Hydrophilic Surface Properties Research Articles

Polyvinylidene fluoride-based loose nanofiltration membrane with graphene oxide intercalation for efficient small organic molecules desalination

Graphene oxide (GO) loose nanofiltration (LNF) membranes show immense potential for the desalination of small organic molecules. However, it remains a significant challenge to compare the performance of GO LNF membranes prepared via different doping methods and study the mechanisms that influence the separation abilities of the membranes. In this study, LNF membranes prepared via three GO doping methods were examined for flux, retention rate, and the separation performance of small organic molecules and inorganic salts. The membranes coated with dopamine (DA) and GO, and subsequently formed polydopamine (PDA)–GO intercalation, showed the best results. A novel LNF membrane material (PVDF/PDA–GO–TFN; PVDF: polyvinylidene fluoride, TFN: thin-film nanocomposite) was developed to enhance the separation performance of small organic molecules and inorganic salts while improving membrane surface stabilization and anti-fouling performance and reducing the “trade-off” effect. The optimal conditions for PDA–GO intercalation and the best combination for interfacial polymerization (IP) were also determined. The intercalation structure was identified via scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, atomic force microscopy, and Fourier-transform infrared spectroscopy. Furthermore, the separation mechanism of the membrane was determined to be based on the Donnan and steric hindrance effects, according to the correlation analysis of the membrane surface electrical properties (zeta potential), hydrophilicity (contact angle), and pore properties. The PVDF/PDA–GO–TFN LNF membrane displayed a maximum water permeance of 10.45 L/(m2·h·bar), with an 88 % rejection of PEG2000 and a 6.83 % rejection of Na2SO4. Moreover, the membrane exhibited excellent anti-fouling performance and long-term stability, with a mean flux recovery rate of 99.06 % after four cycles of filtration and backwashing tests using small organic molecules and inorganic salt solutions. The inorganic salt retention rate was analyzed using SPSS software, and the results indicated excellent membrane stability. In summary, the preparation of PVDF/PDA–GO–TFN membrane materials provides a novel approach for fabricating LNF membranes that can effectively separate small organic molecules and inorganic salts.

Surface modification of polylactide films and their hydrolytic degradation performances in artificial seawater

AbstractBenzophenone (BP) and N‐vinylpyrrolidone (NVP) were used to modify the surface of polylactide (PLA) films by UV grafting method. The effects of light distance, temperature, reaction time, and modifier concentration on the structure and properties of PLA films were investigated by Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy (XPS), nuclear magnetic resonance spectroscopy, differential scanning calorimetry (DSC), and universal testing machine (UTM). With BP and NVP UV grafting, the hydrophilicity of PLA films is improved, but their thermal and mechanical properties are reduced under different surface modification condition. Base on the principle of good surface hydrophilicity, better mechanical and thermal properties, the hydrolytic degradation performance of modified PLA films in artificial seawater at 70°C was studied by scanning electron microscopy, XPS and DSC. The research results show that the degradation of modified PLA films mainly occurs in the amorphous region, and the degradation process conforms to surface hydrolysis mechanism. The grafting modification of NVP is better than BP to accelerate the degradation process of PLA films in artificial seawater. The degradation of modified PLA undergoes water molecule erosion and autocatalytic degradation reaction. The degradation of BP‐PLA obeys the first‐order kinetics in part, while the degradation of NVP‐PLA is more complex. Therefore, surface hydrophilicity modification is an effective technique for improving the degradability of PLA.

The investigation on targeted micro-surface treatment methods for waste tires recycling in cementitious construction materials

Defects in the interfacial transition zone (ITZ) between recycled tire rubber and cement matrix obstacle to the large-scale application of sustainable rubberized cementitious materials. This paper proposed and evaluated different targeted treatment methods for micro-surface properties enhancement of rubber aggregate by the Polyvinyl Alcohol (PVA), Polyethylene Glycol-200 (PEG), and Hydroxypropyl methylcellulose (HY) polymer solutions through copolymerization and drafting processes. The optimum modification condition was determined through the FT-IR analysis, contact angle, and surface free energy of treated rubber aggregates and the micro-surface morphology and element distribution were analyzed by using ESEM and EDX, respectively. The flexural strength and pore size distribution of steel fiber-reinforced rubberized mortar with relatively high replacing volumes (20%, 40%, and 60%) were evaluated to validate the targeted micro-surface modification efficiency. The surface microstructure and hydrophilic properties of rubber aggregate were significantly improved and the mechanism for enhancing the interface adhesion between rubber and cement matrix was revealed.

Microstructural and Hydrophilic Properties of Polylactide Polymer Samples with Various 3D Printing Patterns.

The aim of the work is to study the effect of the 3D printing process on the microstructural and hydrophilic properties of polylactic acid (PLA) samples with various model printing patterns obtained from the black filament PLA by sequentially applying polymer layers using the FDM (fused deposition modeling) method. X-ray phase analysis revealed the partial crystallization of PLA polymer chains in the printed samples, which occurs under thermal and mechanical action on the original amorphous PLA filament during 3D printing to varying degrees, depending on the geometry of the pattern and the morphology of its surface. At the same time, IR spectroscopy data indicate the preservation of all intrastructural chemical bonds of polylactide. Measured at the original installation, the values of the wetting edge angles on the surface of the printed samples are in the range φ = 50-60°, which is significantly less than the right angle. This indicates the hydrophilic properties of the whole sample's surface. At the same time, the influence of different geometries of model drawings in printed samples was found not only on the morphology of the sample's surface according to SEM data but also on its wettability.

Fabrication of Perfluoropolyether Microfluidic Devices Using Laser Engraving for Uniform Droplet Production.

A perfluoropolyether (PFPE)-based microfluidic device with cross-junction microchannels was fabricated with the purpose of producing uniform droplets. The microchannels were developed using CO2 laser engraving. PFPE was chosen as the main material because of its excellent solvent resistance. Polyethylene glycol diacrylate (PEGDA) was mixed with PFPE to improve the hydrophilic properties of the inner surface of the microchannels. The microchannels of the polydimethylsiloxane microfluidic device had a blackened and rough surface after laser engraving. By contrast, the inner surface of the microchannels of the PFPE-PEGDA microfluidic device exhibited a smooth surface. The lower power and faster speed of the laser engraving resulted in the development of microchannels with smaller dimensions, less than 30 μm in depth. The PFPE and PFPE-PEGDA microfluidic devices were used to produce uniform water and oil droplets, respectively. We believe that such a PFPE-based microfluidic device with CO2-laser-engraved microchannels can be used as a microfluidic platform for applications in various fields, such as biological and chemical analysis, extraction, and synthesis.

Improving antifouling performance of FO membrane by surface immobilization of silver nanoparticles based on a tannic acid: diethylenetriamine precursor layer for municipal wastewater treatment.

In this study, a facile method for multifunctional surface modification on forward osmosis (FO) membrane was constructed by surface immobilization of AgNPs based on tannic acid (TA)/diethylenetriamine (DETA) precursor layer. The cellulose triacetate (CTA) FO membranes modified by TA and DETA with different co-deposition time (6 h, 12 h, 24 h) were investigated. Results indicated that the TA/DETA (24)-Ag CTA membrane with a TA/DETA co-deposition time of 24 h was identified to be optimal, which attained more hydrophilic. And it had the bacterial mortality of Escherichia coli and Staphylococcus aureus reaching 98.23% and 99.83% respectively and possessed excellent physical and chemical binding stability. Meanwhile, the coating layer resulted in the antifouling ability without damaging the membrane intrinsic transport characteristics. As for synthetic municipal wastewater treatment, the water flux of CTA FO membrane decreased approximately 49% of the initial flux after running for 14 days. In contrast, the flux decline rate of TA/DETA (24)-Ag CTA membrane was about 37%. Furthermore, less foulant deposition and higher recovery rate of water flux was observed for TA/DETA (24)-Ag CTA membrane, implying that the modified membrane effectively alleviated membrane fouling and processed a lower flux decline during municipal wastewater treatment. It was attributed to the enhanced surface hydrophilicity and antibacterial property of the coating layer, which improved antifouling property.

Trapped Water on Silicates in the Laboratory and in Astrophysical Environments

The existence of strongly bound water molecules on silicate surfaces, above the desorption temperature of water ice, was first predicted by computational studies and has recently been demonstrated by laboratory experiments. Such trapped water may be present in various astrophysical environments and there is now evidence for its presence in the diffuse interstellar medium (ISM) and in extraterrestrial particles. We present here new results of a laboratory study of the phenomenon of trapping (strong bonding) of water molecules by silicates. We show that the efficiency of the trapping is strongly dependent on the properties and composition of the surface. Our results point out that the presence of trapped water should be due to the hydrophilic properties of the silicate surface and that the nature of the trapping is physical (physisorption rather than chemisorption). We demonstrate that water can be trapped on silicates up to temperatures of about 470 K, which speaks for the presence of wet silicate grains in the terrestrial planet formation zone in planet-forming disks. Studying the thermal and UV stability of trapped water, we conclude that the detection of trapped water in the diffuse ISM speaks for its efficient continuous formation. We discuss our results as relevant to fundamental scientific questions, such as the oxygen depletion problem, the origin of water on Earth, and the formation of rocky planets.

Exploring the application of poly(1,2-ethanediol citrate)/polylactide nonwovens in cell culturing.

Biomaterials containing citric acid as a building unit show potential for use as blood vessel and skin tissue substitutes. The success in commercializing implants containing a polymer matrix of poly(1,8-octanediol citrate) provides a rationale for exploring polycitrates based on other diols. Changing the aliphatic chain length of the diol allows functional design strategies to control the implant's mechanical properties, degradation profile and surface energy. In the present work, poly(1,2-ethanediol citrate) was synthesized and used as an additive to polylactide in the electrospinning process. It was established that the content of polycitrate greatly influences the nonwovens' properties: an equal mass ratio of polymers resulted in the best morphology. The obtained nonwovens were characterized by surface hydrophilicity, tensile strength, and thermal properties. L929 cell cultures were carried out on their surface. The materials were found to be non-cytotoxic and the degree of porosity was suitable for cell colonization. On the basis of the most important parameters for assessing the condition of cultured cells (cell density and viability, cell metabolic activity and lactate dehydrogenase activity), the potential of PLLA + PECit nonwovens for application in tissue engineering was established.

In-situ interfacial polymerization of polyamide TFN membranes by adding a diamino-silane coupling agent: Toward enhanced desalination performance

The primary challenge faced by thin film nanocomposite (TFN) membrane in nanofiltration (NF) process is to effectively resolve the trade-off effect between permeability and selectivity. Herein, a polyamide (PA) TFN membrane with enhanced NF performance was prepared through in-situ interfacial polymerization (in-situ IP) method, using piperazine (PIP) and 3-diamino-methyl-cyclohexyl triethoxysilane (DTES) as co-amine monomers to undergo a reaction with 1,3,5-benzenetricarbonyl trichloride (TMC). This study investigated the effects of DTES on the surface chemical composition, morphologies, hydrophilicity, separation efficiency, and anti-fouling properties of the novel DTES/PIP/TMC TFN membranes. It was found that SiO2 nanoparticles were generated in-situ from the reacted DTES through hydrolysis and self-condensation, resulting in their uniform distribution within the formed PA selective layer with high compatibility and without aggregation. The optimal PA TFN membrane was achieved by adjusting the ration of Si-OH group in formed SiO2 nanoparticles through varying the concentration of DTES concentration. Meanwhile, the induction of SiO2 into the PA layer resulted in an enlargement in membrane pore size and improved surface hydrophilicity. When the concentration of added DTES was 0.333 wt%, the optimal PA TFN membrane (TFN-4) exhibited the highest quantity of formed Si-OH groups, resulting in the excellent performance, including a markedly enhanced water permeability flux of 76.8 L·m−2·h−1 (2-fold larger than that of the pure TFC membrane), a great Na2SO4 rejection of 97.5 %, and a superior Cl−/SO42− permeation selectivity of 46.0. Moreover, the TFN-4 membrane exhibited exceptional stability and superior antifouling properties attributed to its unparalleled hydrophilicity. This work provided a strategy for preparing uniform and high-performance TFN membranes.

Disc ceramic membrane modified with nano-TiO2 for separating oil-water emulsion under dynamic membrane filtration

A disc ceramic membrane was modified nano-TiO2 via an impregnation and in-situ hydrolysis method, resulting in the generation of nano-TiO2 particles on the surface and inside the pores of disc ceramic membrane. The uniform distribution of nano-TiO2 enhanced the superior hydrophilic property of the membrane surface, and improved pure water flux and increased anti-fouling capacity. The modified disc ceramic membrane was employed to effectively separate stable oil-water emulsions under dynamic membrane filtration mode. Here, the preparation process of nano-TiO2 and operational parameters of equipment on the separation efficiency of the modified disc ceramic membrane were investigated. The findings indicate that an increase in the permeability and separation rate of the modified disc ceramic membrane. Moreover, the modified disc ceramic membrane maintained a steady flux for a continuous separation time of 120-min at a TMP of 0.04 MPa. The rejection rate of oil-water emulsion also reached 99.9%. The excellent performance of the modified disc ceramic membrane was ascribed to the nano-TiO2 modification and the dynamic membrane filtration applied together to alleviate membrane fouling, leading to improve the oil-water separation efficiency and permeate flux. This study presents a new technique for the separation of oil-water emulsions with high concentration, achieving outstanding separation stability and cost-effectiveness.

Construction of dual receptors imprinted polymers by precise control of sequential assembly efficiency in confined sites to enhance specific separation of adenosine 5′-monophosphate

Sequential assembly strategies are employed to incorporate various monomers, thereby enhancing the specific binding capability of imprinting sites towards the target molecule and ultimately improving the selectivity of molecular imprinted polymers (MIPs). However, the effectiveness of sequential assembly in improving discriminative separation requires further investigation. For the specific functional groups present in AMP molecules, the utilization of confining metal ion sites guided by metal–organic frameworks (MOFs) material can effectively mitigate disordered competition, enhance the efficiency of imprinted assembly, and facilitate the controlled growth of imprinted sites. In this study, we have successfully achieved precise control over the efficiency of sequential assembly in hydrophilic Zr-MOFs nanosheets in order to fabricate dual receptor surface molecularly imprinted sorbents (D-MIPs) for selectively separating AMP. The hydrophilic Zr-MOFs nanosheets (D-PABA) possess a significantly high surface area of approximately 282.52 m2 g−1. The water contact angle of Zr-BTB-FA nanosheets was measured to be 32°, while that of D-MIPs was 25°. The hydrophilic surface properties of materials promote the dispersion of the adsorbent in aqueous solutions and enhance the rapid mass transfer of water-soluble target molecules. Additionally, the half-equilibrium time (t1/2) was found to be 0.578 h. The D-MIPs demonstrate a significant adsorption capacity (286.7 μmol g−1 at 298 K) for AMP compared to other nucleoside analogues, such as dC, dG, dA, ADP and ATP. Additionally, an imprinting factor (IF) of 2.764 was observed for D-MIPs compared to their non-imprinted counterpart. In addition, the selective extraction of 97 % AMP from the spiked diluted biofermentation broth sample can be achieved using D-MIPs. This finding highlights the potential of D-MIPs as an efficient solution for the selective capture of AMP from biological samples.

Tough polycyclooctene nanoporous membranes from etchable block copolymers.

Porous materials with pore dimensions of the nanometer length scale are useful as nanoporous membranes. ABA triblock copolymers are convenient precursors to such nanoporous materials if the end blocks are easily degradable (e.g., polylactide or PLA), leaving nanoporous polymeric membranes (NPMs) if in thin film form. The membrane properties are dependent on midblock monomer structure, triblock copolymer composition, overall molar mass, and polymer processing conditions. Polycyclooctene (PCOE) NPMs were prepared using this method, with tunable pore sizes on the order of tens of nanometers. Solvent casting was shown to eliminate film defects and allowed achievement of superior mechanical properties over melt processing techniques, and PCOE NPMs were found to be very tough, a major advance over previously reported NPMs. Oxygen plasma etching was used to remove the surface skin layer to obtain membranes with higher surface porosity, membrane hydrophilicity, and flux of both air and water. This is a straightforward method to reliably produce highly tough NPMs with high levels of porosity and hydrophilic surface properties.

Impact of carrier particle surface properties on drug nanoparticle attachment

HypothesisThe stabilization and isolation to dryness of drug nanoparticles has always been a challenge for nano-medicine production. In the past, the use of montmorillonite (MMT) clay carrier particles to adsorb drug nanoparticles and maintain their high surface area to volume ratio after isolation to dryness has proven to be effective. We hypothesise that the distribution of hydrophilic and hydrophobic patches on the clay’s surface as well as its porosity/roughness, hinder the agglomeration of the drug nanoparticles to the extent that they retain their high surface area to volume ratio and display fast dissolution profiles. ExperimentsIn this work, the distribution of hydrophobicity and hydrophilicity, and the porosity/roughness, of the surface of selected silica carrier particles were varied and the impact of these variations on drug nanoparticle attachment to the carrier particle and subsequent dissolution profiles was studied. FindingsThe fastest dissolution profiles at the highest drug nanoparticle loadings were obtained with a periodic mesoporous organosilane carrier particle which had a homogeneous distribution of hydrophobic and hydrophilic surface properties. Carrier particles with rough/porous surfaces and a combination of hydrophobic and hydrophilic patches resulted in nanocomposite powders with faster dissolution behaviour than carrier particles with predominantly either a hydrophobic or hydrophilic surface, or with non-porous/smoother surfaces.

Gelatin films reinforced by tannin-nanocellulose microgel with improved mechanical and barrier properties for sustainable active food packaging

In this study, reactive tannin-nanocellulose (TANC) microgels, prepared using dialdehyde nanocellulose and tannin through the condensation reaction, were incorporated into gelatin matrix to fabricate GE-TANC films for the potential application as active food packaging materials. AFM, FT-IR, XRD, and TG analysis were employed for characterization of TANCs and the composite films. AFM images and FT-IR analysis confirmed the successful crosslinking of nanocellulose with tannin. Their surface hydrophilicity, UV-blocking capability, antioxidant activity and mechanical properties were measured to investigate the impact of TANC microgels on the film properties. The tannin-containing films displayed excellent antioxidant and UV-blocking properties, maximally scavenging 79% of DPPH free radicals and absorbing 98% of ultraviolet light. The surface hydrophilicity, water vapor transmission rate (WVTR) and water solubility of the composite films decreased compared to those of the neat gelatin film, resulting from the formation of more chemical and physical crosslinkings within the film. The tensile strength tripled from 40 MPa to 108 MPa, and the elongation at break increased from 3.87% to 6.28% with only 5% of TANC2. The GE-TANC films in this work demonstrated high mechanical properties, oxidation and UV resistance, and thus have a prospective application as the sustainable active food packaging materials.

Zeolite A with waste material: Morphological effect of laser treatments in air

The goal of this work is to investigate the action of femtosecond (fs) laser treatment performed under atmospheric conditions on morphology of zeolite A (LTA topology) synthesized with the addition of a waste material rich in iron such as red mud (RMFe-LTA) or introducing nanomagnetite (NMFe-LTA) during the hydrothermal synthesis. Both zeolite samples were analyzed by Scanning Electron Microscopy (SEM) technique. LTA zeolite formed using pure sources was assumed as reference. The results confirm that the presence of iron has a significant influence on laser-matter interactions affecting the morphology of the final treated synthetic material. Comparing to our previous data performed in vacuum conditions, these new results indicate that zeolite structure is generally preserved by fs laser treatment under atmospheric conditions although the presence of the Fe oxides distributed on the zeolite surfaces due to the use of red mud or in the form of nanomagnetite at specific locations, determines clear changes in treated zeolite morphology. However, the best performing results in terms of homogeneity of treatment and potential improvement of hydrophilic surface properties take places on zeolite formed with the addition of waste material (RMFe-LTA).

Long chain imidazole derivative as a novel corrosion inhibitor for Q235 steel in 15 % HCl medium under hydrodynamic condition: Experimental and theoretical examinations

The research in the paper focused in the development of ecologically favorable inhibitor via microwave method. The inhibitor namely N-(2-(2-pentadecyl-2,5-dihydro-1H-imidazole-1-yl)ethyl)palmitamide palmitate, a derivative of imidazole (IPP) was synthesized in one single step and screened its inhibitive property in strongly acidic medium (15 % HCl) for protection of Q235 steel at 1500 rpm rotational speed. The study used for exploring the inhibition effect of IPP includes weight loss, Potentiodynamic polarization, and electrochemical impedance spectroscopy. The estimated results confirmed the inhibition data of 97.41 % and 98.70 % at 308K with 200 mg/L/only IPP and IPP + KI/150 mg/L+0.5 mM respectively, and the influence of temperature has little effect over the inhibition property. The weight loss results show that the IPP belongs to a mixed-type corrosion inhibitor. The SEM, EDX, AFM, SKP, and contact angle analysis results showed that the IPP formed a film on the surface of Q235 steel through adsorption, which changed the hydrophilic and hydrophobic properties of the Q235 steel surface. Further XPS study confirmed the adsorption of IPP molecules over the Q235 steel surface.

Development of high performance thin-film (nano) composite membranes for forward osmosis desalination applications- a review

The impact of different additives on the achievement of FO membranes was designed, reviewed, and highlighted the performances of nanocomposite over traditional membranes with evidenced literature support. This review found that the surface hydrophilicity, roughness, porosity, FO water permeation, solute retention, reverse solute permeates (RSP), and specific reverse salt permeate (SRSP) has been greatly affected by the alteration of a skin layered structure of FO membrane. The review revealed that the TFN-FO membranes showed very high surface hydrophilic properties than the TFC-FO membranes. For example, the graphene quantum dots (GODs) based UiO66-NH2 crystals (GQDs@UiO66-NH2, 250 ppm, TFN-0.25%) membrane had a goniometer (contact angle) reading of 12° which indicated a super-hydrophilic property of nanocomposite membrane over traditional TFC membranes. In addition, the TFN-FO membrane showed the highest FO permeation rate of 84.7 L m-2h−1 for the ZnO-based TFN membrane (TFN-ZnO-0.5) and a very lower RSP value of 0.005 g/L for nylon-6 (N6) substrate containing silica dioxide (SiO2) nano particle (NP) support membrane with polyamide (PA) layer nano membrane (E. Spun N6/SiO2-PA/SiO2 TFN) suggested an excellent FO performance than TFC membranes. This review also suggested that the TFN membranes provided enhanced salt rejection and FO water flux with superior fouling resistant properties which are important parameters to enhance FO performances. Hence, TFN-FO membranes can utilize as a suitable candidate for desalination applications compared to TFC membranes.

Extraction and Characterization of Natural CASCABELA Thevetia Bast Fibers: A Potential Candidate as Reinforcement in Epoxy Composites

ABSTRACT The aim of this study is to explore the potential of CASCABELA thevetia (CT) bast fibers as reinforcement in polymer composites. For this purpose, the extracted fibers were chemically treated with various chemicals such as sodium hydroxide, potassium permanganate, sodium chlorite, and benzoyl chloride. After surface modifications, its physical and mechanical properties, chemical composition, and structure were studied. The X-ray diffraction (XRD) results revealed an increase in crystallinity index of the fibers as compared to untreated fibers with benzoyl chloride treated fibers showing the optimum result which agrees with the results obtained in the mechanical tests. Composites were fabricated by taking various wt.% of benzoyl chloride treated CT fibers in an epoxy matrix (i.e. 5, 10, 15, 20, 25, and 30 wt%) and their mechanical and wettability tests were carried out. It was observed that composites with 20 wt% of fiber loading show the highest mechanical properties (52.79 MPa tensile strength, 2.45 GPa Young’s modulus, 71.72 MPa flexural strength). All the fabricated composites showed contact angle less than 90°, which is associated with composite hydrophilic surface properties. These composites can be utilized in lightweight structural material and in automobile industries owing to its better properties.

Optimization of the Preparation of Hydrophilic Poly(DHPMA-co-MBA) Monolithic Capillary Columns: A New Support for Affinity Chromatography

In miniaturized affinity chromatography, the development of hydrophilic organic monoliths with reduced non-specific interactions and high-protein grafting capacity remains a hot topic. In this work, we propose the one-step synthesis of a diol organic monolith to replace the gold-standard epoxy-based organic monoliths (which require post-modification, namely hydrolysis, prior to use). The synthesis of this new monolith builds upon the use of N-N’-Methylenebis(acrylamide) (MBA), as a hydrophilic crosslinker, and 2,3-dihydroxypropyl methacrylate (DHPMA), a diol monomer that eliminates the time-consuming epoxy ring opening step and its associated side reactions. The optimization of one-step synthesis parameters led to a monolith with a satisfactory permeability ((4.8 ± 0.5) × 10−14 m2), high efficiency (117,600 plates/m at optimum flow velocity (uopt = 0.09 cm s−1)) and reduced non-specific interactions. It is exemplified by its separation ability in the HILIC mode (separation of nucleosides), and by the retention data set of 41 test solutes, which were used to evaluate the non-specific interactions. This new poly(DHPMA-co-MBA) monolith has not only hydrophilic surface properties, but also improved protein grafting capacity compared to the glycidyl-based monolith (13 ± 0.7 pmol cm−1). The potential of this monolith is illustrated in affinity chromatography, where the concanavalin ligands are ranked according to their Kd values.

Role of molybdenum disulfide (MoS2) nanosheets doping position on the thin-film nanocomposite (TFN) membrane during brackish water treatment

Brackish water desalination based on nanofiltration (NF) has been regarded asa feasible solution to address the scarcity of freshwater. However, the trade-off effect and membrane fouling are challenges for the thin-film composite NF membranes, restricting their further application in desalination. Herein, modified thin-film nanocomposite (TFN) membranes were constructed with molybdenum disulfide (MoS2) nanosheets incorporated either into the polyamide layer (P-TFN) or as an interlayer (I-TFN). The surface morphology, chemical element, electronegativity, pore size, hydrophilicity, separation performance and antifouling property of the membranes were systematically evaluated and compared. The P-TFN membrane exhibited superior salt rejection of Na2SO4 up to 98.4% and preeminent flux recovery ratios (FRRs) of 95.4% and 92.2% for humic acid (HA) and bovine serum albumin (BSA) filtration, respectively, which possessed high electronegativity and small effective pore size. While, without compromising its salt retention and foulant resistance, the I-TFN membrane exhibited 51% better permeability than the control TFC membrane, due to its unique crumpled structure of the PA layer and the “dragging effect” of the interlayer on water molecules. Furthermore, we elaborated on the mechanism underlying the differences in surface properties, and verified the effectiveness of the modified membranes in authentic brackish water desalination. Significantly, the comparison provides novel insight for the customization and regulation of the PA layer.