EFFECT OF BENTONITE ADDITION ON THE CHARACTERISTICS OF POLY(VINYLIDENE FLUORIDE) (PVDF) MEMBRANE

• Main Author: AHDIAT (NIM : 90514004) , MOHAMMAD
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/20292
• Institution: Institut Teknologi Bandung

Poly(vinylidene fluoride) (PVDF) is widely used as raw material for preparing membranes since it shows high mechanical and thermal properties. However, its hydrophobic property makes a lower filtration performance. Several methods can be used to improve the hydrophilicity of PVDF membrane; one of them is the addition of charged oxides as clay. Therefore, this study aims to produce high performance PVDF/clay composite membranes using varied composition of polymer and bentonite clay. PVDF/bentonite composite membranes were made using a phase inversion technique. The polymer and bentonite composition were 16-19% and 1-5% (w/w), respectively. The resulting membranes were characterized by water flux, T-500 dextran rejection, mechanical strength, contact angle and morphology analysis using a scanning electron microscope (SEM). The results showed that higher PVDF concentration resulted in lower water flux. Highest water flux, i.e. 14.25 L.m-2.h-1, was obtained by membrane having a PVDF composition of 16%. In addition, increasing the polymer composition led to an increase of T-500 dextran rejection. Highest dextran rejection, i.e. 90.79% , was obtained by PVDF membrane with a concentration of 19%. This data indicated that this membrane had smaller pores and hence, retained more dextran molecules. The contact angle measurements showed an increase in hydrophobicity properties along with increasing PVDF concentration in the membranes. The contact angles of membranes with 16% and 19% PVDF were 114? and 155?, respectively. The characteristics of PVDF/bentonite composite membranes showed a decline of water flux and an increase of dextran rejection with the increase of bentonite in the composite membrane. Highest water flux, i.e. 12.47 L.m-2.h-1 was reached by a composite membrane with a concentration of 16% PVDF and 1% bentonite, indicating that those membranes have largest pores. The decrease of water flux was due to the blockage of pores by bentonite resulting in smaller pore size. Thus, increasing the concentrations of bentonite produced membranes with higher dextran rejection. The highest value, i.e. 95.62%, was obtained by a composite membrane with a concentration of 17% PVDF and 3% of bentonite. It was also found that the addition of bentonite affected the contact angle of the produced membranes. The highest contact angle was performed by membrane with 17% PVDF and 1% bentonite, which showed also the highest hydrophobicity properties. On the other hand, smallest contact angle or highest hydrophilicity was shown by membranes with 18% PVDF and 5% bentonite. So, based on all the experimental data, it can be concluded that the optimum composition PVDF/bentonite composite membrane was 16% PVDF and 5% bentonite.