Marine-inspired chitosan-coated ceramic membranes for efficient oil-in-water emulsion separation

Abstract

Marine industries generate a substantial amount of waste, particularly from shrimp shells, which can cause ecological degradation due to improper disposal, resulting in pollution and ecological imbalance. Shrimp shells are a valuable source of chitosan (CS), and chitosan is considered an excellent biomaterial for membranes. In this study, chitosan (CS) was successfully extracted from shrimp shells through deacetylation and used to modify ceramic membranes via surface coating, followed by crosslinking with trimesoyl chloride (TMC) to enhance surface stability. The resulting membrane was highly uniform and hydrophilic, with a water contact angle of 15°. In addition, the underwater oil contact angle reached 157.6°, indicating excellent oil-repelling behavior. The separation performance was evaluated for various oil-in-water emulsions. The CS coating has substantially improved the membrane's performance, increasing from 69.4 % to 99.8 % with an exceptionally high permeability of 315.28 L m² h¹. In addition, the coated membrane was found to have excellent fouling recovery, with FFR% greater than 99 % for 30 filtration runs, without compromising separation performance. Shrimp waste can become a valuable, eco-friendly bio-source for designing chitosan membranes, which can be effectively used for the separation of oil-in-water emulsions with high permeability and separation efficiency. Therefore, the chitosan membrane showed a promising filtration performance, indicating that it could be not only an eco-friendly solution but also a cost-effective and sustainable method for oil-in-water separation.