Metformin, a widely prescribed antidiabetic drug, is a representative small (≈0.5–0.6 nm), hydrophilic (log P ≈ −1.43), and positively charged (pKₐ ≈ 12.4) emerging contaminant. Because its molecular size is well below the pore size of ultrafiltration membranes (>2 nm), it cannot be efficiently removed by size exclusion alone, and its high solubility and poor biodegradability further complicate conventional treatment. In this context, hybrid ceramic membranes incorporating adsorptive functionalities offer a promising alternative. However, the fouling behavior of such hybrid systems remains quantitatively uncharacterized. This study provides a quantitative assessment of flux decline and fouling reversibility in kaolin-based membranes containing 0, 5, and 10 wt.% activated carbon, evaluated for metformin removal under dead-end filtration at 4 bars, using a synthetic feed concentration of 20 mg L−1 at neutral pH (≈6.8) over 60 min. Increasing AC content raises open porosity from 29.1% (M0%) to 34.2% (M5%) and 39.1% (M10%), and water permeability from 3.3 to 10.9 and 28.4 L m−2 h−1 bar−1, respectively, without significantly compromising mechanical integrity (>20 MPa). The porosity enhancement is accompanied by a systematic improvement in apparent metformin removal, consistent with a contribution from carbon- and phosphorus-containing phases detected after thermal treatment (which provides abundant surface functional groups for electrostatic and π–π interactions) and is consistent with the observed improvement in permeability and apparent metformin removal. Consequently, metformin apparent removal after 60 min increases from 56.1% (M0%) to 76.2% (M5%) and 91.1% (M10%), while total fouling decreases from 38.5% to 20.5% and 11.0%, and irreversible fouling from 23.1% to 13.6% and 6.0%, respectively.
Vanillin-functionalized TiO2 nanotube–polysulfone (PolySulf–VOH@TNT) composite membranes were developed to enhance water permeability, antifouling resistance, and mechanical performance. VOH@TNTs were incorporated into a polysulfone matrix (1–7 wt%) via non-solvent-induced phase separation. Incorporating VOH@TNTs markedly improved surface hydrophilicity, reducing the water contact angle from 83° (pristine polysulfone membrane, PSM) to 59.6° (5 wt%), and increased water uptake and porosity from 36% and 38% to 61% and 52%, respectively. Mechanical strength rose from 5.3 to 8.3 MPa due to strong polymer–filler interfacial bonding. The PolySulf–VOH@TNT (5%) membrane, identified as the best-performing formulation based on its physicochemical properties and humic acid (HA) filtration performance, exhibited a pure-water flux of 195.4 L m−2 h−1, approximately 125% higher than that of pristine PSM, while achieving 98.8% HA rejection and a 19% reduction in foulant adsorption. Antifouling tests showed a flux recovery ratio (FRR) of ~91% and irreversible fouling (Rir) of ~7%. The membrane also achieved >96% rejection for humic acid (HA), bovine serum albumin (BSA), and sodium alginate (SA), maintaining ~94% flux recovery after cleaning. These enhancements result from the formation of a VOH- and Ti–OH-derived hydration layer, electrostatic repulsion, and improved pore interconnectivity. The findings demonstrate that VOH@TNT incorporation is a promising approach for improving the permeability, separation efficiency, and short-term antifouling performance of polysulfone ultrafiltration membranes under the investigated experimental conditions. However, further studies are required to establish their long-term stability, environmental safety, and practical applicability in water treatment.
Diabetic cardiomyopathy (DCM) is a highly specific cardiovascular complication of diabetes that occurs independently of hypertension and coronary atherosclerotic heart disease, and is primarily characterized by diffuse myocardial fibrosis and impaired diastolic and systolic function. In recent years, mitochondria-associated membranes (MAMs), as dynamic membrane contact points connecting the endoplasmic reticulum and mitochondria, have attracted much attention in maintaining calcium homeostasis in myocardial cells, regulating energy metabolism and cell survival fate. This article systematically reviews the structural composition of MAMs and their core roles in apoptosis, mitophagy, inflammatory response and calcium homeostasis regulation. It focuses on the molecular mechanisms by which FUNDC1/IP3R2, Bmal1/Bcl-2/IP3R and PPARα/Mfn2 MAM-related signaling pathways mediate calcium overload in DCM, and reviews the research progress of drugs such as dapagliflozin, ferulic acid, quercetin, and ginsenoside Rb1 in improving DCM by targeting the MAM–calcium homeostasis axis. Finally, this review discusses the key scientific issues and future translational research directions in this field, aiming to provide references for mechanism research and new drug development in DCM.
Membrane fouling limits the sustainable application of polymeric membranes in wastewater treatment and water reuse. Strong adsorption of biomacromolecules and microorganisms can cause irreversible fouling, reducing membrane permeability and operational lifetime. This study developed conductive polyvinylidene fluoride (PVDF) membranes with multiwalled carbon nanotubes (hereafter referred to as CNTs) for electrochemically assisted removal of bovine serum albumin (BSA) foulants. A CNT-incorporated membrane (PVDF–CNT), prepared by phase inversion, and a CNT surface-coated membrane (CNT/PVDF), fabricated by vacuum filtration, were compared with pristine PVDF and a commercial hydrophilic PVDF membrane (c-PVDF). PVDF–CNT membrane exhibited an outstanding electrochemical response at approximately +1.6 V and the most pronounced signal variation after BSA addition. This enhanced response might be contributed by the combined contributions of β-phase-associated dipolar polarisation and interfacial polarisation at the CNT and PVDF interface, potentially promoting local charge accumulation and redistribution. After 3 min of electrochemical rinsing at +1.6 V in 0.2 mol/L Na2SO4 electrolyte, the PVDF–CNT membrane achieved a flux recovery ratio (FRR; the percentage of flux recovered after rinsing) of 67%, exceeding those of the pristine PVDF membrane (55%) and c-PVDF membrane (47%). Although the CNT/PVDF membrane exhibited a higher apparent FRR (91%), this behaviour was attributed to pore blockage by the deposited CNT layer and partial CNT detachment during rinsing, indicating limited structural stability. Across four consecutive fouling–rinsing cycles, the PVDF–CNT membrane showed smaller reductions in flux recovery (42.1%, 4.7%, and 23.8%) than c-PVDF (65.5%, 21.6%, and 25.5%). These findings highlighted the structural stability and electrochemical rinsing performance of the PVDF-CNT membrane and also suggested that tailoring the membrane’s combined polarisation-related behaviours offered a direction for improving electrochemically assisted foulant removal and flux recovery.
Electromembrane extraction (EME) applies an electric field and a supported liquid membrane to transfer charged analytes into a small acceptor phase. For metal and metalloid analysis, the field contribution is coupled to aqueous speciation, interfacial reactions, membrane composition, and acceptor-side trapping. This critical narrative review evaluates direct analytical EME evidence and distinguishes it from removal, recovery, and materials studies. The analysis links species-dependent transport and coordinated method design to the strength of evidence for different measurement claims. Available studies primarily support multication determination and Cr(III)/Cr(VI) differentiation in water, together with targeted As(V), As(III), Hg(II), and total-mercury workflows. Broader applicability to food and biological matrices remains insufficiently established. Reported enrichment or selective response alone does not demonstrate preservation of native species, matrix robustness, or universal multielement performance. Reliable translation therefore requires claim-matched validation in authentic matrices, control of species conversion, analyte-specific performance assessment, mass-balance verification, reproducible operating windows, and transparent reporting. This framework delineates the demonstrated capabilities and current evidence boundaries of analytical EME while identifying priorities for more reproducible and transferable separation and sample-preparation workflows.
