Dual modification of reverse osmosis membranes with NH2-MIL-125 and functionalised multiwalled carbon nanotubes for enhanced nanoplastic removal.

The present study describes a novel double-modified strategy for developing high-performance thin-film composite reverse osmosis (TFC-RO) membranes by incorporating titanium-based metal organic frameworks (NH2-MIL-125) and functionalised multiwalled carbon nanotubes (MWCNTs) into the support layer and selective layer, respectively. Initially, the support layer was subjected to successive modifications using NH2-MIL-125 mixed with polysulfone (PSF) in dimethylformamide DMF solution to investigate their impact on the performance and properties of the support layer and resultant TFC-RO membranes. Results indicated that the new structure of the modified support layer had significant influences on the developed TFC-RO membranes. Notably, the pristine PSF support exhibited a large surface pore size, medium porosity, and strong hydrophobicity, resulting in a low-flux TFC-RO membrane. However, after modification with NH2-MIL-125, the optimal blend support demonstrated a small surface pore size, high porosity, and improved hydrophilicity, favouring the formation of a high performance TFC-RO membrane. The incorporation of functionalised MWCNTs nanochannels into the selective layer, using the optimal NH2-MIL-125-PSF blended support, resulted in a smoother and more hydrophilic TFC-RO membrane with enhanced negative charge to improve antifouling properties against negative foulants (i.e., nanoplastics (NPs) and bovine serum albumin (BSA)). The double-modified membrane (TFC-RO-DM) exhibited superior performance over the conventional PSF-TFC-RO membrane. Notably, the maximum water flux reached 39 L m-2.h-1 with 98.4% NaCl rejection. The membrane exhibited a high flux recovery rate of 92% following a 30-min physical cleaning process. Additionally, the TFC-RO-DM membrane displayed reduced fouling against NPs suggesting the great promise of this innovative double-modification approach for the advancement of high-performance TFC-RO membranes.

Resilient forward osmosis membranes against microplastics fouling enhanced by MWCNTs/UiO-66-NH2 hybrid nanoparticles.

The escalating presence of microplastics (MPs) in wastewater necessitates the investigation of effective tertiary treatment process. Forward osmosis (FO) emerges as an effective non-pressurized membrane process, however, for the effective implementation of FO systems, the development of fouling-resistance FO membranes with high-performance is essential. This study focuses on the integration of MWCNT/UiO-66-NH2 as metal-organic frameworks (MOFs) and multi-wall carbon nanotubes (MWCNT) nanocomposites in thin film composite (TFC) FO membranes, harnessing the synergistic power of hybrid nanoparticles in FO membranes. The results showed that the addition of MWCNT/UiO-66-NH2 in the aqueous phase during polyamide formation changed the polyamide surface structure, and enhanced membranes' hydrophilicity by 44%. The water flux of the modified FO membrane incorporated with 0.1 wt% MWCNTs/UiO-66-NH2 increased by 67% and the reverse salt flux decreased by 22% as in comparison with the control membrane. Moreover, the modified membrane showed improved antifouling behavior against both organic foulant and MPs. The MWCNT/UiO-66-NH2 membrane experienced 35% flux decline while the control membrane experienced 65% flux decline. This proves that the integration of MWCNT/UiO-66-NH2 nanoparticles into TFC FO membranes is a viable approach in creating advanced FO membranes with high antifouling propensity with potential to be expanded further to other membrane applications.

Enhanced carbohydrate-based plastic performance by incorporating cerium-based metal-organic framework for food packaging application.

The development of biodegradable active packaging films with hydrophobic characteristics is vital for extending the shelf life of food and reducing the reliance on petroleum-based plastics. In this study, novel hydrophobic cerium-based metal-organic framework (Ce-MOF) nanoparticles were successfully synthesized. The Ce-MOF nanoparticles were then incorporated into the cassava starch matrix at varying concentrations (0.5 %, 1.5 %, 3 %, and 4 % w/w of total solid) to fabricate cassava-based active packaging films via the solution casting technique. The influence of Ce-MOF on the morphology, thermal attributes, and physicochemical properties of the cassava film was subsequently determined through further analyses. Biomedical analysis including antioxidant activity and the cellular morphology evaluation in the presence of the films was also conducted. The results demonstrated that the consistent dispersion of Ce-MOF nanofillers within the cassava matrix led to a significant enhancement in the film's crystallinity, thermal stability, antioxidant activity, biocompatibility, and hydrophobicity. The introduction of Ce-MOF also contributed to the film's reduced water solubility. Considering these outcomes, the developed cassava/Ce-MOF films undoubtedly have significant potential for active food packaging applications.

Recent advances in surface tailoring of thin film forward osmosis membranes: A review.

The recent advancements in fabricating forward osmosis (FO) membranes have shown promising results in desalination and water treatment. Different methods have been applied to improve FO performance, such as using mixed or new draw solutions, enhancing the recovery of draw solutions, membrane modification, and developing FO-hybrid systems. However, reliable methods to address the current issues, including reverse salt flux, fouling, and antibacterial activities, are still in progress. In recent decades, surface modification has been applied to different membrane processes, including FO membranes. Introducing nanochannels, bioparticles, new monomers, and hydrophilic-based materials to the surface layer of FO membranes has significantly impacted their performance and efficiency and resulted in better control over fouling and concentration polarization (CP) in these membranes. This review critically investigates the recent developments in FO membrane processes and fabrication techniques for FO surface-layer modification. In addition, this study focuses on the latest materials and structures used for the surface modification of FO membranes. Finally, the current challenges, gaps, and suggestions for future studies in this field have been discussed in detail.

Synergistic effects of microplastics and organic foulants on the performance of forward osmosis membranes.

Microplastics (MPs) are emerging contaminants that are abundantly present in the influent and effluent of wastewater treatment plants (WWTPs). Forward osmosis (FO) is an advanced treatment technology with potential applications in WWTPs. The presence of MPs in WWTP effluents can contribute to FO fouling and performance deterioration. This study focuses on FO membrane fouling by MPs of different sizes, and the interactional impacts of MPs and Humic acid (HA) (as the most common organic foulant in WWTPs) on FO membrane performance. The synergistic effect of combined MPs and HA fouling is shown to cause higher flux decline for FO membranes than that of HA or MPs alone. Reverse salt flux increased in the presence of MPs, and decreased when HA was present. Further, full flux recovery was obtained for all fouled membranes after hydraulic cleaning. This indicates the efficiency of FO systems for treating wastewater with high fouling potential. This study highlights the necessity of considering MPs in studying fouling behaviour, and for mitigation strategies of membranes used in WWT. The fundamentals created here can be further extended to other membrane-assisted separation processes.

Thermo-Responsive Hydrophilic Support for Polyamide Thin-Film Composite Membranes with Competitive Nanofiltration Performance.

Poly(N-isopropylacrylamide) (PNIPAAm) was introduced into a polyethylene terephthalate (PET) nonwoven fabric to develop novel support for polyamide (PA) thin-film composite (TFC) membranes without using a microporous support layer. First, temperature-responsive PNIPAAm hydrogel was prepared by reactive pore-filling to adjust the pore size of non-woven fabric, creating hydrophilic support. The developed PET-based support was then used to fabricate PA TFC membranes via interfacial polymerization. SEM-EDX and AFM results confirmed the successful fabrication of hydrogel-integrated non-woven fabric and PA TFC membranes. The newly developed PA TFC membrane demonstrated an average water permeability of 1 L/m2 h bar, and an NaCl rejection of 47.0% at a low operating pressure of 1 bar. The thermo-responsive property of the prepared membrane was studied by measuring the water contact angle (WCA) below and above the lower critical solution temperature (LCST) of the PNIPAAm hydrogel. Results proved the thermo-responsive behavior of the prepared hydrogel-filled PET-supported PA TFC membrane and the ability to tune the membrane flux by changing the operating temperature was confirmed. Overall, this study provides a novel method to fabricate TFC membranes and helps to better understand the influence of the support layer on the separation performance of TFC membranes.

Pharmaceuticals removal by immobilized laccase on polyvinylidene fluoride nanocomposite with multi-walled carbon nanotubes.

The presence of pharmaceutical micropollutants in water and wastewater is considered a serious environmental issue. To eliminate these pollutants, biodegradation of pharmaceuticals using enzymes such as laccase, is proposed as a green method. In this study, immobilized laccase was used for the removal of two model pharmaceutical compounds, carbamazepine and diclofenac. Polyvinylidene fluoride (PVDF) membrane modified with multi-walled carbon nanotubes (MWCNTs) were synthesized as a tailor-made support for enzyme immobilization. Covalently immobilized laccase from Trametes hirsuta exhibited remarkable activity and activity recovery of 4.47 U/cm2 and 38.31%, respectively. The results also indicated improvement in the operational and thermal stability of the immobilized laccase compared to free laccase. Finally, by using immobilized laccase in a mini-membrane reactor, removal efficiencies of 27% in 48 h and 95% in 4 h were obtained for carbamazepine and diclofenac, respectively. The findings suggest that immobilized laccase on PVDF/MWCNT membranes is a promising catalyst for large-scale water and wastewater treatment which is also compatible with existing treatment facilities.