Investigating the effect of the addition of different molecular weight poly (vinyl alcohol) in chitosan beads synthesis for metal ions adsorption

• Main Author: Yong, Shu Fei
• Other Authors: Chian Kerm Sin
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2020
• Subjects: Engineering::Mechanical engineering
• Online Access: https://hdl.handle.net/10356/141428
• Institution: Nanyang Technological University

In the current highly industrialised world, there is an increased need in manufacturing and production to keep up with the constant demand for the world’s consumption needs. As a result, many manufacturing plants whilst are in operation, consequently produce huge waste by-products, including metal ions, which are subsequently released into the ocean. As there will be serious medical complications when these metal ions are ingested above the safety threshold for human, there is an inexplicable need to remove the contaminant before releasing the wastewater into the ocean. Out of the many methods available, including ions exchange, chemical precipitation and adsorption, adsorption using adsorbents such as carbon and chitosan has a clear advantage in terms of cost-effectiveness. To leverage on the cheap cost of adsorbent materials, there is a need to research on new ways to improve their adsorptive capability to achieve a material that is cheap and simultaneously has excellent performance. In this study, poly(vinyl-alcohol) (PVA) of two different molecular weights were studied as doping agents to improve the adsorptive capability of chitosan beads, a well-studied adsorbent material. Briefly, PVA of 10 kDa and 22 kDa of different concentrations (10 %, 20 % and 30 %) were dissolved in chitosan-acetic acid solution and homogenized before making chitosan-PVA beads (chitosan/10kPVA and chitosan/22kPVA, respectively). Following that, these beads were then placed inside either copper or nickel ions solution to test for their respective adsorption capability. It was shown that the addition of 30% PVA in chitosan/10kPVA beads had the highest improvement in their copper ions adsorptive capability by 27.5 %, with no significant improvement from using chitosan/22kPVA. On the contrary, doping with 10 % PVA in chitosan/22kPVA showed a most drastic improvement of 55.7 % in nickel adsorption, with minimal improvement from further increasing PVA concentration. Overall, I was able to demonstrate better adsorptive capability in copper and nickel ions using PVA as doping agent in chitosan beads, paving the way for a cheap and better performing materials to be developed in wastewater treatment.