The effect of sulfonated polysulfone on the compatibility and structure of polyethersulfone-based blend membranes

Preparation of Porous Polymeric Membranes Based on a Pyridine Containing Aromatic Polyether Sulfone

Polymeric membranes, based on a polysulfone-type aromatic polyether matrix, were successfully developed via the non-solvent induced phase separation (NIPS) method. The polyethersulfone type polymer poly[2-(4-(diphenylsulfonyl)-phenoxy)-6-(4-phenoxy) pyridine] (PDSPP) was used as the membrane matrix, and mixed with its sulfonated derivative (SPDSPP) and a polymeric porogen. The SPDPPP was added to impart hydrophilicity, while at the same time maintaining the interactions with the non-sulfonated aromatic polyether forming the membrane matrix. Different techniques were used for the membranes' properties characterization. The results revealed that the use of the non-sulfonated and sulfonated polymers of the same polymeric backbone, at certain compositions, can lead to membranes with controllable porosity and hydrophilicity.

Multifunctionalized polyethersulfone membranes with networked submicrogels to improve antifouling property, antibacterial adhesion and blood compatibility

Intensive efforts have been employed in modifying biomedical membranes. Among them, blending is recognized as a simple method. However, the conventional blending materials commonly lead to an insufficient modification, which is mainly caused by the poor miscibility between the blending materials and the matrixes, the elution of the hydrophilic materials from the matrixes during the use and storage, and the insufficient surface enrichment of the blending materials. Aiming to solve the abovementioned disadvantages, we developed novel polyethersulfone/poly(acrylic acid-co-N-vinyl-2-pyrrolidone) networked submicrogels (PES/P(AA-VP) NSs), which were blended with PES to enhance the antifouling properties, antibacterial adhesion and haemocompatible properties of PES membranes. As results, the PES/P(AA-VP) NSs showed good miscibility with the PES matrix, and hydrophilic submicrogels would enrich onto the membrane surface during the phase inversion process due to the surface segregation. The entanglement between the PES matrix and the networked submicrogels would effectively limit the elution of the submicrogels. In conclusion, the modified PES membranes prepared by blending with the PES/P(AA-VP) NSs might draw great attention for the application in haemodialysis fields.

Application and modification of polysulfone membranes

Polysulfone (PSf) is a favorite polymer for the production of membrane due to its excellent physicochemical properties, including thermal stability; good chemical resistance to different materials such as different bases, acids, and chlorine; sufficient mechanical strength; and good processability. The present study offers an overview of the recent development in the application and modification of PSf membranes, focusing on some applications such as water and wastewater treatment, membrane distillation, pollutant removal, gas separation, separator for lithium ion battery, and support of composite membranes. In general, there are two major difficulties in the use of membranes made of PSf: membrane fouling and membrane wetting. Therefore, PSf membrane with good anticompaction and antifouling properties is reviewed. Finally, important issues related to the modification of PSf membranes for real applications are discussed. This article provides an intelligent direction for the progress of PSf membranes in the future.

Triple-Action Self-Healing Protective Coatings Based on Shape Memory Polymers Containing Dual-Function Microspheres

In this study, a new self-healing shape memory polymer (SMP) coating was prepared to protect the aluminum alloy 2024-T3 from corrosion by the incorporation of dual-function microspheres containing polycaprolactone and the corrosion inhibitor 8-hydroxyquinoline (8HQ). The self-healing properties of the coatings were investigated via scanning electron microscopy, electrochemical impedance spectroscopy, and scanning electrochemical microscopy following the application of different healing conditions. The results demonstrated that the coating possessed a triple-action self-healing ability enabled by the cooperation of the 8HQ inhibitor, the SMP coating matrix, and the melted microspheres. The coating released 8HQ in a pH-dependent fashion and immediately suppressed corrosion within the coating scratch. After heat treatment, the scratched coating exhibited excellent recovery of its anticorrosion performance, which was attributed to the simultaneous initiation of scratch closure by the shape memory effect of the coating matrix, sealing of the scratch by the melted microspheres, and the synergistic effect of corrosion inhibition by 8HQ.

Low-Pressure Nanofiltration Hollow Fiber Membranes for Effective Fractionation of Dyes and Inorganic Salts in Textile Wastewater

In this work, novel loose nanofiltration (NF) hollow fiber membranes with ultrahigh water permeability and well-defined nanopore and surface charge characteristics were developed for effective fractionation of dyes and inorganic salts in textile wastewater treatment. The as-spun NF hollow fiber possesses a high pure water permeability (PWP) of 80 L·m^-2·h^-1·bar^-1 with a small pore size of 1.0 nm in diameter and a MWCO of 1000 Da. The surface modification by means of hyperbranched polyethylenimine (PEI) further lowers the pore diameter to 0.85 nm and MWCO to 680 Da. The membrane surface also becomes more hydrophilic and positively charged after the PEI modification. Because of the synergistic effects from size exclusion and charge repulsion, the newly developed NF hollow fibers show high permeation fluxes of 7.0-71.2 L·m^-2·h^-1 and great rejections of 95.5-99.9% to various dyes at a low operating pressure of 1 bar. At the same time, they have ultralow rejections of less than 10% to inorganic salts (i.e., Na₂SO₄), suggesting that more than 90% of the salts would permeate through the fibers. In addition, the two hollow fibers exhibit outstanding performance stability, low fouling tendency, and great fouling reversibility. Their fluxes can be brought back to be more than 80% of the original values by a simple physical backwash. The newly developed loose NF hollow fiber membranes may have great potential for effective fractionation and treatment of textile wastewater.

Mesh-Embedded Polysulfone/Sulfonated Polysulfone Supported Thin Film Composite Membranes for Forward Osmosis

In this work, mesh-embedded polysulfone (PSU)/sulfonated polysulfone (sPSU) supported thin film composite (TFC) membranes were developed for forward osmosis (FO). The robust mesh integrated in PSU/sPSU sublayer imparts impressive mechanical durability. The blending of hydrophilic sPSU in PSU sublayer affects the hydrophilicity, porosity, pore structure, and pore size of mesh-embedded PSU/sPSU substrates, and the total thickness, cross-linking degree, and roughness of the corresponding TFC-FO membrane active layers. An appropriate incorporation of sPSU not only significantly decreases the structural parameter, S of the mesh-embedded substrate to 220 μm, which is the lowest reported value for fabric backed FO membrane, but also optimizes the permselectivity of the formed active layer. Regarding the osmosis performance, TFC membranes with sPSU modified substrates gain a higher water flux (J_w) while keeping the specific reverse salt flux (J_s/J_w) low. The optimal TFC-FO membrane has a J_w of 31.76 LMH with J_s/J_w of 0.19 g/L in FO mode when using deionized water feed and 1 M NaCl draw solution. This paper is practical for developing TFC-FO membrane on hydrophilic support membrane materials.

Improved filtration performance and antifouling properties of polyethersulfone ultrafiltration membranes by blending with carboxylic acid functionalized polysulfone

Ultrafiltration membranes with improved filtration performance and antifouling properties have been synthesized through blending polyethersulfone with carboxylic acid functionalized polysulfone.

Phase Inversion Directly Induced Tight Ultrafiltration (UF) Hollow Fiber Membranes for Effective Removal of Textile Dyes

This study has demonstrated the application of tight ultrafiltration (UF) membranes for effective removal of textile dyes from water at a low pressure. Novel UF hollow fiber membranes with well-defined nanopores and surface charges were developed via a single-step spinning process without any post-treatment. The newly developed tight UF hollow fibers not only possess a small mean pore diameter of 1.0-1.3 nm with a molecular weight cutoff (MWCO) of 1000-2000 Da but also have a high pure water permeability (PWP) of 82.5-117.6 L m^-2 h^-1 bar^-1. Through the synergistic effects of size exclusion and charge repulsion, the novel UF hollow fibers can effectively remove various dyes with impressive rejections of 93.2-99.9% at 1 bar. At the same time, more than 92% of inorganic salts (i.e., NaCl and Na₂SO₄) would permeate through the fibers, reducing the detrimental effects of concentration polarization and providing an attracted avenue for salts reuse. The tight UF hollow fibers also exhibit robust performance in a continuous operation of 170 h or at a high feed recovery of 90%. The fouled fibers can be easily regenerated by backwash of water with a flux recovery of larger than 92%. The newly developed tight UF hollow fiber membranes display huge potential for treating textile wastewater and other impaired effluents because of their great separation performance and simple fabrication process.