Poly (N-vinyl imidazole) gel-filled membrane adsorbers for highly efficient removal of dyes from water.

Energy-efficient and time-saving process for recovery of hazardous dyes from wastewater is highly desired in dyeing industry. In this work, poly(N-vinyl imidazole) (PVI) gel-filled membrane adsorbers were developed for highly efficient recovery of dyes through adsorption filtration. The membrane adsorbers were fabricated via dip-coating of Nylon macroporous membranes in PVI solutions followed by quaternization crosslinking with p-xylylene dichloride (XDC).

Surface zwitterionicalization of poly(vinylidene fluoride) membranes from the entrapped reactive core-shell silica nanoparticles.

We demonstrate the preparation and properties of poly(vinylidene fluoride) (PVDF) filtration membranes modified via surface zwitterionicalization mediated by reactive core-shell silica nanoparticles (SiO2 NPs). The organic/inorganic hybrid SiO2 NPs grafted with poly(methyl meth acrylate)-block-poly(2-dimethylaminoethyl methacrylate) copolymer (PMMA-b-PDMAEMA) shell were prepared by surface-initiated reversible addition fragmentation chain transfer (SI-RAFT) polymerization and then used as a membrane-making additive of PVDF membranes. The PDMAEMA exposed on membrane surface and pore walls were quaternized into zwitterionic poly(sulfobetaine methacrylate) (PSBMA) using 1,3-propane sultone (1,3-PS) as the quaternization agent.

Improving antifouling ability and hemocompatibility of poly(vinylidene fluoride) membranes by polydopamine-mediated ATRP.

The present work aims to improve the antifouling properties and hemocompatibility of poly(vinylidene fluoride) (PVDF) membranes by polydopamine-mediated atom transfer radical polymerization (ATRP). Polydopamine (PDA) was first prepared by the oxidation and self-polymerization in basic aqueous solution. The obtained PDA was used as an additive in the preparation of PVDF membranes via non-solvent induced phase separation (NIPS).

Ion Exchange and Antibiofouling Properties of Poly(ether sulfone) Membranes Prepared by the Surface Immobilization of Brønsted Acidic Ionic Liquids via Double-Click Reactions.

Brønsted acidic ionic liquids (BAILs) are unique ionic liquids that display chemical structures similar to zwitterions, and they were typically used as solvents and catalysts. In this work, an imidazole-based BAIL monolayer was fabricated onto poly(ether sulfone) (PES) membranes via surface clicking reactions, and the multifunctionality, including ion exchange and biofouling resistance to proteins and bacteria, was demonstrated, which was believed to be one of few works in which BAIL had been considered to be a novel fouling resistance layer for porous membranes. The successful immobilization of the BAILs onto a membrane surface was confirmed by X-ray photoelectron spectroscopy analysis, contact angle measurement, and ζ potential determination.

Versatile antifouling polyethersulfone filtration membranes modified via surface grafting of zwitterionic polymers from a reactive amphiphilic copolymer additive.

Here we describe the development of versatile antifouling polyethersulfone (PES) filtration membranes modified via surface grafting of zwitterionic polymers from a reactive amphiphilic copolymer additive. Amphiphilic polyethersulfone-block-poly(2-hydroxyethyl methacrylate) (PES-b-PHEMA) was beforehand designed and used as the blending additive of PES membranes prepared by phase inversion technique. The surface enriched PHEMA blocks on membrane surface acted as an anchor to immobilize the initiating site.

Route to hemocompatible polyethersulfone membranes via surface aminolysis and heparinization.

Polyethersulfone (PES) membranes with improved hemocompatibility were prepared via solid-liquid interface aminolysis and heparinization. Reactive amino groups were generated by immersing solid PES membranes in proper diamine solution. Heparin was covalent immobilized on the surface via amide bond.

Antifouling and antimicrobial polymer membranes based on bioinspired polydopamine and strong hydrogen-bonded poly(N-vinyl pyrrolidone).

A facile and versatile approach for the preparation of antifouling and antimicrobial polymer membranes has been developed on the basis of bioinspired polydopamine (PDA) in this work. It is well-known that a tightly adherent PDA layer can be generated over a wide range of material surfaces through a simple dip-coating process in dopamine aqueous solution. The resulting PDA coating is prone to be further surface-tailored and functionalized via secondary treatments because of its robust reactivity.

Hemocompatible and antibacterial porous membranes with heparinized copper hydroxide nanofibers as separation layer.

Here we report the fabrication of a novel heparinized copper hydroxide (Cu(OH)2) nanofiberous membrane with satisfying hemocompatibility and antibacterial properties. The positively charged Cu(OH)2 nanofibers were prepared in a weakly alkaline copper nitrate solution in the presence of 2-aminoethanol. A heparin (Hep) solution was then added dropwise into the solution of nanofibers to immobilize negatively charged heparin onto the Cu(OH)2 nanofibers by electrostatic interaction.

Surface characteristics of a self-polymerized dopamine coating deposited on hydrophobic polymer films.

This study aims to explore the fundamental surface characteristics of polydopamine (pDA)-coated hydrophobic polymer films. A poly(vinylidene fluoride) (PVDF) film was surface modified by dip coating in an aqueous solution of dopamine on the basis of its self-polymerization and strong adhesion feature. The self-polymerization and deposition rates of dopamine on film surfaces increased with increasing temperature as evaluated by both spectroscopic ellipsometry and scanning electronic microscopy (SEM).

Fabrication of superhydrophilic poly(styrene-alt-maleic anhydride)/silica hybrid surfaces on poly(vinylidene fluoride) membranes.

Superhydrophilic organic/inorganic hybrid surfaces have been fabricated on blend membranes of poly(vinylidene fluoride) (PVDF) and poly(styrene-alt-maleic anhydride) (SMA). The blend membranes were prepared from PVDF/SMA mixed solution with N,N-dimethylacetamide (DMAc) as solvent by immersion-precipitation phase inversion process. The gained blend membranes were immersed into γ-aminopropyltriethoxysilane (APTS) solution to generate SMA/silica hybrid surfaces by the reaction between anhydrides and APTS.

Immobilization of bovine serum albumin onto porous polyethylene membranes using strongly attached polydopamine as a spacer.

Based on the self-polymerization and strong adhesion characteristics of dopamine in aqueous solution, a novel and convenient approach was developed to immobilize protein onto porous polyethylene (PE) membranes. A thin polydopamine (pDA) layer was formed and tightly coated onto PE membrane by dipping simply the membrane into dopamine aqueous solution for a period of time. Subsequently, bovine serum albumin (BSA) was bound onto the obtained PE/pDA composite membranes via the coupling between BSA and the reactive polydopamine layer.

[Membrane fouling control in a free-end comb-like hollow fiber membrane bioreactor].

A free-end comb-like hollow fiber membrane bioreactor was applied to treat wastewater. The results clearly showed that membrane fouling, defined as permeate flux decline, was greatly influenced by membrane module configuration. The permeate flux decline was much less for module b, demonstrating the superiority of module b over module a.

Surface modification of PVDF porous membranes via poly(DOPA) coating and heparin immobilization.

Based on the strong adhesive behavior of poly(3,4-dihydroxy-l-phenylalanine) (or poly(DOPA)) on solid surface, poly(vinylidene fluoride) (PVDF) microporous membranes were surface-modified by the self-polymerization of DOPA in aqueous solution. Subsequently, heparin was immobilized covalently onto the obtained PVDF/poly(DOPA) composite membranes by the coupling between heparin and poly(DOPA) coating. The modified membranes were subjected to a long-term washing, and the firm immobilization of poly(DOPA) and heparin was confirmed by X-ray photoelectron spectroscopy (XPS).

Improving hydrophilicity and protein resistance of poly(vinylidene fluoride) membranes by blending with amphiphilic hyperbranched-star polymer.

To endow hydrophobic poly(vinylidene fluoride) (PVDF) membranes with reliable hydrophilicity and protein resistance, an amphiphilic hyperbranched-star polymer (HPE-g-MPEG) with about 12 hydrophilic arms in each molecule was synthesized by grafting methoxy poly(ethylene glycol) (MPEG) to the hyperbranched polyester (HPE) molecule using terephthaloyl chloride (TPC) as the coupling agent and blended with PVDF to fabricate porous membranes via phase inversion process. The chemical composition changes of the membrane surface were confirmed by X-ray photoelectron spectroscopy (XPS), and the membrane morphologies were measured by scanning electron microscopy (SEM). Water contact angle, static protein adsorption, and filtration experiments were used to evaluate the hydrophilicity and anti-fouling properties of the membranes.

Improved protein-adsorption resistance of polyethersulfone membranes via surface segregation of ultrahigh molecular weight poly(styrene-alt-maleic anhydride).

A styrene-maleic anhydride (SMA) alternating copolymer with ultrahigh molecular weight (M(w)>10(6)) synthesized in super critical carbon dioxide (SC CO(2)) medium was used as hydrophilic polymeric additive in the preparation of polyethersulfone (PES) membranes. The PES/SMA blend membranes were prepared by immersion precipitation process. X-ray photoelectronic spectroscopy (XPS) measurements confirmed that the hydrolyzed SMA preferentially segregated to membrane-coagulant interface during membrane formation.

[Study on the process for wastewater treatment in submerged rotating membrane bioreactor].

The process for wastewater treatment in submerged rotating membrane bioreactor (SRMBR) was studied. It was found that the effluent COD reduced to 20 mg/L after one day running when the influent COD varied from 160 mg/L to 368 mg/L. The equilibrium membrane flux increased rapidly with increasing rotation speed of membrane in the range of 0 to 25r/min.

Novel, fluorescent, magnetic, polysaccharide-based microsphere for orientation, tracing, and anticoagulation: preparation and characterization.

A fluorescent, magnetic composite poly(styrene-maleic anhydride) microsphere, suitable for conjugation with polysaccharide, was synthesized using magnetite/europium phthalate particles as seeds by copolymerization of styrene and maleic anhydride. The magnetite/europium phthalate particles were wrapped up by poly(ethylene glycol), which improved the affinity between the seed particles and the monomers. The composite microspheres obtained, with a diameter of 0.

[Separation of carbon dioxide from gas mixture by membrane contactor].

In this paper, membrane contactor made of hydrophobic hollow fiber polypropylene porous membrane (HFPPM) was used for separating carbon dioxide (CO2) from CO2/N2 mixtures. The effects of absorbents, concentration and flow rate of feeding gas and absorbent solution, lumen/shell side processes and gas permeability of HFPPM(P) on the CO2 absorption efficiency were investigated. It was found that the absorption efficiency of three absorbents ranged in order of ethanolamine > sodium hydroxide > diethanol amine.

[Processing conditions of recirculated MBR for wastewater treatment].

In this paper, wastewater was treated with Recirculated Membrane Bio-Reactor (RMBR) and effluent quality became stable after four days running continuously. Critical membrane flux was increased with increasing crossflow velocity between 0.9-1.