Nanomaterials can be incorporated in the synthesis of membrane to obtain mixed-matrix membrane with marked improvement in properties and performance. However, stability and dispersion of the ...nanomaterials in the membrane matrix, as well as the need to use high ratio of nanomaterials for obvious improvement of membrane properties, remain a major hurdle for commercialization. Hence, this study aims to investigate the improvement of polyamide 6,6 membrane properties with the incorporation of silver nanoparticles decorated on graphene oxide (Ag-GO) nanoplates and at the same time focus is given to the issues above. Graphene oxide nanoplates were synthesized using the modified Hummers' method and decorated with silver before embedded into the polyamide 6,6 matrix. Physicochemical characterizations were conducted on both nanoplates and the mixed-matrix Ag-GO polyamide 6,6 membrane. The issues of Ag agglomeration and leaching were not observed, which could be attributed to the decoration of Ag on GO that helped to disperse the nanomaterials and provided a better anchor point for the attachment of Ag nanoparticles. The synthesized membrane showed marked improvement regarding flux (135% increment) and antifouling (40% lower irreversible fouling), which could be ascribed to the more negative charge of membrane surface (-14 ± 6 to -31 ± 3.8 mV) and hydrophilicity (46% enhancement) of the membranes. With minimal embedment of Ag nanoparticles, the membrane showed superior antibacterial property where the E. coli bacteria could not form a single colony on the membrane surface. Overall, the decoration of Ag on GO nanoplates could be a promising approach to resolve the agglomeration and leaching issues as well as reduce the amount of precious Ag in the synthesis of Ag-GO polyamide 6,6 membrane.
•PI mixed matrix membranes (MMM) with synthesized GO nanosheets has NF properties.•PI/GO MMM has better rejection in diluted and concentrated salt solution than pure PI.•XRD analysis shows consistent ...changes in membrane structure in various salt concentrations.•Various salt concentrations influence MMM structure thus the membrane performance.•Optimum amount of GO in MMM ensure high rejection for various salt concentrations.
A membrane usually suffers from a reduction in membrane rejection performance when exposed to a concentrated salt solution. A fabricated polyimide (PI)/graphene oxide (GO) mixed matrix membrane (MMM) was prepared at different GO/PI concentrations (ranging from 0 to 3.5 wt%) to investigate membrane performance in diluted and concentrated salt solutions. Results showed that the MMM possess nanofiltration (NF) properties with high water permeability and excellent salt rejection (99%) in diluted conditions regardless of the applied filtration pressure. The water and permeate permeability increased with the increase in GO content. Interestingly, for concentrated salt solutions, PI/GO MMM only showed at most 4% reduction in rejection, unlike in pure PI membrane, which experienced 16% reduction. A higher amorphous region of the MMM compared to the pure PI in salt solutions was found through XRD. The ionization of GO increases the amorphous structure thus enhances the effective thickness of membrane maintaining the MMM rejection performance. 0.9 wt% GO/PI in MMM showed the highest rejection (98%) in 0.15 M Na2SO4. The presence of GO with its unique properties and highly porous structure was found to retain the membrane rejection properties, especially in concentrated solution.
Polymeric nanoparticles (NPs) are commonly used as nanocarriers for drug delivery, whereby their sizes can be altered for a more efficient delivery of therapeutic active agents with better efficacy. ...In this work, cross-linked copolymers acted as core-shell NPs from acrylated palm olein (APO) with polyol ester were synthesized via gamma radiation-induced reversible addition-fragmentation chain transfer (RAFT) polymerisation. The particle diameter of the copolymerised poly(APO-b-polyol ester) core-shell NPs was found to be less than 300 nm, have a low molecular weight (MW) of around 24 kDa, and showed a controlled MW distribution of a narrow polydispersity index (PDI) of 1.01. These properties were particularly crucial for further use in designing targeted NPs, with inclusion of peptide for the targeted delivery of paclitaxel. Moreover, the characterisation of the synthesised NPs using Fourier Transform-Infrared (FTIR) and Neutron Magnetic Resonance (NMR) analyses confirmed the possession of biodegradable hydrolysed ester in its chemical structures. Therefore, it can be concluded that the synthesised NPs produced may potentially contribute to better development of a nano-structured drug delivery system for breast cancer therapy.
The utilisation of palm oil-based polymers as biomaterials has received considerable interest to support further expansion in the biomedical field as they pose the potential capability of competing ...with synthetic polymers per their physicochemical, thermal, and crystallinity properties. In this study, the synthesis of a new green biopolymer, namely acrylated palm olein (APO) from a palm oil-based precursor, was developed. The APO was synthesised via the ring-opening process of the epoxidised palm olein (EPOo) with acrylic acid and triethylamine. The acrylation process produced an APO of a high yield (86.64%) with a molecular weight of 1750 Da. The ester group representing the APO was confirmed through the proton nuclear magnetic resonance (
1
H-NMR), carbon-13 nuclear magnetic resonance (
13
C-NMR) and Fourier transform infrared (FTIR), which revealed the promising biodegradable point of the APO molecular structure. Meanwhile, thermal and crystallisation profiles of the APO showed a single-stage decomposition pattern and its triglycerides (TAGs) crystal formation and melting behaviour. As a result, the desired APO polymer was obtained, which possessed potential biodegradable chemical functional group, amorphous, and low molecular weight properties.
Interest in the use of zinc oxide nanoparticles (ZnO NPs) in surface coatings and films has increased as its incorporation can significantly improve the mechanical and antimicrobial properties of ...coatings and film solutions. In an effort to produce green or eco-friendly products, the potential use of ZnO NPs biosynthesized from natural resources to replace conventional petroleum-derived polymers has been investigated. This review provides an insight into the growing trend of incorporating ZnO NPs into synthetic or semi-synthetic or bio-based polymeric materials via different synthesis methods as well as its characteristics and potential applications in surface coatings and films. The antimicrobial potential of ZnO NPs to inhibit the growth of various types of microorganisms as well as its use in surface coatings or films to impart antimicrobial activities that prevent the spread of microorganisms, especially the COVID-19 virus, was also discussed.
In the past few decades, nanotechnology has been receiving significant attention globally and is being continuously developed in various innovations for diverse applications, such as tissue ...engineering, biotechnology, biomedicine, textile, and food technology. Nanotechnological materials reportedly lack cell-interactive properties and are easily degraded into unfavourable products due to the presence of synthetic polymers in their structures. This is a major drawback of nanomaterials and is a cause of concern in the biomedicine field. Meanwhile, particulate systems, such as metallic nanoparticles (NPs), have captured the interest of the medical field due to their potential to inhibit the growth of microorganisms (bacteria, fungi, and viruses). Lately, researchers have shown a great interest in hydrogels in the biomedicine field due to their ability to retain and release drugs as well as to offer a moist environment. Hence, the development and innovation of hydrogel-incorporated metallic NPs from natural sources has become one of the alternative pathways for elevating the efficiency of therapeutic systems to make them highly effective and with fewer undesirable side effects. The objective of this review article is to provide insights into the latest fabricated metallic nanocomposite hydrogels and their current applications in the biomedicine field using nanotechnology and to discuss the limitations of this technology for future exploration. This article gives an overview of recent metallic nanocomposite hydrogels fabricated from bioresources, and it reviews their antimicrobial activities in facilitating the demands for their application in biomedicine. The work underlines the fabrication of various metallic nanocomposite hydrogels through the utilization of natural sources in the production of biomedical innovations, including wound healing treatment, drug delivery, scaffolds, etc. The potential of these nanocomposites in relation to their mechanical strength, antimicrobial activities, cytotoxicity, and optical properties has brought this technology into a new dimension in the biomedicine field. Finally, the limitations of metallic nanocomposite hydrogels in terms of their methods of synthesis, properties, and outlook for biomedical applications are further discussed.
Sodalite (SOD) zeolitic-imidazolate frameworks (ZIFs) with uniform angstrom scale apertures can offer high gas sieving ability for separation applications. Fixed apertures of ZIFs can effectively ...separate specific gas pair but may not be able to provide similar level of separation for larger or smaller gas pairs. Multivariate (i.e., mixed-linker) ZIFs with controlled linker incorporation can provide desired aperture tuning but difficult to synthesize especially when incorporating linkers that would normally form different structures. Herein, we report a systematic narrowing of SOD ZIF-8 by partially replacing 2-methylimidazole (mIm) linkers of ZIF-8 with 2-ethylimidazole (eIm) via delayed linker addition (DLA) method. Percentages of eIm in the hybrid frameworks were determined to be around 14.3%, 9.1%, and 5.1% for ZIF-8 nuclei formed in 5, 12.5, and 20 min, respectively. Ethyl moiety of eIm restricts framework flexibility of the hybrid ZIF-8, shifts ZIF-8 gate-opening pressure to higher value, and eventually diminishes the gate-opening effect. Polysulfone (PSF)-based mixed-matrix membranes utilizing eIm-doped ZIF-8 as fillers displayed slight reduction in CO
2
permeability (18.56 Barrer to 14.85 Barrer) which result in H
2
/CO
2
ideal selectivity improvement. DLA method is expected to work well for other imidazole-based linkers and can perhaps be used to synthesize mixed-linker of other SOD ZIFs.
Batik is a piece of woven cloth decorated with beautiful patterns and designs and has become a signature product of the Malay Archipelago, including Malaysia and Indonesia. Batik industry consumes a ...large volume of water and produces a large amount of wastewater during the boiling process and dyeing process, both for hand-drawn (batik lukis) and block-printed (batik cap) batik. The release of colored effluents that contain a large number of dyes and chemicals can harm the environment and become a human health concern, particularly in south east Asian countries. Therefore, treatments of batik effluent are very crucial and have caught a lot of attention from researchers. The color removal is a major challenge, especially from this industry, as up until now there is no single and cost-effective treatment that can effectively decolorize as well as treat the dye effluent. Since batik is part of the textile industry, most treatment methods have been adapted from textile effluent treatment. Here, we review a variety of textile wastewater treatment techniques to make a good consideration of selecting the most appropriate method to be applied in batik wastewater. First, we briefly review the batik process, including the potential dyes that are mostly used in batik processing. Secondly, we describe all possible techniques and their performance to reduce dye concentration and decolorization. Finally, we review all advantages and disadvantages of these techniques for domestic and industrial applications.
Proton exchange type polymer electrolyte membranes (PEM) consisting of ion conducting alkylsulfonic acid and hydrophilic groups such as a hydroxyl group were successfully synthesized by ...radiation-induced graft polymerization of vinyl acetate (VAc) into a poly(ethylene-co-tetrafluoroethylene) (ETFE) film, followed by saponification and alkylsulfonation with 1,3-propanesulfone. In contrast to the typical SN2 reactions in a solution, the base-catalyzed nucleophilic ring-opening reactions of hydroxyl groups of poly(vinylalcohol) grafts with 1,3-propanesultone in solid state ETFE films hardly proceeds in the hydrophilic solvents, but it does proceed in hydrophobic toluene with a weak base (triethylamine) to yield ETFE-grafted poly(vinylalcohol-co-vinylsulfopropyl ether) (PEM–OH) with various values of ion-exchange capacity (IEC) and molar ratio of hydroxyl to sulfo groups in the grafts. The relative-humidity (RH) dependence of the proton conductivity of the sulfonated membrane was compared with that of poly(styrenesulfonic acid)-grafted ETFE (PEM–PSSA) with a similar IEC (∼1.3 mmol g−1) at 80 °C. The PEM–OH showed a conductivity of 1.0×10−3 S cm−1 under 30% RH, which is higher than those of PEM–PSSA. Further, the PEM–OH with higher IEC (1.9 mmol g−1) prepared with a grafting degree of 82% and a sulfonation degree of 41% showed 3.8×10−3 S cm−1 under 30% RH at 80 °C. The conductivity is higher than that of PEMs based on sulfonated polyimide and poly(ether sulfone) with a similar IEC. Furthermore, the tensile strength of PEM–OH was 48 MPa with the elongation at break of 422%, which are better than those of Nafion. These results strongly indicate that the radiation-grafted PEM with hydroxyl groups is a promising material with excellent mechanical and electrochemical properties, which are important characteristics for a fuel cell operating at a high temperature and low humidity.
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▸ PEM having sulfoalkyl and hydroxyl groups were prepared by radiation-grafting. ▸ Membrane showed a conductivity of 3.8×10−3 S cm−1 under 30% RH at 80 °C. ▸ Hydroxyl groups in sulfoalkyl grafts affect proton mobility even at low RH. ▸ Mechanical properties of the membrane are better than those of Nafion.
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