Conventional Phase Inversion Research Articles

Constructing a monolithic amino-functionalized poly(ether sulfone) loose nanofiltration membrane for efficient dye/salt fractionation

Loose nanofiltration (LNF) is a promising new technique for dye/salt separation, but LNF membranes still suffer from low permeance and inadequate selectivity. In this study, novel monolithic amino-functionalized poly(ether sulfone) (PES) LNF membranes were developed in three steps, PES powder-grafted with polyacrylonitrile (PAN) under gamma-ray irradiation and membrane preparation via non-solvent-induced phase separation, followed by an amination process. The resultant aminated PES LNF membrane with tetraethylenepentamine (APES-TP) had a thinner skin layer and unusual irregular vesicle-like pore structure in its sublayer compared with the original PES substrate. The amination process increased the hydrophilicity of the APES-TP membranes and partially neutralized the surface zeta-potential. The permeation test confirmed that the APES-TP membrane exhibited 100 % NaCl permeation together with high levels of pure water permeance (77.9 L m–2h−1 bar−1) and dye rejection (98.5 % for Congo red, 97.1 % for Nair blue, and 97.6 % for methyl blue). Even when paired with simulated industrial wastewater containing multiple direct dyes and inorganic salts (1 g L–1 dye and 5 g L–1 salts), the APES-TP membrane still rejected 99.4 % of the mixed dyes, proving its practical applicability to treating industrial dye wastewater. Furthermore, the APES-TP membrane exhibited excellent endurance to harsh conditions (such as acidic, alkaline, and oxidative) and exceptional recyclability (97.9 % permeance recovery rate). This study bridges the gap between conventional nonsolvent phase inversion and the emerging LNF membrane fabrication technology, allowing the LNF technique to be used to fractionate organic matters with salts in batch mode.

Development and investigation of high‐flux antifouling NF PES membranes decorated by aniline oligomers and application for wastewater treatment

AbstractIn this research, first branched aniline oligomers functionalized polyethersulfone (BAO‐PES) were prepared by diazonium‐induced grafting, and then the embedded membranes were fabricated at five different compositions using the conventional phase inversion process. The influence of BAO‐PES as a modifier on membrane preparation was investigated in terms of membrane topography, membrane morphology, hydrophilicity, permeability, antifouling performance, and chemical stability. The function of blended membranes was evaluated by computational analysis, Fourier transform infrared (FTIR) analysis, scanning electron microscopy (SEM), atomic force microscopy (AFM), and water contact angle (WCA) measurement. Our computational analysis has substantiated that BAO‐PES (25 wt. %)/PES, characterized by a lower Flory–Huggins parameter (0.65), emerges as a promising contender for the blending of BAO‐PES with PES. The maximum water flux of 67.6 kg/m2 h was observed for the M1 membrane with the optimum dosage of BAO‐PES (25 wt. %) at a low pressure of 3 bar. To assess the nanofiltration performance of the mixed matrix BAO‐PES/PES membranes, the removal efficiency was studied for Direct Red 16 and tannic acid dye. From the results, it was found that the loose BAO‐PES/PES membranes had great dye rejection ability (more than 97%) compared to the bare membrane (88%–89%). The fouling resistance property of the loosely prepared membranes was tested by protein rejection, and the results revealed that the best antifouling property was observed at optimum dosage of the BAO‐PES modifier (25%, FRR = 98.37%). The embedded BAO‐PES/PES membranes, after exposure to harsh environments, exhibited such long‐term chemical stability that it is an important specification for real management in industry.

Poly(m-phenylene isophthalamide) (PMIA) membranes as a support for WO3/g-C3N4 for the degradation of diclofenac in water

One of the obstacles hampering large-scale semiconductor photocatalysis is the requirement for the recovery and reuse of photocatalytic nanoparticles. Polymeric membranes are viable and practical support materials for photocatalytic nanoparticles to result in multifunctional photocatalytic membranes. PMIA membranes were applied as support for photocatalytic WO3/g-C3N4 nanoparticles and evaluated for the photodegradation of diclofenac (DFC). The PMIA photocatalytic membranes were prepared using the conventional phase inversion method in which the photocatalyst was embedded into the membranes. SEM, XRD, XPS, and FTIR analysis confirmed the incorporation of WO3/g-C3N4 into PMIA membranes. The contact angle of the PMIA/WGC membranes was reduced from 56.3° for the pure PMIA membrane to 37.5°, and porosity was increased from 74.7 up to 85.3%. The photocatalytic membranes were irradiated in the visible light region. M5, which contains 2% of WO3/g-C3N4 in the PMIA membrane, presented the highest degradation of DFC (85%) after 150 min compared to the other membranes. The degradation performance of DFC using PMIA/WGC was mainly driven by hydroxyl radicals and singlet oxygen. The photodegradation performance within 10 cycles had a difference of less than 5%, indicating the stability of membranes. The PMIA membranes are viable photocatalyst support materials with potential dual functionality in water treatment.

Preparation and characterization of fluoroalkyl activated carbons/PVDF composite membranes for water and resources recovery by membrane distillation

Membrane distillation is a promising technology for recovering resources and water from brackish water and wastewater. However, characteristics of current membranes limit the employment of membrane distillation in these areas. In this paper, activated carbon modified membrane has been studied. Agglomeration of activated carbon (AC) particles in the membrane matrices has negative influence on the performance of AC/PVDF composite membrane. To solve this problem in this study, the AC was functionalized with fluoroalkyl groups via the reaction between carboxylic activated carbons and octafluoropentanol (OFP). The AC-OFP/PVDF composite membrane was prepared by blending PVDF and the functionalized AC-OFP particles via a conventional phase-inversion method. In comparison with the AC particles, the dispersion of AC-OFP particles in membrane matrix was improved greatly. The maximum DCMD flux increased from 29.8 kg/m2h (AC/PVDF membrane) to 40.4 kg/m2h (the AC-OFP/ PVDF membrane) by just adding 0.15 wt% AC-OFP particles.

High zeolite loading mixed matrix membrane for effective removal of ammonia from surface water

While zeolite-based mixed matrix membrane (MMM) has been proven effective to remove the ammonia in the wastewater by adsorption, its adsorption capacity is limited by the low zeolite loading due to the need of a high concentration of polymer matrix to maintain the mechanical strength. To break the bottleneck, in this study we proposed a facile solvent evaporation method instead of conventional phase inversion method to prepare the zeolite-based MMMs. With this new preparation method, the loading of zeolite could reach up to ∼90wt.% while the MMM still maintained a good mechanical property. The zeolite-based MMM could treat 910 L·m−2 of feedwater before reaching the ammonia breakthrough point (0.5 mg-N·L−1) when treating the synthetic wastewater water. In addition, it showed a high rejection of turbidity and natural organic material (NOM) (∼90%), mainly due to its high negative surface charge density. When applied to treat real surface water, the membrane demonstrated a high normalized treatable capacity (∼900 L·m−2) with a high rejection to NOM (87.4%). Moreover, the MMM even showed a higher fouling resistance than the PVDF microfiltration membrane. Regeneration and cleaning with NaClO could efficiently recover the adsorption capacity and water flux of the MMM. After four cycles of operation, the MMM still maintained a high treatable capacity (850 L·m−2) with a high NOM rejection. This study provides a new strategy for the preparation of high-loading zeolite-based MMM for the effective removal of ammonia from surface water.

A Polysulfone/Cobalt Metal–Organic Framework Nanocomposite Membrane with Enhanced Water Permeability and Fouling Resistance

Ultrafiltration membranes are widely used in water and wastewater applications. The two most important membrane characteristics that determine the cost-effectiveness of an ultrafiltration membrane process are membrane permeability and fouling resistance. Metal–organic frameworks (MOFs) have been intensively investigated as highly selective sorbents and superior (photo) catalysts. Their potential as membrane modifiers has also received attention recently. In this study, a non-functionalized, water-stable, nanocrystalline mixed ligand octahedral MOF containing carboxylate and amine groups with a cobalt metal center (MOF-Co) was incorporated into polysulfone (PSF) ultrafiltration (UF) membranes at a very low nominal concentration (2 and 4 wt %) using the conventional phase inversion method. The resultant PSF/MOF-Co_4% membrane exhibited water permeability up to 360% higher than of the control PSF membrane without sacrificing the selectivity of the membrane, which had not been previously achieved by an unmodified MOF. In addition, the PSF/MOF-Co_4% membrane showed strong resistance to fouling by natural organic matter (NOM), with 87 and 83% reduction in reversible and irreversible NOM fouling, respectively, compared to the control PSF membrane. This improvement was attributed to the increases in membrane porosity and surface hydrophilicity resulting from the high hydrophilicity of the MOF-Co. The capability of increasing membrane water permeability and fouling resistance without compromising membrane selectivity makes the MOF-Co and potentially other hydrophilic MOFs excellent candidates as membrane additives.

A Metal-organic composite ultrafiltration membrane synthesized via Quadratic phase inversion

• Stainless steel wire mesh as substrate was used to fabricate composite UF membrane. • A novel strategy denoted as“Quadratic Phase Inversion (QPI)” was proposed. • Composite UF membrane showed high pure water flux and desirable BSA rejection. • Composite UF membrane prepared with “QPI” showed superior running stability. According to the Pore-flow model describing the mass transfer process of Ultrafiltration (UF) membranes, the thickness of the separation layer directly determines the separation performance of an UF membrane: pure water flux (PWF) and foulant rejection. However, the flexibility and limited supporting capacity of the conventional supporting layer (non-woven fabric) limits the further reduction of the separation layer thickness. In this study, stainless steel wire mesh (SSWM) was employed as the supporting layer to fabricate a metal/polymer composite UF membrane via a novel strategy denoted as “Quadratic Phase Inversion (QPI)”, in which the SSWM was firstly modified with a casting solution with low PVDF concentration, and then another PVDF selective layer was constructed on the modified substrate with the conventional phase inversion method. Orthogonal experiment was conducted to optimize the fabrication parameters. A series of characterization was adopted to analyze the performance and structural evolution. The results demonstrate that a composite UF membrane with ultrathin PVDF selective layer could be fabricated on the PVDF modified SSWM. The optimized sample was obtained with the SSWM modification reagent of 3 wt% PVDF, the casting solution of 20 wt% PVDF, the casting thickness of 75 μm, and NMP as solvent, which had a MWCO of 149 kDa and mean pore diameter of 7.2 nm. Meanwhile, it presented a high PWF around 448.8 L m −2 h −1 bar −1 , desirable BSA rejection about 96.3% and good operation stability. The outcome of this research is expected to provide a valuable route for promoting the separation performance of UF membranes.

Numerical and experimental study of the second ejection from a grooved tin surface under laser-driven shock loading

In this paper, we perform a numerical and experimental study of the second ejection from a grooved tin surface under laser-driven shock loading. First, the second ejection under laser-driven shock loading is simulated using the smoothed particle hydrodynamics method, and the physical mechanism of this ejection event is investigated in detail. The numerical results reveal that the second ejection is dominated by successive Richtmyer-Meshkov instabilities created by the second incident shocks meeting the two density interfaces formed after the first ejection. The spatial structure of the second ejection is mainly characterized by the formation of a noticeable second jet with a head velocity much lower than that of the first microjet, and the root of the high-density jet slug is significantly enhanced, which is distinctly different from the conventional phase inversion under supported shocks. Then, laser-driven shock loading experiments for the second ejection are conducted and X-ray radiographic images of the second ejection are obtained. The main features of the simulation results for the second ejection are in good agreement with the experimental results, and the simulation results are verified by the laser-driven shock loading experiments. Additionally, the effects of the time interval on the second ejection are discussed. The formation capability of the second jet gradually increases with the time interval, and the cumulative area density gradually increases with the time interval and converges to a constant value.

Evaluation of dynamic behavior of hydrophilic and photocatalytic self-cleaning PES nanofiltration membrane post treating biologically treated palm oil mill effluent (POME)

The photocatalytic nanocomposite NF membranes blended with K-B-N triple TiO2 were fabricated employing conventional wet phase inversion method. The dynamic performance of the photocatalytic membranes was evaluated by filtering biologically treated palm oil mill effluent (POME) at dark and light conditions. The performance of the chosen membrane was checked using central composite design (CCD) of response surface methodology (RSM) under continuous visible light irradiation and various variables in a dynamic mode. According to experimental results, the 0.5 wt. % membrane indicated less flux reduction without scarifying COD rejection capacity as a function of time while filtering POME under continuous visible light irradiation. The largest values of FRR and COD removal efficiency were reported to be 97 % and 100 %, respectively, at the highest feed flow rate of 150 L/min, the lowest operating pressure of 5 bar, and the lowest COD concentration of 1000 mg/L. While, the highest value of flux (33.9 kg/m2h) was obtained at operating pressure of 9 bar, feed flow rate of 50 L/h and COD concentration of 1000 mg/L. By judging from results, the photocatalytic NF membrane by benefiting from both photocatalytic and self-cleaning properties has enough potential to be applied in practical applications.

Tubular PAN/CNC thin film nanocomposite (TFN) pressure retarded osmosis (PRO) membrane: fabrication and preliminary evaluation in desalination process

The pressure retarded osmosis (PRO) process requires high performance, high flux, high rejection, and resistant membranes under harsh conditions. Since conventional phase-inversion membranes are insufficient to permit the required water flux, alternative membrane fabrication methods need to be developed. Many studies have recently been carried out to fabricate strong enough nanofiber PRO membranes resistant to higher pressure while providing high flux and high rejection rates. This work aims to fabricate tubular nanofiber PRO membranes by the electrospinning technique. In the study, cellulose nanocrystals (CNCs) were added to polyacrylonitrile (PAN) polymer solution to fabricate nanocomposite nanofiber PRO membranes. According to the scanning electron microscopy (SEM), FT-IR, dynamic mechanical analysis, porometer, and contact angle analysis results, it is concluded that PAN and CNCs provided a complete mixture, and the addition of CNCs increased the mechanical strength in the PAN membranes, which is the crucial phenomena in PRO applications. In this study, the newly fabricated membrane achieves a higher PRO water flux of 405.38 LMH using 1 M NaCl and a DI as feed water. The corresponding salt flux is found as 2.10 gMH, which is higher than our previous study. The selectivity of the reversed flux represented by the ratio of the water flux to the reversed salt flux (Jw/Js) was able to be kept as high as 193.03 L/g for PRO operation. As far as we know, the performance of the work-developed membrane in this study has shown better performance than all PRO membranes reported in the literature previously.Graphic abstract

Improved carbon dioxide stripping by membrane contactors using hydrophobic electrospun poly(vinylidene fluoride-co-hexafluoro propylene) (PVDF-HFP) membranes

Electrospun poly(vinylidene fluoride-co-hexafluoro propylene) (PVDF-HFP) nanofibre membranes are developed for CO2 stripping within a membrane contactor. The porous and hydrophobic nature of the membranes is ideal for membrane CO2 stripping applications, providing fast gas transport, high CO2 recovery and mechanical strength. Three different morphologies of the PVDF-HFP membranes are assessed: nanofibre membranes (NFM), bead-on-string membranes (NFM-BS) and microparticles on nanofibre membranes (NFM-MP). We illustrate that both the bead-on-string and microparticles on nanofibre membranes are more hydrophobic compared to nanofibre constructs and a traditional asymmetric control membrane. The NFM-BS and NFM-MP membranes both exhibit significantly improved CO2 stripping flux over short times, while the NFM-BS membranes provides significantly improved stripping flux over longer times (240 h) compared to all other treatments, including conventional asymmetric phase inversion membranes. The structures may also show promise for membrane distillation applications.

Selection of substrate manufacturing techniques of polyamine‐based thin‐film composite membranes for forward osmosis process

AbstractThis paper is a comparative study on the preparation techniques used to make the support layer of polyamide‐thin‐film composite forward osmosis (TFC‐FO) membranes. The role played by the support layer preparation technique in membrane performance is thoroughly investigated in this study. Electrospinning is shown to produce membranes of lower structural parameter compared to those obtained by conventional phase inversion techniques. The electrospun polyamide selective layer can also be tailored with the required properties. This makes electrospinning a promising process to design efficient FO membrane substrates. It is shown in this work that the FO water flux is more dependent on the internal structure of the support layer than the preparation materials. The main challenge remaining for substrates to operate in FO is to achieve simultaneously a low structural parameter, a high surface porosity, and the required mechanical properties. As most of today's approaches are not suitable, further materials development is essential in future investigations on TFC‐FO membranes.

Highly solvent-durable thin-film molecular sieve membranes with insoluble polyimide nanofibrous substrate

Permselective thin-film composite membranes are gaining a significant role in solvent-based molecular sieving applications. Nevertheless, the lack of desirable substrate materials, which combines high flux, solvent resistance as well as a straightforward fabrication process, is still the biggest bottleneck for large-scale commercial implementation. For the first time, we propose to fabricate an insoluble polyimide nanofibrous substrate by a sequential strategy involving electrospinning polyamic acid followed by a thermal imidization. The water-absent electrospinning process leads to 1-fold enhanced mechanical strength and higher solvent-resistance of substrate compared to the conventional phase inversion process. The resultant thin-film nanofibrous composite (TFNC) membranes exhibit exceptional potential for nanofiltration by showing high permeability, rejection, and stability in water as well as polar aprotic solvents such as dimethylformamide, dimethyl sulfoxide, and tetrahydrofuran compared to state-of-art membranes. The strategy of using electrospun insoluble polyimide as the substrate establishes a scalable approach to design high-performance TFNC membranes for a wide range of challenging molecular sieving applications.

Upper surface imprinted membrane prepared by magnetic guidance phase inversion method for highly efficient and selective separation of Artemisinin

Molecularly imprinted membrane fabricated by conventional phase inversion method often suffers from low selectivity and low efficiency due to nonselective recognition sites resulted from usual swelling of the polymeric material and polymer-embedded imprinted sites. In this study, a new magnetic molecularly imprinted membrane (MMIM) with imprinted sites located and dispersed on the membrane up-surface was successfully prepared via phase inversion method by virtue of the magnetic field force for selective separation of Artemisinin (ART) and Artemether (ARE), in which magnetic imprinted particles coated by imprinted nanolayers with controllable thickness of ca. 10 nm were first synthesized and functioned as the original imprinted sites for the membrane. In comparison with the control membrane (MMIM0) without magnetic guidance, the magnetic molecularly imprinted membrane (MMIM1) exhibited significant enhancement in recognized adsorption and highly efficient separation for ART and ARE mixture owing to the imprinted sites concentrated on the up-surface. For the batch competitive permeation experiments, the value of βART/ARE for MMIM reached up to 5.98, higher than that of MMIM0 (βART/ARE=3.12). For the dynamic cross-flow separation system, the αvalue of MMIM1 in the initial time could be promoted to be 22.0, while that of MMIM0 was onlyα = 2.5. 1H NMR spectra and density functional theory (DFT) verified that the enhanced selective separation efficiency for MMIM1 towards ART and ARE could be originated from both the shape of imprinted cavities and the interaction between ART and functional groups. This work highlights that the dynamic separation system over magnetic molecularly imprinted membrane provides an alternative potential “applicable platform” for large-scale separation and extraction of natural products.

Cellulose acetate butyrate graphene oxide nanocomposite membrane: Fabrication, characterization, and performance

In this study, the effects of graphene oxide (GO) nanosheets on the physicochemical properties and performances of cellulose acetate butyrate (CAB) membranes were investigated. Nanocomposite membranes were fabricated using CAB and a small amount of GO in the range of 0 to 0.07 wt.%, using a conventional phase-inversion method. Membranes were characterized by different methods and their performances were tested using a dead-end filtration system. Compared with pristine CAB membrane, experimental results demonstrated an improvement in features such as hydrophilicity, permeability, salt rejection, antifouling, and stability. The results proved an increase in the porosity and pore sizes of membranes with GO addition. Furthermore, the membrane containing 0.07 wt.% of GO exhibited a low contact angle of 37??and a dramatic improvement in water flux of about 450% (from 2 to 11 L/(m2 h)). Moreover, it demonstrated a salt rejection of 39% for NaCl and 87% for Na2SO4, corresponding to improvements of about 144 and 93%, respectively. Furthermore, the results revealed a higher antifouling property with an 86% improvement in flux recovery and higher stability in terms of performance and thermal properties compared to CAB.

β-cyclodextrin functionalized MWCNTs as a promising antifouling agent in fabrication of composite nanofiltration membranes

In this research, the manufacture and properties of polyethersulfone (PES)-based mixed matrix nanofiltration (MM-NF) membranes modified with β-cyclodextrin functionalized multiwalled carbon nanotubes (β-CD/MWCNTs) were studied. The β-CD/MWCNTs nanocomposite was synthesized using the soft cutting method. Stable dispersivity of the resulting nanocomposite was checked for 12 h. Then, the membranes containing up to 1 wt% β-CD/MWCNTs were prepared using conventional phase inversion method. The impact of varied mass loadings of the β-CD/MWCNTs on the morphological features and performance of the amended membranes was evaluated. It was deduced that membrane hydrophilicity, porosity, pore size, water contents, dye rejection and antifouling capacity were noticeably improved after incorporating the β-CD/MWCNTs nanomaterials. In comparison with the bare membrane, the β-CD/MWCNTs amended membranes displayed higher hydrophilicity, and consequently pure water flux (PWF). Since β-CD can exploit the structure advantages of MWCNTs via enhancement of the dispersivity, devoting unique features to the β-CD/MWCNTs nanomaterial. The 0.1 wt% nanocomposite membrane sample revealed the highest pure water flux of 21.5 Kg/m2.h due to increase in pore size (5.0 nm). While, the membrane contributed with the β-CD/MWCNTs-0.5 revealed better performance in terms of dye rejection and antifouling capability than the bare and modified membranes. It indicated a dye rejection of above 92%, flux recovery ratio (FRR) of 89% and an irreversible resistance of 11.1%. The β-CD/MWCNTs-0.5 acted as a potential nanofiller in nanofiltration (NF) membranes improving their antifouling performance at different operational conditions.

Low temperature, easy scaling up method for development of smart nanostructure hybrid lipid capsules for drug delivery application

Lipid Nanocapsules (LNCs) have been used for drug delivery in cells and animal models for several years. LNCs with unique physicochemical properties for favorable biorecognition, biocompatibility and stimuli responsive (pH/temperature etc.) properties i.e., smart-LNCs, are most promising for future nanomedicine applications. However, conventional phase inversion temperature (PIT) method of LNCs preparation may not be suitable for the fabrication of thermally labile drug loaded LNCs and smart-LNCs. Herein, we report for the first time, a novel low temperature (LT) method for the preparation of LNCs (including smart-LNCs of size 25–150 nm), hereafter, named as nanostructure hybrid lipid capsules (nHLCs), comprising safe excipients such as oil (Labrafac™ PG), surfactant (Kolliphor® HS 15, Brij® S100), and lipid (Lipoid S-75, Lipoid S PC-3, Lipoid PE 18:1/18:1, Lipoid PC 16:0/16:0 etc.). Effects of process parameters on the physicochemical properties of nHLCs were probed to optimize the process. Ternary phase diagram shows that our method allows for great flexibility in the formation of nHLCs with tailored size and composition. This method resulted in drug loaded (regorafenib used as model drug) nHLCs with 95 % encapsulation efficiency and sustained release profile at 37 °C. The drug loaded nHLCs (as prepared or in lyophilized form) has excellent storage stability at 4 °C (for more than one month) as well as biocompatibility similar to that of LNCs prepared by PIT method. Our novel LT method of LNCs (i.e. nHLCs) preparation is a generic method for the development of drug loaded (including thermally labile) and smart-LNCs for future nanomedicine applications.

Understanding the morphology of MWCNT/PES mixed-matrix membranes using SANS: interpretation and rejection performance

We describe the relationship between the morphology and rejection performance by the mixed-matrix membranes as a unique class of high water flux nanofiltration membranes comprising polyethersulfone/functionalized multiwalled carbon nanotubes (PES/f-MWCNTs). These membranes contain aligned MWCNTs uniformly distributed inside a PES matrix prepared using conventional phase-inversion technique. The small-angle neutron scattering analysis confirmed the high porosity and uniformity among of the pores of CNTs in the membranes. The frictionless water transport from vertically oriented f-MWCNTs were verified to facilitate remarkable enhancement in the water flux through the membranes. The water transportation speed, as well as rejection, of selected heavy metals increases nearly about 3 times and 2–3.5 times, respectively, than the pristine PES membrane, depending upon CNTs loading. Low working pressure and good retention properties make these membranes to be an ideal for the application of highly efficient filtration units.

Olive oil nanoemulsion preparation using high-pressure homogenization and d-phase emulsification – A design space approach

Olive oil has been extensively applied in the pharmaceutical and cosmetic industries due to its biological properties. These are attributed to monounsaturated fatty acids like oleic acid and other minor components, such as phenolics and triterpenic acids. Oil-in-water nanoemulsion may enhance the solubility of poorly water-soluble drugs, which comprise about 40% of the currently marketed ones. However, the development of vegetable oil nanoemulsions is challenging due to their complex composition. In this study, olive oil nanoemulsions were prepared using high-pressure homogenization (HPH) and d-phase emulsification (DPE), as high- and low-energy processes, respectively. DPE has the potential to overcome the drawbacks of conventional Phase Inversion Methods. Aiming to achieve a deeper understanding of HPH and DPE processes, a design of experiment approach was successfully applied. This approach allowed identifying and understanding the relationship between input factors and their associated output response, at the stage of the nanoemulsion development. Moreover, in a specific range of critical process parameters and compositions, within the design space, nanoemulsions with similar mean particle sizes of 275 nm were achieved with equal composition, regardless of the use of the HPH or DPE process.

Zwitterionic functionalized MoS2 nanosheets for a novel composite membrane with effective salt/dye separation performance

Polyethersulfone (PES) has been widely used as an ultrafiltration (UF) or nanofiltration (NF) membrane material in multiple industrial fields. But PES is hydrophobic in nature and easily contaminated. Thus, it is necessary to modify the PES membrane surface by physical or chemical methods for improving its hydrophilicity and other function. Herein, MoS2 modified by zwitterionic 2-methacryloyloxy ethyl dimethyl (3-sulfopropyl)-ammonium hydroxide sulfobetaine methacrylate (MoS2-PSBMA) was synthesized with a reverse atom transfer radical polymerization method (RATRP) and used to prepare MoS2-PSBMA/PES composite membranes via conventional phase inversion. The effect of MoS2-PSBMA content on the structure and properties was investigated by SEM, FT-IR, AFM and contact angle measurements. It was found that the hydrophilicity of the composite membrane increased with the content of zwitterionic functionalized MoS2nanosheets. Moreover, the composite membranes possessed a higher water flux (108.3 L m−2 h−1 at 0.6 MPa) and dye retention, 98.2% for Reactive Black 5% and 99.3% for Reactive Green 19. However, the rejection of Na2SO4, MgCl2 NaCl and MgSO4 was low, i.e., 2.2%, 1.2%, 1.1% and 0.3%, respectively. In summary, the synthesized composite membrane exhibited high selectivity for dye/inorganic salts and had a large potential for dye waste water treatment.