Today, environmental contamination is a big concern for both developing and developed countries. The primary sources of contamination of land, water, and air are extensive industrialization and intense agricultural activities. Various traditional methods are available for the treatment of different pollutants in the environment, but all have some limitations. Due to this, an alternative method is required which is effective and less toxic and provides better outcomes. Nanomaterials have attracted a lot of interest in terms of environmental remediation. Because of their huge surface area and related high reactivity, nanomaterials perform better in environmental clean-up than other conventional approaches. They can be modified for specific uses to provide novel features. Due to the large surface-area-to-volume ratio and the presence of a larger number of reactive sites, nanoscale materials can be extremely reactive. These characteristics allow for higher interaction with contaminants, leading to a quick reduction of contaminant concentration. In the present review, an overview of different nanomaterials that are potential in the remediation of environmental pollutants has been discussed.

Ultraviolet radiation causes damages to the human body, such as skin ageing, skin cancer, and allergies throughout the world. Applying zinc oxide nanoparticles (ZnO NPs) in sunscreen products (like cloths or textiles) to protect human skin by absorbing the ultraviolet radiations that emerged from the sun. The main aim of this study is to investigate both absorbance and transmittance characteristics of the untreated and treated cotton textiles. For ZnO NPs using hydrothermal methods, they were made from Zn(NO₃)₂·6H₂O and NaOH at a constant annealing temperature of 300°C. Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-vis spectroscopy were used to analyze the produced ZnO NPs. From the FT-IR result, ZnO NPs were observed in the region of 400-600 cm^-1. Wurtzite hexagonal structure of ZnO NPs with the average crystal size nm was observed from XRD results. Flowers in the shape of synthesized ZnO NPs were observed from SEM images. The UV-vis penetration peaks were identified at 264 nm and 376 nm, with energy band gaps of 4.68 and 3.536 eV, respectively. When compared to bulk ZnO, the energy band gap of ZnO NPs was blue-shifted due to the impact of quantum confinement. The peaks in UV-vis absorption were caused by an electronic transition from the valiancy to the conduction bands. The high energy band shows high absorbance of the synthesis sample in the case of 264 nm. The ZnO NPs were manufactured and applied to 100% of raw cotton to impart sunscreen action to both untreated and treated cotton fabrics. The performance of treatment has been evaluated utilizing UV-vis spectroscopy through quantifying ultraviolet protective factors (UPF) and percentage of transmitted (%T) radiations. The treated cotton textiles have 61.50% UPF while 2.65% ultraviolet radiations were transmitted. In other words, untreated cotton textiles have 1.63% UPF while 74.56% ultraviolet radiation was transmitted. Therefore, the treated cotton textiles have excellent protection categories when compared to untreated cotton textiles.

Titanium dioxide nanoparticles (TiO₂NPs) were prepared byCaricaceae(Papaya) Shell extracts. The Nanoparticles were analyzed by UV–Vis spectrums, X-ray diffractions, and energy-dispersive X-rays spectroscopy analyses with a scanning electron microscope. An antifungal study was carried out for TiO₂NP in contradiction of S.sclerotiorums, R.necatrixsand Fusarium classes that verified a sophisticated inhibitions ratio for S.sclerotiorums(60.5%). Germs of pea were individually preserved with numerous concentrations of TiO₂NPs. An experience of TiO₂NPs (20%, 40%, 80% and 100%), as well as mechanisms that instigated momentous alterations in seed germinations, roots interval, shoot lengths, and antioxidant enzymes, were investigated. Associated with controls, the supreme seeds germinations, roots and plant growth were perceived with the treatments of TiO₂NPs. Super-oxide dis-mutase and catalase activities increased because of TiO₂NPs treatments. This advocates that TiO₂Nanoparticles may considerably change antioxidant metabolisms in seed germinations.

The widespread use of plastic goods creates huge disposal issues and environmental concerns. Increasing emphasis has been paid to the notion of a circular economy, which might have a significant impact on the demand for plastic raw materials. Post-consumer plastics recycling is a major focus of the nation’s circular economy. This study focuses on energy recovery from waste plastics as an alternative fuel source to meet the circular economy demand. Waste plastic fuel produced through pyrolysis has been claimed to be utilized as a substituted fuel. This work focuses to determine the performance and emission standards of Waste Plastic Fuel (WPF) generated from the pyrolysis of High-Density Polyethylene (HDPE) in a single-cylinder Direct Injection Diesel Engine (DIDE). Three different ratios of WPF were combined with 10% ethanol and 10% ethoxy ethyl acetate as an oxygenated additive to create quaternary fuel blends. The ethanol has a low viscosity, a high oxygen content, a high hydrogen-to-carbon ratio as favourable properties, the quaternary fuel results the improved brake thermal efficiency, fuel consumption and reduced emissions. The blend WEE20 exhibits 4.7% higher brake thermal efficiency, and 7.8% reduced fuel consumption compared to the diesel. The quaternary fuel blends demonstrated decreased carbon monoxide of 3.7 to 13.4% and reduced hydrocarbons of 2 to 16% under different load conditions.

The production of zinc oxide nanoparticles (ZnO NPs) utilizing different vegetable extracts (onion, cabbage, carrot, and tomato) was performed in this research owing to its excellency over other methods of synthesis, namely, simplicity, environmental friendliness, and the elimination of harmful compounds. Fresh extracted onion, cabbage, carrot, and tomato of ZnO NPs are characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-visible spectroscopy. FTIR findings demonstrate that the prepared nanoparticles were observed in the spectrum of 626cm^-11219cm^-1 with some other functional groups. Wurtzite hexagonal structure of the prepared ZnO NPs was observed from XRD results. In addition, the prepared nanoparticles were failed into nanoscales (17nm, 18nm, 24nm, and 15nm) calculated from Scherrers equation. Nearly spherical shapes were seen from SEM image for onion and tomato extraction while rod and tube for carrot and cabbage, respectively. Two broad peaks were observed from UV-vis spectroscopy results for each extract. The presence of a wide range of energy bandgaps in the region of 3-4eV was detected, indicating that ZnO NP material can be employed in metal oxide semiconductor-based systems. The dye-sensitive solar cell based on ZnO NPs has been successfully synthesized, and the efficiency of the device has been evaluated by measuring the current density-voltage behaviour under the presence of artificial sunshine. The increased effectiveness of the manufactured dye-sensitive solar cell is attributable to a large improvement in dye molecular adsorption onto the surface of ZnO NPs. Thus, the usage of the green produced ZnO NPs with creating dye sensitivity solar cell is a simple and viable way for the well-being of our future.

Biosynthesis of nanoparticles is a new way to produce nanoparticles by using bioorganic foundations. It is attainment care because it is cost‐effective, eco‐friendly, and comprehensive measure manufacture potentials. The application of leaf extract to depose nanoparticles has been taken as a green method. In this study (Carissa spinarum L.), leaf extracts were reserved for examining their possibility to prepare zinc oxide nanoparticles (ZnO NPs). Zinc acetate is used as the source of zinc; deposition temperature and time were 80 degree Celsius and 60 minutes, respectively. The characterization study was done by UV‐Vis spectroscopy, X‐ray diffraction (XRD), scanning electron microscope (SEM), and photoluminescence (PL). The surface plasmon resonance around 358 nm from the UV–Vis qualitative evaluation result represents the ZnO NPs formation. The crystalline shape of nanoparticles is disclosed inside the XRD result, morphology confirmed through SEM effects, and consequently, the ZnO NPs scale was predicted. We have given allotted the image‐catalytic degradation of excitement dye at 365 nm in image reactor victimization ZnO NPs. This will be our preliminary strive at the Carissa spinarum L. extract on ZnO NPs guidance, and degradation reveals that ZnO NPs showcase clever image‐catalytic belongings, and zinc oxide (ZnO) nanoparticles were created to be operative against Bacillus and Staphylococcus.