Microfiltration Membranes Research Articles

Industrial oily wastewater treatment by microfiltration using silver nanoparticle-incorporated poly (acrylonitrile-styrene) membrane

Membrane filtration exhibit operational limitations such as biofouling, which leads to concentration polarization and reduces permeability and selectivity, despite advantages such as low operating cost, high selectivity, and permeability. In recent years, the antibacterial properties of silver nanoparticles (AgNPs) have been investigated for improving membrane processes; however, the fouling phenomena in presence of AgNPs in the membrane matrix have not been fully discussed. Herein, the antifouling properties of a poly (acrylonitrile-styrene) copolymer incorporated with AgNPs were studied in a microfiltration membrane process. The Creighton method was used to synthesize AgNPs, and the effects of AgNPs on the porosity, morphology, pore size, mechanical strength, permeability, and selectivity of the membranes were investigated. Moreover, to investigate the biofouling of the obtained membranes, microfiltration of industrial oily wastewater was performed at constant pressure over three cycles. Using AgNPs in the membrane matrix resulted in enhanced antifouling properties of the copolymer membrane, which is related to the structure of the AgNPs in the casting solution, as proven by SAXS analysis. The results show that the CFU% for Staphylococcus aureus and E.coli reach 2% and 6%, respectively. Finally, the Derjaguin–Landau–Verwey–Overbeek (DLVO) thermodynamic model was applied to study the antifouling mechanism, correctly predict the separation behavior in the membrane, and design, simulate, and optimize the separation processes in the membrane separation plantsa. The DLVO model could predict the separation behavior in the synthesized membranes, and the poly(acrylonitrile-styrene) copolymer membranes containing AgNPs were proven have promising industrial wastewater treatment applications.

Flavonoids from Peony Seed Meal by Nanofiltration Membrane Separation

Flavonoids are polyphenolic compounds with a wide range of biological activities (antioxidation, antitumor, and immunomodulatory). The membrane separation method of flavonoids has a high recovery and biological activity, overcoming the shortcomings of traditional methods for the separation of bioactive molecules. In this study, ethanol-water ( v / v ) solution was used to extract peony seed meal. The extraction rate of total flavonoids from peony seed meal was 35.28%. Five microfiltration membranes, polypropylene (PP), polyvinylidene fluoride (PVDF), cellulose acetate (CA), polyether sulfone (PES), and polyamide (PA), were selected to pretreat the extracts, and their separation performance was investigated. A new PA-supported silicone film was prepared by sol-gel method using 1,2-bis(TRIMETHOXYSILYL)ETHANE (BTESE) as a carrier. The synthesized BTESE/PA composite membrane was applied to the purification of organic silica PSMF solution by nanofiltration process. The optimal pressure of nanofiltration operation is 0.8 MPa, and the membrane flux can reach 2.06 kg·m-2·h-1. The mass concentration of flavonoids in the retention solution was decreased to 860.56 mg·L-1, and the permeable components of PSMF were effectively separated. The total flavonoid content of the purified lyophilized powder was 146.12 mg·g-1, which was 2.4 times that before purification. The results show that PSMF can be effectively separated by BTESE/PA membrane, and the membrane solution has good antioxidant activity.

An advanced treatment process for 3-high wastewater discharged from crude oil storage tanks.

The wastewater discharged from crude oil storage tanks (WCOST) contains high concentrations of salt and metal iron ions, and high chemical oxygen demand (COD). It belongs to "3-high" wastewater, which is difficult for purification. In this study, WCOST treatments were comparatively investigated via an advanced pretreatment and the traditional coagulation-microfiltration (CMF) processes. After WCOST was purified through the conventional CMF process, fouling occurred in the microfiltration (MF) membrane, which is rather harmful to the following reverse osmosis (RO) membrane unit, and the effluent featured high COD and UV254 values. The analysis confirmed that the MF fouling was due to the oxidation of ferrous ions, and the high COD and UV254 values were mainly attributable to the organic compounds with small molecular sizes, including aromatic-like and fulvic-like compounds. After the pretreatment of the advanced process consisting of aeration, manganese sand filtration, and activated carbon adsorption in combination with CMF process, the removal efficiencies of organic matter and total iron ions reached 97.3% and 99.8%, respectively. All the water indexes of the effluent, after treatment by the advanced multi-unit process, meet well the corresponding standard. The advanced pretreatment process reported herein displayed a great potential for alleviating the MF membrane fouling and enhanced the lifetime of the RO membrane system in the 3-high WCOST treatment.

Influence of organic matter on the photocatalytic degradation of steroid hormones by TiO2-coated polyethersulfone microfiltration membrane

Water treatment in photocatalytic membrane reactors (PMR) holds great promise for removing micropollutants from aquatic environments. Organic matter (OM) that is present in any water matrix may significantly interfere with the degradation of steroid hormone (SH) micropollutants in PMRs. In this study, the interference of various OM types, humic acid (HA), Australian natural organic matter (AUS), worm farm extract (WF), tannic acid (TA), and gallic acid (GA) with the SH degradation at its environmentally relevant concentration (100 ng/L) in a flow-through PMR equipped with a polyethersulphone-titanium dioxide (PES-TiO2) membrane operated under UV light (365 nm) was investigated. Results of this study showed that OM effects are complex and depend on OM type and concentration. The removal of β-estradiol (E2) was enhanced by HA at its levels below 5 mgC/L while the enhancement was abated at higher HA concentrations. The E2 removal was inhibited by TA, and GA, while no significant interference observed for AUS, and WF. The data demonstrated diverse roles of OM that acts in PMRs as a light screening agent, a photoreactive species scavenger, an adsorption alteration trigger, and a photosensitizer. The time-resolved fluorescence measurement showed that HA, acting as a photosensitizer, promoted the sensitization of TiO2 by absorbing light energy and transferring energy/electron to the TiO2 substrate. This pathway dominated the mechanism of the enhanced E2 degradation by HA. The favorable effect of HA was augmented as increasing the light intensity from 0.5 to 10 mW/cm2 and was weakened at higher light intensities due to the increased scavenging reactions and the limited amount of HA. This work clarifies the underlying mechanism of the OM interference on photocatalytic degradation of E2 by the PES-TiO2 PMR.

Impacts of hydration and dehydration on microfiltration point-of-use filters: performance and cleaning impacts

Abstract This research examines the performance of two commercially available point-of-use (POU) microfiltration membrane filters (MF) under hydrated (wet) versus a multi-day dry period (dehydrated). Filter performance is monitored in terms of water quality and flowrate, as well as flowrate recovery following different cleaning regimes. The cleaning methods tested were backwashing with filtrate at room temperature, filtrate heated to 45 °C, filtrate at 45 °C with gentle shaking, and a vinegar solution (5% acetic acid). The selected cleaning methods reflect easily accessible cleaning methods with a goal to assess their impacts on flowrate recovery under both wet and dry conditions. After initial testing, hydrated MF flowrate varied between 197 ± 22 mL/min and backwashing with filtrate at room temperature was sufficient to maintain the membrane flowrate, while any of the other methods initially improved the system flowrate. In experiments where the filters were subject to a 5-day dry condition MF flowrates dropped to 65 ± 35 mL/min and filtrate at room temperature did not recover the flowrate sufficiently, however heated filtrate (45 °C) with/without gentle shaking was effective at recovering the MF for use. Water quality remained similar throughout the study, and 0 CFU/mL of E. coli were found in filtrate samples.

High-flux whisker layer ceramic membrane prepared by gel spin-coating method for low-pressure oil/water emulsion filtration

Insufficient permeability and membrane fouling significantly influence the efficiency of ceramic microfiltration (MF) membranes in oil/water emulsion treatment. In this study, a high-flux whisker layer ceramic MF membrane with super-hydrophilicity was successfully fabricated through gel-spin coating method and a low-temperature oxidation method, which was used to separate oil/water emulsion. The effects of the whisker layer and surface wettability were systematically investigated, and the mechanism of in-situ gelling and pore size distribution was proposed. The super-hydrophilic ceramic MF membrane with an average pore size of 250 nm exhibited a high gas flux of 934 m3/(m2·h·bar) and excellent pure water flux of 9754 L/(m2 h bar). Even after a long-term circulating filtration process, the super-hydrophilic ceramic MF membrane still maintained a high water flux of over 50 L/(m2·h) at a transmembrane pressure of 5 KPa during the treatment of oil-in-water emulsion with a concentration of 1000 mg/L. Overall, the developed ceramic MF membrane demonstrated high permeability and excellent anti-fouling performance, making it a promising candidate for oil/water emulsion wastewater treatment.

Emerging membrane technology and hybrid treatment systems for the removal of micropollutants from wastewater

Currently, substances have been detected that have always been present but have long been unnoticed; among these substances called emerging pollutants are pharmaceuticals, pesticides, cosmetics, cleaning, and personal care products, among others. Membrane Bioreactor (MBR) technology has gained extensive popularity in enhancing the treatment and reutilization of wastewater. It exhibits efficiencies ranging from 40 to 79 % for treating high organic loads such as dairy wastewater while achieving impressive rates of up to 90 % for effectively removing emerging contaminants. However, traditional MBRs with ultrafiltration or porous microfiltration membranes are not intended to remove hazardous micropollutants from water, which are constantly present in trace concentrations and can adversely affect terrestrial and aquatic ecosystems. Several effective techniques have been used to remove hazardous micropollutants from water, especially for hydrophilic and resistant chemicals. These tactics consist mainly of improving the operating environment, using high-retention membranes instead of porous membranes, adding functional materials to the bioreactor, and including additional procedures for effluent treatment. To ensure almost complete removal of micropollutants, the MBR can be complemented with effluent treatment, recently the use of high retention membranes, hybrid MBR-nanofiltration systems, or other processes such as electrocoagulation or advanced oxidation (AOP) have been reported. Nevertheless, additional investigation is required to assess these strategies' technical and economic viability, particularly regarding real-time effectiveness. This evaluation is crucial for identifying the most appropriate techniques for industrial applications.

Hybrid electrolysis and membranes system for apple packing houses water treatment.

The apple industry uses high flows of potable quality water to transport and clean the apple, which is regularly contaminated. Thus, it is necessary to implement an efficient water treatment system during the industrial process, providing reductions in the intake and release flows. A hybrid system was developed by applying the electrolytic treatment by electrocoagulation using a batch process (Step 1) and a continuous process (Step 2), followed by a microfiltration membrane separation (MSP) process (Step 3). The optimal conditions for removal of organic matter, chemical oxygen demand, total suspended solids (TSS), turbidity, color, and fungi obtained in Step 1 were a hydraulic detention time of 40 min, stirring at 40 rpm, current density of 20 A/m2, pH of 8.00, and temperature of 10 °C. These findings led to a successful implementation in Step 2, which evolved into Step 3, where tests in the combined continuous electrolytic reactor together with MSP showed significant removal rates, notably reaching up to 54% organic matter (OM) removal, 72% chemical oxygen demand (COD) removal, 83% TSS removal, 92% haze and color removal, and 100% mildew removal. The hybrid system proved to be a promising alternative for implementation in the processing industry, minimizing environmental impacts and costs.

Construction of antimicrobial peptides/alginate multilayers modified membrane: Antibiofouling performance and mechanisms

Biofouling remains to be one of major obstacles for membrane-based technology in water and wastewater treatment, calling for the development of antibiofouling membranes. For the traditional release-killing strategy, uncontrollable release of biocides and thus a short lifetime as well as the potentially environmental risk are thorny issues for the modified membranes. Herein, hydrophilic hydrogel multilayers with controllable thickness at nanometer scale on a poly(vinylidene fluoride) (PVDF) microfiltration membrane were constructed via layer-by-layer (LbL) self-assembly of non-drug-resistant antimicrobial peptides (AMPs) and alginate. The AMPs/alginate multilayers modified membranes exhibited enhanced hydrophilicity, well-controlled pore size distribution and prominent antimicrobial ability against Escherichia coli and Staphylococcus aureus. As the number of multilayers of alginate increased, both initial and steady release rate of Ponericin G1 reduced; in particular, the AMPs/alginate modified membranes with fifteen multilayers (MSA15) had the slowest release kinetics (i.e., an initial release rate of 1.79 ± 0.07 μg/cm2 d and a steady release rate of 0.55 ± 0.03 μg/cm2 d), resulting in about 60% less release compared with the AMPs/alginate modified membranes with five multilayers (MSA5). Long-term antibiofouling tests showed that the AMPs/alginate modified membranes with ten multilayers (MSA10) exhibited a significantly reduced transmembrane pressure increase rate of 0.81 ± 0.01 kPa/d which was much lower than that of the control membranes (1.80 ± 0.20 kPa/d), mainly attributed to the antibacterial activity imparted by the lasting release of AMPs and competing membrane basic properties. Furthermore, the AMPs/alginate multilayers modified membranes revealed high stability suffering from long-term operation and chemical cleaning cycles. The novel AMP/alginate-incorporated modifying method provides a new dimension to enhance antibiofouling performance of membranes for water and wastewater treatment.

Rejection and fouling of track-etched microfiltration membranes by Acholeplasma laidlawii: Clues to mycoplasma behavior during “sterile” dead-end filtration

Mycoplasma contamination is commonplace during processing of biopharmaceuticals necessitating its sterile filtration. Consequently, we measured the passage of Acholeplasma laidlawii (a small bacterium lacking cell wall like mycoplasma) across track-etched membranes rated at 100 nm and 220 nm that are designated as “sterile filters” and analyzed the entire progression of fouling beginning with pore occlusion before transitioning to a cake. Initial biofouling was quantified to be intermediate blocking before bacteria formed highly compressible cakes. Under identical experimental conditions, phase inversion membranes of the same nominal pore rating rejected A. laidlawii to a significantly greater extent suggesting depth filtration and capture within the polymer matrix in contrast to surface capture by their track-etched counterparts. A facile fluorescence microscopy method to rapidly detect slow-growing A. laidlawii cells was demonstrated under conditions of low retention. Evidence of cake relaxation by depressurizing the filter and subsequent mobilization of individual cells upon re-pressurization is given. Multiple lines of evidence demonstrated the pressure-induced deformation of individual cells resulting in their incomplete rejection by membranes with pore ratings smaller than the bacterium's unstressed diameter: (i) complete retention of rigid silica colloids of similar size, shape, and zeta potential regardless of pressure in contrast to incomplete A. laidlawii removals, (ii) reduced bacterial removal by both membranes with increasing filtration pressure, (iii) 150–600 fold less permeable bacterial cakes at any given pressure compared with silica cakes, and (iv) presence of flattened and irregularly shaped A. laidlawii cells in electron micrographs whereas they were near perfect cocci at atmospheric pressure.

Protein valorisation from acid whey – Screening of various micro- and ultrafiltration membranes concerning the filtration performance

Cross-flow filtration allows a product-preserving and energy-saving unit operation for the production of whey protein concentrates (WPC) from acid whey. In micro- and ultrafiltration applications, size-exclusion is the governing separation mechanism. Flux and retention characteristics of 12 organic membranes of pore sizes between 5 and 450 nm were compared. Screening on a laboratory filtration plant revealed large differences regarding hydraulic resistance of the membrane and resistance of the deposit layer that forms on the membrane surface during filtration. As a result, notable variations in the permeate flux were observed between membranes. In contrast, the differences in protein retention were less pronounced. The protein transmission for all ultrafiltration membranes was below 5% whereas microfiltration membranes showed a deposit layer-dependent transmission behaviour. Compared with the conventional WPC35 production, the overall filtration efficiency with regard to the process duration for a comparable membrane area was 3-fold enhanced by a more appropriate membrane selection.

Influence of Tween 80 on enzymatic hydrolysis of corn straw integrated with membrane separation

This study aimed to investigate the influence of Tween 80 on the enzymatic hydrolysis of corn straw integrated with two-step membrane separation of reaction products and recovery of enzymes. Supplementation of the reaction mixture with 0.6% (w/v) Tween 80 resulted in an increased yield of hydrolysis carried out with Cellic® CTec2, both in batch and membrane bioreactor, compared to the enzymatic process conducted without surfactant. In the microfiltration membrane bioreactor, the glucan and xylan saccharification yields were, on average 31.2% and 25.5%, respectively, higher than without using Tween 80. Besides, the addition of Tween 80 significantly enhanced membrane permeability during hydrolysis without impacting its retention coefficients toward catalytic proteins. The ultrafiltration enables partial enzyme recovery and supply enzymes for a new hydrolysis process. Results obtained in this study proved the benefits of using Tween 80 in enzymatic hydrolysis of lignocellulosic biomass. Reduction of membrane fouling by surfactant during hydrolysis increases the filtration efficiency and extends the membrane lifetime.

Performance Evaluation of Ceramic Membrane Based Process for Microalgal Biomass Harvesting: Analyzing the Effect of Membrane Pore Sizes, Process Optimization and Fouling Behavior

Microalgal biofuel emerges as a potential resource of renewable energy in view of global energy demand and increasing greenhouse gases. However, substantial challenges of efficient up-concentrating of biomass act as a bottleneck in large scale production of biofuel. The study is aimed towards unravelling the obstacles encountered during dewatering of biomass from mixed-microalgae consortia using ceramic membrane based process with varying pore sizes in the microfiltration (MF) and ultrafiltration (UF) range. For clay and alumina based MF membrane, 1.2 µm pore size (average) and for alumina supported nano-alumina coated UF membrane, ∼0.01 µm pore size (average) was used. The effect of various recirculation parameters was studied for process optimization. Resistance-in-series model was employed for analyzing fouling behavior of the membranes. MF membrane was observed to have better harvesting efficiency than the UF counterpart in terms of productivity (124.41). Optimum permeate flux of microalgal suspension was found to be 315.29 L.m−2.h−1 for MF membrane. Regeneration of membranes by air assisted backpulsing process showed up to 97.71% of flux recovery for MF membrane. Volume reduction factor/ membrane area (371) was found to be considerably high compared to various reported studies. The study highlighted efficient harvesting of microalgae using indigenously developed ceramic MF membrane integrated filtration towards cost-effective production of biofuel.

Solid-state blending for the preparation of porous eco-friendly PCL membranes: Potential for filtration applications

Cryomilling is a promising method for fabricating polymeric blend and composite powder raw materials for various subsequent manufacturing processes. In this study, biodegradable porous membranes were fabricated from poly (ε-caprolactone) (PCL) using the cryomilling/hot pressing/porogen leaching approach. Powder mixtures of six different model compositions were compounded by cryomilling; thereafter, films were fabricated by hot-pressing. Poly (ethylene-oxide) (PEO) and salt were utilized as eco-friendly porogens in these mixtures, which were dissolved in water to introduce porosity in the films. Wood sawdust (WSD) and alum were investigated as fillers potentially capable of manipulating the hydrophilicity, mechanical and antimicrobial properties of the membranes. The morphological, hydrophilicity, mechanical, and filtration efficiency properties were explored and compared to those of commercial laboratory microfiltration (MF) membranes. SEM analysis revealed dense membrane skins for all compositions, along with lamellar porous structures. Mean pore radius ranged from 0.15 to 0.21 μm, which is within the MF pore size range. Water contact angle measurements averaged 70° and decreased with the addition of WSD and alum, indicating increased hydrophilicity. Tensile test results showed a decrease in mechanical properties, with higher porosities and with the addition of WSD. Adding alum (≥10 wt%) resulted in embrittled membranes. Filtration performance was evaluated in terms of pure water flux and turbidity reduction for textile wastewater, and it compared favorably to commercial membranes. In conclusion, this study has successfully introduced a new facile and versatile membrane fabrication approach.

Car wash wastewater treatment combination: A systematic review

Car wash wastewater is a source of water pollution. Processing car wash waste is crucial to prevent environmental pollution. In this issue, car wash treatment has the potential to sustain of clean water. However, the effective treatment of car wash wastewater is still being determined, complicated to solve, limited resource capabilities, inadequate surrounding environmental support, and very expensive processing costs. This systematic review paper aims to review the combination technology of car wash wastewater treatment systematically. A literature survey was conducted, and 11 research articles were found suitable for inclusion in the investigation, which extracted information, country of origin, and method used. The best 8 of 11 articles were removed as secondary data for writing this manuscript to be included in the analysis table. Studies on flocculation-column-flotation, coagulation-flocculation, ultra-microfiltration, coagulation-flocculation, electrocoagulation, sedimentation-filtration, filtration-ozonation, electrocoagulation-adsorption, and each n=1. This systematic review shows that ultrafiltration and microfiltration membrane treatment methods effectively remove pollutants from car wash wastewater.

Recovery of Membrane Permeability after Filtration of Sago Starch Suspension by Tangential Flow Filtration

Sago starch is extracted from the stems of the sago palm, Metroxylon sagu, in south-east Asia. Sago starch processing generates approximately 20 tons of starch containing effluents that can be recovered and marketed to sustain a small-scale industry. Tangential flow filtration (TFF) using microfiltration membranes (MFM) has been demonstrated as an effective method for separating suspended solids in biological effluents. When TFF was applied to concentrate sago starch suspensions (SSS), membrane permeability and lifecycle were impacted due to frequent fouling. This study evaluated cleaning methods to recover the permeability and extend the lifecycle of MFM following TFF application. Polysulfone membrane filter cassettes of pore size 0.45 µm and surface area 0.1 m2 were each used to separate starch in 100 L of SSS. Following separation, six chemical and physical cleaning methods were tested at laboratory-scale and the degree of cleaning was measured by normalized permeate flux (NPF) and normalized water permeability (NWP). The results showed that soaking the membranes in a 0.2 M NaOH solution (up to 91%, (p<0.05) within the shortest time of 72 h, (p<0.05) was the best cleaning method. The procedure has been utilized to maintain and extend the lifecycle of the MFM for streams containing starch suspensions.

Designing poly(vinylidene fluoride) membranes with narrow pore size distribution for microplastics removal from water

AbstractMicroplastics have been recognized as a critical threat to the aquatic ecosystem. Membrane separation technology displays great potential to address this issue, while current commonly‐used polymeric microfiltration membranes fall short of high separation efficiency due to their wide pore distribution. A perfectly simple strategy for homoporous membranes fabrication using commercial poly(vinylidene fluoride) (PVDF) was reported in this work, enabling precise removal of microplastics. In this strategy, hydrophilicity of dope solution was enhanced by adding proper amphiphilic surfactants initially, followed by a novelly‐inserted air exposure progress to gently provide water vapor. Both of the two easy steps induced a surface microscopic phase separation to achieve the growth of homopores. Furthermore, the as‐prepared PVDF membrane displayed high surface porosity and bi‐continuous cross‐section structure. As expected, a high rejection (over 97%) towards 500 nm polystyrene microparticles could be achieved along with satisfying water flux of 662 L m−2 h−1 bar−1, which was superior to most current membranes. This work provides not only a new and facile strategy for preparing homoporous membranes employing commercial polymers rather than rarely‐obtained block polymers, but a promising alternative for the efficient separation of aquatic microplastics.

Immersion in Advanced Oxidation Water Followed by AGET-ATRP to Develop Low-Fouling Microfiltration Membranes by Grafting Poly(2-methoxyethyl acrylate)

Immersion in Advanced Oxidation Water Followed by AGET-ATRP to Develop Low-Fouling Microfiltration Membranes by Grafting Poly(2-methoxyethyl acrylate)

Scalable Zwitterionic Polymer Brushes for Antifouling Membranes via Cu0-Mediated Atom Transfer Radical Polymerization

Polymer brush layers have attracted significant interest for versatile, controlled surface modification enabling fabrication and functionalization of membranes for water treatment and reuse applications. In particular, zwitterionic polymer brushes have been shown to provide strong resistance to organic fouling, oil fouling, biofouling, and inorganic fouling as membrane coatings for a variety of membrane processes. However, despite the demonstrated performance of polymer brush membranes, there are significant challenges associated with commercial scale-up of traditional fabrication methods. In this work, we demonstrate scalable grafting of zwitterionic polymer brushes from microfiltration membrane substrates under ambient conditions, and with low chemical consumption, for the first time, via Cu0-mediated surface-initiated atom transfer radical polymerization (Cu0-SI-ATRP). We demonstrate that Cu0-SI-ATRP is effective for brush grafting from porous membrane substrates, including samples of up to 150 cm2. Furthermore, we systematically investigate the effect of polymerization in confinement on brush growth kinetics and fouling resistance, using colloid probe force microscopy and dynamic fouling experiments. Results demonstrate that Cu0-SI-ATRP results in poly(sulfobetaine methacrylate) brush layers that significantly improve fouling resistance; however, polymerization methods significantly impact fouling resistance, for both Si wafer and membrane substrates. We identify polymerization methods that enhance fouling resistance even for thin brush layers. The results of this study provide pathways to the scalable fabrication and design of robust, antifouling membranes for applications in water treatment, water reuse, and resource recovery from waste streams.

Polydopamine- and MOFs-based molecularly imprinted microfiltration membranes in syringe filter for selective capture of thiamphenicol, florfenicol and chloramphenicol in milk samples

In this study, molecularly imprinted microfiltration membranes (MIMFMs) based on polydopamine and metal–organic framework were innovatively proposed, and successfully prepared for capturing thiamphenicol, florfenicol and chloramphenicol from milk samples through syringe filter device. The provision of PDA and coupling of MOF particles enabled the filter membranes to have great permeability and binding capacity. Cleverly, hydrophilicity and heightened rebinding selectivity (IF = 2.42) of filter membranes was provided using two functional monomers (methacrylate and acrylamide), and microfiltration-grade composite membranes were generated by adjusting the imprinting polymerization time. The combination of the selective filter membranes and the syringe filter devices can effectively simplify the operation process, minimize the extraction time and reduce the tested sample volume. The method was validated by coupling with ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) and obtained a good correlation (r2 > 0.99). The limit of detection (LOD) of three analytes was 0.0800–0.6583 µg kg−1 and the mean recovery ranged from 85.5% to 91.2% within relative standard deviations (RSDs) less than 8.2%. Finally, an effective MIMFMs-UHPLC-MS/MS method was established for the recognition and detection of three amphenicol antibiotics in milk samples. The MIMFMs filtration technique offered in this work provides valuable science references and potential application prospects for complicated sample pretreatment.