Papers by Keyword: Membrane

Abstract: Membrane technology advancement has gained momentous consideration around the globe because of their appealing highlights, such as effectiveness, low expenses, and effective solutions for longstanding issues in alchemical industries. This study expected to incorporate graphene nanoparticles into Polyvinylidene difluoride (PVDF) to form nanofiltration (NF) layers using DMF (Dimethyl formamide) as solvent via DIPS (diffusion induced phase separation) technique. PVDF polymer membrane performances with varied percent (1 – 6% wt.) of graphene concentrations are studied Infrared spectral, water uptake, water contact angle, and ion rejection measurements. Scanning electron microscope (SEM) analysis showed that the pore size is often regulated by incorporating graphene nanoparticles (80-90 nm) as compared to PVDF membranes. The PVDF membranes exhibited a relative increase in the contact angle from PVDF to PVDF-G6% i.e. 50.3° to 63.46 ± .3, thus, showing a relative increase in hydrophobicity. The higher percent of graphene (> 6% by wt.) results in nanoparticle accumulation that showed the performances of PVDF/graphene rejection possessing relatively the same results. The results confirmed that the prepared membranes possess an excellent ability to treat wastewater.

Abstract: In this study, chitosan (Chi), alginate (Alg), and mesoporous phosphotungstic acid (mPTA) were used as electrolyte membrane materials for DMFC. Chi and Alg will be crosslinked with mPTA filler to improve the performance of the electrolyte membrane. Characterizations carried out include tensile tests, methanol permeability, and proton conductivity. The results of the tensile test showed that the Chi-Alg(3:1) membrane had a higher tensile strength value (26.64 N/mm²) than the pure chitosan membrane (11.97 N/mm²). The results of methanol permeability show that the Chi-Alg(3:1)/mPTA(2.0%) membrane has a lower methanol permeability value (8.17 × 10^-6 cm² s^-1) and a relatively high proton conductivity value, (45.8 × 10^-3 S cm^-1). Chi-Alg/mPTA membrane, simplicity of the used simple preparation method and the cost reduction can be applied as an electrolyte membrane for DMFC.

Abstract: Biogas is one of the renewable energy alternatives. The heat of burning biogas depends on the percentage of CH₄ (methane) gas and CO₂ (carbon dioxide) gas. Biogas with high impurity gas components, such as CO₂ and H₂S (hydrogen sulfide), can cause a decrease in heating value. Therefore, purification efforts are needed. The adsorber membrane was successfully made from oil palm empty fruit bunches (OPEFB) which were pyrolyzed as physical activation. The adsorber membrane is activated to form a porous structure and a usable surface area for gas separation. This study aims to see the effect of variations in the carbon weight of OPEFB on reducing CO₂ levels in the Gunung Kupang landfill biogas. Preparation of OPEFB adsorber membrane by mixing PVA (polyvinyl alcohol) and PEG (polyethylene glycol) polymers into OPEFB with varying weights, namely 12.5, 15, and 17.5 g (grams). Membrane performance is determined based on the results of the flame test and gas chromatography test results. Based on the results of the flame test of the biogas that has been passed on the adsorber membrane, overall all samples showed a predominantly bright blue flame color. Meanwhile, the chromatographic test results showed a decrease in CO₂ levels in samples of 12.5, 15, and 17.5 g, respectively 19.6%, 32.02%, and 61.58%. The results of the flame test and gas chromatography test prove that the difference in mass weight affects the performance of the samples tested where the greater the mass of adsorber membrane used, the greater the increase in absorbed CO₂ gas content.

Abstract: Plastic, a non-biodegradable material has always been a concern to the environment and people. This single-use item generates waste to landfills and it persists for centuries once disposed. The urge of transforming such material into a highly valuable product has sought attention from many researchers. This study emphasizes on a nanotechnological approach to synthesize vertically-aligned carbon nanotubes (CNTs) on a substrate template using commercially available plastic bags as carbon precursor. CNTs are grown inside a hexagonally arranged nanoporous anodic alumina membranes (NAAMs). CNTs are liberated by wet chemical etching to dissolve the alumina matrix. The resulting CNTs are used as adsorption media filters for water treatment purpose. The high adsorption affinity towards heavy metals, organic matters and microbes, ability to antifouling and self-cleaning function have made CNTs a better choice over others. This article briefly discusses the catalyst-free synthesis, growth mechanism, characterization and functionalization of CNTs for water treatment application.

Abstract: This study reports the effect of plasticizers namely isopropanol, polyethylene glycol, maltitol and spermidine on the properties of the sodium alginate composite membrane. The concentration of each potential plasticizer was set at minimum to execute performance. Properties of sodium alginate were studied through characterization studies - Field Emission Scanning Electron Microscope (FESEM) to observe on the morphology structure. The membrane performance is also seen through water uptake and swelling ratio tests. Isopropanol produced better plasticizer with the lowest water uptake of 575.53% and less hydrophilic compared to spermidine (1268.46%), polyethylene glycol (1014.30%) and maltitol (595.82%). Further study may require copolymerization to support polyol for ensuring structure firmness. This study proven the plasticizers could enhance membrane’s flexibility in DMFC and becoming a promising choice of additives for better alginate-based membrane establishment.

Abstract: Synthesis of alginate/zeolite membrane with the glycerol plasticizer for separation of CH₄ towards CO₂ has been carried out. This study aimed to investigate the effect of glycerol addition towards physical and mechanical properties of membrane on the permeability and selectivity of CH₄/CO₂. Membrane fabrication was done with mixing of alginate and activated zeolite in the aquabidest with glycerol addition as plasticizer with mass ratio of alginate:glycerol 1:0, 1:0.25, 1:0.5, 1:1 and stirring for 24 h and templeting at room temperature. Membrane formed was tested with FTIR, XRD, SEM, Texture Analyzer and Permeation gas cell. Result showed that glycerol addition into alginate can decrease tensile strength and increase elongation value for about 20% on the mass ratio alginate:glycerol 1:1. Besides, gas permeation rate was also influence by the glycerol addition. The highest permeability of CH4 was obtained with alginate:glycerol 1:0,25 and with permeation rate 1.03 × 10^-4 cm³ (STP) cm^-2 s^-1 cmHg^-1. Meanwhile, the highest permeability of CO₂ was obtained with the mass ratio alginate:glycerol 1:0,5 with permeation rate about 1,19 × 10-5 cm³ (STP) cm^-2 s^-1 cmHg^-1. The highest selectivity indicated that separation of CH₄/CO₂ occurred well about 49.2 for alginate:glycerol 1:1.

Abstract: A series of accelerated degradation experiments at high temperatures have been performed for Pd-coated V-10 mol% Fe alloy membranes in order to investigate the degradation behavior of hydrogen permeability. The degradation of the membrane becomes severer with increasing testing temperature. The temperature dependence of the 20% degradation rate almost obeys the Arrhenius relationship, suggesting that the degradation phenomenon occurs by a kind of thermal activation process. It is found that the addition of a small amount of W into Pd overlayer improves the durability of the membrane significantly.

Abstract: PAN membranes were prepared from mixture of good and weak solvents by two different methods. Immersion precipitation method with and without volatile component evaporation used for membrane preparation. From analysis of Hansen solubility parameters DMSO chosen as good solvent and acetone chosen as weak solvent. The effect of volatile weak solvent investigated on pore size and filtration performance. By evaporation of acetone, it was possible to increase polymer concentration on casting solution and obtain smaller pore size in comparison to membrane prepared from DMSO. Membranes prepared from DMSO/acetone without solvent evaporation had even lower pore size and higher filtration performances. It was shown, that presence of acetone creates more pronounced effect on pore size than increase of polymer concentration. As a result membranes with pore size 3.7 nm obtained from Acetone/DMSO mixture with composition 50:50 and polymer concentration 50 % by immersion precipitation Resulted membranes have permeance 23 kg/m²·h·bar and retention of Lysozime 99 %.

Abstract: Samples of nanoscale nano-PAF-10 and nano-PAF-24 porous aromatic framework-like polymeric materials were synthesized using the Suzuki reaction in a microemulsion. Monomers were tetrakis-(p-bromophenyl)methane and 1,4-phenylenediboronic acid. The main idea of the approach is to use 1,4-phenylenediboronic acid not only as a direct participant in the reaction, but also as a surfactant, which allows to stabilize the drops of the emulsion. Using this procedure, samples of PAF-like polymers were synthesized from the mixture, containing the mixture of tetrakis(p-bromophenyl)methane and 1,4-phenylenediboronic acid in ratio from 1:2 to 1:6; the reaction was conducted from 10 to 24 hours. The resulting materials were characterized by IR spectroscopy, NMR spectroscop. To estimate the particle size of the obtained materials, transmission electron microscopy was used. The object of the study were polymers, that were synthesized in 10-hour and 24-hour reactions. The particle size in the first material was in the range of 3-10 nm, in the second - from 30 to 100 nm.

Abstract: Polysulfone/ Recam® composite membranes were prepared via the wet-phase inversion method. The interactions between polysulfone and additive were revealed by Fourier-transformed infrared spectroscopy and atomic force microscopy. Material properties, such as thermal and mechanical ones, were also analyzed. The increase of rugosity by augmenting the Recam® content was depicted by AFM images. Infrared spectroscopy provided very useful information about the interactions between polymer chains and additive. Thermal stability and mechanical resistance showed dependence on the additive content, which were higher for higher contents.