Grafting Of Glycine, Alanine, Serine, And Threonine On Cellulose Membranes And Their Role In Regulating The Uniport, Symport, And Antiport Permeation Of Glucose

Four cellulose membranes were grafted with glycine, L-alanine, L-serine, and L-threonine amino acids. The grafted membranes were characterized by different physicochemical techniques (ATR-IR, gravimetry, thermal degradation and ninhydrin test). The degree of substitution was found to range from 0.29 to 0.85 per glycoside unit, mainly occurring at C-6. This structural modification was further examined and found to modestly alter the thickness, hydrophilicity, pore size, porosity, tortuosity, and flux behavior of the native Cell-OH membranes. Accordingly, the performance of the modified membranes toward the permeation of D-glucose (D-Glu) was investigated in the presence of NaCl, KCl, and NaHCO(3)salts under uniport, symport, and antiport conditions. Data analysis allows the inspection of the role played by [Na](+)/[K](+)cations and [Cl](-)/[HCO3](-)in the permeation process of D-Glu. All data were examined in comparison with those obtained for the native Cell-OH membrane. The introduced functionalities are found to hinder the passage D-Glu under uniport conditions, while dramatically affect the symport and antiport migrations. The modified membranes facilitate the passage of D-Glu in symport mode where the anions (Cl(-)and HCO3_) play a key role in comparison with the cations (Na+, K+). However, the role of both cations and anions is seen in the antiport mode.