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Ultralow-pressurized ultrafiltration membrane process with low energy consumption is promising in surface water purification. However, membrane fouling and low selectivity are significant barriers for the wide application of this process. Herein, an ultrathin zwitterionic hydrogel nanolayer was in-situ grown on polysulfone ultrafiltration membrane surface through interfacially-initiated free radical polymerization. The hydrogel-modified membrane possessed improved biological fouling resistance during the dynamic filtration process (bovine serum albumin, Escherichia coli and Staphylococcus aureus), comparing with commercial polysulfone membrane. The enhanced biofouling resistance ability of zwitterionic hydrogel nanolayer was derived from the foulant repulsion of hydration shell and the bactericidal effect of quaternary ammonium, according to the results of foulant-membrane interaction energy analyses and antibacterial performances. In surface water treatment, the zwitterionic hydrogel layer inhibited biofouling and resulted in the formation of a loose and thin biofilm. In addition, the hydrogel-modified membrane possessed 22% improvement in dissolved organic carbon (DOC) removal and 134% increasement in stable water flux, compared to commercial polysulfone membrane. The in-situ grown zwitterionic hydrogel nanolayer on membrane surface offers a prospectively alternative for biofouling control in ultralow-pressurized membrane process., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

[Display omitted] • IM-BTO membrane is prepared by homogenization spin coating strategy. • Homogenization spin coating achieves porous structure and catalytic site exposure. • IM-BTO membrane has high water flux and photocatalytic self-cleaning ability. • The selective coefficient of IM-BTOM relative to BTOM can reach 2.66. Photocatalytic membrane technology is a promising technology for advanced water treatment. However, as a simple, fast, and stable spin coating method for photocatalytic membrane preparation, the spin coating solution often used in spin coating can cause the pore plugging on the membrane surface and encapsulates photocatalysts, which seriously affects the flux of the membrane and the exposure of the photocatalytic active site. Here, this work adopted a homogenization spin coating strategy, using polyvinylidene difluoride (PVDF) solution as the spin coating solution to prepare the highly exposed imprinted bismuth titanate porous photocatalytic membrane (IM-BTOM). Due to the same composition of PVDF solution as the PVDF substrate membrane, IM-BTOM basically retained the good porous structure of the membrane. The homogenization spin coating strategy not only endowed IM-BTOM with high flux (4545.45 L m-2h−1 bar−1), but also prevented the encapsulation of IM-BTO powder materials, fully exposing the photocatalytic active sites, thereby obtaining better photocatalytic ability and selectivity. The degradation rate of tetracycline with IM-BTOM was nearly three times that with the conventional cellulose acetate spin coating membrane. Meanwhile, the existence of imprinting cavities also endowed IM-BTOM with high selectivity for the target pollutant, with a selectivity coefficient of up to 2.66. This work provides a new idea for preparing high-efficient photocatalytic membrane by spin coating. [ABSTRACT FROM AUTHOR]

• PCA improved SMX removal in Fe(III)/PAA system under truly neutral pH conditions. • PCA enhanced the catalytic activity of Fe(III) on PAA under neutral pH conditions. • CH 3 C(O)OO-Fe(III)-PCA was proposed as the primary reactive specie for SMX removal. • PCA/Fe(III)/PAA system had strong anti-interference ability to water constituents. • PCA/Fe(III)/PAA system exhibited high SMX removal efficiency in nature waters. The practical application of the Fe-catalyzed peracetic acid (PAA) processes is seriously restricted due to the need for narrow pH working range and poor anti-interference capacity. This study demonstrates that protocatechuic acid (PCA), a natural and eco-environmental phenolic acid, significantly enhanced the removal of sulfonamide antibiotics in Fe(III)/PAA process under actually neutral pH conditions (6.0–8.0) by complexing Fe(III). With sulfamethoxazole (SMX) as the model contaminant, the pseudo-first-order rate constant of SMX elimination in PCA/Fe(III)/PAA process was 63.5 times higher than that in Fe(III)/PAA process at pH 7.0, surpassing most of the previously reported strategies-enhanced Fe-catalyzed PAA processes (i.e., picolinic acid and hydroxylamine etc.). Excluding the primary contribution of reactive species commonly found in Fe-catalyzed PAA processes (e.g., •OH, R-O•, Fe(IV)/Fe(V) and 1O 2) to SMX removal, the Fe(III)-peroxy complex intermediate (CH 3 C(O)OO-Fe(III)-PCA) was proposed as the primary reactive species in PCA/Fe(III)/PAA process. DFT theoretical calculations indicate that CH 3 C(O)OO-Fe(III)-PCA exhibited stronger oxidation potential than CH 3 C(O)OO-Fe(III), thereby enhancing SMX removal. Four potential removal pathways of SMX were proposed and the toxicity of reaction solution decreased with the removal of SMX. Furthermore, PCA/Fe(III)/PAA process exhibited strong anti-interference capacity to common natural anions (HCO 3 −, Cl−and NO 3 −) and humic acid. More importantly, the PCA/Fe(III)/PAA process demonstrated high efficiency for SMX elimination in actual samples, even at a trace Fe(III) dosage (i.e., 5 μM). Overall, this study provided a highly-efficient and eco-environmental strategy to remove sulfonamide antibiotics in Fe(III)/PAA process under actually neutral pH conditions and to strengthen its anti-interference capacity, underscoring its potential application in water treatment. [Display omitted] [ABSTRACT FROM AUTHOR]