Effects of surface crosslinking on sieving characteristics of chitosan/poly(acrylonitrile) composite nanofiltration membranes

Abstract

Effects of surface crosslinking of chitosan/poly(acrylonitrile) (PAN) composite nanofiltration membranes at different crosslinker (glutaraldehyde) concentrations and crosslinking times on their surface chemical composition and sieving properties such as pure water permeation, molecular weight cut-off and the rejection of mono/divalent salts and mono/oligosaccharides were investigated. Fourier transform infrared-attenuated total reflectance spectroscopy (FTIR-ATRS) and X-ray photoelectron spectroscopy (XPS) studies revealed the crosslinking of chitosan with glutaraldehyde as well as variations in chemical composition with glutaraldehyde concentration and crosslinking time. Pure water permeation/swelling in water decreased and rejection of salts and sugars increased with increasing glutaraldehyde concentration, indicating pore contraction and increase in hydrophobicity as well as pore tortuosity due to crosslinking. Molecular weight cut-offs of surface crosslinked membranes were in the range of 550 -700 Da, a characteristic of nanofiltration membranes, whereas uncrosslinked membrane had cut-off of \ 1500 Da. The crosslinked membranes were found to be stable over 10-h operation for pure water permeation and the stability increased with increasing glutaraldehyde concentration.

Endothelialization of chitosan porous conduits via immobilization of a recombinant fibronectin fragment (rhFNIII7–10)

“…The decrease in the peaks at 1070 and 1032 cm -1 (C-O stretching and C-N stretching in >CH-NH2 [33][34][35]) further confirms the grafting of rhFNIII7-10 at the expense of CH primary amines. Spectrum analysis also revealed an increase in the Amide I peak (C@O stretching in primary amides) amounts of rhFNIII7-10 compared with DA 4% (Fig.…”

UV-curable enzymatic antibacterial waterborne polyurethane coating

“…The phenomenon suggested that the combination of enzymes and coatings was not based on simple blending, but on covalent incorporation of enzymes into polyurethane matrix as schematically illustrated in Scheme 1. Such covalent incorporation possibly resulted in the insertion of hydrophobic carbon skeleton, similar to some crosslinking reaction [34], therefore led to the increase in contact angle of the coating.…”

Electrospun Nanofiber Membranes and Their Applications in Water and Wastewater Treatment

“…PAN is resistant to most solvents and therefore a common polymer in preparation of ultrafiltration [74], nanofiltration [75], and reverse osmosis membranes [76]. Chitosan is a hydrophilic biopolymer that is commonly used for its anti-fouling characteristics [77]. A thin layer of chitosan coated on the surface of the PAN ENM would allow water to permeate with minimum resistance and, because of its smooth surface, would minimize fouling.…”