MODIFICATION OF POLYVINYLIDENE FLUORIDA (PVDF) MEMBRANE WITH CHITOSAN (CS) FOR DYES MICROFILTRATION

• Main Author: Siti Wiryani, Ani
• Format: Theses
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/55380
• Institution: Institut Teknologi Bandung

Dye waste produced by the textile industry became the largest contributor to the wastewater pollutant. Most of the dye compounds in textile wastewater are toxic and nonbiodegradable, which affect the public health and cause severe environmental concern. During the last few years, various solutions have been explored for minimizing textile wastewater pollution. One way to overcome this problem is the application of membrane technology. Membrane-based water treatment technologies has a great progress compared with other technologies because of high efficiency and low energy consumption. Polyvinylidene fluoride (PVDF) is an ideal membrane-forming material because it exhibits excellent mechanical strength, abrasion resistance and dielectric strength. Unfortunately, PVDF is highly hydrophobic, so it is not efficient for dye filtration. Therefore, the addition of chitosan (CS) to PVDF is expected to increase the membrane hydrophilicity so that the permeability and selectivity of membranes towards the dyes also increase. Previous studies reported that the PVDF membrane was modified on its surface by coating it with CS. The disadvantage of this method was the resulting lower water permeability of the membrane with increasing CS concentration. In this study, the PVDF and the CS were blended in a mixed matrix membrane. The PVDF/CS membranes were prepared using N,N-dimethylacetamide (DMAc) as the solvent and polyethylene glycol (PEG) as the pore agent. The mixture of those four components formed a dope solution which was then casted on a glass plate and immersed in water as the coagulation medium. The aim of the study was to determine the effects of CS with varied concentrations between 1 and 2,5% on the performance of 18% PVDF membranes prepared by phase inversion method. The analysis of the CS within the polymer matrix was carried out by using ATR- FTIR (Attenuated Total Reflection - Fourier Transform Infrared) spectroscopy, the hydrophilicity was measured the water contact angle, the porosity by gravimetric method, the largest membrane pores by bubble-point method, the mechanical properties by tensile strength analysis, the permeability by flux determination and the membrane selectivity by rejection towards Methylene Blue (MB) and Reactive Yellow 145 (RY145) solutions. The experiments showed that the PVDF/CS membranes were successfully synthesized by phase inversion method. The ATR-FTIR analysis showed that the CS has been incorporated in the membrane due to the presence of peaks at 3450 cm-1 and 1655 cm-1 indicating primary amine (-NH2) and carbonyl group (C=O). The hydrophilicity, porosity, and the radius of the largest pore increased as the concentration of CS increased. The mechanical properties of the membranes showed that the increase of CS concentration resulted in lower tensile strength but higher elongation at break. The filtration performance of PVDF/CS membrane towards dyes solution showed better results compared to PVDF pristine membrane. The flux and rejection increased towards RY145 than MB. It was found that the best filtration performance was shown by membrane composed of PVDF/CS 18/1.5, with a rejection value of 79.53% and 93.84% for methylene blue (MB) and reactive yellow 145 (RY145), respectively. Regarding the flux of both dye solutions, values of 10.50 L/m2.h and 9.94 L/m2.h were obtained for MB and RY145, respectively. The Flux Recovery Ratio (FRR), as a measure of fouling resistant test of PVDF/CS 18/1.5 membrane showed a value of 73.35% for MB and 67.08% for RY145. So, regarding the physical properties and the performance of PVDF/CS 18/1.5 membrane, it is concluded that this membrane is potential for dye microfiltration.