Researchers at King Abdullah University of Science and Technology (KAUST) have succeeded to produce a durable thin-film compound membrane with the help of prawn shells, plant extracts, and the recycling of plastics that can replace fossil fuels-based traditional membranes
In applications such as the treatment of wastewater, separation of gas, and production of chemicals thin-film compound membrane is widely used that consists of unsecured support with an ultra thin layer with Nano-scale holes to trap molecules and small particles while letting liquid solvents be passed.
Gyorgy Szekely led the research team at KAUST to re-engineer some of the toxic membranes that are mostly based on extracts of fossil fuels, by using the processing of green materials.
The team produced the permeable support using reprocessed plastic and covered it with a natural non-poisonous polymer known as chitosan, obtained from prawn shells. In Saudi Arabia, the National Aquaculture Group (Naqua) produces approximately 50,000 tons of prawn shell waste each year. This is used in the production of 135 tons of chitosan annually.
The researchers used 2, 5-furandicarboxaldehyde (FDA) to make chitosan into Nano pores membranes after combining its polymer chains, a substance obtained from plant waste through the green process. The researchers chose a solvent, eucalyptol, made from the leaves of the eucalyptus tree, for this reaction. They also used a catalyst (TMG), a green alternative to hard compounds commonly used to accelerate cross linking,
“Converting the plentiful useless biomass into a value-added material, like this membrane, not only resolves the problem of waste management but also creates a valued product,” He added that the use of useless material also means that the cost of a new membrane is equal to that of a traditional membrane.
After improving the process of membrane preparation, the researchers used acetone to examine membranes, which contained polystyrene molecules of various lengths, as well as a small molecule known as methyl styrene dimer.
The membrane allows acetone to pass through at the same rate as traditional membranes. Kang Yang, a Ph.D. student team member, said it could also filter molecules the same size as dyes or pharmaceutical active ingredients. “Therefore, this membrane is applicable to biomedical, pharmaceutical, textile, or food industries.”
Researchers have also shown that they can fix membrane properties with Tami Solve, a non-toxic solvent. He now hopes to work with local prawn farms to ensure a viable supply of chitosan and develop the process of mass-making membranes.