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.

Oily wastewater (OW) is detrimental towards the environment and human health. The complex composition of OW needs an advanced treatment, such as membrane technology. Membrane distillation (MD) gives the highest rejection percentage of pollutants in wastewater, as the membrane only allows the vapor to pass its microporous membrane. However, the commercial membranes on the market are less efficient in treating OW, as they are prone to fouling. Thus, the best membrane must be identified to treat OW effectively. This study tested and compared the separation performance of different membranes, comparing the pressure-driven performance between the membrane filtration and MD. In this study, several ultrafiltration (UF) and nanofiltration (NF) membranes (NFS, NFX, XT, MT, GC and FILMTEC) were tested for their performance in treating OW (100 ppm). The XT and MT membranes (UF membrane) with contact angles of 70.4 ± 0.2° and 69.6 ± 0.26°, respectively, showed the best performance with high flux and oil removal rate. The two membranes were then tested for long-term performance for two hours with 5000 ppm oil concentration using membrane pressure-filtration and MD. The XT membrane displayed a better oil removal percentage of >99%. MD demonstrated a better removal percentage; the flux reduction was high, with average flux reduction of 82% compared to the membrane pressure-filtration method, which experienced a lower flux reduction of 25%. The hydrophilic MT and XT membranes have the tendency to overcome fouling in both methods. However, for the MD method, wetting occurred due to the feed penetrating the membrane pores, causing flux reduction. Therefore, it is important to identify the performance and characteristics of the prepared membrane, including the best membrane treatment method. To ensure that the MD membrane has good anti-fouling and anti-wetting properties, a simple and reliable membrane surface modification technique is required to be explored. The modified dual layer membrane with hydrophobic/hydrophilic properties is expected to produce effective separation in MD for future study.

In the realm of nanoscience, the inherent antibacterial potential of nanoparticles (NPs) stands as an alluring prospect for the development of pharmaceutical interventions. Yet, conventional chemical and physical NPs fabrication methods pose environmental and safety concerns. The aim of this study is to greenly-synthesize zinc oxide nanoparticles (ZnO NPs) using aloe vera gel (AVG) and aloe vera gel-honey (AVG-honey) under different reactant-to-chemical reductant (or precursor-to-reducing agent) ratio conditions, facilitated by sonication. Structural and optical characteristics of synthesized ZnO NPs were explicated through Fourier Transformation Infrared Spectroscopy (FTIR) and Ultraviolet-visible Spectroscopy (UV–vis). Concurrently, x-ray diffraction (XRD) and Field Emission Scanning Electron Microscope (FESEM) delineated the crystalline disposition and morphological behaviors. The antibacterial susceptibility of ZnO NPs against Methicillin-resistant Staphylococcus aureus (MRSA) and Klebsiella Pneumoniae (K. pneumoniae) was investigated using the disc diffusion method. The structures of biosynthesized ZnO NPs were confirmed through distinctive peaks in FTIR and UV–vis spectra. XRD unveils hexagonal wurtzite crystallinity, while FESEM captured distinct morphologies, which are spherical and rice-shaped, in ZnO NPs/AVG, while ZnO NPs/AVG-honey revealed micro-size spherical structures surrounded by numerous tiny lumps. Notably, ZnO NPs/AVG at a 1:6 ratio exhibits a 26.5 nm size, showcasing superior antibacterial efficacy against MRSA (ZOI = 12 mm) and K. pneumoniae (ZOI = 13 mm) compared to other reactant-to-chemical reductant ratios and ZnO NPs/AVG-honey. In conclusion, the study revealed that ZnO NPs synthesized solely using AVG exhibited finer particle sizes and slightly enhanced antibacterial efficacy compared to ZnO NPs formulated with a combination of AVG and honey. This outcome shows that utilization of two reducing agents will contribute to large size of nanoparticles, thus reduce the efficiency of the antibacterial susceptibility. Moreover, the concentration ratios of reactants-to-chemical reductants emerged as crucial determinants in the nanoparticle synthesis process.