Antifouling Capacity Research Articles

Tubular nanofiber membranes combined with Z-scheme CuS@Co3S4 heterojunction catalyst for high-efficient removal of polyvinyl alcohol from waste water with high COD

Polyvinyl alcohol (PVA), a typical water-soluble polymer with huge global production, is becoming one of the most ubiquitous pollutants and indeed the villain of the piece contributing high chemical oxygen demand (COD) in wastewater. Membrane technology is an effective method for wastewater purification, in particular, with the combination of peroxymonosulfate (PMS)-assisted advanced oxidation or photocatalytic process, is capable of maintaining high water flux and anti-fouling. Herein, a ZIF-67 derived Z-scheme CuS@Co3S4 heterojunction catalyst immobilized by poly (m-phenylene isophthalamide) (PMIA) tubular nanofiber membrane (CuS@Co3S4/PMIA-TNM) is designed using a polyester braided tube as interior reinforcement. The resultant membrane features with outstanding superhydrophilicity and commendable porosity (82.1 %), leading to a significantly enhanced permeability (water flux > 82.3 L·m−2·h−1). Meanwhile, the membrane shows promising PVA removal efficiency (> 99.9 %) with a high COD removal efficiency (∼ 83.4 %) and enhanced antifouling capacity (flux recovery ratio > 99.7 %) with the assistance of PMS driven by an ultra low-power LED lamp. The universal applicability and environmental adaptability are also verified in various reaction conditions. In terms of ecotoxicological impacts of the PVA wastewater before and after treatment on aquatic organisms, Zebrafish embryonic development dynamically demonstrated that the treated PVA waste water by the developed hybrid membrane is healthy for fish to grow. Our study definitely opens up a new avenue to develop high-performance catalytic membranes for PVA-based wastewater treatment.

Boosting water flux and dye removal: Advanced composite membranes incorporating functionalized AC-PAA for wastewater treatment

This study addresses the challenge of enhancing dye removal and antifouling properties in wastewater treatment by developing a composite membrane incorporating poly(acrylic acid)-functionalized activated carbon (AC-PAA) into a polyethersulfone (PES) matrix. The activated carbon was functionalized using surface-initiated atom transfer radical polymerization (SI-ATRP), followed by hydrolysis to introduce hydrophilic poly(acrylic acid) chains. The AC-PAA composite was characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, and energy-dispersive X-ray analysis, confirming successful grafting and functionalization. Compared to pristine PES, the addition of 0.5 wt% AC-PAA led to significantly enhanced water flux (54 L/m2h vs. 30 L/m2h) and superior dye removal, achieving 63 % for methyl orange and 67 % for methylene blue at alkaline pH. Poly(acrylic acid) was selected for its carboxyl groups, which enhance adsorption capacity and antifouling characteristics. In addition to effective dye removal, the composite membranes were antifouling, with a flux recovery ratio of 72 %. Response surface methodology optimized parameters, confirming highest performance at pH 11 and 6 bar. AC-PAA functionalized membranes are an efficient solution in wastewater treatment, increasing dye removal and antifouling capacity versus current membrane technologies.

ZrO2 Nanoparticles Filler-Based Mixed Matrix Polyethersulfone/Cellulose Acetate Microfiltration Membrane for Oily Wastewater Separation

Membrane technology has emerged as a dynamic field of study in academia and industry for treating produced oily wastewater. ZrO2 nanoparticles (ZrO2 NPs) filler-based mixed matrix polyethersulfone/cellulose acetate microfiltration membranes were fabricated and inspected in the oily wastewater remediation. The fabricated bare PES membrane, PES/CA blended polymers membrane, and PES/CA blended polymers incorporating ZrO2 NPs (ZrO2@PES/CA) membranes by phase inversion technique were inspected by field emission scanning electron microscopy, atomic force microscopy, Fourier-transform infrared spectroscopy, and measurement of water contact angle and porosity. The ZrO2@PES/CA membrane which consisted of 0.5 wt.% ZrO2 NPs (0.5%ZrPC) afforded increased hydrophilicity and reduced water contact angle from 70° for P membrane to 30.23°. Also, the 0.5%ZrPC membrane gave pure water flux of 88.89 L/m2.h, high oil rejection of 98.2% and showed remarkable antifouling capacity with a high flux recovery ratio of 89.3% and relative flux reduction of 34.3%. The effect of transmembrane pressure (1, 2, 3, and 4 bar), feed temperature (25, 40, and 50 °C), and an initial oil concentration (250, 500, 750, and 1000 mg/L) on the permeation flux and oil rejection of the 0.5%ZrPC membrane was investigated. The results revealed that ZrO2@PES/CA membranes have a significant potential for effective oil removal with high permeability and antifouling ability. The 0.5%ZrPC membrane confirmed its durability and reusability when kept an acceptable oil removal after 5 cycles.

Bioinspired Homonuclear Diatomic Iron Active Site Regulation for Efficient Antifouling Osmotic Energy Conversion.

Membrane-based reverse electrodialysis is globally recognized as a promising technology for harnessing osmotic energy. However, its practical application is greatly restricted by the poor anti-fouling ability of existing membrane materials. Inspired by the structural and functional models of natural cytochrome c oxidases (CcO), the first use of atomically precise homonuclear diatomic iron composites as high-performance osmotic energy conversion membranes with excellent anti-fouling ability is demonstrated. Through rational tuning of the atomic configuration of the diatomic iron sites, the oxidase-like activity can be precisely tailored, leading to the augmentation of ion throughput and anti-fouling capacity. Composite membranes featuring direct Fe-Fe motif configurations embedded within cellulose nanofibers (CNF/Fe-DACs-P) surpass state-of-the-art CNF-based membranes with power densities of ca. 6.7Wm-2 and a 44.5-fold enhancement in antimicrobial performance. Combined, experimental characterization and density functional theory simulations reveal that homonuclear diatomic iron sites with metal-metal interactions can achieve ideally balanced adsorption and desorption of intermediates, thus realizing superior oxidase-like activity, enhanced ionic flux, and excellent antibacterial activity.

Transparent coating based on multienzyme-mimicking Janus nanozyme for synergetic biofouling control in seawater

The problem of marine biofouling persists in marine resource development, particularly for marine observation. While nanomaterials with enzyme-mimicking activity show promise in combating marine biofouling, their unique physicochemical properties that enable nanozymes with multiple enzymatic activities for a synergetic antifouling effect have yet to be explored. Here, it is shown that a transparent zwitterionic coating based on Ag/Ag2S Janus nanoparticles (Ag/Ag2S JNPs) with peroxidase-, light-activated oxidase-, and haloperoxidase-mimicking activities contributes to antifouling synergy. The mechanism of the nanozyme action is revealed in a detailed experimental and computational study, in which unique Janus structures guarantee multi-enzyme-mimicking properties and produce OH, HOBr, and O2− to combat biofouling. Through the formation of hydration layers, zwitterionic coatings further enhance this antifouling capacity, as demonstrated by both indoor and outdoor marine field antifouling tests. Consequently, a coating like this shows a clear transmittance and excellent antifouling ability after 90 days in marine immersion, reducing fouling by 74.91 % and 39.71 % compared to a control coating and a commercial coating, respectively. This study not only demonstrates synergetic antifouling actions via multi-enzyme-mimicking activities but also uncovers a new paradigm in nanozyme-based environmentally friendly, sustainable antifouling strategy.

Green solutions for desalinated water drip irrigation systems: Organic acids outperform inorganic acids in fouling control

Desalinated saline water (DSW) has been widely applied in many fields due to global water scarcity. However, fouling formation in desalinated saline water distribution systems (DSWDS) raises serious technical concerns. The conventional approaches (e.g., inorganic acids) for DSWDS fouling control is not only ineffective sometimes but also lead to serious environmental and health risks. Accordingly, this study introduces a greener method utilizing organic acids for antifouling in DSWDS. The performances and influences of three types of inorganic acids (hydrochloric acid (HCl), phosphoric acid (H3PO4) and hydrofluoric acid (HF)) and three types of organic acids (citric acid (C6H8O7), formic acid (CH2O2) and oxalic acid (H2C2O4)) on DSWDS fouling control were investigated and compared. The obtained results indicated that in general, organic acids exhibited higher antifouling capacities than inorganic acids. Among the selected six acids, CH2O2 was the most effective, followed by H2C2O4, H3PO4, C6H8O7, HCl, and HF. In comparison with the most commonly used inorganic HCl, the fouling dry weights in the samples treated with C6H8O7, CH2O2, and H2C2O4 reduced by an average of 8.9 %, 45.3 %, and 33.2 %, respectively. Despite the higher acidity of inorganic acid solutions compared to organic acids, the latter exhibited a stronger chelating capacity for cations (e.g., Ca2+, Mg2+) in DSW, showing a lower tendency to form precipitation in their treated groups. Moreover, organic acids could increase the crystal cell volume and change the chemical bond length of chemical precipitation, resulting in lattice distortions. Furthermore, organic acids can slow down the flocculation and settling of suspended particulate matter, thereby alleviating the formation of particulate fouling. Overall, these findings suggest that the application of organic acids is a more effective and environmental-friendly approach for fouling control compared to inorganic acids, which provides qualitative and quantitative insights into developing greener antifouling protocol for DSW delivery in actual field practices.

Filtration performance of biofilm membrane bioreactor: Fouling control by threshold flux operation

Membrane fouling is the major factor that restricts the furtherly widespread use of membrane bioreactor (MBR). As a new generation of MBR, biofilm membrane bioreactor (BF-MBR) demonstrates high treatment efficiency and low sludge growth rate, however the filtration performance improvement and membrane fouling control are still the challenges for its further development. This work investigated the filtration performance using resistance in series model and membrane fouling control via threshold flux for BF-MBR. At first, the flux behavior and filtration resistance under various operating conditions, including agitation speed, membrane and TMP, were explored by resistance in series model. Because of the desirable anti-fouling capacity, UP100 and UP030 had the high threshold flux (100 and 90 L m−2 h−1) and low irreversible fouling resistance (1 and 1.3 × 10−10 m-1). Higher shear stress produced by higher agitation speed could reduce membrane fouling, while greatly promote the threshold flux (138 L m−2 h−1) and membrane cleaning efficiency (96%). Moreover, increasing shear stress or selecting membrane with large pore size could decrease the fouling rate and raise the threshold flux. As for TMP, high TMP reduced the removal rate for organic and nutrient, and enhanced the irreversible fouling. Besides, the aerobic-BF-MBR (101 L m−2 h−1 and 1.3 × 10−10 m-1) with lower foulant concentration had a better filtration performance than anoxic-BF-MBR (90 L m−2 h−1 and 1.5 × 10−10 m-1). Additionally, the long-term tests with 10 cycles were conducted to evaluate the industrial application value of BF-MBR (45–58 L m−2 h−1). This work provides the technical support for sustainable filtration performance of BF-MBR.

A multifunctional Ag NPs/guar gum hydrogel as versatile platform for catalysts, antibacterial agents, and construction of oil-water separation interfaces

The frequently encountered wastewater contaminations, including soluble aromatic compound and dye pollutants, pathogenic bacteria, and insoluble oils, have resulted in significant environmental and human health issues. It poses a challenge to utilize identical materials for the treatment of complex wastewater. Herein, in this research, multifunctional Ag NPs/guar gum hybrid hydrogels were fabricated using a facile in situ reduction and self-crosslinking method for efficient remediation of complex wastewater. The Ag NPs/guar gum hybrid hydrogel showed remarkable remodeling, adhesive, and self-healing characteristics, which was favorable for its versatile applications. The combination of Ag NPs with the guar gum skeleton endowed the hybrid hydrogel with exceptional catalytic activity for reducing aromatic compounds and dye pollutants, as well as remarkable antibacterial efficacy against pathogenic bacteria. In addition, the Ag NPs/guar gum hybrid hydrogel could be employed to coat a variety of substrates, including cotton fabrics and stainless steel meshes. The hydrogel coated cotton fabrics and meshes presented superhydrophilicity/underwater superoleophobicity, excellent antifouling capacity, and outstanding recyclability, which could be successfully applied for efficient separation of oil-water mixtures. The findings of this work provide a feasible and cost-effective approach for the remediation of intricate wastewater.

Boosting Demulsification and Antifouling Capacity of Membranes via an Enhanced Piezoelectric Effect for Sustaining Emulsion Separation.

Traditional superwettable membranes for demulsification of oil/water emulsions could not maintain their separation performance for long because of low demulsification capacity and surface fouling during practical applications. A charging membrane could repel the contaminants for a while, the charge of which would gradually be neutralized during the separation progress. Here, a superhydrophilic piezoelectric membrane (SPM) with sustained demulsification and antifouling capacity is proposed for achieving prolonged emulsion separation, which is capable of converting inherent pulse hydraulic filtration pressure into pulse voltage. A pulse voltage up to -7.6 V is generated to intercept the oil by expediting the deformation and coalescence of emulsified oil droplets, realizing the demulsification. Furthermore, it repels negatively charged oil droplets, avoiding membrane fouling. Additionally, any organic foulants adhering to the membrane undergo degradation facilitated by the generated reactive oxygen species. The separation data demonstrate a 98.85% efficiency with a flux decline ratio below 14% during a 2 h separation duration and a nearly 100% flux recovery of SPM. This research opens new avenues in membrane separation, environmental remediation, etc.

Long-lasting low fluorinated stainless steel hierarchical surfaces for omniphobic, anti-fouling and anti-icing applications

Stainless steel (SS) alloys are prevalent in many industries, household appliances or other commodities, where a strict control of surface properties is required to tailor their interaction with the environment. In this work we report a new procedure of stainless steel surface processing that provides a multifunctional response including superhydrophobicity, omniphobicity, self-cleaning, anti-fouling and effective anti-icing capacity, while still preserving a corrosion resistance similar to that of this material in compact form. The method consists of a first nanostructuration step followed by a low fluorination. The nanostructured surfaces presented a dual scale roughness of hierarchical character. The liquid free approach developed in this work to get this singular surface nanostructuration entails a first laser treatment of stainless steel flat substrates, followed by the deposition of a nanostructured thin layer of this material by electron beam evaporation in an oblique angle configuration. The resulting hierarchical surfaces were subjected to fluorination by: (i) the plasma-assisted deposition of a thin Teflon-like coating or (ii) the grafting of fluorinated molecules. The self-cleanable, anti-adherent and ice repellent character of the resulting low fluorinated surfaces outperformed the behaviour of classical slippery surfaces obtained by the infusion of high amounts of fluorinated liquids. These hierarchical SS surfaces withstood mild abrasion tests and the effect of water jets. Moreover, the corrosion behaviour of the fluorinated surfaces determined through their potentiodynamic analysis revealed a similar corrosion resistance than the flat SS substrates. Outstandingly, after these corrosion tests, the fluorinated samples obtained by grafting preserved their surface functionalities without significant degradation. The high mechanical and chemical stability of these low fluorinated samples support their usage for a large variety of applications.

Disc ceramic membrane modified with nano-TiO2 for separating oil-water emulsion under dynamic membrane filtration

A disc ceramic membrane was modified nano-TiO2 via an impregnation and in-situ hydrolysis method, resulting in the generation of nano-TiO2 particles on the surface and inside the pores of disc ceramic membrane. The uniform distribution of nano-TiO2 enhanced the superior hydrophilic property of the membrane surface, and improved pure water flux and increased anti-fouling capacity. The modified disc ceramic membrane was employed to effectively separate stable oil-water emulsions under dynamic membrane filtration mode. Here, the preparation process of nano-TiO2 and operational parameters of equipment on the separation efficiency of the modified disc ceramic membrane were investigated. The findings indicate that an increase in the permeability and separation rate of the modified disc ceramic membrane. Moreover, the modified disc ceramic membrane maintained a steady flux for a continuous separation time of 120-min at a TMP of 0.04 MPa. The rejection rate of oil-water emulsion also reached 99.9%. The excellent performance of the modified disc ceramic membrane was ascribed to the nano-TiO2 modification and the dynamic membrane filtration applied together to alleviate membrane fouling, leading to improve the oil-water separation efficiency and permeate flux. This study presents a new technique for the separation of oil-water emulsions with high concentration, achieving outstanding separation stability and cost-effectiveness.

Effect of nanobubble concentrations on fouling control capacity in biogas slurry wastewater distribution systems

Nanobubble (NB) represents a promising practice for mitigating fouling in biogas slurry distribution systems. However, its anti-fouling effectiveness and optimal use dosage are unknown. This study investigated the NB anti-fouling capacity at six concentrations (0 %–100 %, denoting the ratio of maximum NB-infused water; particle concentrations in 0 % and 100 % ratios were 1.08 × 107 and 1.19 × 109 particles mL−1, respectively). Results showed that NB effectively mitigated multiple fouling at 50 %–100 % ratios, whereas low NB concentration exacerbated fouling. NB functioned both as an activator and a bactericide for microorganisms, significantly promoting biofouling at 5 %–25 %, and inhibiting biofouling at 50 %–100 %. Owing to an enhanced biofilm biomineralization ability, low NB concentration aggravated precipitate fouling, whereas high NB doses effectively mitigated precipitates. Additionally, higher NB concentrations demonstrated superior control efficiency against particulate fouling. This study contributes insights into NB effectiveness in controlling various fouling types within wastewater distribution systems.

Zwitterion mediated anti-protein adsorption on polypropylene mesh to reduce inflammation for efficient hernia repair

The effectiveness of polypropylene (PP) mesh is often compromised by severe inflammation. Engineering anti-inflammatory coatings has significant implications for PP mesh to repair unwanted hernias. Here, we presented a facile strategy to develop an anti-fouling coating consisting of zwitterionic poly(carboxybetaine methacrylate) (PCBMA), which could prohibit protein adsorption to endow PP mesh with anti-inflammatory efficacy. The incorporation of PCBMA coating had little impact on the raw features of PP mesh. While the modified mesh PCBMA-PP possessed noticeable hydrophilicity increase and surface charge reduction. The excellent lubricity and surface stability enabled PCBMA-PP to exhibit superior anti-fouling capacity, thus efficiently inhibiting the adsorption of proteins. In vivo experiments showed that incorporating the PCBMA layer could provide PP meshes with outstanding anti-inflammatory effects and tissue compatibility for repairing hernias.

Development of an antimicrobial and antifouling PES membrane with ZnO/poly(hexamethylene biguanide) nanocomposites incorporation

Although polyethersulfone (PES) membranes are extensively utilized in water and wastewater treatment, they typically encounter serious bio/organic fouling problems. In this work, an antimicrobial and antifouling PES membrane was developed through incorporating novel ZnO/PHMB (zinc oxide/ polyhexamethylene biguanide hydrochloride) nanocomposites on the surface of a commercial PES membrane, with PDA (polydopamine) serving as an intermediate connection layer. XPS, along with synchrotron-based XRF and ATR-FTIR results confirmed the successful synthesis of the ZnO/PHMB nanocomposites and ZnO/PHMB membranes. The ZnO/PHMB nanocomposites exhibited an impressive antimicrobial rate of 99.99 % with a minimal amount of PHMB addition (wtZnO:wtPHMB = 1:0.01). The concentration of the ZnO/PHMB nanocomposites had the most significant impact on the antimicrobial performance of the ZnO/PHMB membrane. The 600ZP membrane (i.e., the PES membrane modified with 600 mg/L ZnO/PHMB nanocomposites) emerged as the optimal choice, as evidenced by its commendable antimicrobial performance (92.80 %), water flux (249.02 LMH), RB (Rose Bengal sodium salt) rejection (93.96 %), and cost-benefit considerations. Compared to the pristine PES membrane, the 600ZP membrane showed 5.32 %, 15.76 %, and 7.62 % increased hydrophilicity, water flux, and RB rejection rate, respectively. Additionally, the 600ZP membrane possessed a bactericidal rate of 92.80 % and a flux recovery rate of 89.24 % after three cycles of SA (sodium alginate) filtration, indicating enhanced antimicrobial and antifouling capacities. The 600ZP membrane exhibited a remarkable 91.05 % higher water flux following prolonged (72 h) treatment of secondary effluent, compared to the PES membrane. Attribute to the increased hydrophilicity, outstanding antimicrobial activity, as well as excellent stability and durability, the as-prepared ZnO/PHMB membrane shows great potential for wastewater treatment.

Nanobubbles for the Mitigation of Fouling in Wastewater Distribution Systems

The increasing demand for wastewater treatment has become a notable trend for addressing global water scarcity. However, fouling is a significant challenge for wastewater distribution engineering systems. This study provides an approach using nanobubbles (NBs) to control fouling. The antifouling capacities of three types of NBs, six oxygen concentrations, and two application procedures (prevention and removal) are investigated. The results show that NBs effectively mitigate composite fouling—including biofouling, inorganic scaling, and particulate fouling—in comparison with the non-NBs group. More specifically, hydroxyl radicals generated by the self-collapse of NBs oxidize organics and kill microorganisms in wastewater. The negatively charged surfaces of the NBs transform the crystalline form of CaCO3 from calcite to looser aragonite, which reduces the likelihood of ion precipitation. Furthermore, the NBs gas-liquid interfaces act as gas “bridges” between colloidal particles, enhancing the removal of particles from wastewater. Lastly, although the NBs inhibit the growth of fouling, they do not significantly remove the already adhered fouling in non-NBs treated groups. This study anticipates that the application of NBs will address the significant fouling issue for various wastewater distribution engineering systems in order to meet the global challenge of sustainable water supplies.

Preparation and properties of PEEK-g-PNIPAm separation membranes with thermo-responsiveness for emulsion and organic liquid separation

Although poly (ether ether ketone) (PEEK) exhibits excellent solvent resistance, it could not be prepared directly by non-solvent induced phase separation (NIPS) method due to its poor solubility. Herein, PEEK porous membranes were successfully fabricated by combining NIPS and acid hydrolysis. The superhydrophilic thermo-responsive poly (N-isopropylacrylamide) (PNIPAm) polymer was in-situ grafted on the PEEK membrane surface via the UV grafting polymerization and improved the membrane interface hydrophilicity, making the membrane water contact angle changed from 89.5° to 0° at 25 °C. After heating the membrane surface to 40 °C, the membrane exhibited hydrophobicity (100°), realizing the thermo-responsiveness via switching the temperature. Furthermore, due to the transferred membrane wettability at different temperatures, PEEK-g-PNIPAm could separate different types of oil-bearing systems with high rejection above 99.0 %. What’s more, the PNIPAm layer also enhanced the membrane anti-fouling capacity. Benefiting from the extraordinary solvent resistance of the PEEK matrix, PEEK-g-PNIPAm maintains its intact morphology after 6 h immersion in various organic solvents, addressing the commonly reported problem of polymer membranes having certain solubility in solvents. The PEEK-based membranes with excellent solvent resistance could be useful in the oil-bearing separation.

Elevating oil-in-water emulsion separation: Unleashing the power of exfoliated graphitic carbon nitride composite membranes

The current study describes composite membranes that utilise exfoliated graphitic carbon nitride (Eg-C3N4) as a promising membrane additive for oily-water separation, owing to its hydrophilic nature and high functionality. The integrated membranes have been discovered to have outstanding properties when Eg-C3N4 is used as a composite material in polysulphone (PSf) membranes. The study provides provide insights into the usage of such nanosheets to achieve good chemical interaction with the membrane matrix, enabling both Eg-C3N4 and PSf synergistic characteristics. The well-planned exfoliated g-C3N4-PSf composite demonstrated promising oil-water separation with an oil rejection capacity of >99 %. Furthermore, these exfoliated laminar planes interacted well with the polymer, resulting in membranes that were both thermally and mechanically stable. The membrane also has a high porosity range of 46.13 % to 76.03 % and a high-water uptake range of 42.23 + 1.68 % to 71.34 + 1.24 %, which explains the membrane's enhanced hydrophilicity and appropriate oily-water treatment capacity. Furthermore, the addition of Eg-C3N4 lowers surface roughness, which explains for the great antifouling capacity exhibited by the composite membrane, demonstrating a remarkable flux recovery ratio of about 99.1 % with no compromise in oil rejection during subsequent cycles.

Synergistic effect of POSS and chitosan on highly enhancing the separation selectivity and antifouling capacity of polyamide membranes

The trade-off limit between permeability and selectivity, along with membrane fouling, has consistently posed significant challenges impeding the practical implementation of water purification membranes. In this paper, a combination of polyhedral oligomeric silsesquioxanes (POSS) and chitosan is introduced into the polyamide layer through interfacial polymerization and crosslinking to optimize the physical, chemical structure of membrane simultaneously. The resulting P/CS-2-POSS-2 membrane exhibits a notable water flux of 221.3 L m−2 h−1 MPa−1 and a substantial Na2SO4 rejection of 97.1 %. The selectivity of water molecules over sulfates in the optimized hybrid membrane is approximately 4 times greater than that observed in the pristine polyamide membrane. This finding underscores the success of the developed method in mitigating the trade-off between permeability and selectivity. Furthermore, the hybrid membranes exhibit superior antifouling properties, as evidenced by an impressive flux recovery ratio of 95.8 % for bovine serum albumin. Additionally, the mass transport properties of the prepared membranes are explored via molecular dynamics (MD) simulations. The results highlight that chitosan primarily enhances the membrane's hydrophilicity, whereas POSS predominantly regulates the membrane's pore size. Both fillers synergistically enhance the comprehensive performance of the membrane by effectively utilizing steric hindrance and the Donnan effect.

Carbon/MnO2-x nanofibrous membrane for superior O/W emulsions purification with robust and comprehensive-fouling mitigation

Filtration membranes (FMs), with high separation efficiency, robust/comprehensive anti-fouling capacities, and highly anti-corrosive performance, are highly desirable for practical complex oil/water emulsions purification, but still a challenge unsolved. Herein, FM containing oxygen vacancy engineered MnO2-x nanolayer on the outer surface of carbon nanofibrous membrane has been fabricated to address this challenge. Given the existence of oxygen vacancy of the MnO2-x nanolayer, multiple functions have been realized simultaneously: (i) stronger water affinity than oils; (ii) robust anti-corrosion towards diverse corrosive media (e.g., 1M HCl, 1M NaOH, 10 wt % NaCl, N,N-dimethylformamide, and dimethyl sulfoxide); (iii) efficient degradation of organic dyes (methylene blue and rhodamine B) via photocatalytic process; (iv) comprehensive anti-fouling capacities for oils, organic dyes, bovine serum albumin, and humic acid . Consequently, our FM displays superior separation efficiencies (≥ 99.3 %) towards complex oil/water emulsions with high flux (the maximum: 41,557 ± 350 L m−2 h−1bar−1), robust and comprehensive anti-fouling capacity for different pollutants (e.g., oils, bovine serum albumin, humic acid, and organic dyes) via simple water rinse or photocatalytic degradation to 100 % recover permeation flux for 40 cycles. These outstanding functions make our FM with great potential in practically complex O/W emulsions treatments under harsh conditions.

Study of sustainable HDPE-based materials for aquaculture applications: effects on fouling

This study addresses one of the most common problems faced by the marine sector, namely the accumulation of organic matter and organisms on submerged surfaces. This biological phenomenon causes structural problems in aquatic systems and its mitigation implies a large economic outlay for marine aquaculture industry. Antifouling paints are being developed to help control this undesirable process; however, these treatments are problematic as they degrade and release biocides and heavy metals into the environment. In this context, our study focuses on developing more environmentally friendly antifouling strategies. For this purpose, we designed high-density polyethylene (HDPE) material functionalized with different copper compounds or silica, and subsequently tested their effects on biofilm formation by aquatic organisms at both laboratory and pilot scale. Bacterial species (Vibrio harveyi and Cellulophaga lytica) and diatoms (Nitzschia ovalis) known for producing biofilm were used. Our study revealed that material including copper pyrithione (CuPT) was highly effective in inhibiting bacterial and algal biofilm formation. Moreover, the ecotoxicological study covering three trophic levels (bacteria, algae and rotifers) indicated that none of the materials developed and tested herein was toxic. HDPE is easily moldable and suitable to produce built-in aquatic structures, and our results show that its functionalization with CuPT greatly improves its antifouling capacity. These findings represent a step forward in the fight against fouling in marine environments.