Casting Knife Research Articles

GROWTH AND CHARACTERIZATION OF POLYMERIC MEMBRANE MODIFIED BY MAGNETIC NANOPARTICLES

In this study, we aimed to modify polymeric membranes by incorporating magnetic nanoparticles (NPs) to enhance their properties. The structural and chemical properties of magnetic NPs of iron oxide were prepared via a wet chemical method. Iron oxide nanoparticles (IONPs) were used as the core and were coated with polymers polyvinyle alcohol (PVA) and polyvinylpyrrolidone (PVP). The prepared samples were cast on a glass substrate using a casting knife. The aim of this study is the use of a specific type of magnetic NPs, coated with a polymer, and their application in membrane modification. We employed a facile synthesis method to coat the IONPs with the polymer and characterized the resulting material using various techniques, including X-ray Diffraction (XRD), scanning electron microscope (SEM), Fourier Transform Infrared (FTIR) Spectroscopy, and UV/Visible (UV–Vis) Spectroscopy for structural, morphological, chemical bonding, and optical properties studies. Our results show that the modified polymeric membranes exhibited improved properties, such as increased permeability and selectivity. We also observed that the magnetic NPs helped in the easy recovery of the modified membranes using an external magnetic field. Some agglomeration of IONPs was also observed, and the polymer membrane caused a decrease in crystallinity of IONPs. Overall, this study presents a promising approach for enhancing the properties of polymeric membranes using magnetic NPs and can potentially have practical applications in various fields, such as water treatment, food processing, and biotechnology.

Superhydrophilic micro/nano hierarchical functionalized-CuO/PVDF nanocomposite membranes with ultra-low fouling/biofouling performance for acetate wastewater treatment: MBR application

In membrane bioreactor (MBR) application, there are considerably influencing factors on membrane performance over time making serious problems, including reduced permeation flux and rejection percentage as well as formed thick fouling/biofouling layer. This study provided a new preparation strategy to fabricate extraordinary superhydrophilic CuO/PVDF nanocomposite membranes with micro/nano hierarchical structure, using a wet micro-pattern casting knife with simultaneous bombardment of hydrophilic CuO nanoparticles/non-solvent solution via cold spray coating (s-NIPs method). When compared to the neat membrane, the main characteristics of the superhydrophilic membrane enhanced such as surface area (70%) and pure water flux (PWF) (400%). Protein rejection (PR) and chemical oxygen demand (COD) removal were also obtained as about 96.7% and 97.8% at constant mixed liquor suspended solids (MLSS = 6000 mg/l) in a submerged aerobic MBR, fed by the synthesized sodium acetate wastewater (compared to the neat case: 78% and 91%), respectively. Furthermore, its excellent antifouling/biofouling properties were proved via significantly less formation of biofilm and adherence of extracellular polymeric substances (EPSs) and soluble microbial products (SMPs) on the membrane surface. Low variation of sludge flux and COD removal by increasing MLSS from 6000 (348 LMH and 96.7%) to 12000 mg/L (200 LMH and 94.2%) proved the significant impact of the preparation method on the membrane performance. Stability of the F–CuO coated layer caused superhydrophilicity and antibacterial properties to be maintained under long-period. The obtained results demonstrated potential of the fast, facile, simple, and one-step preparation method without compromising the membrane separation ability, while simultaneously providing superhydrophilicity, antibacterial activity, and ultra-low fouling/biofouling formation.

Design and performance evaluation of edible film printing machine based on automatic casting knife

The development of edible films has been widely applied in recent years as an environmentally friendly food packaging, increasing shelf life and improving food quality. The most commonly used technique for producing starch-based films was classical casting, leading to film thickness measurement difficult. Therefore, this study aimed to design an edible film printing machine based on an automatic casting knife. The method used in this research was the engineering method. The edible printing machine was designed for a laboratory scale with a 1200 mm length, 500 mm width and 300 mm height. There were three main parts, namely an automatic casting knife, automatic pouring and control box. The performance evaluation showed that the automatic casting knife could be printing an edible film thickness between 0-20 mm with an accuracy level of 99.3%. An edible film with a length of 200 mm and 130 mm width can be printed in a shorter time (10 seconds). The edible film also has a smoother appearance on microscopic observation and was preferred by panellists to its appearance, texture and transparency parameters compared with edible film from manual casting. Based on the performance evaluation results that promise to be more efficient in printing edible film, this machine was expected to be scaled up and become a solution for the realization of Indonesian green packaging in the industrial revolution 4.0.

Superhydrophobic nanocarbon-based membrane with antibacterial characteristics.

To overcome the biofouling challenge which faces membrane water treatment processed, the novel superhydrophobic carbon nanomaterials impregnated on/powder activated carbon (CNMs/PAC) was utilized to successfully design prepare an antimicrobial membrane. The research was conducted following a systematic statistical design of experiments technique considering various parameters of composite membrane fabrication. The impact of these parameters of composite membrane on Staphylococcus aureus growth was investigated. The bacteria growth was analyzed through spectrophotometer and SEM. The effect of CNMs' hydrophobicity on the bacterial colonies revealed a decrease in the abundance of bacterial colonies and an alteration in structure with increasing the hydrophobicity. The results revealed that the optimum preparative conditions for carbon loading CNMs/PAC was 363.04 mg with a polymer concentration of 22.64 g/100 g, and a casting knife thickness of 133.91 μm. These conditions have resulted in decreasing the number of bacteria colonies to about 7.56 CFU. Our results provided a strong evidence on the antibacterial effect and consequently on the antibiofouling potential of CNMs/PAC in membrane.

Tuneable interlayer spacing self-assembling on graphene oxide-framework membrane for enhance air dehumidification

Isothermal-based air dehumidification results in energy problems, low water vapour permeability and poor selectivity. Graphene oxide framework (GOF) membranes exhibit remarkable advantages in effective air dehumidification. In this work, different crosslinking agents, including glyoxal (GLX), oxalic acid (OXA) and ethylenediamine (EDA), were employed to tune the properties of GOF membranes through the casting knife technique. The physicochemical properties of the as-prepared membranes were investigated by using various techniques. The 2D arrangement of GO-based membranes ensured the frictionless nano-channels with an efficient flow rate and storage of water along with chemical interaction while hydrophilic groups on the GO surface. However, crosslinking restricted the mobility between consecutive GO layers, and the free volume and pore size became tuneable in the crosslinking structure. Given its capacity for low energy-efficient air dehumidification, the GLX-cross-linked GO membrane exhibited an excellent selectivity value of 2.8 × 106, and the less energy-consuming stability performance lasted for 120 h. These results indicate that the GLX-cross-linked GO membrane is suitable for practical applications.

Preparation of patterned flat-sheet membranes using a modified phase inversion process and advanced casting knife construction techniques

High fluxes and low fouling are practically highly desired in all membrane processes. One generic way to realize this is by introducing surface patterns on the membrane to increase the active area and the surface roughness. A new method to prepare flat-sheet patterned membranes using a patterned knife combined with a modified phase inversion process is now presented. After casting the polymer solution, the patterned knife shapes the top surface into the desired pattern. Non-solvent is sprayed immediately after the passage of the knife to rapidly solidify the polymer and preserve the pattern. To construct the patterned knife, different materials and techniques were evaluated: (1) an aluminium knife shaped by electrical discharge micromachining, (2) a gypsum knife shaped by powder-based 3D-printing, and (3) an acrylate resin, shaped by photopolymerization 3D-printing (stereolithography). As such, replacing the conventional non-solvent contact in the phase inversion via immersion by spraying already increased membrane permeance, but a significant further increase of permeance resulted from the increased surface area realized through the patterning. A minimum viscosity of the casting solution of around 7.5–10 Pa.s was required to realize well-pronounced patterns on the membrane, as screened for polyacrylonitrile and cellulose acetate, both dissolved in dimethyl sulfoxide and using water as non-solvent.

Study of Polymeric Membranes Potential for Eugenol Purification from Crude Clove leaf Oil

Clove oil is an agricultural commodity with economic value. This essential oil can be obtained from flowers, stems, and leaves of clove plants. The quality of clove oil can be evaluated from eugenol levels in oil. An increase in eugenol levels from 70% to 98% can increase oil prices by up to 3 times. Oil obtained from clove leaves has a low eugenol content of 60-70%, therefore the purification is needed to improve the quality of oil. Membrane based separation for eugenol purification was suggested in this paper as new concept in essential oils purification processes. This study aimed to explore the suitable polymer as membrane material for eugenol purification. PES, PA, CA and PI were used in this study, where the membranes were prepared via NIPS technique using manual casting knife to form flat sheet membranes. The membranes were immersed in eugenol to evaluate the solubility. The insoluble membrane was used for purification performance test in membrane filtration cell. The results show that PES and PA membranes were completely dissolved in eugenol in less than 1 minute, while PI and CA membranes were insoluble in eugenol. However, the PI membrane has much lower solvent permeability than CA membrane. The thermal annealed PES membrane for 3 h at 180°C dissolved in eugenol in 30 minutes for complete dissolution. It is concluded that PI and CA membranes can be used as membrane material for eugenol purification but CA more favorable, while PES membrane has a potential for similar purposes after being thermal annealed. However, these findings can offer an important reference for the application of polymeric membranes for clove oil purification through an effective and efficient process.

Development of Novel Nano-ZnO Enhanced Polymeric Membranes for Water Purification

ZnO nanoparticles (NPs) were treated using three different polymers: polysulfone (PSF), polyvinylpyrrolidone (PVP), and polyvinylidene fluoride (PVDF). 10 wt% of ZnO NPs and ternary polymer-blended membrane were prepared by a simple and effective method based on ultrasonication. A highly-dispersed and stable polymeric membrane based on ZnO NPs was obtained. This polymer blended based nanocomposite (NC) has proven to have important industrial applications. The thermal stability of the pure polymer blends and ternary polymer blends/ZnO NPs was analyzed by thermogravimetric analysis (TGA) and differential scanning calorimetry. The morphology and the structural analysis of the resultant NCs were then evaluated by scanning electron microscopy, X-ray diffraction and Fourier transform-infrared spectroscopy. Molecular weight cut-off test was applied to study the rejection behavior of the membranes. The best results were achieved by PSF@PVP@PVDF–ZnO NP-incorporated membrane when the durability test was performed; it was observed that the samples were not swollen for 45 days when kept at pH 7. The experimental results showed that ZnO NPs were dispersed homogeneously in the ternary polymer blend matrix in nanoscale and enhanced the chemical and thermal stability of the membranes. Fabrication of PSF/PVP/PVDF–ZnO NP-blende membrane on glass plate using a film casting knife.

PVDF-co-HFP/superhydrophobic acetylene-based nanocarbon hybrid membrane for seawater desalination via DCMD

Surface hydrophobicity is the most desirable characteristic for high DCMD performance. Superhydrophobic carbon nanomaterials/powder activated carbon (CNMs/PAC) has unique properties and believed to be the proper candidate to increase the membrane hydrophobicity with maintaining good mechanical properties and high porosity at the same time. In this work, we introduce a phase inversion process based on central composite design, aimed at minimizing the number of experiments required for membrane fabrication. The hydrophobic membrane fabrication conditions are modeled as independent parameters, with the flux provided as the model response. The analyses performed on the membrane structure and surface, as well as its mechanical properties revealed that the superhydrophobic CNMs/PAC significantly enhances the hydrophobicity of the composite membrane surface. The accuracy measurements obtained by analysis of variance showed that the model developed and all the proposed parameters have significant effects on the flux. However, the CNMs/PAC emerged as the most significant influential factor and interacted with polymer concentration and casting knife thickness to exert effects on the permeate flux. The optimum preparation parameters were 775.21mg carbon loading, PVDF-HFP concentration of 21.86g and casting knife thickness of 118.93μm, as these values yield the highest flux of about 102kg/m2h.

FOULING BEHAVIOR OF MODIFIED CELLULOSE ACETATE ASYMMETRIC MEMBRANES FOR DIFFERENT BRACKISH WATER TREATMENT

Water treatment technology which is being widely developed is membrane technology as an alternative technology with sieving mechanism principle.The main purposes of this research are to investigate the effects of additives and thermal treatment on the cellulose acetate membrane morphology and performance in treating brackish water.The membrane was fabricated by preparation of dope solution consits of cellulose acetate and acetone. The membrane was casted via NIPS method using mechanic casting knife. Dope solution was prepared by varying the PEG concentration of 1 and 5wt-% and the annealing temperature at 60°C and 25°C for 10 seconds. The backwash technique was used to solve fouling mechanism in this system .The results of SEM and FTIR showed that theb higher PEG addition to the dope solution resulted in larger membrane pore size and increase the hydrophilic properties of membrane. However the higher temperature and the longer annealing timg, the skin layer of membrane become denser. The result was also shown that back wash technique can reduced fouling phenomenon in the membrane.

Application of a colorimetric technique in quality control for printed pediatric orodispersible drug delivery systems containing propranolol hydrochloride

The feasibility of a colorimetric technique was investigated in CIELAB color space as an analytical quality control method for content uniformity of printed orodispersible pediatric delivery systems. Inkjet printing was utilized to fabricate orodispersibe film formulations containing propranolol hydrochloride in a colored ink base using three different edible substrates. A thin sweetener coating layer of saccharin was successfully included in the final dosage forms for palatability purposes using a casting knife. Optical microscopy, scanning electron microscopy and scanning white light interferometry analyses were conducted to study the effect of printing on the surface morphology and topography of the substrates. Differential scanning calorimetry and attenuated total reflectance infrared spectroscopy were used to study the solid state properties and possible interactions between the drug and the excipients. The inkjet printing technique deposited precise and uniform escalating doses (0.08⿿3.16mg) of the active pharmaceutical ingredient onto the substrates (R2⿥0.9934). A disintegration test with clear end-point detection confirmed that all the substrates meet the requirements of the Ph. Eur. to disintegrate within 180s. The colorimetric technique proved to be a reliable method to distinguish the small color differences between formulations containing an escalating dose of propranolol hydrochloride.

Effect of a TiO2 additive on the morphology and permeability of cellulose ultrafiltration membranes prepared via immersion precipitation with ionic liquid as a solvent

This work studies structure and properties of cellulose ultrafiltration membrane created by coupling of TiO2 nanoparticles onto the cellulose matrix. Supported cellulose ultrafiltration membranes were cast out of cellulose-titanium dioxide-ionic liquid solution via phase inversion. The aim was to determine the effect of titanium dioxide concentration on cellulose membrane morphology and performance. 1-ethyl-3-methylimidazolium acetate ([emim][OAc]) was used to obtain cellulose-ionic liquid solutions at a concentration of 9 %. Thin polymeric films of 250 µm thickness were cast onto a non-woven PET support material with an adjustable casting knife. Pure deionized water was employed as a non-solvent agent. The obtained product morphology (cross-section) was examined with field emission scanning electron microscopy. Filtration tests were made to determine pure water flux and molar mass cut-off (MMCO). Filtration tests with humic acid solutions were carried out to provide initial indications of performance in industrial applications. The obtained results showed that addition of titanium dioxide particles in small amounts had a positive impact on virgin cellulose ultrafiltration membranes. Tested samples had good mechanical stability, stable pure water flux and a MMCO typical for commercial ultrafiltration membranes. In addition, all tested samples showed excellent fouling resistance to humic acid solutions. In general, incorporation of titanium dioxide particles into cellulose matrix membrane should be taken into account as a potential way to create ultrafiltration membranes with high operation performance.

Effect of citrate-based non-toxic solvents on poly(vinylidene fluoride) membrane preparation via thermally induced phase separation

The replacement of commonly-used substances with non-toxic equivalents is attracting a great amount of attention in membrane preparation processes. In order to address this issue, we prepared poly(vinylidene fluoride) (PVDF) flat membranes via thermally-induced phase separation using non-toxic citrate-based solvents (Citroflex): acetyl tributyl citrate (ATBC); acetyl triethyl citrate (ATEC); and triethyl citrate (TEC). It was found that the three kinds of Citroflex showed the different solubility with PVDF: the solubility was improved in the following order of ATBC<ATEC<TEC. The prepared porous PVDF membranes were characterized in terms of their morphology observed by scanning electron microscopy, porosity, pore-size, contact angle, and tensile properties. The pore structures of the membranes were affected by the solvent's affinity with PVDF, as well as by the gap between the casting knife and plate. This result was explained by taking into account the polymer / solvent phase separation behavior during the membrane formation. In the microfiltration test of pure water, the water permeability of the membranes widely changed depending on their pore structures. In conclusion, the prepared PVDF flat membranes exhibited the great potential for practical separation processes.

Blends of enteric and GIT-insoluble polymers used for film coating: physicochemical characterization and drug release patterns

The objectives of this study were: (i) to use blends of gastrointestinal tract (GIT)-insoluble and enteric polymers (ethyl cellulose and Eudragit ® L) as coating materials for multiparticulate controlled release dosage forms; (ii) to investigate the effects of the polymer blend ratio and coating level on the resulting drug release patterns; and (iii) to explain the observed phenomena based on the physicochemical properties of the systems. Propranolol HCl-loaded pellets were coated in a fluidized bed coater with organic polymer solutions; thin, drug-containing and drug-free, polymeric films were prepared using a casting knife. In vitro drug release, water uptake and dry weight loss studies were performed in 0.1 M HCl and phosphate buffer pH 7.4, respectively. The apparent drug diffusion coefficients within the polymeric systems were determined using different experimental and theoretical techniques (side-by-side diffusion cells, in vitro drug release from thin films; exact and approximate solutions of Fick’s second law of diffusion). A broad range of drug release patterns from coated pellets could be achieved by varying the GIT-insoluble:enteric polymer blend ratio. With increasing relative amounts of Eudragit ® L, the release rates in both media significantly increased. The increase at low pH could be attributed to an increase in water uptake, as observed with thin films. Interestingly, only partial Eudragit ® L leaching occurred in phosphate buffer pH 7.4 even at high enteric polymer contents, indicating that the GIT-insoluble polymer effectively hindered the dissolution of the entrapped Eudragit ® L. At high pH, both polymer leaching and polymer swelling contributed to the control of drug release. The determined apparent drug diffusion coefficients take the two effects adequately into account.