Table 1 Surface modification of polyamide TFC RO membranes
Materials | Treatment | Fabrication method | Salt rejection | Water permeability (L/m2 h), Operating pressure | Tolerance:(Chlorination and biofouling test), clorine testing period | Modification properties improving the tolerance | References |
|---|---|---|---|---|---|---|---|
Metaphenylene diamine (MPD) and polyacyl chloride monomer (trimesoyl chloride, TMC) | Post-treatment (hydroxyl and cross-linking agents) | Interfacial polymerization | [NaCl]: 100 ppm, R: 90% | Flux 135, 60 psi, Ph l9.8 | [NaClO]: 3450 ppm for 10 h, chlorine tolerance | Thermal cross-linking and cross-linking density of PA, cross-linking contain hydroxyl groups | |
Sulfonated poly(arylene ether) (SPAE) 1.End-group Cross linked 2.C-ESFx-BP Non-cross-linked N-ESFx-BP | Thermal treatment | Polycondensation interfacial polymerization | [NaCl]: 2000 ppm 1. R: 98.4% 2. R: 90.3% | 1. 0.6 L μm/m2 h bar pH 4,1000 psi 2. 0.81 L μm/m2 h bar | [NaClO]: 4000 ppm for 30 days, chlorine tolerance | Partial fluorinated polymer membrane, cross-linking and the degree of sulfonation of the membrane | |
N,N’- DMMPD and 1,3,5-benzenetricarbonyl trichloride (TMC) | __ | Interfacial polymerization | [NaCl]: 1500 ppm, R: 90.0% | 48 L/m2 h, 1.5 MP | [NaClO]: 200 ppm [CaCl2]: 500 ppm 96 h, Chlorine tolerance | Electron-withdrawing properties for aromatic diamines and amide bonds is sterically hindered at ortho position | |
m-phenylene diamine (MPD) and 1,2,4,5-benzene tetracarbonyl chloride (BTC) | Thermal imidization | Interfacial polymerization | [NaCl]: 2000 ppm, R: 98.8% | 32 L/m2 h, 1.5 MP | [NaClO]: 6000 ppm, chlorine resistance, 168 h. | Amide linkage replaced by imide linkage | |
Film poly(amide-urethane@imide) | __ | Two-step interfacial polymerization | [NaCl]: 2000 ppm, R: 95% | 35 L/m2 h 1.55 MPa | [NaOCl]: 8000 ppm, 24 h chlorine-tolerant property, antifouling property. | Formation of the imine-like and quinone-like | |
Hexafluoro alcohol(HFA)-and diamine and trimesoyl chloride (TMC) | Pre-treated PSF membrane with UV-Ozone | Interfacial polymerization | [NaCl]: 2000 ppm, R: 100% | 65 L/m2 h 27.6 bar | [HOCl]: 1000 ppm, 24 h, chlorine-tolerant property | Steric hindrance and electron-withdrawing properties of the HFA group. | |
2,6-DAT and MPD | __ | Interfacial polymerization | [NaCl]: 1000 ppm, R: 100% | 0.23 L/m2 h 1 MPa | [NaClO]: 2000 ppm, 100 h chlorine-tolerant property | Electron donating (CH3 and OCH3) attached to the phenyl ring of MPD group | |
Sorbitol polyglycidyl ether (SPGE) | __ | -Interfacial polymerization -In situ polymerization | 0.2 wt% NaCl, R: 98% | 44 L/m2 h 1.5 MP | [NaClO]: 100 ppm, 1 h chlorine-tolerant property | Glycerol prevented membrane drying out during the ring-opening reaction. | |
PA N,N’-dimethyl-m-phenylene diamine (N,N’-DMMPD) | Heat treatment | Interfacial condensation polymerization | [NaCl]:1500 ppm, R: 92% | 22 L/m2 h 1.5 MP | [NaClO]: 200 ppm, [CaCl2]: 500 ppm, 96 h, chlorine-tolerant property | Secondary-to-tertiary amide replacement and a highly crosslinked structure. | |
Layered double hydroxide (LDH) FO | __ | Induced immobilization | __ | Over 0.015 L/m2 h | [NaClO]: 1000 ppm, 1 h Chlorine-resistant 96 times, resistance to organic fouling and reduce the attachment of bacteria. | The LDH layer served as a barrier | |
Zwitterionic polymers poly(sulfobetaine) and poly(carboxybetaine) | __ | Â | __ | __ | Biofouling property and has biomedical and industrial applications | Electrostatic interactions and steric repulsive barrier | |
Glycidoxypropyltrimethoxysilane (GPPTMS) | Heat treatment | Interfacial polymerization | [NaCl]: 2000 ppm R: 99.2% | 21.26–4.90 L/m2 h 1.52 MPa | [NaClO]: 1000 ppm, at improve the chlorine tolerance | Hydrophilic epoxy compound |
