Karakteristik Fluks Membran Kitosan Termodifikasi Poli(Vinil Alkohol) Dengan Variasi Poli(Etilena Glikol) Sebagai Porogen

Abstract

Chitosan-poly(vinyl-alcohol) membrane with glutaraldehyde as cross-linked agent was classified as semi-interpenetrating network (semi-IPN) hydrogel structure. Chitosan is naturally abundant and renewable polysaccharide extracted from crustacean shells (e.g. shrimp and crab). Poly(vinyl-alcohol) or PVA is a synthetic polymer with excellent mechanical properties. Nine types of chitosan- PVA membrane were prepared from dope constituted of chitosan solution 3% (b/v), 33.30 μM glutaraldehyde 25% (v/v), and concentration of both PEG (poly(ethylene glycol)) and PVA varied from 0.0, 2.5, and 5.0%. Diluted acetic acid 1% (v/v) was used as the solvent for the dope preparation. Membrane dope was casted onto a glass plate surface and evaporated for a night at room temperature. It was then immersed in NaOH 1 M as nonsolvent for 2-3 hours. The resulting membrane was rinsed and neutralized by water and then the flux determined using destilled water (pH 7.3) and buffer phosphate pH 6 solution as feed fluids. The flux was measured at various pressure of 2.5, 5.0, 7.5, and 10.0 psi for destilled water and from 2.5 and 10.0 psi for buffer. The flux of destilled water was higher than the flux of buffer. These phenomenon showed sensitive property of hydrogel membrane upon pH environment, as the hydrogel itself was swollen in acetic condition cause reducing the membrane pore diameter. The flux decreased as PVA percentage increased, while increasing PEG percentage as the porogen increased the flux. The applied pressures was the main driving force on membrane transport and the effect on flux decreased the applied pressure increased. It was caused by compaction phenomenon occured on the matrix of membrane as related with the hydrogel structure.