Self‐doped sulfonated polyaniline ultrafiltration membranes with enhanced chlorine resistance and antifouling properties

Abstract

Membranes heavily rely on chlorination to diminish (bio)fouling, but chlorination can also lead to membrane degradation. We developed sulfonated polyaniline (S‐PANI) ultrafiltration (UF) membranes with improved chlorine resistance and intrinsic antifouling properties. The S‐PANI membranes were synthesized through Non‐solvent Induced Phase Separation (NIPS). Membrane performance was evaluated under harsh chlorine conditions (250 ppm sodium hypochlorite for 3 days under different pH conditions). The S‐PANI membranes showed improved chlorine resistance including a stable performance without changes in model foulant BSA rejection. In contrast, PANI membranes suffered critical structural damage with complete leakage and commercial PES membranes showed a 76% increase in pure water flux and a noticeable change in BSA rejection. Small changes in S‐PANI membrane performance could be linked to membrane structural changes with pH, as confirmed by SEM, IR spectroscopy, and contact angle measurements. Additionally, the S‐PANI membranes showed better antifouling properties with a high flux recovery ratio in comparison to PANI membranes using alginic acid, humic acid, and BSA model foulants. Chemical cleaning by sodium hypochlorite re‐instated the transport properties to its initial condition. Overall, the developed S‐PANI membranes have a high chlorine tolerance and enhanced antifouling properties making them promising for a range of UF membrane applications.

Impact of Chlorinated-Assisted Backwash and Air Backwash on Ultrafiltration Fouling Management for Urban Wastewater Tertiary Treatment

“…With NaClO addition both in CB and AB, it seems that the condition YYYY can reach to more than 100% recovery of the decreased permeability in a filtration cycle. The increase of permeability was also observed by Alhweij et al and Wienk et al [ 28 , 54 ]. The UF membrane showed quite good removal efficiency on parameters such as turbidity, microplastics, bacteria, virus, and organic matter of UF feed in all conditions, and the permeate quality was detected to be good enough to be reused in non-potable applications as it met reuse guidelines of the WHO [ 55 ], reuse standards of France [ 56 ], and the most recent EU regulation for agricultural irrigation [ 57 ].…”

“…Referring to impacts of chlorinated disinfectants on membranes, many studies have reported that NaClO can attack the chemical bonds of polymeric membranes and degrade the membrane material due to long-term exposure or excessive dosage of chemicals [ 13 , 23 , 54 , 55 , 56 , 57 , 58 , 59 ]. Similarly, excessive chlorine can impact the PES membranes, but the degree of impact varies a lot in different studies.…”

“…On the contrary, some researchers found slight modification on PES membranes. Alhweij et al [ 54 ] found that only slight changes in PES surface roughness was observed after exposure to 238 mg Cl 2 ·L −1 of NaClO for 3 days. The permeability of PES membrane increased by 74% after chlorine exposure, but SEM images confirmed that there were no observed structural damages on the membrane.…”

Perspectives on adsorption technology as an effective strategy for continuous downstream bioprocessing

“…Material engineering and polymer shielding can offer a solution to these drawbacks 70,71 . Some approaches to improve membrane characteristics vis‐à‐vis foulants are the use of polymers with high hydrophilicity, polymer grafting, nano‐structuring, and ad hoc functionalization 72,73 …”

A conductive, antibacterial, and antifouling hydrogel based on zwitterion

“…To this end, researchers have developed many antifouling strategies, for example, preparing membrane materials with antifouling properties and changing the surface properties of substrates. [7][8][9] Lin et al reported that a copolymer P(VCL-co-PEGMA-co-QAS-co-VTMO) was sprayed on the surface of TNTs/Ti to obtain a smart composite material that could improve the adhesion resistance to bacteria by adjusting light and heat. 10 Hydrogels are widely used in dressings, electronic skin, strain sensor, health monitoring, drug delivery, and other fields due to their good water absorption, biocompatibility and ability to match different soft tissues.…”