Increasing the Permeability of Polyphenylene Sulfone Hollow Fiber Ultrafiltration Membranes by Switching the Polymer End Groups.

The influence of the molecular weight and chemical structure of polyphenylene sulfone (PPSU) end groups on the formation of the porous structure of ultrafiltration (UF) hollow fiber membranes was investigated. Polymers with a molecular weight ranging from 67 to 81 kg/mol and with a hydroxyl-to-chlorine end group ratio ranging from 0.43 to 17.

Effect of Side Substituent on Comb-like Polysiloxane Membrane Pervaporation Properties During Recovery of Alcohols C2-C4 from Water.

The pervaporation properties of membranes based on comb-like polysiloxanes when C-C alcohols are removed from water were studied for the first time. It was established that membranes based on comb-like polysiloxanes with linear aliphatic and organosilicon substituents have increased permeability selectivity for C alcohols. The obtained results were interpreted from the point of view of the solubility of the components of the separated mixture in polysiloxanes.

High-Performance Porous Supports Based on Hydroxyl-Terminated Polysulfone and CO/CO-Selective Composite Membranes.

The scope of this work was to develop a thin-film composite (TFC) membrane for the separation of CO/CO mixtures, which are relevant for many processes of gas processing and gasification of carbon-based feedstock. Special attention was given to the development of highly permeable porous polysulfone (PSF) supports (more than 26,000 GPU for CO) since both the selective and support layers contribute significantly to the overall performance of the TFC membrane. The PSF porous support is widely used in commercial and lab-scale TFC membranes, and its porous structure and other exploitation parameters are set during the non-solvent-induced phase separation (NIPS) process.

Removal of Phenol by 1CP after Dormancy: Insight into Enzymes' Induction, Specificity, and Cells Viability.

Biodegradation of phenol is an effective method for removing this toxicant from contaminated sites. Phenol is a toxic compound for living cells, so many bacteria degrade phenol in relatively low concentrations, up to 0.75 g L.

Highly Permeable Ultrafiltration Membranes Based on Polyphenylene Sulfone with Cardo Fragments.

For the first time, copolymers of polyphenylene sulfone (PPSU) with cardo fragments of phenolphthalein (PP) were synthesized to develop highly permeable flat-sheet ultrafiltration membranes. By introducing cardo fragments into the polymer chain, we achieved a mechanical strength 1.3 times higher than the strength of commercial PPSU.

Pervaporation and Gas Separation Properties of High-Molecular Ladder-like Polyphenylsilsesquioxanes.

This paper presents the results of studies on the pervaporation properties (for benzene/hexane mixtures) and gas permeability (for He, H, N, O, CO, CH, CH, and CH) of ladder-like polyphenylsesquioxanes (L-PPSQ) with improved physical and chemical properties. These polymers were obtained by condensation of -tetraphenylcyclotetrasiloxanetetraol in ammonia medium. The structure of L-PPSQ was fully confirmed by a combination of physicochemical analysis methods: H, Si NMR, IR spectroscopy, HPLC, powder XRD, and viscometry in solution.

Membranes Based on Cellulose and Copolymers of Acrylonitrile Prepared from Joint Solutions.

Cellulose and copolymers of acrylonitrile (PAN) are characterized by their chemical resistance to several conventional solvents. Therefore, these polymers are often used to obtain membranes for the recovery of such solvents. In this work, for the first time, composite membranes formed from highly concentrated mixed solutions based on cellulose and PAN are considered (the total content of polymers is 18 wt.

Stability of Porous Polymeric Membranes in Amine Solvents for Membrane Contactor Applications.

Membrane gas-liquid contactors have great potential to meet the challenges of amine CO capture. In this case, the most effective approach is the use of composite membranes. However, to obtain these, it is necessary to take into account the chemical and morphological resistance of membrane supports to long-term exposure to amine absorbents and their oxidative degradation products.

Monoethanolamine (MEA) Degradation: Influence on the Electrodialysis Treatment of MEA-Absorbent.

The thermal-oxidative degradation of aqueous solutions of carbonized monoethanolamine (MEA, 30% wt., 0.25 mol MEA/mol CO) was studied for 336 h at 120 °C.

The Effect of Non-Solvent Nature on the Rheological Properties of Cellulose Solution in Diluted Ionic Liquid and Performance of Nanofiltration Membranes.

The weak point of ionic liquids is their high viscosity, limiting the maximum polymer concentration in the forming solutions. A low-viscous co-solvent can reduce viscosity, but cellulose has none. This study demonstrates that dimethyl sulfoxide (DMSO), being non-solvent for cellulose, can act as a nominal co-solvent to improve its processing into a nanofiltration membrane by phase inversion.

Characterization of a New Strain Ch2, a Degrader of Toxic Anthropogenic Compounds -Caprolactam and Glyphosate.

In this work, a new Ch2 strain was isolated from soils polluted by agrochemical production wastes. This strain has a unique ability to utilize toxic synthetic compounds such as -caprolactam (CAP) as a sole carbon and energy source and the herbicide glyphosate (GP) as a sole source of phosphorus. Analysis of the nucleotide sequence of the 16S rRNA gene of Ch2 revealed that the strain belongs to the species .

Eco-Friendly OSN Membranes Based on Alginate Salts with Variable Nanofiltration Properties.

In this work, membranes for organic solvents nanofiltration (OSN) based on a natural polymer, sodium alginate, were fabricated. They are chemically stable in organic solvents, including aprotic polar solvents. The unique advantage of these membranes is the absence of toxic reagents and solvents during their production.

Film Distillation with a Porous Condenser for Seawater Desalination: Evaluation of Materials' Stability in the Tropical Climate of Vietnam.

Desalination and treatment of wastewater has become critical for Asia regions with water scarcity. In this work, the concept of thin-film distillation equipped with a porous condenser (FDPC) was considered for its implementation in a tropical climate of Vietnam. It was found that samples with a concentration of biocide of 0.

Morphological Analysis of Poly(4,4'-oxydiphenylene-pyromellitimide)-Based Organic Solvent Nanofiltration Membranes Formed by the Solution Method.

Poly-(4,4'-oxydiphenylene) pyromellitimide or Kapton is the most widely available polyimide with high chemical and thermal stability. It has great prospects for use as a membrane material for filtering organic media due to its complete insolubility. However, the formation of membranes based on it, at the moment, is an unsolved problem.

Effect of Composition and Viscosity of Spinning Solution on Ultrafiltration Properties of Polyphenylene Sulfone Hollow-Fiber Membranes.

In this work, PPSUs with different molecular weights were synthesized for the development of highly permeable ultrafiltration hollow fiber membranes for the first time. The M of the synthesized polymers was controlled by varying the monomers molar ratio within 1:1-1.15 under the same synthesis conditions.

Alginate Ag for Composite Hollow Fiber Membrane: Formation and Ethylene/Ethane Gas Mixture Separation.

Membranes based on natural polymers, in particular alginate, are of great interest for various separation tasks. In particular, the possibility of introducing silver ions during the crosslinking of sodium alginate makes it possible to obtain a membrane with an active olefin transporter. In this work, the creation of a hollow fiber composite membrane with a selective layer of silver alginate is proposed for the first time.

Selective Destruction of Soluble Polyurethaneimide as Novel Approach for Fabrication of Insoluble Polyimide Films.

Polymeric coatings and membranes with extended stability toward a wide range of organic solvents are practical for application in harsh environments; on the other hand, such stability makes their processing quite difficult. In this work, we propose a novel method for the fabrication of films based on non-soluble polymers. The film is made from the solution of block copolymer containing both soluble and insoluble blocks followed by selective decomposition of soluble blocks.

Structure, Morphology, and Permeability of Cellulose Films.

The work is focused on the study of the influence of the cellulose type and processing parameters on the structure, morphology, and permeability of cellulose films. The free volume of the cellulose films was evaluated by the sorption of n-decane, which is a non-solvent for cellulose. The structural features of the membranes and their morphology were studied using X-ray diffraction, IR spectroscopy, SEM, and AFM methods.

Polymeric Membranes for Oil-Water Separation: A Review.

This review is devoted to the application of bulk synthetic polymers such as polysulfone (PSf), polyethersulfone (PES), polyacrylonitrile (PAN), and polyvinylidene fluoride (PVDF) for the separation of oil-water emulsions. Due to the high hydrophobicity of the presented polymers and their tendency to be contaminated with water-oil emulsions, methods for the hydrophilization of membranes based on them were analyzed: the mixing of polymers, the introduction of inorganic additives, and surface modification. In addition, membranes based on natural hydrophilic materials (cellulose and its derivatives) are given as a comparison.

Recovery of Model Pharmaceutical Compounds from Water and Organic Solutions with Alginate-Based Composite Membranes.

In this work, we combined the non-solvent induced phase separation (NIPS) and further cross-linking by cations towards the preparation of nanofiltration membranes based on sodium alginate, a biodegradable, natural polymer. Acetone, ethanol, toluene, and hexane were used as non-solvents, and cations of calcium, silver, and aluminum-for polymer cross-linking, respectively. Results showed the precipitation strength of non-solvent played a noticeable role in the membrane's performance; for instance, the toluene permeability changed by four orders of magnitude with the decrease of precipitation strength of the non-solvent: acetone ( = 0.

Express Method of Preparation of Hollow Fiber Membrane Samples for Spinning Solution Optimization: Polysulfone as Example.

This article describes a new technique for the preparation of hollow fiber (HF) membrane samples using an automatic manipulator unit. The manipulator uses a syringe needle to form a HF of a given geometry. The needle in automatic mode is sequentially immersed, first into the polymer solution and then into the coagulation bath.

Characterization of Soil Bacteria with Potential to Degrade Benzoate and Antagonistic to Fungal and Bacterial Phytopathogens.

The intensive development of agriculture leads to the depletion of land and a decrease in crop yields and in plant resistances to diseases. A large number of fertilizers and pesticides are currently used to solve these problems. Chemicals can enter the soil and penetrate into the groundwater and agricultural plants.

Morphology and transport properties of membranes obtained by coagulation of cellulose solutions in isobutanol.

The evolution of structural-morphological transformations of cellulose membranes obtained from solutions in N-methylmorpholine-N-oxide through various temperature isobutanol coagulation baths and subsequent treatment with water and their transport properties were studied. Using SEM, it was found that during coagulation in water and drying of the membranes, a uniform monolithic microheterogeneous texture was formed. The replacement of an aqueous precipitation bath with an isobutanol one leads to the formation of a porous structure with wide pore size and shape distributions.

Phase Separation within a Thin Layer of Polymer Solution as Prompt Technique to Predict Membrane Morphology and Transport Properties.

In this work, the precipitation of a thin layer of a polymer solution was proposed to imitate the process of asymmetric membrane formation by a non-solvent induced phase separation (NIPS) technique. The phase inversion within the thin (<500 μm) and bulk (~2 cm) layer of polyamic-acid (PAA) in N-methyl-2-pyrrolidone (NMP) by using water as non-solvent was considered. It was shown that polymer films formed within the "limited" layer of polymer solution showed a good agreement with the morphology of corresponded asymmetric flat-sheet membranes even in the case of three-component casting solution (PAA/NMP/EtOH).

Alternative Naphthalene Metabolic Pathway Includes Formation of ortho-Phthalic Acid and Cinnamic Acid Derivatives in the Rhodococcus opacus Strain 3D.

Naphthalene, as a component of crude oil, is a common environmental pollutant. Biochemical and genetic aspects of naphthalene catabolism have been examined in most detail in the bacteria of Pseudomonas genus. In pseudomonads, the key intermediate in naphthalene degradation is salicylate.