Spray coating polymer substrates from a green solvent to enhance desalination performances of thin film composites

TY - JOUR

T1 - Spray coating polymer substrates from a green solvent to enhance desalination performances of thin film composites

AU - Lin, Shiliang

AU - He, Shanshan

AU - Sarwar, Sulaiman

AU - Milescu, Roxana

AU - McElroy, Rob

AU - Dimartino, Simone

AU - Shao, Lu

AU - Hon Lau, Cher

PY - 2023/1/4

Y1 - 2023/1/4

N2 - Toxic solvents like n,n-dimethylformamide (DMF), n,n-dimethylethanamide (DMAc), and 1-methyl-2-pyrrolidone (NMP) are commonly used to fabricate polymer support membranes. Replacing these toxic solvents with green solvents such as Cyrene™ can imbue sustainability into membrane fabrication, but at the expense of poor membrane separation performances. Here we overcome this limitation by spray coating Cyrene™-based polymer dope solutions to form highly porous asymmetric membranes. The pure water flux of spray coated polyethersulfone (PES) membranes reached 206.6 L m-1 h-1, 7-folds higher than knife cast membranes. This significant increase in flux was ascribed to a porous, thin skin layer and macrovoids interconnected with finger-like pores in spray coated PES films. However, this did not impact on the ability to yield thin film composites (TFCs) with high separation performances. Through interfacial polymerisation, we deposited a polyamide selective layer on to the surface of spray coated PES films to yield TFCs for desalination of a 2000 ppm NaCl solution. The salt rejection rate and flux of such TFCs reached 93 % and 5.3 L m-1 h-1, respectively. This desalination performance was similar to knife cast membranes produced from DMF-, NMP- and DMAc-based polymer dope solutions, but fabricated here in a more sustainable manner. This indicated that spray coating could overcome the trade-off between poor membrane separation performance and sustainability.

AB - Toxic solvents like n,n-dimethylformamide (DMF), n,n-dimethylethanamide (DMAc), and 1-methyl-2-pyrrolidone (NMP) are commonly used to fabricate polymer support membranes. Replacing these toxic solvents with green solvents such as Cyrene™ can imbue sustainability into membrane fabrication, but at the expense of poor membrane separation performances. Here we overcome this limitation by spray coating Cyrene™-based polymer dope solutions to form highly porous asymmetric membranes. The pure water flux of spray coated polyethersulfone (PES) membranes reached 206.6 L m-1 h-1, 7-folds higher than knife cast membranes. This significant increase in flux was ascribed to a porous, thin skin layer and macrovoids interconnected with finger-like pores in spray coated PES films. However, this did not impact on the ability to yield thin film composites (TFCs) with high separation performances. Through interfacial polymerisation, we deposited a polyamide selective layer on to the surface of spray coated PES films to yield TFCs for desalination of a 2000 ppm NaCl solution. The salt rejection rate and flux of such TFCs reached 93 % and 5.3 L m-1 h-1, respectively. This desalination performance was similar to knife cast membranes produced from DMF-, NMP- and DMAc-based polymer dope solutions, but fabricated here in a more sustainable manner. This indicated that spray coating could overcome the trade-off between poor membrane separation performance and sustainability.

U2 - 10.1039/D2TA07200A

DO - 10.1039/D2TA07200A

M3 - Article

SN - 2050-7488

VL - 11

SP - 891

EP - 900

JO - Journal of Materials Chemistry A

JF - Journal of Materials Chemistry A

IS - 2

ER -