Phase Inversion Method Research Articles

Development of a novel hydrophilic SiO2/PVDF Janus membrane via different modification methods for robust antiwetting and antifouling membrane distillation

The development of novel membrane distillation (MD) membranes with high resistance to wetting and fouling has a great importance for the treatment of surfactant or oil-containing wastewater. In this study, superwettable Janus membranes were produced using hydrophilic silica nanoparticles (SiO2 NPs) via blending phase inversion (M1), delayed phase inversion (M2), and spray coating (M3) methods. Scanning electron microscopy coupled with energy dispersive X-ray spectrometry (SEM/EDS) and Fourier transform infrared spectrometry (FTIR) analysis showed that SiO2 NPs were successfully deposited on the top layers of the membranes, while no SiO2 NPs were detected on the bottom layers. Furthermore, underwater superoleophobic properties were achieved for M2 and M3 membranes, while M1 membrane showed a satisfactory underwater oleophobicity. In MD filtration tests, the M2 membrane exhibited the highest membrane wetting and fouling resistance, followed by the M1 membrane. However, the sprayed SiO2 NPs coating layer on the M3 membrane did not remain stable, resulting in a similar permeate water flux and rejection profiles to the pristine membrane after a short time. This study indicates that Janus membranes fabricated by blending and delayed phase inversion methods could be a strong candidate in MD for the treatment of complex wastewater containing surfactants and oil.

Innovative Aqueous Nanoemulsion Prepared by Phase Inversion Emulsification with Exceptional Homogeneity.

Formulating low-solubility or low-permeability drugs is a challenge, particularly with the low administration volumes required in intranasal drug delivery. Nanoemulsions (NE) can solve both issues, but their production and physical stability can be challenging, particularly when a high proportion of lipids is necessary. Hence, the aim of the present work was to develop a NE with good solubilization capacity for lipophilic drugs like simvastatin and able to promote the absorption of drugs with low permeability like fosphenytoin. Compositions with high proportion of two lipids were screened and characterized. Surprisingly, one of the compositions did not require high energy methods for high droplet size homogeneity. To better understand formulation factors important for this feature, several related compositions were evaluated, and their relative cytotoxicity was screened. Optimized compositions contained a high proportion of propylene glycol monocaprylate NF, formed very homogenous NE using a low-energy phase inversion method, solubilized simvastatin at high drug strength, and promoted a faster intranasal absorption of the hydrophilic prodrug fosphenytoin. Hence, a new highly homogeneous NE obtained by a simple low-energy method was successfully developed, which is a potential alternative for industrial application for the solubilization and protection of lipophilic actives, as well as (co-)administration of hydrophilic molecules.

A tight polyethersulfone ultrafiltration membrane fabricated via polyion complex assisted phase inversion for dye desalination

In this work, a tight polyethersulfone (PES) -based ultrafiltration (UF) membrane was fabricated to separate dye and salt of textile wastewater via a novel polyion complex assisted phase inversion method in one step. Thereinto, sulfonated polysulfone (SPSF) and poly-(diallyl dimethylammonium chloride) (PDADMAC) were added into the PES dope and coagulation bath, respectively. During the phase inversion process of the precast PES/SPSF film, polycation PDADMAC could assemble with anionic SPSF and facilitate SPSF enrichment on membrane surface, forming a dense barrier layer via the electrostatic interaction between quaternary ammonium and sulfonate groups. Morphology, chemical composition, surface charges and pore size analysis characterized via SEM, FTIR, XPS, Zeta potential and Dextran filtration experiment, respectively, testified that a nonporous skin layer comprising of polyion complex and enriched SPSF was successfully constructed on the top of the PES matrix with an effective pore radius of 1.44 nm, which is smaller than that of the reference membrane prepared without using polyion complex assisted phase inversion (2.74 nm). This resultant membrane exhibited a high pure water permeance of 94 LMH/bar. When it was utilized to separate a dye/salt mixture of 100 ppm Congo red (CR) and 2 g/L Na2SO4 at 1 bar, the rejection of CR could reach 99.7%, alongside a very low Na2SO4 rejection of 8.4%, while the water permeance of dye solution maintained 61 LMH/bar. In addition, the membrane also possessed excellent stability in the pH range of 1–13 due to the strong electrostatic interaction between SPSF and PDADMAC and long-term operation stability, demonstrating its application potential in textile wastewater treatment.

Application of Impact Elastic Wave Method in Nondestructive Testing Technology

This paper summarizes the research status of nondestructive testing technology of building structures, focuses on the technical principles and characteristics of the first wave phase inversion method and the impact elastic wave method, and on this basis, the nondestructive detector based on the first wave phase reversal and impact elastic wave were used to conduct experimental research on cracks, materials, defects and thickness of the test block. The results show that the first wave phase inversion has low requirements for the test environment, and the test results are affected by the water, dust, steel reinforcement and signal attenuation inside the crack, which have a tendency to be shallow compared with the actual value. The first wave of defect location, size and other results are consistent with the actual situation, which verifies the good reliability of the nondestructive testing technology based on impact elastic wave.

Detoxification of harmful pollutants using highly efficient visible light active Ru/TiO2/PVDF photocatalytic membranes

In this study, the pristine PVDF and x% Ru/TiO2/PVDF (x = 0. 5, 1 & 1. 5 wt.%) photocatalytic composite membranes were cast by the phase inversion method. The prepared photocatalysts and photocatalytic membranes were characterized by various analytical techniques. All the prepared photocatalysts and photocatalytic membranes were evaluated for their photocatalytic activities towards the degradation of two significant hazardous textile dyes, namely methylene blue and crystal violet under visible light illumination. The% decolorization values of MB and CV dyes over 1% Ru/TiO2 photocatalyst & 1% Ru/TiO2/PVDF photocatalytic composite membrane were found to be 99% & 97% and 84% & 83% respectively under visible light irradiation. The photocatalytic decolorization followed the pseudo-first-order reaction, according to the kinetics investigations. The mineralization of MB and CV dyes was determined by TOC analysis and found to be 64% & 61% respectively. The recyclability of 1% Ru/TiO2/PVDF photocatalytic composite membrane test revealed high stability.

Synergistic effect of silica aerogel and titanium dioxide in porous polyurethane composite coating with enhanced passive radiative cooling performance

Passive daytime radiative cooling is a promising technology that can mitigate the increasing issues of global warming and urban heat island effects. In this work, a series of porous polyurethane (PPU) composite coatings containing silica aerogel (SA) and/or titanium dioxide (T) were prepared though a wet phase inversion method. The effects of the filler types on relevant properties of composite coatings, such as pore microstructure, radiative cooling, mechanical, and hydrophobic performances, were systematically investigated. The typical PPU-SA10@T10 composite coating showed an interleaving porous structure, and the incorporated SA and T fillers were uniformly stacked in the pore cavities. Taking advantages of the strong light-back scattering and molecular oscillation functions, the solar reflectance, thermal emittance in the atmospheric transparency window, and the net cooling power of the PPU-SA10@T10 coating reached 0.917, 0.973, and 87.8 W/m2, respectively, which results in a sub-ambient cooling of 7.8 °C at midday under a solar irradiance of ∼640 W/m2. Moreover, the PPU-SA10@T10 coating possessed well balanced mechanical properties and superior hydrophobicity (water contact angle was 121.7°). The present work provides a viable way for developing radiative cooling coating with desirable mechanical properties and water-repellency.

Effects of Surfactant Characteristics on Fuel Properties of Emulsions of Alternative Engine Fuel through the Phase Inversion Method

Emulsions that mix two or more immiscible phases are broadly applied in pharmaceutics, chemistry, and industries. The phase inversion temperature (PIT) method is an emulsifying approach to preparing an emulsion with low energy consumption and cheap equipment. The effects of surfactant characteristics and processes of cooling or heating on the fuel properties of emulsions composed of silicone oil by the emulsifying method, such as mean droplet sizes of the de-ionized water phase, were considered herein. The application of the silicone oil emulsion as engine fuel was first evaluated. The results show that the emulsions added with the polyol surfactant mixture appeared to have a larger mean water-droplet size, a larger number of dispersed water droplets, a wider range of dispersed-water sizes, and lower kinematic viscosity than those with Brij 30 surfactant. Increasing the surfactant concentration of either Tween 20 mixed with Span 80 or Brij 30 surfactant increased kinematic viscosity and the number of dispersed droplets while decreasing mean droplet sizes. After being subjected to fast heating and then fast cooling, the silicone oil emulsion appeared to form many smaller dispersed droplets than those being proceeded with slow cooling. The emulsion of silicone oil was found to have adequate engine fuel properties.

PES/Fe3S4@NiO self-cleaning membrane with rapid catalysis for effective emulsion separation and dye degradation

The Fenton membrane is effective in removing organic pollutants from wastewater through the synergy of Fenton catalysis and membrane separation. However, the preparation of a Fenton membrane with excellent self-cleaning performance, catalytic ability, and stability remains a key research direction. Herein, a polyethersulfone (PES)/Fe3S4@NiO membrane was obtained via a non-solvent phase inversion method. The intercalation of photo-Fenton catalytic Fe3S4@NiO into the PES membrane can not only enhance the hydrophilicity but also endow the membrane with photo-Fenton catalytic activity. The separation efficiency of the obtained membrane for multiple oil-in-water emulsions exceeded 98.8%. In addition, the membrane presented excellent self-cleaning performance and stability, the separation efficiency remained high and stable even after 10 cycles of oil-in-water emulsions. Meanwhile, the effective degradation of several organic dyes under visible light was simulated; results showed that the membrane can achieve nearly 100% degradation of methylene blue in 9 min as well as rhodamine B and methyl orange in 3 min, and this membrane maintained high degradation efficiency (>98.7%) even after 5 cycles. Therefore, the results indicate that this PES/Fe3S4@NiO membrane has excellent separation performance and photo-Fenton activity, and the proposed membrane has a potential application scope for efficient emulsion separation and speedy dye degradation.

Developing a PVDF catalytic membrane with high permeability, fouling resistance and self-cleaning capability for efficient oil/water emulsion separation

To impart PVDF membranes with excellent antifouling performance and catalytic self-cleaning capability, a novel modifier PVDF-g-Py-FePc (PPF) was facilely designed and architecturally constructed through grafting 4-aminopyridine (4-NH2-Py) followed by axial coordinating iron phthalocyanine (FePc) on PVDF backbones. An original PPF@PVDF catalytic membrane has been successfully fabricated though incorporating the Fenton-like modifier PPF into PVDF matrix using the phase inversion method. The influences of the introduction of PPF on membrane micro-structure and separation performance were investigated in detail by XPS, contact angle measurement, SEM, and cross-flow filtration experiment. Owing to the introduction of the modifier PPF, the porosity, mean pore size and surface hydrophilicity of PVDF membrane were enhanced obviously, which results in PVDF membrane with high permeation and excellent fouling resistance. Most importantly, the embedded PPF possesses catalytic active and can more effectively degrade the oil foulants adsorbed on membrane surface or trapped within membrane pores. Thereby, PVDF membrane was endowed a catalytic self-cleaning capability for high-efficient oil/water emulsion separation. As a whole, the PPF@PVDF catalytic membrane as a potential candidate will be applied in the treatment of wastewater containing oil and sewage.

PVDF ultrafiltration membranes containing copper oxide-charcoal based graphene oxide nanohybrids with enhanced performance and antifouling properties

Charcoal based graphene oxide-copper oxide (GO-CuO) nanohybrids were successfully synthesized via the co-precipitation method. It was then used to improve polyvinylidene fluoride (PVDF) ultrafiltration (UF) membrane properties and performance. The PVDF/GO-CuO UF nanocomposite membranes containing different contents of the synthesized GO-CuO nanohybrids were prepared via the phase inversion method. It was found that hydrophilicity of PVDF membrane containing 0.2 wt% of the synthesized GO-CuO nanohybrids increases than the neat PVDF membrane, so that its water contact angle (WCA) decreases from 80.68±1.23° for the neat PVDF membrane to 60.53±5.25° for the modified membrane containing 0.2 wt% of the synthesized GO-CuO nanohybrids. On the other hand, compared to the neat PVDF membrane, pure water flux (PWF) of this modified nanocomposite membrane increases by about 77% (from 101.1±1.82 to 178.87±1.47 LMH) and exhibits 94.28±0.93% rejection of bovine serum albumin (BSA). This improvement is due to increased hydrophilicity, porosity, average membrane pore size, and decreased membrane surface roughness. The results of fouling measurements showed 42%, 60%, and 8% reduction in total fouling ratio (Rt), irreversible fouling ratio (Rir), and reversible fouling ratio (Rr), respectively. This indicated that antifouling properties of the modified membrane is significantly improved. It was found that the fabricated PVDF/GO-CuO nanocomposite membrane exhibits better performance than the neat PVDF membrane. Also, the results showed that this membrane also exhibits better properties and performance than the PVDF/GO and PVDF/CuO nanocomposite membranes. Therefore, it can be concluded that the fabricated PVDF/GO-CuO nanocomposite membrane has excellent potential for water and wastewater treatment applications.

Polysulfone-based mixed matrix membranes loaded with a multifunctional hierarchical porous Ag-Cu dendrites@SiO2 core-shell nanostructure for wastewater treatment

Eliminating pollutants from wastewater is a crucial approach to securing the global water supply. It is well known that membrane purification technologies are remarkably attractive due to their high efficacy and low energy consumption. The neat polysulfone (PSF) polymer membranes, though, are prone to be fouled by organic pollutants, causing pore blockage and waned separation performance. We herein report and describe the rational design of a hierarchical porous Ag-Cu dendrites@SiO2 core-shell nanostructure/PSF mixed matrix membranes (MMMs) by coupling heterogeneous dendritic Ag-Cu@SiO2 core-shell nanostructure with PSF polymer matrix using facile phase inversion method for efficient separation of the protein (Bovine Serum Albumin; BSA) and Rose Bengal (RB) dye removal. Besides, for the first time, a theoretical mapping of molecular electrostatic potential (MESP) maps for chemical structure has been used for studying the interaction between the compounds (membrane moieties and pollutants). Practically, the SiO2 nanoparticles provide excellent hydrophilicity causing a sequential efficient, antifouling protein and dye separation with an outstanding rejection rate of over 96 % for both BSA and RB. In addition, the porous hierarchical scaffold formed from the hydrophilic Ag-Cu nanosheets embedded with SiO2 nanoparticles greatly assists the rapid permeation of water with a high flux rate of up to 50 L m−2 h−1 bar−1 for pure water. Furthermore, the hydrophilic nature of Ag and Cu nanoparticles also renders this membrane with a high removal capability for dye blocking enabling it to remove soluble pollutants in molecular dimensions as well. This design strategy not only provides an outstanding membrane for water purification but also sheds light on the design of multi-purpose functional membranes for a variety of energy and environment-related applications.

Efficiency of Fabricated Adsorptive Polysulfone Mixed Matrix Membrane for Acetic Acid Separation.

The ultrafiltration mixed matrix membrane (UF MMMs) process represents an applicable approach for the removal of diluted acetic acid at low concentrations, owing to the low pressures applied. The addition of efficient additives represents an approach to further improve membrane porosity and, subsequently, enhance acetic acid removal. This work demonstrates the incorporation of titanium dioxide (TiO2) and polyethylene glycol (PEG) as additives into polysulfone (PSf) polymer via the non-solvent-induced phase-inversion (NIPS) method to improve the performance of PSf MMMs performance. Eight PSf MMMs samples designated as M0 to M7, each with independent formulations, were prepared and investigated for their respective density, porosity, and degree of AA retention. Morphology analysis through scanning electron microscopy elucidated sample M7 (PSf/TiO2/PEG 6000) to have the highest density and porosity among all samples with concomitant highest AA retention at approximately 92.2%. The application of the concentration polarization method further supported this finding by the higher concentration of AA solute present on the surface of the membrane compared to that of AA feed for sample M7. Overall, this study successfully demonstrates the significance of TiO2 and PEG as high MW additives in improving PSf MMM performance.

Covalent organic frameworks modified with TA embedded in the membrane to improve the separation of heavy metals in the FO

The Schiff base network-1 (SNW-1) was synthesized by the Schiff-base reaction method and then modified using tannic acid (TA). To make a thin film nanocomposite (TFC) membrane by using the nonsolvent-induced phase inversion (NIPs) method, it was embedded in the matrix of the forward osmosis (FO) polyethersulfone (PES) membrane and used to check the performance of the desalination and removal of heavy metals. SNW-1 and covalent organic framework modified tannic acid (STA) nanoparticles were characterized using FTIR, XRD, FESEM, TEM, BET, and TGA analyses. The results indicated the successful synthesis and modification nanoparticles. The effect of SNW-1 and STA nanoparticles on the surface properties of membranes were investigated using contact angle, porosity, pore size, ATR-FTIR, SEM, and AFM analyses. The results showed an extraordinary increase in hydrophilicity, softening of the membrane surface, and an enhancement in finger-like pores for water passage. Due to the presence of the hyperbranched polymer like TA next to SNW-1, in addition to creating a synergistic effect in increasing hydrophilicity and porosity, caused the removal of impurities. The results showed an increase in the permeability and rejection of the membranes modified with STA compared to the pure membrane and the modified membrane with SNW-1. Also, the TFC-STA membrane showed lower coefficient of salt permeability (B) to coefficient of water permeability (A) of RO setup (B/A), and lower salt permeation (Js) to water permeation (Jw) of FO setup (Js/Jw) coefficients than the modified TFC@SNW-1 membranes.

Influence of polyethyleneimine layer and zinc nitrate on morphology and structure of PES‐based membranes with highly selective properties

AbstractIn this paper, nanofiltration (NF) polymer membranes based on polyestersulphone (PES) were prepared by the phase inversion method. Polyethyleneimine (PEI) and zinc nitrate (Zn(NO3)2) as a surface modifier and glutealdehyde (GA) as cross‐linker was used. Fourier transform infrared spectroscopy analysis (FTIR) was used to confirm the chemical composition on the membrane surface. Membranes were also characterized using field emission scanning electron microscopy (FESEM) and 3D surface images. Water contact angle, average pore size and porosity measurements, water flux, salt rejection, and membrane anti‐fouling ability were discussed. Modified membranes showed a smoother surface than the original membrane. The amount of pure water flux decreased with increasing the concentration of modifiers at the surface, but the yield of Na2SO4 salt increased, 53% in virgin membrane and 83% in M3 membrane. Modified membranes had better anti‐fouling and hydrophilicity properties than primary membranes. The lowest contact angle value was 26.2° for M4. Also, the best anti‐clogging comparable properties were for the M3 membrane with FRR = 63.37%, Rr = 10.69%, Rir = 36.6%, and Rt = 47.3%. By increasing the concentration of modifiers, the removal of CuNO3− and CuSO4 improved that the M1 membrane (97.59%) had the highest Cu(NO3)2 separation and the M4 membrane (87.5%) had the most increased CuSO4 separation.

Low thermal conductivity and thermal radiation of La2Zr2O7 ceramics with hierarchical structure above 1000 K

The hierarchically porous La2Zr2O7 (LZO) microsphere fabricated by the electro-spraying assisted phase inversion (ESP) method is a promising feedstock for thermal barrier coatings (TBCs), due to its low thermal conductivity, quite high near-infrared reflectivity and high temperature structure stability. However, the thermal properties of hierarchically porous LZO ceramics above 1000 K are still unclear, limiting its application in TBCs. The effect of hierarchical structure on thermal conduction and thermal radiation was investigated in comparison with mono-sized pores, using the ESP microspheres (LZO-ESP) and other two carbon fillers to modulate the pores. The results showed that LZO-ESP samples exhibited ultra-low thermal conductivity (1.28 W m−1 K−1 at 1173 K), which was 30% lower than that of the reference samples of similar porosity. Heat flux simulation revealed that hierarchical structure can induce more disorder domains than the randomly distributed mono-sized pores. The disorder domains with high tortuosity of heat flux played a predominant role in the reduction of thermal conductivity. Additionally, the hierarchical structure significantly reduced thermal radiation by 36% compared with dense sample due to the decrease in transmissivity.

Preparation and Characterization of Biodegradable Cellulose Acetate‐Fibroin for Dialysis Application

AbstractMembrane separation technology is an efficient and high‐performance technique. It is a thin flat sheet and acts like a delicate barrier for the selective transport of substances under the influence of pressure. Low cost and various applications in industry as well as in medical make it more important. The basic property of a dialysis membrane is the ability to remove toxic materials from blood in minimum time, and maximum protein rejection, and must have the ability to moderate the water flux. Protein deposition or adsorption on the surface of the membrane results in low flux and change of selectivity of membrane for low toxic removal. In this work we prepared cellulose acetate membrane through the phase inversion method. The effects of additives are characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infra‐Red (FT‐IR), and Contact Angle. The membrane performance is also studied in pure water flux, water uptakes, porosity, BSA rejection, and Urea clearance test. This membrane is modified by adding various types of organic and inorganic additives which will perform specific functions. M‐3 membrane showed excellent results its hydrophilicity is 133.33 %, leaching point is 2.08, pure water permeation flux 97.19 L/m2h, porosity is 13.97 nm, BSA rejection value is 91 % and Urea clearance is 92 %. These results show that M‐3 is excellent for dialysis operations.

A facile synthesis approach for GO-ZnO/PES ultrafiltration mixed matrix photocatalytic membranes for dye removal in water: Leveraging the synergy between photocatalysis and membrane filtration

Photocatalytic membranes offer a unique opportunity of exploiting the combined benefits of membrane filtration and photocatalytic degradation, however, striking a practical balance between the two processes remains a challenging prospect. In this work, we explored the filtration and simulated solar light-mediated photocatalytic performance of polyethersulfone (PES) ultrafiltration membranes embedded with graphene oxide-zinc oxide (GO-ZnO) nanocomposite photocatalyst. A novel and simple double casting phase inversion method was used to fabricate the GO-ZnO/PES mixed matrix photocatalytic membranes with varying GO-ZnO loadings. Polyvinylpyrrolidone (PVP) was used as a pore-forming agent to minimize the pore blocking effect of high concentrations of GO-ZnO nanocomposite. The membranes were characterized for surface morphology and functionality, pore size, water uptake, and solute rejection properties using various techniques including scanning electron microscopy, atomic force microscopy, Raman spectroscopy, contact angle measurements, streaming potential analysis and cross-flow filtration. The incorporation of GO-ZnO improved the hydrophilicity of the membranes and the addition of PVP augmented the pure water flux of the PVP membranes compared to the PES membranes. Meanwhile, both PES and PVP membranes displayed poor overall salt rejection, which improved with increase in the GO-ZnO concentration. The rejection of carbamazepine and brilliant black (BB) followed a similar trend, with the highest rejection (carbamazepine ≈ 80%) and BB (≈ 70%) attained at 1% GO-ZnO. Furthermore, the PVP membrane with 1% GO-ZnO showed the highest photocatalytic degradation of BB, and the degradation kinetics were nearly 25 times higher than those recorded over the PVP membrane without nanoparticles. Overall, this work demonstrated that membrane filtration and photocatalytic properties can be improved by tailoring the membrane synthesis method to ensure high photocatalyst loading while retaining high flux, rejection, and photocatalytic capability.

Effect of the Preparation Conditions on Polyvinyl Chloride/Aliquat-336 Microspheres’ Efficiency: Optimization Using Surface Response Methodology

Polyvinyl chloride (PVC)/Aliquat-336 microspheres were prepared with the phase inversion method and optimized for red Cibacron dye adsorption. Response surface methodology (RSM) was used to maximize the adsorption capacity. The optimized parameters were the PVC fraction in the dimethylformamide (DMF) solvent, the Aliquat-336/polymer ratio, and the volume fraction of ethanol in the water coagulation bath. The model significant parameters found were the Aliquat-336/polymer ratio and the ethanol volume fraction. The maximum adsorption of 73.7425 mg g−1 was obtained by optimization with an Aliquat-336/PVC mass ratio of 1.5 and an ethanol volume fraction of 0.0934. This theoretical maximum adsorption capacity was confirmed with the experimental one, which had a close value of about 70.25 mg g−1. Both intraparticle and interparticle diffusion mechanisms controlled the adsorption kinetics, and the equilibrium adsorption time was established as 180 min.

Recovery of Pure Water, Salicylic Acid Crystals, and Paracetamol using PVDF-MWCNT Membranes by Membrane Distillation-crystallization

Membrane distillation-crystallization (MDC) is presented as a novel technique in the treatment of waste concentrated water which produces valuable crystals along with pure water. In the present study, multi-walled carbon nanotubes (MWCNT)/polyvinylidene fluoride (PVDF) flat sheet membranes were prepared via the wet phase inversion method and applied in MDC for the treatment of pharmaceutical waste. The pure and modified membrane surface properties are characterized with the help of SEM, FTIR, and contact angle measurement. The present work reported the effect of MWCNT content and feed temperature on the MDCperformance and measured pure water flux and pharmaceutical compounds recovery. The observed maximum permeate flux and crystal recovery for Salicylic acid system was 5.5 kg/m2h and 50%, respectively for PVDF+0.5% CNT membrane and 5 kg/m2h and 48%, respectively for pure PVDF. Also, for paracetamol system it was 3.9 kg/m2h and 41% for PVDF +0.5% CNT membrane and 3.5 kg/ m2h and 38% for pure PVDF. Obtained results show that MDC has good potential in treating pharmaceutical waste.

Antibacterial PES/Vancomycin ultrafiltration membranes with enhanced water flux and low BSA rejection

AbstractPolyethersulfone (PES) blended with glycopeptide Vancomycin was fabricated via phase inversion method. The fabricated membranes were characterized by scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), contact angle (CA) and optical profilometry. The PES/Vancomycin membranes showed a notable increase in hydrophilicity, porosity, pore size, antibacterial activity and water flux in comparison with pristine membranes. The changes are due to the hydrophilic nature of Vancomycin molecules and ability to form hydrogen bond quickly. The surface hydrophilicity of PES/Vancomycin membranes decreased up to 48° with increase in surface roughness (Ra), that is, 0.347 μm, thus increasing the water flux of PES/Vancomycin membranes up to 340 L/m2. h. The bovine serum albumin (BSA) rejection decreases, that is, pristine 70.9% to PES/Vancomycin 26% and BSA flux increases at constant ionic strength (0.1) and above the isoelectric point (IEP) of the BSA. Under these conditions, electrostatic interactions are expected to be minimum between protein and the membrane surfaces.