Antifouling Tests Research Articles

One-step fabrication of multifunctional TPU/TiO2/HDTMS nanofiber membrane with superhydrophobicity, UV-resistance, and self-cleaning properties for advanced outdoor protection

This study successfully fabricated thermoplastic polyurethane (TPU)-titanium dioxide (TiO2)-hexadecyltrimethoxysilane (HDTMS) composite nanofibrous membrane (CNM), exhibiting superhydrophobicity, robust UV resistance, and anti-fouling properties, via electrostatic spinning technology. The nanofibrous membranes' (NM) microstructures were meticulously characterized using techniques such as field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FTIR), Raman scattering spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and 3D optical profiling. Performance evaluations included water contact angle measurement, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and uniaxial tensile and UV transmission tests. Results indicate that the CNM has an average fiber diameter of 179.28 nm, a static water contact angle (WCA) of 166.2 ± 0.5°, a sliding angle of 3.5 ± 0.8°, and a surface energy of 9.18 ± 0.6 mN/m. It also demonstrates commendable thermal stability with a tensile strength of 3.9 MPa, an elongation at break of 145.80 %, and an ultraviolet protection factor (UPF) of 1485 ± 13.2. It has considerable mechanical stability and can withstand 4000 tensile or 5000 compression cycles. The anti-fouling and moisture permeability tests reveal the membrane's superior functional performance. These attributes suggest a wide application potential for the CNM in anti-fouling outdoor protective clothing, sports footwear, and related fields.

High-performance of anti-bacterial composite membrane prepared from polyethersulfone-polyethylene glycol-silver nanoparticles

A bench-scale study of river water treatment using composite polyethersulfone (PES) membrane was carried out. Polyethylene glycol-silver nanoparticles (PEG-AgNPs) additive was designed to support the simultaneous filtration and disinfection performance of PES membranes via in situ incorporation. Significant improvements in the PES membranes after modification with PEG-AgNPs were observed. The experimental results showed that the PEG-AgNPs increased the PES membrane water flux from 2.87 to 172.84 L/m2·h. The anti-fouling test of the PES membrane toward humic acid molecules after the addition of PES/PEG-AgNPs increased the reversible fouling and decreased the irreversible fouling. In terms of filtration performance, the PES/PEG-AgNP membranes showed high filtration performance, with a water disinfection ability of 99.99 %. Moreover, the leach of silver particles from the PES membrane forced by ultrasonication was <50 ppb, indicating the security and stability of the PES/PEG-AgNP membrane.

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.

Fabrication of superamphiphobic micro-reentrant structures by inverted electrochemical deposition

Due to excellent oil resistance and shortened liquid-solid contact time, superamphiphobic surfaces have promising application prospects in oil transportation, and petroleum pollution control. Although superamphiphobic surfaces have been constructed on various substrates, there is still a lack of high-efficient methods for fabricating micro-reentrant structures on engineering metal substrates. This paper proposes a new method combining laser processing and inverted electrochemical deposition techniques to achieve high-efficient and large-scale fabrication of superamphiphobic surfaces on copper substrates. Firstly, micropillar array structures are constructed by laser processing, and the structures exhibit excellent superhydrophobicity after low surface energy modification. Then, inverted electrochemical deposition is performed after polishing the top of the array, and local angle of the gas/liquid interface can be controlled by adjusting the distance between the top of the micropillar and the electrolyte level, thus regulating micro-morphology of the roof structure. The influences of electrochemical deposition parameters on characteristics of the micro-reentrant structures are systematically investigated. Finally, superamphiphobic micro-reentrant structures (roof diameter > 190 μm, micropillar spacing <250 μm) with water and oil contact angles exceeding 150° are prepared after lowering the surface energy of the deposited structures. After anti-fouling, blowing, ultrasonic vibration, and tape adhesion tests, the prepared superamphiphobic micro-reentrant structures maintained good water and oil repellency, showing excellent chemical stability and durability. The research may provide a simple, efficient, and low-cost method for high-efficient constructing superamphiphobic surfaces on engineering metal substrates, enriching the fabrication techniques of micro-reentrant structures and facilitating their practical applications.

FABRICATION AND CHARACTERIZATION OF POLYETHERSULFONE (PES) MEMBRANES BY BLENDING POLYMERS FOR REMOVAL OF ORGANIC COMPOUNDS IN AIR

The PES membrane was modified using a polymer blending method to improve the performance and characteristics of the membrane. This research aims to see the effect of adding biosilica additives on the performance characteristics of PES membranes and determine the optimal composition of additives and solvents for making membranes. The membrane was made using the Non-solvent Induced Phase Separation (NIPS) method with a composition consisting of 18% PES, with the addition of varying concentrations of silica (1%, 2%, 3%, and 4%) and the membrane using the solvent N-Methyl- 2 Pyrrolidone (NMP) and Dimethyl Sulfoxide (DMSO). Membrane characterization was carried out by observing membrane morphology using Scanning Electron Microscopy (SEM), membrane surface functional group analysis test using Fourier Tranform Infrared (FTIR), membrane porosity test using the dry-wet weight procedure method, the highest porosity value was found on membrane B2 using a solvent DMSO with 2% silica is 16.88%. Membrane performance was carried out by pure water flux testing, the highest pure water flux value was found in membrane B2 with 2% silica, namely 64.14 L/m2.h. The antifouling test uses flux ratio recovery, the highest antifouling value is found on the A3 membrane with 3% silica, namely 91.3%. As well as rejection of the humic acid solution as a Natural Organic Matter (NOM) sample model using the ultrafiltration (UF) module with a dead end filtration flow system, the highest rejection value was found on the B2 membrane with 2% silica, namely 64.4%.

Fabrication of PVDF membranes via γ-ray irradiation and investigation into their membrane formation mechanisms and water treatment properties

Polyvinylidene fluoride (PVDF) membrane is a cheap and commonly used separation material, but its inherent hydrophobicity results in significant membrane contamination, which limits its engineering application and further development. The hydrophilic PVDF-g/co-NVP membrane was prepared through low-dose γ-ray irradiation and using N-vinyl-2-pyrrolidinone (NVP) as a modifier in this study. The effects of γ-ray dose and incorporating NVP additive on the microstructure, hydrophilicity, anti-fouling capability, and mechanical capacity of membranes were discussed. Molecular dynamics (MD) simulation method was used to comprehensively investigate the impact of the NVP on the physicochemical characteristics of membrane structure. Under a specific NVP load, the water contact angle of the membrane decreases from 87.92° to 52.66°. The pure water permeance reaches 362.1 L/m2 h, and the porosity increases to 55.21 %±1.29 %, which indicates that γ-ray irradiation with NVP addition can effectively adjust the pore structure and hydrophilicity of the membrane. During anti-fouling test against bovine serum albumin (BSA), the modified membrane exhibits remarkable anti-fouling characteristics, including reduced BSA accumulation, enhanced flux recovery, lower irreversible contamination level, and extended cleaning cycle compared with the original pure PVDF membrane because of its higher hydrophilicity and positive zeta-potential value. This study elucidates the mechanism underlying γ-ray graft modification of PVDF membranes, thereby providing valuable insights into the development of efficient functional membrane materials.

Enhancing Water Purification by Integrating Titanium Dioxide Nanotubes into Polyethersulfone Membranes for Improved Hydrophilicity and Anti-Fouling Performance.

Water pollution remains a critical concern, one necessitated by rapidly increasing industrialization and urbanization. Among the various strategies for water purification, membrane technology stands out, with polyethersulfone (PES) often being the material of choice due to its robust mechanical properties, thermal stability, and chemical resistance. However, PES-based membranes tend to exhibit low hydrophilicity, leading to reduced flux and poor anti-fouling performance. This study addresses these limitations by incorporating titanium dioxide nanotubes (TiO2NTs) into PES nanofiltration membranes to enhance their hydrophilic properties. The TiO2NTs, characterized through FTIR, XRD, BET, and SEM, were embedded in PES at varying concentrations using a non-solvent induced phase inversion (NIPS) method. The fabricated mixed matrix membranes (MMMs) were subjected to testing for water permeability and solute rejection capabilities. Remarkably, membranes with a 1 wt% TiO2NT loading displayed a significant increase in pure water flux, from 36 to 72 L m2 h-1 bar-1, a 300-fold increase in selectivity compared to the pristine sample, and a dye rejection of 99%. Furthermore, long-term stability tests showed only a slight reduction in permeate flux over a time of 36 h, while dye removal efficiency was maintained, thus confirming the membrane's stability. Anti-fouling tests revealed a 93% flux recovery ratio, indicating excellent resistance to fouling. These results suggest that the inclusion of TiO2 NTs offers a promising avenue for the development of efficient and stable anti-fouling PES-based membranes for water purification.

Bio-inspired co-deposition of dopamine and N-oxide zwitterionic polyethyleneimine to fabricate anti-fouling loose nanofiltration membranes for dye desalination

Developing anti-fouling loose nanofiltration membranes (LNMs) that can achieve dye desalination of saline textile wastewater through dye retention and salt permeation for resource utilization remains an urgent challenge that needs to be addressed. Inspired by the biomimetic adhesion of mussels and the excellent fouling resistance of saltwater fish surfaces, novel LNMs were prepared through co-deposition strategy using dopamine (DA) and N-oxide zwitterionic polyethyleneimine (ZPEI) as biomimetic functional materials. There are multiple interactions between them, including Schiff base reaction, Michael addition reaction, cation-π interaction and covalent polymerization. Compared with PEI-LNM prepared under the similar method, the optimized ZPEI-LNM displays more uniform surface, smaller average roughness (6 nm vs 22 nm), and denser pore size (0.69 nm vs 0.79 nm), indicating the zwitterionic N-oxide moieties in ZPEI regulate the deposition process and the cross-linking structure of the selective layer. ZPEI-LNM exhibits a high pure water flux of 203.0 L m−2h−1 under 0.6 MPa. Importantly, ZPEI-LNM shows high retention towards different dyes, including Congo red (CR, negative, 696.8 g/mol) of 100.0 %, Acid fuchsin (AF, negative, 585.5 g/mol) of 99.5 %, Crystalline violet (CV, positive, 408.0 g/mol) of 98.2 %, and Indigo carmine (negative, 466.4 g/mol) of 96.0 %, while the rejection of NaCl (8.7 %) and Na2SO4 (12.7 %) are both lower. As expected, for the mixture solution of AF/NaCl, the dyes are efficiently rejected, while salts can pass through, indicating that ZPEI-LNM displays an excellent dye desalination capability. Furthermore, multiple-cycle antifouling tests for bovine serum albumin (BSA) and sodium alginate (SA) reveal that the flux recovery ratios are higher than those of PEI-LNM (BSA: 90.4 % vs 81.9 %; SA: 86.6 % vs 80.5 %), indicating ZPEI-LNM exhibits better anti-fouling performance towards different model foulants owing to the outstanding hydration layer caused by zwitterionic N-oxide moieties and lower surface roughness. Consequently, the work offers a new viewpoint for the fabrication of anti-fouling LNMs via biomimetic strategy for dye desalination.

Novel in-situ zwitterionization of carbon quantum dots on membrane surface for oil/water separation

Industrial growth led to an increase in the release of hazardous oily wastewater that seriously threatens human health and the ecosystem. Developing polymeric membranes for treating such wastewater has garnered significant attention, yet their fouling resistance remains a challenge. In this study, an anti-fouling zwitterionic cellulose acetate (CA) membrane, called ZQDs-g-CA, was fabricated by grafting carbon quantum dots (CQDs) on the surface of the CA membrane, followed by zwitterionization of CQDs (Zwitterionic carbon quantum dots, ZQDs). The grafting of ZQDs increased the hydrophilicity and oleophobicity of the membrane due to the hydrophilic functional groups present in the nanomaterial. The surface roughness was increased, allowing a greater surface area for contact between water molecules and the membrane. The modified CA membrane demonstrated excellent water flux (602.2 ± 30.2 L m−1 h−1 bar−1 (LMHB)) and oil/water emulsion separation performance, with a permeation flux of 426.1 ± 9.6 LMHB and oil rejection of 99.4 %. Additionally, the anti-fouling tests demonstrated remarkable performance with more than 96 % flux recovery ratio (FRR), 30.35 % reversible fouling ratio (Rr), and 3.05 % irreversible fouling ratio (Rir). The results showed that the in-situ ZQDs on the CA membrane exceeded the 96 % rejection rate for different oil/water emulsions. ZQDs were successfully applied on the CA membrane, which would provide a reference for the application of ZQDs-g-CA in oil/water separation.

Highly efficient antifouling and toughening hydrogel for ship coatings

Hydrogels possess characteristics of anti-protein adsorption, which have attracted significant attention in the field of ship antifouling. Traditional hydrogels often exhibit poor mechanical properties and lack long-term application value. Herein, a PEGp hydrogel for underwater antifouling applications was prepared. PEGp hydrogel demonstrates excellent water retention, elasticity, and antifouling properties. It can effectively resist the adsorption of proteins and bacteria. The long-term antifouling test shows that PEGp hydrogel has application prospects in the marine environment. Additionally, molecular dynamics (MD) simulations show that water molecules interact with the PEGp to form a hydration layer, endowing PEGp hydrogel with hydrophilicity. These studies offer a novel approach to developing ship antifouling materials and exploring new directions for environmental protection and antifouling.

Evaluation of the performance of Fe3O4-NPs/PVDF nanocomposite membrane for removal of BTEX from contaminated water

With the increase in reported cases of toxic organic contaminants such as benzene, toluene, ethylbenzene, and xylene (BTEX) in the aquatic environment, membrane technology offers a viable option for removing BTEX from wastewater. However, hydrophilic modification of the membranes is vital to reduce the rapid accumulation of the BTEX organic contaminants and maintain improved membrane performance in BTEX removal. In this study, biogenically-synthesized Fe3O4-NPs were embedded into a PVDF membrane to endow the membrane with hydrophilicity, which necessitates the reduction in BTEX accumulation on the membrane, consequently maintaining improved membrane performance towards BTEX removal. Different Fe3O4-NPs loadings (0 wt% to 5 wt%) were used for the PVDF modification to establish the optimum blending amount of the Fe3O4-NPs required to achieve the most effective membrane. The water contact angle was reduced from 84.2° (pristine PVDF) to 52° for the membrane modified with 1 wt% of the Fe3O4-NPs. Other membrane features such as porosity, surface roughness, and mechanical strength were also enhanced. Performance evaluation of the membranes revealed that the flux and BTEX rejection of the Fe3O4-NPs/PVDF membrane were improved. The antifouling test results showed a reduction in the total fouling from 52.1 % (pristine membrane) to 36.3 % for the membrane modified with 1 wt% of the Fe3O4-NPs. Our findings provide a strategy utilizing biogenically synthesized Fe3O4-NPs to enhance PVDF membranes' performance for removing BTEX from wastewater.

Separation performance enhancement of PEEKWC/PEI cross-linked ultrafiltration membranes by poly(ethylene glycol) and polyvinylpyrrolidone as polymeric additives

In order to improve both pure water flux and retention rate of the cross-linked ultrafiltration membranes based on phenolphthalein-based poly(ether ether ketone) (PEEKWC) and polyethyleneimine (PEI), poly(ethylene glycol) (PEG) and polyvinylpyrrolidone (PVP) were used as polymeric additives in non-solvent-induced phase separation process. The characterizations, separation effectiveness, and anti-fouling performance of membranes were investigated. Compared with n-butanol additive, the PEG and PVP could accelerate the phase separation rate and form thinner and denser skin layer, and then that led to an increase in the fluxes of pure water and better dye retention performance. In addition, the impact of variable additive dosage on the pure water flux and retention for dye solutions was investigated, and the pure water flux of membranes could reach 3270.8 L·m−2·h−1 and 2494.5 L·m−2·h−1 at a PEG or PVP concentration of 0.5 wt%, respectively. These membranes also exhibited excellent retention performance for Coomassie brilliant blue and Congo red greater than 98%. The simultaneous improvement of pure water flux and retention performance also could be related to the more efficient water transmission channel forming which was investigated by atomic force microscope phase images. In anti-fouling performance tests, the membranes demonstrated effective anti-fouling properties with a high flux recovery ratio after external cleaning with water only.

A novel fabrication method of slippery lubricant-infused porous surface by thiol-ene click chemistry reaction for anti-fouling and anti-corrosion applications

Abstract A novel and simple way for efficiently preparing stable and non-toxic slippery lubricant-infused porous surface (SLIPS) will expand its anti-fouling and anti-corrosion applications in marine environments. Herein, vinyl-terminated polydimethylsiloxane was covalently grafted on the surface of nano-SiO2 by a thiol-ene click chemistry reaction. After that, SLIPS was efficiently prepared at room temperature via the spraying method on various substrate surfaces. Surface wettability results showed that a water droplet (10 μL) can slip on the surface with an inclination of 10° and a stained water droplet can slip without stain during the slide process, which proved that SLIPS displayed excellent slippery performance. The existence of molecular-level slippery silicone oil film on the rough surface. Anti-fouling and anti-corrosion tests showed that the prepared SLIPS exhibited stable and excellent anti-fouling and anti-corrosion performance after immersion in Pseudoalteromonas sp. culture solution for 14 days. The SLIPS exhibited a value of more than 98% of bacterial attachment inhibition efficiency and a value of 99.9% of corrosion inhibition efficiency. This facile method provides guidance to fabricate SLIPS for its anti-fouling and anti-corrosion applications in marine environments.

Self-healing and durable antifouling zwitterionic hydrogels based on functionalized liquid metal microgels

Hydrogels are a promising new class of antifouling materials. But their utility is constrained by low mechanical strength and unsatisfactory antifouling performance over the long term. Herein, we successfully prepared zwitterionic polymer PEIS cross-linked gallium-based liquid metal microgels-based (PEIS-Gel@PMPC-GLM) hydrogels via UV-curing and amidation reaction. The as-prepared hydrogels showed preferable mechanical properties and superior hydrophilicity to the original hydrogels. The PEIS-Gel@PMPC-GLM hydrogels could prevent the adhesion of more than 90 % of microalgae and nearly 100 % of bacteria in a short-term antifouling test. PEIS-Gel@PMPC-GLM hydrogels also performed exceptionally well in the high concentration antibacterial test and the long-term antifouling test (remove more than 90 % bacteria and 80 % microalgae). In addition to releasing a high concentration of gallium ions, as shown by the ICP-OES test, PEIS-Gel@PMPC-GLM hydrogels also exhibitedexcellent lubrication performance, as demonstrated by the friction test (coefficient of friction as low as 0.023). Therefore, the antifouling effect of gallium ions combined with the strong hydration ability of the surfaces endowed the hydrogels remarkable antibacterial and antifouling properties. As a result of the exposed gallium atoms inducing further crosslinking of residual vinyl monomer in hydrogels, PEIS-Gel@PMPC-GLM hydrogels revealed certain self-healing performance.

Analysis of the thermal shock and fouling resistance of the Kalimantan zircon based hybrid composite ceramic coating in boiler environment

Power plant boilers operate at relatively high temperatures and pressures. As they are prone to material degradation, fouling and scaling, the materials used must have good thermal and chemical resistance. Coating material is one of the solutions to problems that exist in boilers. In this study, the basic coating material used came from local mineral resources, namely Kalimantan zircon sand and zirconia that had been purified from zircon sand. And there is the addition of filler as a coating reinforcement so that the coating properties become better. The variables of this study are variations of filler materials that have lubricating properties such as hBN, MoS2, graphite and a mixture of the three fillers (hybrid). The coating method used is slurry spray coating and then sintering at 600 °C. The main coating parameter tests carried out were thermal shock and anti-fouling resistance. From the research results, it was found that the purification of Zircon Sand resulted in an increase in Zirconia content from 59 % to 68 %. From the results of the thermal shock resistance and anti-fouling tests, it was found that the coating with purified zircon has better thermal shock resistance while the fouling resistance is not significantly different from unrefined zircon sand, so it is necessary to develop a zircon purification process to obtain a higher ZrO2 content. For filler variations, the hybrid filler produces a coating with better thermal shock and anti-fouling resistance so that it can be used for optimizing ceramic composite coatings

P(MA-AMPS)/PVA@SiO2 hybrid hydrogel coated stainless steel mesh for effective separation of stabilized oil-in-water emulsions under gravity

The superhydrophilic/underwater superhydrophobic membrane offers unique advantages in effectively separating oily wastewater. However, the development of membrane materials that can efficiently separate emulsions only under gravity is still a challenge. A crosslinked network copolymer P(MA-AMPS) was synthesized by radical polymerization of N, n-methylenebisacrylamide (MBA), methacrylamide (MA) and 2-acrylamide-2-methylpropanesulfonic acid (AMPS) initiated by potassium persulfate. Then polyvinyl alcohol (PVA) and nano-SiO2 were inserted to the crosslinked polymer system in order to prepare a P(MA-AMPS)/PVA@SiO2 hybrid hydrogel. The hybrid hydrogel can be sprayed on the surface of stainless steel mesh (SSM) by a simple spraying method, so as to achieve superhydrophilicity/underwater superoleophobicity. The oil-water emulsion permeation flux reached more than 352.94 L·m−2·h−1, while xhibiting a more than 99.5 % separation efficiency under gravity. The anti-fouling tests demonstrated that the membrane exhibited outstanding anti-fouling performance. Moreover, the combination of stable semi-interpenetrating networks and nanoparticles made the membrane exhibit excellent stability and durable separation ability in complex physicochemical environments.

An efficient immersing strategy for enhancing the separation performance of microfiltration carbon membranes for oily wastewater

Here, an immersing strategy was designed to modify the porous structure of microfiltration carbon membranes (MFCMs) made by the pyrolysis of phenolic resin-based plates. The thermal stability of precursors, the functional groups, porous structure, microcrystalline structure, microscopic morphology and surface wettability of MFCMs were characterized by TGA, FT-IR, XRD, SEM, TEM and water contact angle, respectively. The effects of the concentration of immersing solution, soaking time and operational conditions on the separation performance of MFCMs for oily wastewater were investigated. In addition, the anti-fouling ability of the MFCMs was further examined. The results showed that the average pore size and porosity of MFCMs decreased after immersing modification. When the modification condition was adopted at the immersing solution concentration of 3% and soaking time of 60 s, the resultant MFCMs exhibited the minimum average pore size of 0.13 μm and a porosity of 31.96%. At the same time, the optimal separation performance was achieved at 99.85% for oil rejection and 392.16 Kg/m2•h•MPa for water permeation flux. In addition, the oil rejection almost remains intact during antifouling ability test, except for a slight drop trend of water permeation flux. It is evident that the facile immersing protocol holds a promise for effectively modifying MFCMs in the treatment of oily wastewater.

Self-Enhanced Antibacterial and Antifouling Behavior of Three-Dimensional Porous Cu2O Nanoparticles Functionalized by an Organic-Inorganic Hybrid Matrix.

Cu2O is currently an important protective material for domestic engineering and equipment used to exploit marine resources. Cu+ is considered to have more effective antibacterial and antifouling activities than Cu2+. However, disproportionation of Cu+ in the natural environment leads to its reduced bioavailability and weakened reactivity. Novel and functionalized Cu2O composites could enable efficient and environmentally friendly applications of Cu+. To this end, a series of three-dimensional porous Cu2O nanoparticles (3DNP-Cu2O) functionalized by organic (redox gel, R-Gel)-inorganic (reduced graphene oxide, rGO) hybrids─3DNP-Cu2O/rGOx@R-Gel─at room temperature by immobilization-reduction method was prepared and applied for protection against marine biofouling. 3DNP-Cu2O/rGO1.76@R-Gel includes rGO and R-Gel shape 3D porous Cu2O nanoparticles with diameters ∼177 nm and strong dispersion and antioxidant stability. Compared with commercial Cu2O (Cu2O-0), 3DNP-Cu2O/rGO1.76@R-Gel exhibited an ∼50% higher bactericidal rate, ∼96.22% higher water content, and ∼75% lower adhesion of mussels and barnacles. Moreover, 3DNP-Cu2O/rGOx@R-Gel maintains the same excellent, stable, and long-lasting bactericidal performance as Cu2O-0@R-Gel while reducing the average copper ion release concentration by ∼56 to 76%. This was also confirmed by X-ray diffraction, X-ray photoelectric spectroscopy (XPS), atomic absorption spectroscopy, and antifouling tests. In addition, XPS tests of rGO-Cu2+ and R-Gel-Cu2+, photocurrent tests of 3DNP-Cu2O/rGO1.76@R-Gel, and energy-dispersive spectrometry pictures of bacteria confirm that R-Gel and rGO act as electron donors and transfer substrates driving the reduction of Cu2+ (Cu2+ → Cu+) and the diffusion of Cu+. Thus, a self-growing antibacterial and antifouling system of 3DNP-Cu2O/rGO1.76@R-Gel was achieved. The mechanism of accelerated bacterial inactivation and resistance to mussel and barnacle adhesion by 3DNP-Cu2O/rGO1.76@R-Gel was interpreted. It is shown that rGO and R-Gel are important players in the antibacterial and antifouling system of 3DNP-Cu2O/rGO1.76@R-Gel.

Development of micropollutants removal process using thin-film nanocomposite membranes prepared by green new vapour-phase interfacial polymerization method

The presence of emerging micropollutants in water bodies and potable water, has become a topic of great concern globally. In this study, a newly modified vapour-phase interfacial polymerization (VP-IP) method has been used to fabricate thin-film composite (TFC) and thin-film nanocomposite (TFN) nanofiltration (NF) membranes to study the removal of micropollutants, diclofenac (DIC) and triclosan (TRI) from water. The method used is an economically and environmentally greener method as the reaction takes place between the aqueous monomer solution and vapours of the organic phase, thereby avoiding the utilization of organic solvent hence named as vapour-phase interfacial polymerization (VP-IP) method. Polydopamine (PDA) coated polyethersulfone (PES) membranes were used to support the TFC and TFN membranes. The TFN membranes were incorporated with different concentrations of amine-functionalized cloisite Na+ 2D clay nanosheets (NH2-CMMT) to enhance the physicochemical properties of the TFN membranes. The performance study of the prepared TFN membranes based on different hours and pressures demonstrated an excellent rejection percentage of ∼99 ± 0.5% for both DIC and TRI compared to the TFC membrane. The membranes showed improved water permeate fluxes of ∼109 ± 5 Lm-2h-1 for DIC and ∼150 ± 5 Lm-2h−1 for TRI. The prepared TFN membranes demonstrated positive results for the antifouling test as well as exhibited antibacterial activity tested against Escherichia coli (E. coli) bacteria. The findings of this study show that our prepared TFN membranes combined with NH2-CMMT 2D clay nanosheets exhibit enhanced hydrophilicity, improved flux rate, excellent removal efficiency, antibacterial activity, and improved antifouling properties, indicating the potential to be used for removing emerging micropollutants from water.

Effectiveness of different CuO morphologies nanomaterials on the permeability, antifouling, and mechanical properties of PVDF/PVP/CuO ultrafiltration membrane for water treatment

The hydrophobic nature of Poly (vinylidene fluoride) (PVDF) is a significant barrier to use in ultrafiltration, resulting in fouling, flux decline, and reduced lifespan in water treatment. This study examines the effectiveness of different morphologies of CuO nanomaterials (NMs) (spherical, rod, plate, and flower), synthesized by the facile hydrothermal method, to modify PVDF membrane with PVP additive for improving the performance of water permeability and antifouling. Such membrane configurations with different morphologies of CuO NMs improved hydrophilicity with a maximum water flux of 222–263 L m−2h−1 compared to 195 L m−2h−1 for the bare membrane and exhibited excellent thermal and mechanical strengths. The characterization results exhibited that plate-like CuO NMs were dispersed uniformly in the membrane matrix, and their incorporation as a composite improved the membrane properties. From the antifouling test with the bovine serum albumin (BSA) solution, the membrane with plate-like CuO NMs had the highest flux recovery ratio (FRR) (∼91%) and the lowest irreversible fouling ratio (∼10%). The antifouling enhancement was due to less interaction between modified membranes and foulant. Further, the nanocomposite membrane showed excellent stability and negligible Cu2+ ion leaching. Overall, our findings provide a new strategy for developing inorganic nanocomposite PVDF membranes for water treatment.