Environmental Nanotechnology, Monitoring and Management最新文献

Olive mill wastewater (OMW) is a non-biodegradable and toxic effluent that arouses the interest of the scientific community and stockholders owing to its imminent threat to the environment and health. The fluctuating character and the high rate of phenolic compounds complicate the decontamination process of these kinds of effluents. Hence, there is a need for innovative and effective treatments to neutralize these harmful impacts.

The present work aims at the treatment of polyphenolic compounds of OMW through the combination of the coagulation process with an activated lime coagulant and advanced oxidation using hydrogen peroxide (H₂O₂), and the elucidation of the effect of influencing factors to optimize OMW treatment performances. To this end, the optimization was achieved following an experimental design methodology, and the obtained results were very remarkable when compared to similar studies. By operating under the optimal conditions of 12.45, 26.5 mL.L⁻¹, and 2.5 min for pH, hydrogen peroxide (H₂O₂) ratio, and reaction time, respectively, removal efficiencies reached 98 % for polyphenols, 96.2 % for chemical oxygen demand (COD), 98.5 % for turbidity, and 94 % for color, with a low generated sludge volume of 37 mL/100 mL of OMW.

The escalating influx of harmful contaminants and toxic metals into the environment, fueled by rapid technological advancements and population growth, has emerged as a pressing concern. There are numerous physical, chemical, and biological remediation technologies, but their efficacy often falters due to intricate processes. In recent years, many new technologies have been developed to remove toxic pollutants. Among the technologies, bioremediation in combination with nanotechnology is considered the most effective method. Nano-bioremediation is a modern technique of employing plants and microbes for the disintegration of toxic materials, either ex situ or in situ, to combat environmental contamination. Nano-bioremediation provides a versatile array of solutions for reducing pollutants in groundwater, wastewater, and sediment contaminated with heavy metals and hydrocarbons. Silver (Ag) nanoparticles, in particular, have gained recognition as effective catalysts for disinfection across air, water, and surfaces. Its utilization promises a less hazardous, efficient, and sustainable means to mitigate the menace of toxic contaminants in the environment.

Increasing environmental pollutants and the need for efficient photocatalytic and biosensing materials have led to the development of novel green synthesis methods. In this study, MoO₃ nanoparticles (NPs) were successfully synthesized by using green chemistry approach. In that respect, Butea monosperma leaf powder was used as a novel fuel. Structural parameters, optical properties, shape and morphology of MoO₃ NPs are examined using XRD, FTIR, UV–Vis spectrophotometer, Photoluminescence (PL), SEM - EDAX and TEM analysis. The use of MoO₃ NPs as a dusting agent in fingerprint applications results in improved fingerprint visibility, which is useful in forensic investigation. In this study, we modified the GCE electrode surface with MoO₃ NPs to develop a highly sensitive dopamine (DA) sensor. Electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and differential pulse voltammetry (DPV) were used to investigate the electrochemical behaviour and electrocatalytic property of the MoO₃ NPs. The synthesized NPs have excellent performance for detection of highly sensitive biologically active DA. The sensor exhibits a low detection limit of 0.45 μM. Additionally, it shows good stability, simplicity, and selectivity for the rapid detection of DA. MoO₃ NPs shows good photocatalytic activity under UV light for the degradation of important textile industries dye such as methylene blue (MB) and harmful rangoli colors which are available in local shops of Tumkur, Karnataka. The photocatalyst exhibits a remarkable 97 % degradation efficiency for MB dye. Coumarin studies ensure the effective generation of OH radicals on the surface of the photocatalyst, leading to the degradation of organic dyes. Additionally, the MoO₃ NPs reusability was examined, and even after four cycles, the level of photocatalytic activity did not drop much. Therefore, it is a potential photocatalyst for the processing of organic colours.

Water, vital for life, faces contamination threats from both natural and human-induced sources, endangering aquatic life and our well-being. As global demands increase, waste generation rises, posing environmental risks while holding untapped potential in valuable biomolecules. This paper aims to examine the profound impact of water pollution on ecosystems and human health while exploring innovative strategies for effective wastewater treatment. Conventional treatment methods, while limited, set the stage for discussion on newer techniques like Metal-organic frameworks, Alkali-activated materials, Molecular biology, and phytoremediation. These pioneering approaches promise cost-effective, eco-friendly wastewater treatment, coupled with valuable compound extraction. Integrating these solutions fosters a circular bio-economy, optimizing resource use and curbing environmental impacts. This review thus explores a path toward sustainable water pollution mitigation and resource maximization in a rapidly evolving world.

A ternary system MWCNTs/ZnO/Ag₂CO₃ and its novel PANI-supported (MWCNTs = 150 mg) composite were prepared by precipitation and impregnation methods, respectively. The as-synthesized composites were characterized using different instrumentation techniques, including XRD, SEM-EDX, PL, and UV–Vis DRS spectroscopies. The photodegradation efficiency of the PANI-supported MWCNTs/ZnO/Ag₂CO₃ (MWCNTs = 150 mg) composite for the model Methyl Orange dye (MO) and industrial wastewater was examined and found to be 95.94 and 90.29 %, respectively. Using a PANI-supported composite, the effect of operational parameters such as pH = 4, initial dye concentration = 10 ppm, and catalyst dose = 150 mg/L on MO dye photodegradation was investigated. Under optimal conditions, the photodegradation performances of the bare ternary system and its PANI-supported composites were found to be 90.02 and 95.94 %, respectively. Different scavengers demonstrated that the major species actively involved in the degradation of MO dye were ^•O₂^– and ^•OH. During the photodegradation of MO using PANI-supported MWCNTS/ZnO/Ag₂CO₃ as a photocatalyst, the supper oxide (^•O₂^–) was found to be the predominant reactive species. The reusability of the supported photocatalyst was also investigated after five consecutive runs it was found that 49.78 % efficient and this revealed its substantial reusability. The antibacterial efficacy of the PANI-supported MWCNTs/ZnO/Ag₂CO₃ (at MWCNTs = 150 mg) against both gram-negative and gram-positive bacteria was found to be superior to those of the single, binary, and ternary systems.

The presence of elevated nitrate concentrations in natural water bodies is a cause of significant concern, owing to its potential ecological and human health ramifications. Dal lake, a eutrophic lake situated in Srinagar, India, which bears a substantial burden of nutrient pollution stemming from various sources. To tackle high nitrate levels, an indigenous bacterial strain from Dal Lake, Srinagar, India, was used for its biodegradative abilities. To enhance biodegradation, the bacterial strain's efficiency was rigorously tested across various environmental conditions, including temperature, nitrate concentration, pH, contact time, and adsorbent quantity. The active isolate, identified through genetic analysis via 16S rRNA sequencing, was determined to be Bacillus subtilis ON358108. Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), BET (Brunauer–Emmett–Teller) analysis (BET), XRD (X-ray diffraction) was employed.These methodologies were employed to scrutinize various aspects of the adsorbent, including surface area, pore volume, crystalline structure, composition, and internal structure were used in characterizing and elucidating the behaviour of functional groups engaged in the biodegradation process, both prior to and post-nitrate uptake. Adsorption mechanisms were established from experiments using the Langmuir, Freundlich, and Temkin models. We analyzed adsorption kinetics using pseudo-first- and pseudo-second-order models. To optimize the nitrate biodegradation process, we applied Response Surface Methodology (RSM) based on a central composite design approach. This approach successfully removed 91 % (±1.5) of the effluent's nitrate with Bacillus subtilis ON358108.Furthermore, our study demonstrated that the selected isotherm models fit the adsorption process in the following sequence: Langmuir > Temkin > Freundlich. In addition, thermodynamic study revealed the process is spontaneous and endothermic.

In recent years, the use of green synthesized nanoparticles has emerged as a promising approach to address the challenges associated with environmental pollution. The contamination of water resources, particularly the rise in nitrate and textile dye concentrations poses serious risks to both human health and aquatic ecosystems, promoting eutrophication. In this regard, the current study aimed to synthesize iron nanoparticles (FeNPs) from Syzygium aromaticum extract and characterize their physicochemical properties using various analytical techniques, including Scanning Electron Microscopy (SEM), UV–Visible (UV–Vis), Fourier Transform Infrared Spectroscopy (FT-IR), and X-ray Diffraction (XRD). The synthesized nanomaterials were then tested for their efficiency in removing nitrate and degrading the malachite green (MG) in aquatic systems. The batch experiments demonstrated that the green synthesized zero-valent iron particles (SA-FeNPs) and magnetite particles (SA-MNPs), using clove extract, removed 43 % and 36 % of nitrate, respectively, and degraded 29 % and 63 % of MG. These results suggest the feasibility of using green synthesized nanoparticles as a potential remediation strategy for addressing the issue of water pollution. Moreover, the nitrate removal and MG degradation by SA-FeNPs and SA-MNPs followed the pseudo-second-order adsorption model (∼R² = 0.99) in the kinetic study. The findings of the study demonstrate the potential of green synthesized FeNPs for their effectiveness in removing nitrate and degrading MG in aquatic systems. Furthermore, the antibacterial activity of the synthesized FeNPs was evaluated against both gram-negative and gram-positive bacteria. The green synthesized FeNPs demonstrated good antibacterial activity, suggesting their potential to be used as an alternative material for developing effective antimicrobial agents. The results highlight the importance of green synthesis of FeNPs using Syzygium aromaticum extract as a sustainable approach for nitrate removal, MG degradation, and antibacterial activity in aquatic systems.

The facile, eco-friendly, and cost-effective production of nanoparticles using green technology has recently piqued the scientific community's interest. In this work, Bioaugmented ZnO and 5 wt%, 10 wt% and 15 wt% of Ni@ZnO nanoparticles (NPs) were prepared from soursop leaf extract using facile green technology. The ZnO nanoparticles were found to be crystalline with a single phase, according to XRD examination and Scherer's formula was used to compute the average crystallite size was about 36.3, 38.2, 39.8 and 40.6 for ZnO, 5 wt%, 10 wt% and 15 wt% Ni@ZnO respectively. It was noticed that pure ZnO samples showed 0.0015 values, while nickel content of 5 wt% showed nearly 0.001 values, which specifies that doped samples showed compressive strain. The produced samples’ FESEM pictures demonstrate that the NPs are mostly spherical and less than 100 nm in size. The 510 cm⁻¹ band is caused by asymmetric stretching of the Zn-O tetrahedron, according to FTIR. Ni²⁺ ion inclusion causes a small shift in this peak of 10–20 cm⁻¹. ZnO-NPs made from biosynthesis degraded methylene blue dye 94 % in 50 min. The antimicrobial test confirms that Ni@ZnO (15 %) demonstrated a larger mean zone of inhibition than the other three samples. Biocompatible, ZnO and Ni@ZnO NPs are suited for biomedical and environmental applications because of their eco-friendly synthesis and nontoxic properties.

Based on the necessity of evaluating composite packaging wastes from both environmental and economic perspectives, it aimed to obtain carbon nanotube (CNT) from the pyrolysis gas product of this material by the catalytic chemical vapor deposition method (CCVD) via an upcycling approach. In the first stage, composite packaging wastes were pyrolyzed. Secondly, the composition of the gas via gas chromatography was determined. In the third stage, CNT production studies were carried out by the CCVD method in a tubular reactor at four different temperatures between 600 and 900 °C with nickel catalyst. The effects of temperature and carbon source feeding ratio on the properties of the obtained CNTs were investigated. CNTs produced in this study were compared with a commercial product. As a result, high-quality multi-walled carbon nanotube of 20–30 nm diameter and in micrometer scale length comparable to commercial products were produced from the gaseous product at 800 °C under Ni-catalysis.

In the present work, Copper vanadate nanoparticles (Cu₃V₂O₈ NPs) have been Synthesised using a green solution combustion process using green fuel. The optical characteristics, structure, and morphology of the synthesized Cu₃V₂O₈ NPs have been examined using various analytical methods, including X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), UV–visible spectroscopy, photoluminescence spectroscopy (PL), and scanning electron microscopy (SEM). Based on XRD analysis, Cu₃V₂O₈ NPs have an average crystallite size of 45 nm and a triclinic phase structure. The spherical shape of nanoparticles was revealed by SEM data. The optical band gap was calculated using Tauke's theory and found to be 2.47 eV. Synthesised NPs emits red colour under UV light and it is useful in finger print detection. Cu₃V₂O₈ NPs show good action for photocatalytic degradation of Rose Bengal (RB) dye. Photocatalytic degradation (PCD) was performed by altering the dye and catalyst concentrations. The synthesized NPs have been observed as being highly effective in visible-light-driven dye degradation.