Golam Sazid

Quantum dots (QDs) have drawn a lot of attention as photocatalytic materials due to the growing need for environmentally friendly wastewater treatment technologies. Among these, carbon-based QDs, including graphene oxide quantum dots (GOQDs), graphitic carbon nitride (g-C₃N₄), and carbon quantum dots (CQDs), have exceptional optical, electronic, and surface characteristics that increase their suitability for degrading pollutants when exposed to sunlight or visible light. These composites are better at transferring charges, staying stable in light, and breaking down pollutants. Metal-based QDs like ZnO and CdS also have strong photocatalytic activity, but their sustainability remains a concern due to the potential release of toxic ions when they corrode in light. The green synthesis approach addresses these challenges. Using natural extracts, like polyphenols from tea leaves, to biofunctionalize surfaces has been shown to reduce toxicity and improve photocatalytic performance. Green synthesis using renewable precursors solves problems with toxicity, resource depletion, and environmental pollution, which supports a low-impact and circular technological approach. This study examines recent developments in the making, modifying, and use of QD-based photocatalysts in the environment, with a focus on CQD/g-C₃N₄ hybrid systems. Future research should focus on making green, non-toxic, regenerable, and highly active carbon-based QDs for safe large-scale water treatment.

Nanoparticles (NPs) are gaining popularity due to their exceptional size-to-volume ratio, which enables them to efficiently perform a wide range of chemical reactions. The application of these particles has expanded rapidly in various sectors. However, the traditional methods for synthesizing NPs often involve the use of toxic chemicals. Although these toxic chemicals can produce useful target NPs, the production of hazardous byproducts is inevitable. Green synthesis processes always exclude toxic materials from the synthesis procedures and use supplementary materials that are natural or less harmful. This study focuses on the synthesis of these materials without the use of toxic chemicals and the production of NPs from natural resources, such as peels, leaves, petals of flowers, fruits, and roots. These starting materials are cheap and safe and may reduce the impact of waste on the environment. This study also focuses on the application of such NPs in a variety of industries. Some examples of these industries include agriculture, food, and pharmaceuticals.

The widespread application of nanoparticles (NPs) in fields ranging from consumer products to industrial processes has led to increased concerns about their potential toxic effects on human health and the environment. While traditional toxicological studies often evaluate the effects of individual NPs, real-world exposure scenarios typically involve mixtures of NPs, where interactions between particles can significantly alter their toxicological profiles. This study provides an overview of overcoming this gap by possible utilization of high-throughput screening (HTS) for evaluation of the combined effects of NP mixtures under various exposure conditions. This review discusses HTS of metal oxide NPs, which have cytotoxic, genotoxic, and oxidative stress-inducing effects. Using HTS, this review describes multiple studies with multiple mixture ratios and exposure durations using human lung epithelial cells and zebrafish embryo systems. The review also describes a range of interactions, from synergistic effects, where the combined toxicity might be the sum of individual toxicities. Oxidative stress and metal ion release were key drivers of toxicity, particularly in metal oxide-dominant NP mixtures. This theoretical study highlights the importance of integrating HTS into nanotoxicology research to provide a more comprehensive understanding of the toxic behavior of NPs.

Nanoparticles (NPs), which possess unique physicochemical qualities such as large surface area and reactivity, have brought about a revolution in a variety of sectors, including medicine and electronics. The growing ubiquity of these substances, on the other hand, has given rise to worries over the toxicological effects they have on human health and ecosystems. The condition known as oxidative stress, which is caused by an imbalance between the formation of reactive oxygen species (ROS) and antioxidant defenses, is one of the key processes that contribute to the toxicity of NPs. An excessive amount of ROS may cause damage to cellular components such as lipids, proteins, and DNA, which can result in detrimental consequences such as inflammation, apoptosis, and the development of cancer. NP-induced oxidative stress is investigated in this work, which focuses on the molecular mechanisms that are responsible for it. These processes include mitochondrial dysfunction, catalytic redox cycling, and the release of metal ions from particle disintegration. On top of that, we investigate how the features of NPs, such as their size, shape, surface charge, and composition, affect their capacity to produce ROS. Additionally, the consequences of oxidative stress for both acute and chronic health effects are examined, in addition to the function that it plays in the toxicity of the environment. The use of antioxidants and alterations to the surface of NPs are two examples of mitigation measures that are discussed in this article. The findings of this study highlight the significance of gaining knowledge of the processes behind oxidative stress to ensure the safe design and deployment of NPs.

Urban water bodies are facing a growing crisis due to contamination from a diverse array of pollutants, encompassing heavy metals, oil and grease, organic and inorganic chemicals, industrial effluents, and pathogenic microorganisms. This study focuses on the burgeoning field of utilizing metal oxide nanoparticles (MONs) as a potential solution to this pressing environmental challenge. The distinctive physicochemical properties of MONs, including their large surface area, catalytic activity, and photocatalytic ability, position them as promising candidates for water purification technologies. This study also comprehensively discusses the sources of urban water pollution and the specific challenges posed by different types of contaminants. A critical evaluation of MONs’ efficacy in removing heavy metals, oil and grease, organic and inorganic chemicals, and industrial pollutants is presented, with a focus on the underlying mechanisms such as adsorption, photocatalysis, and redox reactions. Furthermore, the potential of MONs to neutralize pathogens and microbial contaminants is investigated. While MONs exhibit significant advantages, this study acknowledges the challenges associated with nanoparticle stability, recovery, and potential environmental repercussions. To fully realize the potential of MONs in water treatment, sustained research is imperative to refine treatment processes, develop economically viable strategies, and ensure the long-term sustainability of these technologies in addressing urban water pollution.