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Synergistic effect of carboxylated-MWCNTs on the performance of acrylic acid UV-grafted polyamide nanofiltration membranes
摘要： Surface modification of a commercial polyamide nanofiltration membrane was achieved by UV induced graft polymerization of acrylic acid and incorporation of carboxylated-MWCNTs (COOH-MWCNTs). The grafting process was done under different monomer concentrations and UV exposure times. The modified membranes were characterized through scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle and zeta-potential analysis, and cross-flow filtration experiments. Changes in the surface hydrophilicity, negative charge and roughness of the modified membranes improved their permeability and fouling resistance significantly. The membrane grafted with 50 g/L acrylic acid under 5 min UV exposure showed the best filtration performance including pure water flux of 38.8 L/m2 h, salt rejections of 97.43% (Na2SO4) and 93.4% (NaCl), and flux recovery ratio (FRR) of 80.2% during bovine serum albumin (BSA) filtration. After optimizing grafting condition, different amounts of COOH-MWCNTs were dispersed in the monomer solution for embedding in the grafting layer. By adding 0.2 wt% COOH-MWCNTs to the grafting layer, a water flux improvement of around 30% was observed. But, excess loading of the COOH-MWCNTs led to compaction of the grafting layer and made it inflexible and subsequently, reduced the hydrophilicity and permeability of the membrane. Fouling tests with BSA aqueous solution showed that antifouling ability of the modified membranes was remarkably improved at all concentrations of the COOH-MWCNTs. Furthermore, salt rejection results displayed that simultaneous surface modification through grafting and COOH-MWCNTs embedding could effectively improve the nanofiltration performance of the membranes in the term of permeability, desalination and fouling resistance.
关键词： Acrylic acid,Nanofiltration,Antifouling,Surface modification,Multiwalled carbon nanotube,Grafting
更新于2025-09-23 15:23:52
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Optically Responsive, Smart Anti-Bacterial Coatings via the Photofluidization of Azobenzenes
摘要： Antibacterial strategies sans antibiotic drugs have recently garnered much interest as a mechanism by which to inhibit biofilm formation and growth on surfaces due to the rise of antibiotic-resistant bacteria. Based on the photofluidization of azobenzenes, we demonstrate for the first time the ability achieve up to a 4 log reduction in bacterial biofilms by opto-mechanically activating the disruption and dispersion of biofilms. This unique strategy with which to enable biofilm removal offers a novel paradigm with which to combat antibiotic resistance.
关键词： photofluidization,azobenzenes,photoresponsive polymers,antibacterial and antifouling strategies,optically responsive materials,antibacterial coatings,smart materials
更新于2025-09-23 15:23:52
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Cu2O photocatalyst modified antifouling polysulfone mixed matrix membrane for ultrafiltration of protein and visible light driven photocatalytic pharmaceutical removal
摘要： This study explains synthesis, characterization of an effective and efficient mixed matrix polysulfone (PSF) ultrafiltration membrane modified with Cu2O photocatalyst, synthesized using electrodeposition method, for pharmaceutical removal. Cu2O photocatalyst, polyethylene glycol, and N-methyl-2-pyrrolidone were used as additive, pore former, and solvent, respectively in the phase inversion method. Characterization techniques, such as XRD, FTIR, FESEM, FESEM-EDX, and AFM were used to characterize the photocatalyst and blended membranes so as to analyze their structural and functional attributes. Further, the membranes were analyzed by using permeation techniques to analyze their flux profiles. Similarly, antifouling nature and hydrophilicity of the membranes were studied by permeating aqueous BSA solutions and measuring the static water contact angle (SWCA), respectively. The pharmaceutical removal studies were carried out using ibuprofen (IBP). The additive improves the membrane attributes, such as flux improved from 34.24 L m-2 h-1 to 179.54 L m-2 h-1 deciphering improved porosity and pore size distribution; SWCA decreased from 71.5° to 45.3° showing increase in the hydrophilicity of the membranes; BSA adsorption decreased from 56 μg cm-2 to 27 μg cm-2; and successful removal of IBP at 86% was achieved under visible light conditions with a removal rate of 32.63 × 10-3 min-1.
关键词： antifouling,Ultrafiltration,mixed matrix membranes,pharmaceutical,Photocatalyst
更新于2025-09-23 15:21:21
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Application of Colloidal Precipitation Method Using Sodium Polymethacrylate as Dispersant for TiO <sub/>2</sub> /PVDF Membrane Preparation and Its Antifouling Properties
摘要： Immobilized titanium dioxide (TiO2) nanoparticles on flat sheet polymeric membranes have been found effective for fouling reduction in recent researches. The main challenge in this field is to obtain ultrafine and stable nanodispersions. In this study, composite polyvinylidene fluoride/TiO2 (PVDF/TiO2) ultrafiltration membranes were prepared via phase inversion and colloidal precipitation method. Stable TiO2 suspensions were prepared using sodium polymethacrylate as dispersant and sonication without altering of the coagulation bath pH. The effect of different concentrations of TiO2 nanoparticles in the coagulation bath was also investigated. The membrane morphology (distribution of nanoparticles on the membrane surface) was observed by scanning electron and atomic force microscopy. Properties of the neat and the composite membranes were also characterized using energy dispersive X-ray spectroscopy and contact angle and membrane porosity measurements. The neat and the composite membranes were further investigated in terms of bovine serum albumin rejection and flux decline in cross flow filtration experiments. The results showed that the PVDF/TiO2 composite membrane using dimethylacetamide/triethyl phosphate as solvent and 0.05 g/L of TiO2 in the coagulation bath exhibits improved antifouling properties.
关键词： TiO2 nanoparticles,antifouling properties,ultrafiltration,colloidal precipitation,PVDF membrane
更新于2025-09-23 15:21:01
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Layer-by-Layer-Assembled Antifouling Films with Surface Microtopography Inspired by Laminaria japonica
摘要： Marine biofouling is an important obstacle to the development of marine resources. Problems such as huge economic losses caused by biofouling and environmental damage caused by toxic antifouling agents have not been resolved. Therefore, it is of great significance to develop a novel, environmentally friendly antifouling (AF) materials. However, in the marine environment, Laminaria japonica still has excellent antifouling ability in a relatively static state compared to those parade creatures. Inspired by this, this study reports a synergistic effect between surface topography and chemical modification to inhibit marine biofouling. Firstly, the surface of the Laminaria japonica was analyzed and its morphology was reproduced using a simple moulding process. Additionally, the polyelectrolyte layer composed of sodium alginate and (guanidine-hexamethylenediamine-PEI) (poly(GHPEI)) was chemically modified on the isotropic microstructure surface of PDMS replicas by layer-by-layer assembly method. The anti-adhesion ability of the biomimetic material was tested with Nitzschia closterium (N. closterium) (9±5 diatoms mm-2 of N. closterium adhered). Meanwhile, the antifouling performance of the modified films were evaluated by Escherichia coli (E. coli), and its antibacterial ability were as high as 96.2±1.3%. The combination of microtopography and (GHPEI/ALG) * n films endow the coating with excellent antifouling ability.
关键词： marine antifouling,surface microtopography,layer-by-layer assembly,alginate,poly(GHPEI),chemical modifications
更新于2025-09-16 10:30:52
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Photocatalytic filtration reactors equipped with bi-plasmonic nanocomposite/poly acrylic acid-modified polyamide membranes for industrial wastewater treatment
摘要： In this study, two new composite membranes with antifouling and anti-biofouling properties were prepared through the modification of commercial polyamide (PA) discs using combination of in-situ polymerization of polyacrylic acid (PAA) and grafting of two synthesized bi-plasmonic Au-Ag and Ag-Au photocatalysts. The synthesis and characterization of the photocatalysts in batch mode were discussed in details as primary studies. Two intense 405-nm and 532-nm lasers for Ag-Au and Au-Ag photocatalysts, respectively and a solar-simulated xenon lamp for both photocatalysts were applied for photodegradation studies and the results were compared. In addition, the effect of other parameters such as type and amount of photocatalysts, and initial concentration of pollutants on the degradation efficiency of ofloxacin (OFX) and methylene blue (MB) as the model pollutant drug and dye were comprehensively investigated and the Langmuir-Hinshelwood adsorption model was used for evaluation of kinetics, degradation rate and half-life time of the reactions. After selection of xenon lamp as the optimum light source, the photodegradation of OFX and MB was evaluated in a dead-end membrane reactor (MR) and flux performance, antifouling property and pollutant removal of the membranes were evaluated using pharmaceutical and textile wastewater samples. In addition, the antibacterial activity of the prepared membranes was evaluated using Gram-negative E. coli bacteria as the model microorganism using thin film assay and Kirby-Bauer disk diffusion methods to examine the anti-biofouling potential of the constructed reactors. It was demonstrated that the prepared MR is able to produce cleaner water with more stable ?ux performance and good membrane fouling/biofouling properties in energy saving manner with respect to the unmodified ones.
关键词： Membrane ?ltration,Wastewater treatment,Permeate ?ux,Bi-plasmonic nanoparticles,Photodegradation,Antifouling/anti-biofouling properties
更新于2025-09-11 14:15:04
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An Integration of Photo-Fenton and Membrane Process for Water Treatment by a PVDF@CuFe2O4 Catalytic Membrane
摘要： Membrane fouling always decreases the separation efficiency and shortens the membrane life, which severely hinders the practical application of the membrane technology. The photo-Fenton process can degrade various foulants with the generation of hydroxyl radicals, and its integration with membrane filtration may become an efficient way to improve the antifouling property and filtration performance of the membrane. In this study, the CuFe2O4 particles were synthesized and doped in the PVDF@CuFe2O4 membranes with increasing concentration from 0 to 1.0%. The degradation measurement of methylene blue (MB) solution shows the optimal conditions for the photo-Fenton process as CuFe2O4 concentration of 1.0%, pH of 3.0, and H2O2 dosage of 400 μL. With the photo-Fenton cleaning process, the PVDF@CuFe2O4 membrane (1.0%) exhibits versatile antifouling property to different types of foulants, including organic dyes (e.g. MB and rhodamine B (RhB)), nature organic matter (e.g. humic acid (HA)), and protein (e.g. bovine serum albumin (BSA)). With the integration of photo-Fenton and membrane process, the PVDF@CuFe2O4 membrane (1.0% of CuFe2O4) dramatically enhanced the separation efficiency, with the results of 99.77% to MB, 81.02% to RhB, 36.35% to HA, and 82.94% to BSA. The flux and rejection have been increased respectively to threefold and double of the corresponding data from the membrane filtration alone. Moreover, even after fifteen cycles of experiments, the average MB rejection is still higher than 70%, which further indicates the good stability and reusability of the PVDF@CuFe2O4 membrane. Therefore, this study provides a promising methodology for the successful fabrication of high-performance membrane through the integration of photo-Fenton and membrane process, and further proposes a new strategy on the design and application of functional materials for new generation of catalytic membranes.
关键词： Membrane,Antifouling,Integration,Filtration,Photo-Fenton Catalysis,CuFe2O4
更新于2025-09-10 09:29:36
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A Bioinspired, Highly Transparent Surface with Dry-Style Antifogging, Antifrosting, Antifouling, and Moisture Self-Cleaning Properties
摘要： Transparent coatings with antireflection, antifogging, antifrosting, antifouling, and moisture self-cleaning properties can dramatically improve the efficiency and convenience of optical elements and thus are highly desirable for practical applications. Here, it is demonstrated that a bionic nanocone surface (BNS) fabricated by a facile, low-cost process consisting of template-assisted prepolymer curing followed by surface modification can possess the multiple functions listed above. The polymer coating firmly adheres to a glass substrate due to bonding agents. After SiO2 nanoparticle deposition and low-surface-energy fluorosilane modification, the coating shows low microdroplet adhesion. As a result, the as-prepared BNS exhibits a high transmittance when exposed to fog and good clarity even when the temperature decreases to ?20 °C in a humid environment. Dipping the BNS into exemplified graphite powder has almost no influence on the transparency, and the BNS can realize self-cleaning of moisture when the surface is covered with a thick layer of man-made contaminants.
关键词： dry-style antifogging,bionic nanocone array,antifouling,moisture self-cleaning,antifrosting
更新于2025-09-10 09:29:36
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Immobilization of functional polymers on poly(4-benzoyl-pxylylene-co-p-xylylene) films via photochemical conjugation for modulation of cell adhesion
摘要： Surface modification with functional materials, such as anti-fouling or thermal responsive polymers, on biomedical devices benefits their clinical performance. Simple and versatile technologies, which could be applied to a wide variety of substrates, are still highly desirable. Chemical vapor deposition (CVD) of 4-benzoyl-[2,2]paracyclophane (Benzoyl-PPX) layers attracts much attention because the photoreactive platform could be deposited onto almost every substrate for the conjugation of functional molecules. In this study, poly(ethylene glycol) (PEG) was conjugated onto Benzoyl-PPX via UV illumination. The deposited PEG films could effectively reduce protein adsorption and cell attachment. The low-fouling properties of the PEG films were positively correlated with the molecular weight and concentration of PEG. We found that a PEG film, thicker than 16 nm and with a water contact angle of 30°, is a prerequisite for effective inhibition of cell attachment. We also demonstrated that the PEG coating was stable under acidic and basic environments. Furthermore, poly(N-isopropyl acrylamide), PNIPAAm, could be also tethered on the Benzoyl-PPX via UV illumination, and possessed thermal-responsive properties. Intact cell sheets could be released from the PNIPAAm film by decreasing culture temperature. The results indicate that Benzoyl-PPX is an excellent photoreactive platform for the conjugation of functional polymers for modulation of cell attachment.
关键词： Poly(4-benzoyl-p-xylylene-co-p-xylylene),Cell sheet,Poly(N-isopropyl acrylamide),Poly(ethylene glycol),Antifouling
更新于2025-09-10 09:29:36