Highly Hydrophilic and Antifouling Ultrafiltration Membranes Incorporated with Water Dispersible Composite Activated Carbon / Chitosan and Activated Carbon / Thiolated Chitosan

Abstract

A rapid increase in population worldwide is giving rise to many issues, safe drinking water availability being the most important one. There is a need to find ways that are effective and economical to be able to meet this challenge. For this purpose, membrane technology has shown a lot of promise but face the biggest challenge of fouling that reduces its life time. Fouling is the continuous buildup of materials that are deposited on membrane surfaces clogging the pores resulting ultimately in membrane failure. Chitosan and activated carbon have been proved to add value to the polymer membranes. Chitosan not only improves membranes hydrophilicity but also increases its anti-fouling properties. Activated carbon maintains taste and odor of the water and also acts as excellent adsorbent that also helps in reduction of fouling. Ultrafiltration polyethersulfone membranes were synthesized in two different concentrations i.e. 16 % wt. and 20 % wt. Chitosan, activated carbon and thiolated chitosan were incorporated individually in both the concentrations to see their effect on polyethersulfone membranes. The membranes were then incorporated with chitosan/activated carbon and thiolated chitosan/activated carbon to evaluate the changes in property by introducing modified chitosan having thiol groups. The membranes were then analyzed using ATR-FTIR, SEM, Optical profilometry, Mechanical Testing and Contact angle. Gravimetric analysis was done to gauge the effect on mean pore size. Water uptake and permeability rate was done to investigate flux rate. BSA (Bovine serum Albumin) was performed to assess the antifouling activity with change in fillers. The results show a general improvement in the membranes properties with the addition of chitosan/activated carbon and thiolated chitosan/activated carbon composites. The results showed increased hydrophilicity, mean pore size and water retention abilities. SEM micrographs also showed better channels for permeability with the addition of composites. Surface roughness for thiolated chitosan/Activated carbon composite was observed at 20 % wt. The mechanical properties for thiolated chitosan/activated carbon incorporated PES membranes showed decrease in mechanical properties which may be because of its solubility in water and high hydrophilicity. There was a significant increase in flux rate and BSA flux. Apart from membranes incorporated with only chitosan, the best BSA flux was shown by 20 % wt. thiolated chitosan/activated carbon composite membrane