Fe(II)-Modulated Microporous Electrocatalytic Membranes for Organic Microcontaminant Oxidation and Fouling Control: Mechanisms of Regulating Electron Transport toward Enhanced Reactive Oxygen Species Activation.

Regulation of the fast electron transport process for the generation and utilization of reactive oxygen species (ROS) by achieving fortified electron "nanofluidics" is effective for electrocatalytic oxidation of organic microcontaminants. However, limited available active sites and sluggish mass transfer impede oxidation efficiency. Herein, we fabricated a conductive electrocatalytic membrane decorated with hierarchical porous vertically aligned Fe(II)-modulated FeCo layered double hydroxide nanosheets (Fe(II)-FeCo LDHs) in an electro-Fenton system to maximize exposure of active sites and expedite mass transfer. The nanospaced interlayers of Fe(II)-FeCo LDHs within the microconfined porous structure formed by its vertical nanosheets highly boost the micro/nanofluidic distribution of target pollutants to active centers/species, achieving accelerated mass transferability. Aliovalent substitution by Fe(II) activates in-plane metallics to maximize the available active sites and makes each Fe(II)-FeCo LDH nanosheet a geometrical nanocarrier for constructing a fast electron "nanofluidic" to accelerate Fe(II) regeneration in Fe(III)/Fe(II) cycles. As a result, the Fe(II)-FeCo LDHs exhibited improved reactivity in catalyzing H2O2 to •OH and 1O2. Accordingly, the membrane exhibited a higher atrazine degradation kinetic (0.0441 min-1) and degradation rate (93.2%), which were 4.7 and 2.1 times more than those of the bare carbon nanotube membrane, respectively. Additionally, the enhanced hydrophilic and strongly oxidized reactivity synergistically mitigated the organic fouling occurring in the pores and surface of the membrane. These findings clarify the activation mechanism of ROS over an innovative electrocatalytic membrane reactor design for organic microcontaminant treatment.

Phenotype and genotype spectra of a Chinese cohort with nephronophthisis-related ciliopathy.

BACKGROUND: Nephronophthisis-related ciliopathies (NPHP-RC) account for the majority of cases of monogenetically caused end-stage renal disease (ESRD) in children. Exploring the correlation between the phenotype and genotype of NPHP-RC is helpful for early diagnosis and management. We investigated the phenotype and genotype spectra of NPHP-RC in a Chinese multicentre cohort. METHODS: Crosss-ectional and longitudinal data of 60 patients from 57 families with pathogenic NPHP-RC gene mutations distributed in 22 regions of China were collected into a unified, anonymous database. The mean observation time of this cohort was 3.5±3.1 years. RESULTS: Mutations in NPHP1 and NPHP3 were the most common genetic defects. Overall, 45% of patients presented with isolated nephronophthisis (NPH), and 55% exhibited the extrarenal phenotype, which frequently involved the liver (41.7%, n=25), central nervous system (26.7%, n=16), eyes (26.7%, n=16) and skeletal system (11.7%, n=7). Accidental detection of elevated serum creatinine and non-specific symptoms caused by chronic kidney disease occurred in 65% of patients. Patients carrying NPHP1 mutations mainly presented with isolated NPH (90%, 18/20) and progressed to ESRD at a mean age of 12.9±0.5 years. The mean age of ESRD onset in the non-NPHP1 group was lower than that in the NPHP1 group (6.2±1.4 years, p<0.001), especially for patients carrying NPHP3 mutations (3.1±1.2 years), showing a heterogeneous phenotype characterised by Bardet-Biedl syndrome (12.5%, n=5), Joubert syndrome (7.5%, n=3), COACH syndrome (2.5%, n=1), Mainzer-Saldino syndrome (2.5%, n=1), short-rib thoracic dysplasia (2.5%, n=1) and unclassified symptoms (32.5%, n=13). CONCLUSIONS: The Chinese Children Genetic Kidney Disease Database registry characterised the spectrum of the phenotype and genotype of NPHP-RC in the Chinese population. NPHP1 and NPHP3 were the most common pathogenic genes. Rapid progression to ESRD and liver involvement were noted in patients with NPHP3 mutations.

Mechanistic Insights of a Thermoresponsive Interface for Fouling Control of Thin-Film Composite Nanofiltration Membranes.

In spite of extensive research, fouling is still the main challenge for nanofiltration membranes, generating an extra transport resistance and requiring a larger operational pressure in practical applications. We fabricated a highly antifouling nanofiltration membrane by grafting poly(N-isopropylacrylamide) (PNIPAM) chains on a bromine-containing polyamide layer. The resulting membrane was found to have a double permeance compared to the pristine membrane, while the rejection of multivalent ions remained the same. In addition, PNIPAM chains yielded a better deposition resistance and adhesion resistance, thereby mitigating the increase of fouling and promoting the recovery of flux during the filtration and traditional cleaning stages, respectively. Moreover, PNIPAM chains shrank when the water temperature was above the lower critical solution temperature (LCST), indicating the formation of a buffer layer between the membrane and pollutants. The buffer layer would eliminate the membrane-foulant interaction energy, thus further enhancing the detachment of pollutants. This simple and efficient cleaning method could act as an enhanced cleaning procedure to remove irreversible fouling. This provides new insights into the fabrication of enhanced antifouling membranes using smart responsive polymer chains.

Nanofiltration Membranes with Octopus Arm-Sucker Surface Morphology: Filtration Performance and Mechanism Investigation.

Precisely tailoring the surface morphology characteristics of the active layers based on bionic inspirations can improve the performance of thin-film composite (TFC) membranes. The remarkable water adsorption and capture abilities of octopus tentacles inspired the construction of a novel TFC nanofiltration (NF) membrane with octopus arm-sucker morphology using carbon nanotubes (CNTs) and beta-cyclodextrin (ß-CD) during interfacial polymerization (IP). The surface morphology, chemical elements, water contact angle (WCA), interfacial free energy (ΔG), electronegativity, and pore size of the membranes were systematically investigated. The optimal membrane exhibited an enhanced water permeance of 22.6 L·m-2·h-1·bar-1, 180% better than that of the TFC-control membrane. In addition, the optimal membrane showed improved single salt rejections and monovalent/divalent ion selectivity and can break the trade-off effect. The antiscaling performance and stability of the membranes were further explored. The construction mechanism of the octopus arm-sucker structure was excavated, in which CNTs and ß-CD acted as arm skeletons and suckers, respectively. Furthermore, the customization of the membrane surface and performance was achieved through tuning the individual effects of the arm skeletons and suckers. This study highlights the noteworthy potential of the design and construction of the surface morphology of high-performance NF membranes for environmental application.

MXene Nanosheet Templated Nanofiltration Membranes toward Ultrahigh Water Transport.

The demand for thin-film composite (TFC) nanofiltration membranes with superior permeance and high rejection is gradually increasing for seawater desalination and brackish water softening. However, improving the membrane permeance remains a great challenge due to the formation of excrescent polyamide in the substrate pores and thick polyamide film. Herein, we fabricated a high-performance TFC nanofiltration membrane via a classical interfacial polymerization reaction on a two-dimensional lamellar layer of transition-metal carbides (MXene). The MXene layer promoted the absorption of the reactive monomer, and higher amine monomer concentration facilitated the self-sealing and self-termination of interfacial polymerization to generate a thinner outer polyamide film from 68 to 20 nm. The almost nonporous lamellar interface inhibited the formation of inner polyamide in the substrate pores. In addition, the MXene lamellar layer could be eliminated by mild oxidation after interfacial polymerization to avoid imparted additional hydraulic resistance. The resulting TFC membrane conferred a high rejection above 96% for Na2SO4 and excellent permeance of 45.7 L·m-2·h-1·bar-1, which was almost 4.5 times higher than that of the control membrane (10.2 L·m-2·h-1·bar-1). This research provides a feasible strategy for fabricating a high-performance nanofiltration membrane using two-dimensional nanosheets as a templated interface.

Ultrathin Thin-Film Composite Polyamide Membranes Constructed on Hydrophilic Poly(vinyl alcohol) Decorated Support Toward Enhanced Nanofiltration Performance.

Traditional polyamide-based interfacial polymerized nanofiltration (NF) membranes exhibit upper bound features between water permeance and salt selectivity. Breaking the limits of the permeability and rejections of these composite NF membranes are highly desirable for water desalination. Herein, a high-performance NF membrane (TFC-P) was fabricated via interfacial polymerization on the poly(vinyl alcohol) (PVA) interlayered poly(ether sulfone) (PES) ultrafiltration support. Owing to the large surface area, great hydrophilicity, and high porosity of the PES-PVA support, a highly cross-linked polyamide separating layer was formed with a thickness of 9.6 nm, which was almost 90% thinner than that of the control membrane (TFC-C). In addition, the TFC-P possessed lower ζ-potential, smaller pore size, and greater surface area compared to that of the TFC-C, achieving an ultrahigh water permeance of 31.4 L m-2 h-1 bar-1 and a 99.4% Na2SO4 rejection. Importantly, the PVA interlayer strategy was further applied to a pilot NF production line and the fabricated membranes presented stable water flux and salt rejections as comparable to the lab-scaled membranes. The outstanding properties of the PVA-interlayered NF membranes highlight the feasibility of the fabrication method for practical applications, which provides a new avenue to develop robust polyamide-based NF desalination membranes for environmental water treatment.

[Clinical effect and mechanism of hemoperfusion in treatment of children with severe abdominal Henoch-Schönlein purpura].

OBJECTIVE: To study the clinical effect and mechanism of hemoperfusion (HP) in the treatment of children with severe abdominal Henoch-Schönlein purpura (HSP). METHODS: A total of 24 children with severe abdominal HSP were divided into two groups: conventional treatment and HP (n=12 each). Ten healthy children who underwent physical examination were enrolled as the control group. Before and after treatment, chemiluminescence was used to measure the serum levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α); thiobarbituric acid colorimetry was used to measure the plasma level of malondialdehyde (MDA); the hydroxylamine method was used to measure the plasma level of superoxide dismutase (SOD); chemical colorimetry was used to measure the plasma level of total anti-oxidant capability (T-AOC). RESULTS: Compared with the control group, the conventional treatment and HP groups had significantly higher IL-6, TNF-α, and MDA levels and significantly lower SOD and T-AOC levels before treatment (P<0.05), but there were no significant differences between the conventional treatment and HP groups (P>0.05). After treatment, the conventional treatment and HP groups had significant reductions in IL-6, TNF-α, and MDA levels and significant increases in SOD and T-AOC levels (P<0.05). The HP group had significantly greater changes than the conventional treatment group; however, there were still significant differences in these indices between the HP and control groups (P<0.05). Compared with the HP group, the conventional treatment group had a significantly lower percentage of children with disappearance of digestive tract symptoms at 4 days after treatment and significantly longer time to disappearance of rash and digestive tract symptoms (P<0.05). Compared with the conventional treatment group, the HP group had a significantly lower amount of glucocorticoid used during treatment and a significantly lower percentage of children who experienced hematuria and/or proteinuria within 6 months of the disease course (P<0.05). There were no significant differences between the two groups in length of hospital stay and recurrence rates of rash and abdominal pain within 6 months of the disease course. CONCLUSIONS: HP can reduce the amount of glucocorticoid used during treatment and the incidence rate of kidney injury in children with severe abdominal HSP, possibly by eliminating IL-6, TNF-α, and MDA.

Dalbergioidin Ameliorates Doxorubicin-Induced Renal Fibrosis by Suppressing the TGF-ß Signal Pathway.

We investigated the effect of Dalbergioidin (DAL), a well-known natural product extracted from Uraria crinita, on doxorubicin- (DXR-) induced renal fibrosis in mice. The mice were pretreated for 7 days with DAL followed by a single injection of DXR (10 mg/kg) via the tail vein. Renal function was analyzed 5 weeks after DXR treatment. DXR caused nephrotoxicity. The symptoms of nephrotic syndrome were greatly improved after DAL treatment. The indices of renal fibrosis, the phosphorylation of Smad3, and the expression of alpha-smooth muscle actin (α-SMA), fibronectin, collagen III (Col III), E-cadherin, TGF-ß, and Smad7 in response to DXR were all similarly modified by DAL. The present findings suggest that DAL improved the markers for kidney damage investigated in this model of DXR-induced experimental nephrotoxicity.

Effects of cations on biofilms in gravity-driven membrane system: Filtration performance and mechanism investigation.

The gravity-driven membrane (GDM) system is desirable for energy-efficient water treatment. However, little is known about the influence of cations on biofilm properties and GDM performance. In this study, typical cations (Ca2+ and Na+) were used to reveal the combined fouling behavior and mechanisms. Results showed that Ca2+ improved the stable flux and pollutant removal efficiency, while Na+ adversely affected the flux. Compared with GDM control, the concentration of pollutants was lower in Ca-GDM, as indicated by the low biomass, proteins, and polysaccharides. A heterogeneous and loose biofilm was observed in the Ca-GDM system, with roughness and porosity increasing by 43.06 % and 32.60 %, respectively. However, Na+ induced a homogeneous and dense biofilm, with porosity and roughness respectively reduced by 17.48 % and 22.04 %. The richness of bacterial communities increased in Ca-GDM systems, while it decreased in Na-GDM systems. High adenosine triphosphate (ATP) concentration in Ca-GDM system was consistent with the abundant bacteria and their high biological activity, which was helpful for the efficient removal of pollutants. The abundance of Apicomplexa, Platyhelminthes, Annelida and Nematoda increased after adding Ca2+, which was related to the formation of loose biofilms. Computational simulations indicated that the free volumes of the biofilms in Ca-GDM and Na-GDM were 13.7 and 13.2 nm3, respectively. The addition of cations changed intermolecular forces, Ca2+ induced bridging effects led to large and loose floc particles, while the significant dehydration of hydrated molecules in the Na-GDM caused obvious aggregation. Overall, microbiological characteristics and contaminant molecular interactions were the main reasons for differences in GDM systems.

Rational design of a hydrophilic nanoarray-structured electro-Fenton membrane for antibiotics removal and fouling mitigation: An intensified catalysis process in an oxygen vacancy-mediated cathodic microreactor.

Electro-Fenton membranes (EFMs) can synchronously realize organic micropollutants destruction and fouling mitigation in a single filtration process with the assistance of hydroxyl radicals (•OH). Herein, a nanoarray-structured EFM (NS-EFM) was designed by assembling Fenton reactive CoFe-LDH nanowires using a low-temperature hydrothermal method. Combined with a defect-engineering strategy, the oxygen vacancies (OVac) in the CoFe-LDH nanoarrays were tailored by manipulating the stoichiometry of cations to optimize the Fenton reactivity of NS-EFMs. The optimized NS-EFM demonstrated exceptional sulfamethoxazole (SMX) removal (99.4%) and fast degradation kinetics (0.0846 min-1), but lower energy consumption (0.22 kWh m-3 per log removal of SMX). In-depth mechanism analysis revealed that the intrinsic electronic properties of OVac endowed NS-EFM with enhanced reactivity and charge transferability at metallic active sites of CoFe-LDH, thereby intensifying •OH generation. Besides, the nanoarray-structured NS-EFM built a confined microreactor space, leading to expedited •OH microflow to SMX. Meanwhile, the hydrophilic nature of CoFe-LDH nanoarrays synergistically contributed to the high flux recovery (95.0%) and minimal irreversible membrane fouling (5.0%), effectively alleviating membrane fouling within pores and on surfaces. This study offers insights into the potential of defect engineering as a foundational strategy in the design of EFMs, significantly advancing the treatment of organic pollutants and control of membrane fouling.

Polyphenol-mediated defect patching of graphene oxide membranes for sulfonamide contaminants removal and fouling control.

Graphene oxide (GO)-based laminar membranes are promising candidates for next-generation nanofiltration membranes because of their theoretically frictionless nanochannels. However, nonuniform stacking during the filtration process and the inherent swelling of GO nanosheets generate horizontal and vertical defects, leading to a low selectivity and susceptibility to pore blockage. Herein, both types of defects are simultaneously patching by utilizing tannic acid and FeⅢ. Tannic acid first partially reduced the upper GO framework, and then coordinated with FeⅢ to form a metal-polyphenol network covering horizontal defects. Due to the enhanced steric hindrance, the resulting membrane exhibited a two-fold increase in sulfonamide contaminants exclusion compared to the pristine GO membrane. A non-significant reduction in permeance was observed. In terms of fouling control, shielding defects significantly alleviated the irreversible pore blockage of the membrane. Additionally, the hydrophilic metal-polyphenol network weakened the adhesion force between the membrane and foulants, thereby improving the reversibility of fouling in the cleaning stage. This work opens up a new way to develop GO-based membranes with enhanced separation performance and antifouling ability.

[Application of continuous blood purification combined with hemoperfusion in the treatment of hemolytic-uremic syndrome in children].

OBJECTIVE: To observe the therapeutic effect of continuous blood purification (CBP) combined with hemoperfusion (HP) in children with hemolytic-uremic syndrome (HUS) and to investigate its possible mechanism. METHODS: Eight children with HUS received CBP combined with HP on the basis of internal medicine treatment in the acute stage. Before and after treatment, serum levels of interleukin-6 (IL-6), IL-8 and tumor necrosis factor-α (TNF-α) were measured by chemiluminescence method, and levels of blood urea nitrogen (BUN), serum creatinine (SCr), alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatine kinase (CK), creatine kinase MB (CKMB), hemoglobin (Hb), platelet (PLT) and C-reactive protein (CRP) were measured. Eight healthy children undergoing physical examination were used as controls. RESULTS: The 8 children with HUS all survived after CBP combined with HP and showed improved conditions. They had increased Hb and PLT levels and decreased serum levels of IL-6, IL-8, TNF-α, BUN, SCr, ALT, CK and CRP after treatment (P<0.05). CONCLUSIONS: CBP combined with HP can quickly remove pathogenic factors, continually eliminate inflammatory mediators and toxins, and reverse multiple organ dysfunction, and is one of effective methods for treating HUS in children.

New insights into the influence of pre-oxidation on membrane fouling during nanofiltration of brackish water considering inorganic-organic complexation and oxidant reduction byproducts.

Even though pre-oxidation is usually considered as a promising method to alleviate membrane fouling, information on performance and inner mechanisms of pre-oxidation-influenced membrane fouling during nanofiltration of brackish water is still limited. This study is the first work in which oxidant reduction byproducts and interaction between different pollutants were particularly considered to address these problems. Herein, nanofiltration experiments with different pre-oxidized synthesis brackish water containing inorganic salts and organic pollutants were conducted. Membrane flux results showed that both NaClO and K2FeO4 aggravated membrane fouling, but 0.45 mg/mg TOC KMnO4 mitigated it when simulation results of NICA-Donnan model showed that the complexation between calcium ions and humic acid (HA) was weakened. However, membrane fouling was enhanced by higher dosage of KMnO4. Fourier transform infrared spectrometer using attenuated total reflection (ATR-FTIR) and X-ray diffraction (XRD) spectrum showed that the aggravated membrane fouling was mainly caused by the generation of amorphous manganese oxide, which was oxidant reduction byproduct and had strong capacity for adsorption of HA. Particle size distribution and zeta potential variation indicated that the accumulation of HA could enhance the crystallization process and then the electrostatic attraction between membrane and bulk crystallization was induced. According to SEM images and fitting results of Hermia's models, the already-formed bulk crystallization by 1.90 mg/mg TOC KMnO4 could deposit on membranes more easily, followed by the formation of a denser fouling layer. Overall, the present study provided new insights into the design of reliable pre-oxidation strategies for alleviating membrane fouling during nanofiltration of brackish water.

Surface modification of Feâ ¢-juglone coating on nanofiltration membranes for efficient biofouling mitigation.

Nanofiltration membranes have increasingly played a vital role in the purification of surface water and the recycling of wastewater. However, the problem of membrane biofouling, which leads to shortened service life and increased energy consumption, has hindered the widespread application of nanofiltration membranes. In this study, we developed functionalized nanofiltration membranes with anti-adhesive and anti-biofouling properties by coordinating FeIII and juglone onto commercial nanofiltration membranes in a facile and viable manner. Due to the hydrophilic nature of the FeⅢ-juglone coating as well as its ultra-thin thickness and minimal impact on the membrane pores, the permeance of the optimally modified membrane even increased slightly (14 %). The outstanding anti-adhesive property of the FeⅢ-juglone coating was demonstrated by a significant reduction in the adsorption of proteins and bacteria. Furthermore, the modified membranes exhibited lower flux decline amplitude and reduced biofilm deposition during dynamic fouling experiment, further supporting the outstanding anti-biofouling performance of the nanofiltration membrane after the modification with FeⅢ-juglone coating. This study presents a novel and feasible approach for simultaneously improving the water permeance, anti-adhesive property and anti-biofouling property of commercial nanofiltration membranes.

A patient with tumor necrosis factor receptor-associated periodic syndrome misdiagnosed as Kawasaki disease: A case report and literature review.

This article reports a case of tumor necrosis factor receptor-associated periodic syndrome (TRAPS) misdiagnosed as Kawasaki disease and summarizes the clinical features and therapeutic progress of TRAPS and the relationship between its clinical manifestations and gene mutations. We retrospectively analyzed a patient with tumor necrosis factor receptor superfamily member 1A (TNFRSF1A) -mutated auto-inflammatory disease who was misdiagnosed with Kawasaki disease in another hospital. The clinical features and therapeutic progress of TRAPS were analyzed by combining clinical features and gene reports of this case and literature review. TRAPS onset occurred in a female pediatric patient at the age of 4 months. The child and in his father at the age of 6 years, both of whom manifested periodic fever, and recurrent rash, as well as elevated leukocytes, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) during episodes but normal between episodes. This child carried a heterozygous mutation in TNFRSF1A located in the region 6442923-6442931 on chromosome 12. The nucleic acid alteration was: c.298 (exon3) _c.306 (exon3) 291 delCTCAGCTGC, resulting in a 3 amino acid deletion p.L100_C 102del 292 (p.Leu100_Cys102del) (NM_001065). After etanercept treatment, the symptoms of fever and rash disappeared, and the levels of ESR, CRP, interleukin (IL)-1, IL-6, and TNF-α levels were normal. Subsequently, no liver, kidney, or cardiac amyloidosis and severe etanercept-related adverse events were observed at 1-year follow-up. TRAPS pathogenesis is associated with TNFRSF1A mutation, which is characterized by periodic episodes of fever, mostly accompanied by recurrent rashes, periorbital edema, abdominal pain, and serious complications of organ amyloidosis. Moreover, etanercept can effectively alleviate the clinical symptoms and high inflammation level of TRAPS.

Synergistic effect of potassium ferrate and ferrous iron for improving ultrafiltration performance in algae-laden water treatment.

The application of ultrafiltration (UF) technology in algae-laden water is limited due to the serious membrane fouling caused by algal foulants. Herein, a Ferrate/FeSO4(Fe(VI)/Fe(II)) pretreatment was proposed aiming to improve the performance of UF. The results showed that the synergistic of Fe(VI) and Fe(II) significantly increased the zeta potential of Microcystis aeruginosa, which enhanced the agglomerative tendency of algal foulants, and the particle size of flocs remarkably increased due to the in-situ generated Fe(III). Results from dissolved organic carbon (DOC), UV254, K+, and fluorescent spectra indicated that the introduction of Fe(II) avoided the excessive oxidation of Fe(VI) to algal cells and reduced the production of intracellular organic matter (IOM), while the strong coagulation efficiency of in-situ Fe(III) further enhanced the removal effect of algal organics. Meanwhile, the molecular weight distribution showed that macromolecular organics were decomposed into low molecular matters under Fe(VI) oxidation, while the Fe(VI)/Fe(II) process reduced the formation of small molecular matters compared with single Fe(VI) pretreatment. The algal-source fouling was efficaciously mitigated under the optimal experimental condition, the terminal membrane flux could be increased from 0.16 to 0.62, while reversible and irreversible fouling decreased by 67.1% and 64.1%, respectively. Modeling analysis demonstrated that the Fe(VI)/Fe(II) process altered the fouling mechanism by delaying the formation of cake filtration. Membrane interface characterization further indicated that large size algal flocs form a loose cake layer and reduce the deposition of algal pollutants on the membrane surface. The Extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory confirmed that the hydrophobic adsorption between the algal foulant and the membrane was weakened, thus relieving the membrane fouling. Overall, this strategy can be considered for application in improving the UF performance and mitigating algal-source membrane fouling.

Insight into the role of biogenic manganese oxides-assisted gravity-driven membrane filtration systems toward emerging contaminants removal.

Effective water purification technologies are required to remove emerging contaminants (ECs) and prevent their extensive occurrence in rural areas. In this work, coupling gravity-driven membrane (GDM) filtration with biogenic manganese oxides (BioMnOx) in the biofouling layer was utilized for treating water containing SMX. Comparisons between BioMnOx-GDM (with BioMnOx) and Control-GDM (without BioMnOx) indicated that BioMnOx could significantly promote the removal of DOC, NH4+-N, and fluorescent pollutants due to its strong oxidating capacity and high biological activity. The formation of BioMnOx increased the abundance of SMX-degrading bacteria, enriched the metabolic pathway and mineralization rate of SMX, and effectively promoted the remove of SMX. More importantly, BioMnOx facilitated the removal of antibiotic resistance genes (ARGs) in the GDM, because it increased the link between microorganisms and reduced the concentration of SMX, thus reduced the expression of ARGs. LB-EPS played an important role in the membrane fouling. Compared with the Control-GDM, the concentration of LB-EPS in BioMnOx-GDM decreased, which was beneficial to alleviate membrane fouling. Although a thicker biofouling layer (1774.88 µm vs.775.54 µm) was formed in BioMnOx-GDM, the biofilm with higher porosity (64.93% vs. 41.24%) had a more positive effect on the flux. Overall, BioMnOx could improve the pollutant removal and stable flux level of the GDM system. BioMnOx-GDM effectively avoided the risks brought by ECs and ensured water safety in rural areas.

Toward emerging contaminants removal using acclimated activated sludge in the gravity-driven membrane filtration system.

The occurrence of emerging contaminants is attracting widespread attention due to its potential threat to aquatic organisms and public health. Gravity-driven membrane (GDM) filtration can effectively eliminate water contamination with pathogenic microorganisms in rural areas while being challenged by various micro-pollutants (MPs). This study investigated the removal and transformation of sulfamethoxazole (SMX) in GDM for the first time, and pre-adding acclimated activated sludge was proposed to improve the removal of MPs. More rapid and higher SMX degradation was observed with pre-adding domestication sludge, and the system had better tolerance to SMX shocks. Besides, in the presence of domesticated sludge, more SMX metabolic pathways and better mineralization rates were obtained, which was related to more SMX-resistant bacteria and easier biodegradable carbon sources in the system. Pre-adding sludge also increased the richness and diversity of bacterial community, which provided higher removal efficiencies of conventional pollutants. Thus, the removal rates of DOC (14.7%), NH4+-N (5.6%) and fluorescent substances were obviously improved compared with the control group. In this study, the crisis of MPs was tackled and the removal of conventional pollutants was enhanced by pre-adding domesticated sludge in GDM, which ensured the water quality in rural areas.

A passive-active combined strategy for ultrafiltration membrane fouling control in continuous oily wastewater purification.

Membrane-based technology has been confirmed as an effective way to treat emulsified oily wastewater, however, membrane fouling is still one of practical challenges in long-term operation. Herein, a novel passive-active combined strategy was proposed to control membrane fouling in continuous oily wastewater purification, where the δ-MnO2 decoration layer helped to reduce the total fouling ratio (passive strategy for fouling mitigation) and the catalytic cleaning effectively removed the irreversible oil fouling (active strategy for fouling removal). The functional membrane was prepared via in-situ modification, referred to as δ-MnO2@TA-PES. The morphology, crystalline phase, chemical structure and surface properties of the membranes were systematically characterized. Compared with PES, the δ-MnO2@TA-PES possessed superhydrophilicity, enhanced electronegativity and narrowed pore size. The δ-MnO2@TA-PES achieved high water permeation flux of 723.9 L·m - 2·h - 1·bar-1, excellent oil rejection with separation efficiency above 98.5% for various emulsions, and durable anti-oil-fouling performance with FRRb of 98.0%. Notably, the oil cake layer fouling on δ-MnO2@TA-PES was greatly alleviated owing to its enhanced surface properties. In addition, δ-MnO2@TA-PES showed high cleaning efficiency in the peroxymonosulfate (PMS) cleaning process, where the radical and nonradical pathways occurred simultaneously. And the active substances generated in the nonradical process (especially 1O2) were considered as the main contributor to the reduction of irreversible fouling. Overall, the novel strategy of fouling control ensured the efficient operation of ultrafiltration membranes for the continuous oily wastewater purification.

A novel ceramic-based thin-film composite nanofiltration membrane with enhanced performance and regeneration potential.

The rational design of a ceramic-based nanofiltration membrane remains a significant challenge due to its performance and fabrication cost. Herein, we report a high-performance ceramic-based thin-film composite (TFC) membrane fabricated via a typical interfacial polymerization on an interwoven net substrate assembled by titanium dioxide (TiO2) nanowires. The chemical properties and morphologies were systematically investigated for ceramic substrates and their corresponding TFC membranes. Due to the significantly improved hydrophilicity of the TiO2 framework, more reactive amine monomers were uniformly adsorbed on the modified surface of the ceramic substrate, yielding an ultrathin polyamide layer with less resistance. In addition, the smooth surface and decreased pore size of the TiO2 framework contributed to forming a defect-free polyamide layer. As a result, the obtained ceramic-based TFC membrane evinced high permeance of 26.4 L m-2 h-1 bar-1 and excellent salt rejection efficiency, leading to simultaneous improvements compared with the control TFC membrane without the TiO2 framework. Notably, the potential regeneration ability of the ceramic-based TFC membrane could be achieved via facile low-temperature calcination and re-polymerization process due to the varied thermostability between the polyamide layer and the robust ceramic substrate. The operation of regeneration helped to prolong the lifetime and decrease the cost for the ceramic-based TFC membrane. This research provides a feasible protocol to fabricate sustainable ceramic-based nanofiltration membranes with enhanced performance for water treatment.