A Dopamine/Tannic-Acid-Based Co-Deposition Combined with Phytic Acid Modification to Enhance the Anti-Fouling Property of RO Membrane

Abstract

Reverse osmosis (RO) membranes are widely used in the field of water treatment. However, there are inevitably various fouling problems during long-term use. Surface engineering of RO membranes, such as hydrophilic modification, has attracted broad attention for improving the anti-fouling performance. In this work, we constructed a green biomimetic composite modification layer on the surface of polyamide membranes using a dopamine (DA)/tannic acid (TA) co-deposited layer to bridge the polyamide surface and hydrophilic phytic acids (PhA). The DA/TA interlayer could firmly adhere to the RO membranes, reducing the aggregation of DA and providing abundant phenolic hydroxyl sites to graft PhA. Meanwhile, the anchored PhA molecule bearing six phosphate groups could effectively improve the superficial hydrophilicity. The membranes were characterized by the SEM, AFM, XPS, water contact angle test, and zeta potential test. After surface modification, the hydrophilicity, smoothness, and surface electronegativity were enhanced obviously. The flux and rejection of the virgin membrane were 76.05 L·m−2·h−1 and 97.32%, respectively. While the modified D2/T4-PhA membrane showed decent permeability with a water flux of 57.37 L·m−2·h−1 and a salt rejection of 98.29%. In the dynamic fouling test, the modified RO membranes demonstrated enhanced anti-fouling performance toward serum albumins (BSA), sodium alginates (SA), and dodecyl trimethyl ammonium bromides (DTAB). In addition, the modified membrane showed excellent stability in the 40 h long-term test.

Enhanced Anti-Biofouling Properties of BWRO Membranes via the Deposition of Poly (Catechol/Polyamine) and Ag Nanoparticles

“…At the end of the filtration process, the virgin and PCPA3-Ag10 membranes were rinsed with DI water for 1 h with the cross-flow rate of 2 L·min −1 at 0.7 MPa. All membranes were tested in two filtration-rinse cycles [ 33 ].…”

Recent advances in thin film nanocomposite membranes containing an interlayer (TFNi): fabrication, applications, characterization and perspectives

“…Tannic acid (TA), a plant processing product, easily modifies the surfaces of substrates via complexation reactions with metal ions and organic substances because of its abundant hydroxyl groups and hydrogen bonds. For example, complexes formed from tannic acid (TA) and Cu 2+ , 49 Fe 3+ , 50 polyethyleneimine (PEI), 51 polydopamine (PDA), 20 and diethylenetriamine (DETA) 52 were used as intercalation nanomaterials to modify TFNi membranes.…”

“… 17 ) and Ag 18 ), 1D ( e.g. , SWCNTs 19 and dopamine 20 and polyethyleneimine 12 ), 2D ( e.g. , MXene, MOFs of the tetrakis(4-carboxyphenyl)porphyrin (TCPP) series and covalent organic frameworks (COFs) of 2D TpPa, etc. )…”

“…MOFs) nanomaterials in combination. Surface coating, 20 predeposition, 22 in situ growth 23 and sacrificial intercalation nanomaterials 17 are used to prepare TFNi membranes.…”

Gypsum Scaling Behavior of the Tannic Acid-Coated Polyamide Reverse Osmosis Membrane

“…Several recent research studies have performed hydrophilic modifications on membrane surfaces that can significantly enhance the resistance to organic fouling. Among the various reported hydrophilic materials used for modification, tannic acid has been extensively investigated due to its abundant charged phenolic hydroxyl groups. , The coating of tannic acid on the polyamide surface has shown higher resistance against organic fouling caused by substances such as polysaccharides, proteins, and humic acid, , making it a suitable material in controlling the occurrence of membrane fouling. ,− Tannic acid’s adhesiveness, mild reactivity, and ability to bind metal ions through coordination bonds make it suitable for surface coating. , In some cases, a tannic acid–iron (Fe 3+ ) complex uniformly coated on a support membrane can act as a defect-free selective layer on its own . However, the investigation of the antiscaling effectiveness of the tannic acid coating layer is lacking in the literature, which is crucial for membranes applied in real applications.…”