0.5 wt% chitosan solution of two different molecular weight chitosans, revealed an excellent CO₂/N₂ separation factor and a CO₂ permeance of 400 and 1.6 × 10⁻⁷ m³ (STP) m⁻² s⁻¹ kPa⁻¹, respectively. SEM observations revealed a defect-free chitosan layer (thickness 200 nm) positioned directly beneath the top surface of the UF membrane substrate. After PAMAM dendrimer treatment, the hybrid chitosan/PAMAM dendrimer layer was observed with a thickness of 300 nm. XPS analysis indicated that the hybrid layer contained about 20–40% PAMAM dendrimer.     

Preparation and characterization of SiO2/TiO2 composite microspheres with microporous SiO2 core/mesoporous TiO2 shell

SiO₂/TiO₂ composite microspheres with microporous SiO₂ core/mesoporous TiO₂ shell structures were prepared by hydrolysis of titanium tetrabutylorthotitanate (TTBT) in the presence of microporous silica microspheres using hydroxypropyl cellulose (HPC) as a surface esterification agent and porous template, and then dried and calcined at different temperatures. The as-prepared products were characterized with differential thermal analysis and thermogravimetric (DTA/TG), scanning electron microscopy (SEM), X-ray diffraction (XRD), nitrogen adsorption. The results showed that composite particles were about 1.8 μm in diameter, and had a spherical morphology and a narrow size distribution. Uniform mesoporous titania coatings on the surfaces of microporous silica microspheres could be obtained by adjusting the HPC concentration to an optimal concentration of about 3.2 mmol L⁻¹. The anatase and rutile phase in the SiO₂/TiO₂ composite microspheres began to form at 700 and 900 °C, respectively. At 700 °C, the specific surface area and pore volume of the SiO₂/TiO₂ composite microspheres were 552 and 0.652 mL g⁻¹, respectively. However, at 900 °C, the specific surface area and pore volume significantly decreased due to the phase transformation from anatase to rutile.     

Thin Pd–23%Ag/stainless steel composite membranes: Long-term stability,life-time estimation and post-process characterisation

The long-term stability of Pd–23%Ag/stainless steel composite membranes has been examined in H₂/N₂ mixtures as a function of both temperature and feed pressure. During continuous operation, the membrane shows a good stability at 400 °C while the N₂ leakage increases very slowly at a temperature of 450 °C (P_feed = 10 bar). After 100 days of operation (P_feed = 5–20 bar, T = 350–450 °C), the N₂ permeance equals 7.0 × 10⁻⁹ mol m⁻² s⁻¹ Pa⁻¹, which indicates that the H₂/N₂ permselectivity still lies around 500, based on a H₂ permeance equal to 3.0 × 10⁻⁶ mol m⁻² s⁻¹ Pa⁻¹. Despite the generation of small pinholes, a membrane life-time of several (2–3) years (T ≤ 425 °C) is estimated for the experimental conditions employed based on long-term stability tests over 100 days. Post-process characterisation shows a considerable grain growth and micro-strain relaxation in the Pd–23%Ag membrane after the prolonged permeation experiment. Changes in surface area are relatively small. In addition, segregation of Ag to the membrane surfaces is observed. The formation of pinholes is identified as the main source for the increased N₂ leakage during testing at higher temperature.     

Hydrogen purification using a SAPO-34 membrane

A SAPO-34 membrane separated CO₂/H₂ and H₂/CH₄ mixtures at feed pressures up to 1.7 MPa. Strong CO₂ adsorption inhibited H₂ adsorption and decreased H₂ permeances significantly, especially at low temperatures, so that CO₂ preferentially permeated and CO₂/H₂ selectivities were higher at low temperatures. At 253 K, CO₂/H₂ separation selectivities were greater than 100 with CO₂ permeances of 3 × 10⁻⁸ mol m⁻² s⁻¹ Pa⁻¹. The CO₂/H₂ separation exceeded the upper bounds (selectivity–permeability plot) for polymer membranes. The SAPO-34 membrane separated H₂ from CH₄ because CH₄ is close to the SAPO-34 pore size and has a lower diffusivity than H₂. The H₂/CH₄ separation selectivity had a small maximum with temperature, and decreased slightly with feed pressure and CH₄ feed concentration.     

Study on composite membranes with high selective permeance properties

Flavonoids are natural products having several biological and physiological properties depending upon their molecular configurations. Flavonoids with similar configuration cannot be separated by traditional separation method and membrane separation technology whose selectivity is lower. This work investigates composite membranes with structural and functional molecular recognition properties prepared according to molecular imprinted technology. Functional silica sol was synthesized by taking luteolin as the template (or imprinting) molecule, γ-aminopropyltriethoxysilane (γ-APTS) as the functional monomer, and tetraethoxysilane (TEOS) as the cross-linker. The resultant functional silica sol was coated on Al₂O₃ microporous substrate followed by the removal of the template molecule. Scanning electron microscope micrographs showed a 5 μm thickness composite membrane with uniformly distributed porosity. Steady state flux was reached at ∼70 min at 215 L m⁻² h⁻¹ for the composite membrane, while a lower value of 168 L m⁻² h⁻¹ was measured for the blank membrane (i.e. non-templated). Further, in an aqueous mixture containing similar template molecules, the selectivity factor of luteolin to rutin was 14.1, thus suggesting that the imprinting process allowed for preferential permeance and affinity selectivity to the template molecule (i.e. luteolin). These results strongly suggest the formation of cavities, which are joined by channels to deliver the percolative effect for the permeation of luteolin. In addition to structural formation, further site recognition properties were accomplished by the functional silica sol in the composite matrix by electrovalent bonds. Considering the percolative effect in tandem with electrovalent bonds and under the influence of a concentration gradient (i.e. driving force), a mechanism of molecular recognition was proposed based on the molecular bond, followed by bond cutting and jumping to another site to form another molecular bond. The preparation method of the composite membrane was applied to other template molecules, and the template molecules can selectively permeate the membrane. So the method was universal for other substance. So it made it possible for the separation of the natural products exactly and efficiently. At the same time, it had great potential for the resolution of the chiral drugs and the preparation of the new membrane reactor.     

Hydrogen gas mixture separation by CVD silica membrane

In this work we investigate the performance of high flux chemical vapour deposition (CVD) silica membranes for the separation of gas mixtures containing H₂ and CO₂ at various temperatures. The membranes were prepared by a counter diffusion CVD method where tetraethyl orthosilicate (TEOS) and O₂ were used as reactants. Single gas permeation resulted in activated transport for the smaller kinetic diameter gases (H₂ and He) whilst the larger kinetic diameter gases (CO₂ and N₂) showed negative activation energy. The single gas permeation of H₂ increased from 5.1 × 10⁻⁷ to 7.0 × 10⁻⁷ mol m⁻² s⁻¹ Pa⁻¹ in the temperature range 100–400 °C, and H₂/CO₂ and H₂/N₂ selectivities reached 36 and 57 at 400 °C, respectively. The H₂ purity in the permeate stream also increased with temperature for H₂:CO₂ binary gas mixture, thus being beneficial for H₂ diffusion. H₂ competitively permeated through the membrane at a several range of gas mixtures, and a saturation level was achieved at H₂:CO₂ 60:40 feed concentration, where the diffusion of CO₂ molecules became negligible delivering ∼99% H₂ purity in the permeate stream. These results substantiate that the counter diffusion CVD method produced thin silica film membranes with a very precise pore size control, in particular suggesting a narrow pore distribution with average pore radius of about 3.1 Å.     

A Uniformly Oriented MFI Membrane for Improved CO2 Separation

Membrane separation of CO₂ from natural gas, biogas, synthesis gas, and flu gas is a simple and energy‐efficient alternative to other separation techniques. But results for CO₂‐selective permeance have always been achieved by randomly oriented and thick zeolite membranes. Thin, oriented membranes have great potential to realize high‐flux and high‐selectivity separation of mixtures at low energy cost. We now report a facile method for preparing silica MFI membranes in fluoride media on a graded alumina support. In the resulting membrane straight channels are uniformly vertically aligned and the membrane has a thickness of 0.5 μm. The membrane showed a separation selectivity of 109 for CO₂/H₂ mixtures and a CO₂ permeance of 51×10^?7 mol m^?2 s^?1 Pa^?1 at ?35 °C, making it promising for practical CO₂ separation from mixtures.     

Cobalt-doped silica membranes for gas separation

Cobalt-doped silica membranes were synthesized using tetraethyl orthosilicate-derived sol mixed with cobalt nitrate hexahydrate. The cobalt-doped silica structural characterization showed the formation of crystalline Co₃O₄ and silanol groups upon calcination. The metal oxide phase was sequentially reduced at high temperature in rich hydrogen atmosphere resulting in the production of high quality membranes. The cobalt concentration was almost constant throughout the film depth, though the silica to cobalt ratio changed from 33:1 at the surface to 7:1 at the interface with the alumina layer. It is possible that cobalt has more affinity to alumina, thus forming CoOAl₂O₃. The He/N₂ selectivities reached 350 and 570 at 160 °C for dry and 100 °C wet gas testing, respectively. Subsequent exposure to water vapour, the membranes was regenerated under dry gas condition and He/N₂ selectivities significantly improved to 1100. The permeation of gases generally followed a temperature dependency flux or activated transport, with best helium permeation and activation energy results of 9.5 × 10⁻⁸ mol m⁻² s⁻¹ Pa⁻¹ and 15 kJ mol⁻¹. Exposure of the membranes to water vapour led to a reduction in the permeation of nitrogen, attributed to water adsorption and structural changes of the silica matrix. However, the overall integrity of the cobalt-doped silica membrane was retained, given an indication that cobalt was able to counteract to some extent the effect of water on the silica matrix. These results show the potential for metal doping to create membranes suited for industrial gas separation.     

Three-layer structure graphene/mesoporous silica composites incorporated with C8-modified interior pore-walls for residue analysis of glucocorticoids in milk by liquid chromatography–tandem mass spectrometry

Three-layer structure graphene/mesoporous silica composites incorporated with C8-modified interior pore-walls (graphene@mSiO₂-C8) were prepared and applied for efficient extraction of glucocorticoid residuals in milk followed by liquid chromatography-tandem mass spectrometry (LC–MS/MS) analysis. The graphene@mSiO₂-C8 nanocomposites were synthesized by coating C8-modified mesoporous silica onto hydrophilic graphene nanosheets through a simple surfactant-mediated co-condensation sol–gel process. The obtained nanosheets possess unique properties of large surface area (632 m²/g), extended plate-like morphology in the exterior surface, highly open pore structure with uniform pore size (2.8 nm), numerous C8-modified interior pore-walls, as well as good water dispersibility. The performance of the prepared graphene@mSiO₂-C8 materials for extracting small hydrophobic molecules directly from complex protein-rich samples was evaluated by analysis of glucocorticoids in milk. Extraction conditions such as sorbents amount, type and volume of eluting solvent, time of adsorption and desorption were investigated and optimized to achieve the best efficiency. Method validations including linearity, recovery, repeatability, and limit of detection (LOD) were also studied. The results indicated that this methodology provided low LOD (S/N = 3, 0.0075–0.03 ng mL⁻¹) and good linearity (0.03–60 ng mL⁻¹, R² > 0.996) for glucocorticoids. Satisfactory reusability and stability were also obtained during the extraction. Finally, the graphene@mSiO₂-C8 composites were successfully applied to the extraction and residue analysis of glucocorticoids in real milk samples. The experimental results showed that this novel approach offered an attractive choice for convenient, efficient and rapid solid-phase extraction of targeted hydrophobic compounds in biological samples.     

Sequential injection methodology for carbon speciation in bathing waters

A sequential injection method (SIA) for carbon speciation in inland bathing waters was developed comprising, in a single manifold, the determination of dissolved inorganic carbon (DIC), free dissolved carbon dioxide (CO₂), total carbon (TC), dissolved organic carbon and alkalinity. The determination of DIC, CO₂ and TC was based on colour change of bromothymol blue (660 nm) after CO₂ diffusion through a hydrophobic membrane placed in a gas diffusion unit (GDU). For the DIC determination, an in-line acidification prior to the GDU was performed and, for the TC determination, an in-line UV photo-oxidation of the sample prior to GDU ensured the conversion of all carbon forms into CO₂. Dissolved organic carbon (DOC) was determined by subtracting the obtained DIC value from the TC obtained value. The determination of alkalinity was based on the spectrophotometric measurement of bromocresol green colour change (611 nm) after reaction with acetic acid. The developed SIA method enabled the determination of DIC (0.24–3.5 mg C L⁻¹), CO₂ (1.0–10 mg C L⁻¹), TC (0.50–4.0 mg C L⁻¹) and alkalinity (1.2–4.7 mg C L⁻¹ and 4.7–19 mg C L⁻¹) with limits of detection of: 9.5 μg C L⁻¹, 20 μg C L⁻¹, 0.21 mg C L⁻¹, 0.32 mg C L⁻¹, respectively. The SIA system was effectively applied to inland bathing waters and the results showed good agreement with reference procedures.     

Microporous Silica Xerogel Membrane with High Selectivity and High Permeance for Carbon Dioxide Separation

The asymmetric microporous silica xerogel membrane was prepared by sol-gel method. A multi-layer (asymmetric) structure was obtained by silica xerogel layer on top of mesoporous silica layer (mean pore diameter of 4 nm), supported by porous alumina tube (mean pore diameter of 0.1 m). The ratio of the permeances, CO₂/N₂ for this membrane attained more than 60 at 298 K. This value is considerably higher than the theoretical Knudsen value (CO₂/N₂ = 0.8). The gas permeances of this membrane were about 5–10 times higher than the previous membrane. Application of the membrane to an enrichment of CO₂ from air was also investigated. CO₂ in the air (about 300 ppm) was concentrated to more than 1000 ppm by using the membrane at 298 K.     

Development of a membrane reactor for decomposing hydrogen sulfide into hydrogen using a high-performance amorphous silica membrane

We have successfully developed a membrane reactor for decomposing hydrogen sulfide into hydrogen using an amorphous silica membrane for the first time. The membrane was prepared by the CVD method with tetramethoxysilane and oxygen, and showed excellent hydrogen permeance at 873 K of the order of 10⁻⁷ mol m⁻² s⁻¹ Pa⁻¹ and high hydrogen/nitrogen permselectivity of 10⁴. The membrane reactor constructed with our membrane and a commercially available catalyst decomposed hydrogen sulfide into hydrogen with higher conversion than the equilibrium conversion. This conversion enhancement was because of the selective extraction of hydrogen from the reaction side to the permeate side by the silica membrane.     

Cerium oxide-deposited mesoporous silica nanoparticles for the determination of carcinoembryonic antigen in serum using inductively coupled plasma-mass spectrometry

CeO₂-deposited mesoporous silica nanoparticles were synthesized as a probe to determine carcinoembryonic antigen (CEA) in serum by inductively coupled plasma-mass spectrometry (ICP-MS). The prepared mesoporous nanoparticles were modified and tagged to the target for sandwich-type immunoassay. Fe₃O₄ magnetic nanoparticles (MNPs) were also synthesized and immobilized with antibody to extract the target biomarker. The calibration curve of the synthesized CeO₂-deposited silica nanoparticles, which was plotted by the signal ratio of ¹⁴⁰Ce/⁵⁷Fe measured by ICP-MS vs. the concentration of CEA, showed excellent linearity and sensitivity owing to the signal amplification and low spectral interference. Under optimal conditions, the sandwich-type analytical method was applied to determine CEA in serum spiked in the range of 0.001–5 ng mL⁻¹ and showed a limit of detection of 0.36 ng mL⁻¹. Since the deposited CeO₂ in the mesoporous silica layer can be substituted by other metal compounds, various kinds of metal-deposited nanoparticles can be prepared as probe materials for multiplex detection in bioanalysis.     

Continuous Porous Aromatic Framework Membranes with Modifiable Sites for Optimized Gas Separation

Continuous microporous membranes are widely studied for gas separation, due to their low energy premium and strong molecular specificity. Porous aromatic frameworks (PAFs) with their exceptional stability and structural flexibility are suited to a wide range of separations. Main-stream PAF-based membranes are usually prepared with polymeric matrices, but their discrete entities and boundary defects weaken their selectivity and permeability. The synthesis of continuous PAF membranes is still a major challenge because PAFs are insoluble. Herein, we successfully synthesized a continuous PAF membrane for gas separation. Both pore size and chemistry of the PAF membrane were modified by ion-exchange, resulting in good selectivity and permeance for the gas mixtures H₂/N₂ and CO₂/N₂. The membrane with Br^? as a counter ion in the framework exhibited a H₂/N₂ selectivity of 72.7 with a H₂ permeance of 51844 gas permeation units (GPU). When the counter ions were replaced by BF₄^?, the membrane showed a CO₂ permeance of 23058 GPU, and an optimized CO₂/N₂ selectivity of 60.0. Our results show that continuous PAF membranes with modifiable pores are promising for various gas separation situations.     

Facile fabrication of a novel high performance CO2 separation membrane: Immobilization of poly(amidoamine) dendrimers in poly(ethylene glycol) networks

Poly(amidoamine) (PAMAM) dendrimers showed high CO₂ separation properties and were successfully immobilized in a poly(ethylene glycol) (PEG) network upon photopolymerization of PEG dimethacrylate. The PAMAM dendrimer incorporation ratio was readily controlled, and a stable self-standing membrane containing up to 75 wt.% PAMAM dendrimer was obtained. The CO₂ separation properties over smaller H₂ were investigated by changing the PAMAM dendrimer content or generation and CO₂ partial pressure (ΔPCO₂$\mathrm{\Delta }{P}_{\text{C}{\text{O}}_2}$) under atmospheric conditions. Especially, a polymeric membrane containing 50 wt.% PAMAM dendrimer (0th generation) exhibited an excellent CO₂/H₂ selectivity of 500 with CO₂ permeability of 2.74 × 10⁻¹⁴ m³(STP)m/(m² s Pa) or 3.65 × 10³ barrer (1 barrer = 7.5 × 10⁻¹⁸ m³(STP)m/(m² s Pa)) when a mixture gas (CO₂/H₂: 5/95 by vol.) was fed at 25 °C and 100 kPa with 80% relative humidity. This polymeric materials are promising for a novel CO₂ separation membrane.     

Single-run ion chromatographic separation of inorganic and low-molecular-mass organic anions under isocratic elution: Application to environmental samples

For the isocratic ion chromatography (IC) separation of low-molecular-mass organic acids and inorganic anions three different anion-exchange columns were studied: IonPac AS14 (9 μm particle size), Allsep A-2 (7 μm particle size), and IC SI-50 4E (5 μm particle size). A complete baseline separation for all analyzed anions (i.e., F⁻, acetate, formate, Cl⁻, NO₂⁻, Br⁻, NO₃⁻, HPO₄²⁻ and SO₄²⁻) in one analytical cycle of shorter than 17 min was achieved on the IC SI-50 4E column, using an eluent mixture of 3.2 mM Na₂CO₃ and 1.0 mM NaHCO₃ with a flow rate of 1.0 mL min⁻¹. On the IonPac AS14 column, it was possible to separate acetate from inorganic anions in one run (i.e., less than 9 min), but not formate, under the following conditions: 3.5 mM Na₂CO₃ plus 1.0 mM NaHCO₃ with a flow rate of 1.2 mL min⁻¹. Therefore, it was necessary to adapt a second run with a 2.0 mM Na₂B₄O₇ solution as an eluent under a flow rate of 0.8 mL min⁻¹ for the separation of organic ions, which considerably enlarged the analysis time. For the Allsep A-2 column, using an eluent mixture of 1.2 mM Na₂CO₃ plus 1.5 mM NaHCO₃ with a flow rate of 1.6 mL min⁻¹, it was possible to separate almost all anions in one run within 25 min, except the fluoride-acetate critical pair. A Certified Multianion Standard Solution PRIMUS for IC was used for the validation of the analytical methods. The lowest RSDs (less than 1%) and the best LODs (0.02, 0.2, 0.16, 0.11, 0.06, 0.05, 0.04, 0.14 and 0.09 mg L⁻¹ for F⁻, Ac⁻, For⁻, Cl⁻, NO₂⁻, Br⁻, NO₃⁻, HPO₄²⁻ and SO₄²⁻, respectively) were achieved using the IC SI-50 4E column. This column was applied for the separation of concerned ions in environmental precipitation samples such as snow, hail and rainwater.     

Novel sponge-like molecularly imprinted mesoporous silica material for selective isolation of bisphenol A and its analogues from sediment extracts

Bisphenol A (BPA) imprinted sponge mesoporous silica was synthesized using a combination of semi-covalent molecular imprinting and simple self-assembly process. The molecularly imprinted sponge mesoporous silica (MISMS) material obtained was characterized by FT-IR, scanning electron microscopy, transmission electron microscopy, and nitrogen adsorption–desorption measurements. The results show that the MISMS possessed a large specific surface area (850.55 m² g⁻¹) and a highly interconnected 3-D porous network. As a result, the MISMS demonstrated a superior specific adsorption capacity of 169.22 μmol g⁻¹ and fast adsorption kinetics (reaching equilibrium within 3 min) for BPA. Good class selectivity for BPA and its analogues (bisphenol F, bisphenol B, bisphenol E and bisphenol AF) was also demonstrated by the sorption experiment. The MISMS as solid-phase extraction (SPE) material was then evaluated for isolation and clean-up of these bisphenols (BPs) from sediment samples. An accurate and sensitive analytical method based on the MISMS–SPE coupled with HPLC–DAD has been successfully established for simultaneous determination of five BPs in river sediments with detection limits of 0.43–0.71 ng g⁻¹ dry weight (dw). The recoveries of BPs for lyophilizated sediment samples at two spiking levels (50 and 500 ng g⁻¹ dw for each BP) were in the range of 75.5–105.5% with RSD values below 7.5%.