Role of reactive manganese and oxygen species in the KMnO/NaSO process for purification of algal-rich water and membrane fouling alleviation.

Ultrafiltration (UF) is a highly efficient technique for algal-rich water purification, but it is heavily contaminated due to the complex water characteristics. To solve this problem, potassium permanganate (KMnO) oxidation enhanced with sodium sulfite (NaSO) was proposed as a pretreatment means. The results showed that the end-normalized flux was elevated from 0.

Ferrate(VI)-based oxidation for ultrafiltration membrane fouling mitigation in shale gas produced water pretreatment: Role of high-valent iron intermediates and hydroxyl radicals.

Ultrafiltration (UF) is increasingly used in the pretreatment of shale gas produced water (SGPW), whereas severe membrane fouling hampers its actual operation. In this work, ferrate(VI)-based oxidation was proposed for membrane fouling alleviation in SGPW pretreatment, and the activation strategies of calcium peroxide (CaO) and ultraviolet (UV) were selected for comparison. The findings indicated that UV/Fe(VI) was more effective in removing fluorescent components, and the concentration of dissolved organic carbon was reduced by 24.

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 (O) in the CoFe-LDH nanoarrays were tailored by manipulating the stoichiometry of cations to optimize the Fenton reactivity of NS-EFMs.

Novel calcium hypochlorite/ferrous iron as an ultrafiltration membrane pretreatment process for purifying algae-laden water.

Algal fouling has become one of the most critical factors hindering the large-scale development of membrane processes in algae-laden water treatment. Herein, novel calcium hypochlorite (Ca(ClO))/ferrous iron (Fe(II)) process was proposed as an ultrafiltration (UF) membrane pretreatment technology, and its effects on membrane fouling and water properties were systematically studied. Results showed that the terminal specific fluxes were significantly elevated to 0.

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/FeSO(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).

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.

Effect of ferrous-activated calcium peroxide oxidation on forward osmosis treatment of algae-laden water: Membrane fouling mitigation and mechanism.

Forward osmosis (FO) is a high-efficiency and low-energy consumption way for algae-laden water treatment, whereas membrane fouling is still an unavoidable problem in its practical application. In this work, a strategy of ferrous-activated calcium peroxide (Fe(II)/CaO) was proposed to control FO membrane fouling in the purification of algae-laden water. With the treatment of Fe(II)/CaO, the aggregation of algal contaminants was promoted, the cell viability and integrity were well preserved, and the fluorescent organics were efficiently removed.

Mutual activation between ferrate and calcium sulfite for surface water pre-treatment and ultrafiltration membrane fouling control.

In this work, ferrate (Fe(VI)) and calcium sulfite (CaSO) were combined to treat surface water for improving ultrafiltration (UF) performance. During the pre-treatment process, the Fe(VI) and CaSO activated each other and a variety of active species (Fe(V), Fe(IV), OH, SO, O, etc.) were generated.

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-MnO 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-MnO@TA-PES.

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 (TiO) nanowires. The chemical properties and morphologies were systematically investigated for ceramic substrates and their corresponding TFC membranes.

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(-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.

The nitrogen-doped multi-walled carbon nanotubes modified membrane activated peroxymonosulfate for enhanced degradation of organics and membrane fouling mitigation in natural waters treatment.

The synthesized catalyst nitrogen-doped multi-walled carbon nanotubes (N-MWCNTs) were introduced into membrane technology for peroxymonosulfate (PMS) activation. The enhanced permeability of the N-MWCNTs-modified membrane might be attributed to the increase in hydrophilicity and membrane porosity. The catalytic degradation and membrane filtration performance for the N-MWCNTs-modified membrane/PMS system in treating different types of natural waters were evaluated.

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 (β-CD) during interfacial polymerization (IP). The surface morphology, chemical elements, water contact angle (WCA), interfacial free energy (Δ), electronegativity, and pore size of the membranes were systematically investigated.

Oxidants-assisted sand filter to enhance the simultaneous removals of manganese, iron and ammonia from groundwater: Formation of active MnOx and involved mechanisms.

Oxidants are routinely employed to remove manganese from groundwater deeply, but the conversion pathway of manganese in the process still needed to be explored. In this study, potassium permanganate and sodium hypochlorite were introduced to explore their start-up effect on sand filters in treating high concentration of manganese (1.42-1.

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).

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.

Toward enhancing the separation and antifouling performance of thin-film composite nanofiltration membranes: A novel carbonate-based preoccupation strategy.

High-performance nanofiltration (NF) membranes with simultaneously improved antifouling and separation performance are of great significance for environmental water purification. In this work, a high-performance thin-film composite (TFC) NF membrane (TFC-Ca) was constructed through in-situ incorporation of calcium bicarbonate during interfacial reaction. The surface morphology and chemical structure of the TFC-Ca membrane were systematically investigated by FTIR, XPS, AFM, and SEM.

Insight into Fe(II)/UV/chlorine pretreatment for reducing ultrafiltration (UF) membrane fouling: Effects of different natural organic fractions and comparison with coagulation.

Fe(II)/UV/chlorine was promoted as a pretreatment strategy for UF membrane to mitigate membrane fouling induced from different organic fractions. This treatment could be an emerging alternative prior to UF process attributed to the coupled role of oxidation and coagulation. To obtain a comprehensive understanding of fouling reduction, the influence of Fe(II)/UV/chlorine process on the characteristics of various feed solutions was inspected, including humic acid (HA), bovine serum albumin (BSA), sodium alginate (SA) and their mixture (HSB).

Ordered Mesoporous Cobalt Containing Perovskite as a High-Performance Heterogeneous Catalyst in Activation of Peroxymonosulfate.

An ordered mesoporous perovskite, LaCoMnO (MLCMO), was synthesized for the first time using a facile method of evaporation-induced self-assembly. The N-sorption, scanning electron microscopy, and transmission electron microscopy measurements indicated that the optimized MLCMO possessed a high specific surface area (58.7 m/g) and was uniformly mesoporous (11.

Supramolecular-Based Regenerable Coating Layer of a Thin-Film Composite Nanofiltration Membrane for Simultaneously Enhanced Desalination and Antifouling Properties.

A high-performance nanofiltration (NF) membrane with simultaneously improved desalination and antifouling properties while maintaining regeneration ability is highly desirable in water treatment. Surface modification is an effective approach to enhance the performance of NF membranes. In the present study, a multifunctional thin-film composite NF membrane (Fe-TFC) was fabricated via coating a regenerable ferric ion-tannic acid (Fe-TA) layer on the nascent polyamide membrane surface.

Effect of metabolic uncoupler, 2,4‑dinitrophenol (DNP) on sludge properties and fouling potential in ultrafiltration membrane process.

Energy uncoupling technology was applied to the membrane process to control the problem of bio-fouling. Different dosages of uncoupler (2,4‑dinitrophenol, DNP) were added to the activated sludge, and a short-term ultrafiltration test was systematically investigated for analyzing membrane fouling potential and underlying mechanisms. Ultrafiltration membrane was used and made of polyether-sulfone with a molecular weight cut off (MWCO) of 150 kDa.

Effect of sulfate radical-based oxidation pretreatments for mitigating ceramic UF membrane fouling caused by algal extracellular organic matter.

Algal extracellular organic matter (EOM) released from Microcystis aeruginosa can cause severe membrane fouling during algae-laden water treatment. To solve this problem, three typical sulfate radical-based advanced oxidation processes (SR-AOPs), i.e.

Immobilized microalgae for anaerobic digestion effluent treatment in a photobioreactor-ultrafiltration system: Algal harvest and membrane fouling control.

A photobioreactor (PBR) coupled with ultrafiltration (UF) system was developed with goals of microalgae cultivation, harvest, and membrane fouling control in the anaerobic digestion effluent purification. Firstly, three-sequencing batch PBRs were started-up with suspended Chlorella vulgaris (C. vulgaris, SCV), immobilized C.