Fabrication of nano CuAl2O4 spinel for copper stabilization and antibacterial application

Single and combined toxic effects of nCu and nSiO2 on Dunaliella salina

There are many studies on the toxic effects of single nanoparticles on microalgae; however, many types of nanoparticles are present in the ocean, and more studies on the combined toxic effects of multiple nanoparticles on microalgae are needed. The single and combined toxic effects of nCu and nSiO2 on Dunaliella salina were investigated through changes in instantaneous fluorescence rate (Ft) and antioxidant parameters during 96-h growth inhibition tests. It was found that the toxic effect of nCu on D. salina was greater than that of nSiO2, and both showed time and were dose-dependent with the greatest growth inhibition at 96 h. A total of 0.5 mg/L nCu somewhat promoted the growth of microalgae, but 4.5 and 5.5 mg/L nCu showed negative growth effects on microalgae. The Ft of D. salina was also inhibited by increasing concentrations of nanoparticles and exposure time. nCu suppressed the synthesis of TP and elevated the MDA content of D. salina, which indicated the lipid peroxidation of algal cells. The activities of SOD and CAT showed a trend of increasing and then decreasing with the increase of nCu concentration, suggesting that the enzyme activity first increased and then decreased. The toxic effect of a high concentration of nCu was reduced after the addition of nSiO2. SEM and EDS images showed that nSiO2 could adsorb nCu in seawater. nSiO2 also adsorbed Cu2+ in the cultures, thus reducing the toxic effect of nCu on D. salina to a certain extent. TEM image was used to observe the morphology of algal cells exposed to nCu.

Hemostatic and antibacterial calcium-copper zeolite gauze for infected wound healing

The design and development of wound dressings with excellent procoagulant and antibacterial activity to achieve high wound healing effectiveness are highly desirable in clinical applications. In this work, we develop a calcium-copper zeolite gauze (CaCu-ZG) by a two-step process involving calcium and copper ion exchange in a zeolite gauze. The CaCu-ZG exhibits remarkable procoagulant and antibacterial abilities, as well as good biocompatibility. Compared with the medical gauze, the blood clotting time of CaCu-ZG significantly decreases and the antibacterial activity increases in both in vivo and in vitro experiments. The remarkable ability of wound healing has been verified using a mouse dorsal skin-infected wound model, demonstrating its great potential for wound treatment in clinical applications.

Preparation and characterization of a novel cobalt-substitution cadmium aluminate spinel for the photodegradation of azo dye pollutants

Modern-year organic contaminants have been highly observed in ecosystems since they are not removed entirely and remain dangerous. Semiconductor binary oxide photocatalysts have been well accredited as capable technology for ecological contaminants degradation in the existence of visible irradiation. In this research, novel Co ions doped CdAl₂O₄ materials were fabricated by a facile co-precipitation approach. The fabricated pure and Co-doped CdAl₂O₄ exhibited the typical peaks of CdAl₂O₄ with the E_g of 3.66, 3.24, 2.57, and 2.41 eV respectively. The HR-TEM microstructures revealed that the Co (0.075 M) doped CdAl₂O₄ has rod-like morphology, and some places are spherical with particle sizes reaching 21 nm. The PL peaks of the Co (0.075 M)-CdAl₂O₄ are much lesser than that of the other dopant and pure CdAl₂O₄, representing much more effectual separation of generated e^- and h⁺ at the interface which in fact outcomes in superior expected photodegradation behaviours. The Co (0.075 M)-CdAl₂O₄ catalyst demonstrated the highest performances of 92 and 94% toward the degradation of both dyes, respectively, owing to the lowest e^- and h⁺ recombination rate. The Co (0.075 M) doped CdAl₂O₄ photocatalyst revealed outstanding reusability and stability under visible irradiation, retaining the performance of about 83 and 86% after the fifth consecutive run of BB and BG elimination. A probable photodegradation mechanism of Co (0.075 M) doped CdAl₂O₄ was suggested since the photoexcited h⁺, OH^- and O₂^- species contributed to the removal process, and that was affirmed by the scavenging test and ESR analysis. This research offers new ways to improve the photodegradation performance of the Co-doped CdAl₂O₄ catalyst that will be employed in pharmaceutical applications and wastewater treatment.

Synthesis and visible-light photocatalytic property of spinel CuAl2O4 for vehicle emissions

Photodegradation of vehicle emissions is a promising approach for dealing with atmospheric pollution in road tunnels. In this research, copper aluminate nanoparticles (CuAl₂O₄) were prepared by the sol-gel method using copper nitrate, aluminum nitrate, and citric acid as precursor materials. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-Vis spectroscopy to validate their structure, surface morphology, and optical properties, respectively. The XRD and SEM results confirm that the CuAl₂O₄ powder has a particle size of 20-37 nm and exhibits a spinel-type structure. The upper limit of the stimulation wavelength in the UV-Vis diffuse reflectance spectrum is located at 725 nm with a band gap (Eg) of about 1.50 eV, which is suitable for effective visible-light degradation. Photocatalytic performance of the CuAl₂O₄ nanoparticles was analyzed by investigating the effects of light source, calcination temperature, and catalyst loading amount on the degradation of vehicle emissions (CO, HC, and NO). Best results were obtained under fluorescent light irradiation by CuAl₂O₄ nanoparticles calcined at 700 °C. The optimum catalyst amount for decomposing CO, HC, and NO were determined as 0.5 g, 0.5 g, and 2 g, respectively. Overall, the photocatalytic performance study verifies that spinel CuAl₂O₄ photocatalyst is a valuable material for next-generation technologies aimed at reducing harmful emissions from vehicles.

Design and Study of Mountaineering Wear Based on Nano Antibacterial Technology and Prediction Model

In order to improve function of mountaineering wear to promote the development of outer mountaineering wear industry, nano antibacterial technology is applied to make mountaineering wear. Firstly, the antibacterial properties of nano materials are discussed. Secondly, the antibacterial performance experiment of nano Ag ion is design, and experimental results show that the antibacterial performance of nano Ag ion, and nano Ag ion has better antibacterial effect on staphylococcus aureus, Escherichia coli, and candida albicans. Thirdly, the antibacterial performance prediction model of nano materials is constructed based on wavelet neural network, and then the training algorithm is designed. Finally, the prediction simulation analysis of antibacterial performance of nano Ag ion in moutaineering wear is carried out, results show that the wavelet neural network has good prediction effect, prediction results from wavelet neural network are agreed with real values, therefore the wavelet neural network has higher prediction precision.

Detection and remediation of pollutants to maintain ecosustainability employing nanotechnology: A review

Environmental deterioration due to anthropogenic activities is a threat to sustainable, clean and green environment. Accumulation of hazardous chemicals pollutes soil, water and air and thus significantly affects all the ecosystems. This article highlight the challenges associated with various conventional techniques such as filtration, absorption, flocculation, coagulation, chromatographic and mass spectroscopic techniques. Environmental nanotechnology has provided an innovative frontier to combat the aforesaid issues of sustainable environment by reducing the non-requisite use of raw materials, electricity, excessive use of agrochemicals and release of industrial effluents into water bodies. Various nanotechnology based approaches including surface enhance scattering, surface plasmon resonance; and distinct types of nanoparticles like silver, silicon oxide and zinc oxide have contributed significantly in detection of environmental pollutants. Biosensing technology has also gained significant attention for detection and remediation of pollutants. Furthermore, nanoparticles of gold, ferric oxide and manganese oxide have been used for the on-site remediation of antibiotics, organic dyes, pesticides, and heavy metals. Recently, green nanomaterials have been given more attention to address toxicity issues of chemically synthesized nanomaterials. Hence, nanotechnology has provided a platform with tremendous applications to have sustainable environment for present as well as future generations. This review article will help to understand the fundamentals for achieving the goals of sustainable development, and healthy environment.

Gold nanoplates with superb photothermal efficiency and peroxidase-like activity for rapid and synergistic antibacterial therapy

Gold nanoplates exhibit 68.5% photothermal conversion efficiency and peroxidase-like activity, and AuNPTs (50 μg mL⁻¹)/H₂O₂ (0.1 mM)/NIR (1 W cm⁻², 3 min) show excellent synergistic antibacterial ability and promote MRSA-infected wound healing in vivo.

Hybrid Polydopamine/Ag Shell-Encapsulated Magnetic Fe3O4 Nanosphere with High Antibacterial Activity

The bacteria, which usually contaminate water environment, often cause terrible infectious diseases thus seriously threaten people's health. To meet the increasing requirement of the public health care, an easily separable nanomaterial with sustainable anti-bacteria performance is required. This work reports a Fe₃O₄@PDA/Ag/PDA core-shell nanosphere in which the Ag nanocrystals immobilized on the magnetic carrier are protected by an external polydopamine (PDA) layer. The magnetic hybrid nanospheres are constructed by a tunable coating method and the particle parameters can be effectively controlled by the experimental condition. The antibacterial potential of the nanospheres is evaluable by using the Staphylococcus aureus and Escherichia coli as the models. The results indicate the Fe₃O₄@PDA/Ag/PDA core-shell nanospheres have a high antibacterial performance by measuring the minimum inhibitory concentration and the minimum bactericidal concentration. Finally, the product is expected to have a sustainable activity because the protecting PDA layer reduce the releasing rate of the Ag⁺ ions and the materials can be magnetically recovered from the media after the disinfection procedure.

Hierarchical hollow manganese-magnesium-aluminum ternary metal oxide for fluoride elimination

Rational designs and syntheses for advanced structures are of immense importance to enhance adsorption performances toward a variety of materials. In this study, the synthesis of a novel hierarchical hollow manganese-magnesium-aluminum ternary metal oxide (MMA) via a green hydrothermal strategy coupled with a calcination process serves as a robust adsorbent for fluoride elimination. Combining the strong affinities Mn, Mg, and Al species have toward fluoride into a 3D-hierarchical hollow structure with an adequately accessible adsorption surface can remarkably boost the migration and diffusion of fluoride and provide more mass diffusion pathways for fluoride elimination. Remarkably, the adsorption process follows the pseudo-second-order model and the Langmuir isotherm model with a considerable performance of 63.05 mg/g. Moreover, the adsorbent retained outstanding selectivity and recyclability. Overall, the results from the universal characterization techniques and batch experiments validate that the potential adsorption mechanisms were electrostatic attraction and ion exchange, and complexation. As such, the present method expands the current adsorbent toolbox by providing a rational design and synthesis of a highly efficient adsorbent material for use in managing environmental pollution.