Biosynthesis of bismuth selenide nanoparticles using chalcogen-metabolizing bacteria

Biosynthesis and Properties of Bismuth Nanoparticles: A Review

Today, nanotechnology is becoming increasingly important among researchers around the world by helping them diagnose and treat various diseases that can threaten human life. Bismuth nanoparticles are among the numerous metal nanoparticles widely used due to their potential therapeutic applications. Variety of studies displayed the high potentials of bismuth nanoparticles in extraordinary antibacterial, antibiofilm, anticancer, and antioxidant effects, and it seems that these potentials can be used to address the challenges in the treatment of many diseases. They are among the metal nanoparticles biosynthesized by the green synthesis method in many studies. The use of green synthesis of nanoparticles has attracted the interest of many investigators because of its environmental friendliness, non-toxicity, and high stability. Microorganisms like bacteria, fungi, yeasts, actinomycetes, viruses, marine algae, and plants have been found to have the inherent potential to create metal nanoparticles intracellularly or extracellularly and are recognized as viable biofactories for the green synthesis of nanoparticles. The goal of this review article was to assess synthesized bismuth nanoparticles based on their green synthesis methods; properties in terms of shape, size, synthesis origin, and structure; and biological applications, including their antibacterial, antibiofilm, antioxidant, and cytotoxic uses.

Selenium volatilization in plants, microalgae, and microorganisms

The augmented prevalence of Se (Se) pollution can be attributed to various human activities, such as mining, coal combustion, oil extraction and refining, and agricultural irrigation. Although Se is vital for animals, humans, and microorganisms, excessive concentrations of this element can give rise to potential hazards. Consequently, numerous approaches have been devised to mitigate Se pollution, encompassing physicochemical techniques and bioremediation. The recognition of Se volatilization as a potential strategy for mitigating Se pollution in contaminated environments is underscored in this review. This study delves into the volatilization mechanisms in various organisms, including plants, microalgae, and microorganisms. By assessing the efficacy of Se removal and identifying the rate-limiting steps associated with volatilization, this paper provides insightful recommendations for Se mitigation. Constructed wetlands are a cost-effective and environmentally friendly alternative in the treatment of Se volatilization. The fate, behavior, bioavailability, and toxicity of Se within complex environmental systems are comprehensively reviewed. This knowledge forms the basis for developing management plans that aimed at mitigating Se contamination in wetlands and protecting the associated ecosystems.

Bio-fabricated bismuth-based materials for removal of emerging environmental contaminants from wastewater

Although rapid industrialization has made life easier for humans, several associated issues are emerging and harming the environment. Wastewater is regarded as one of the key problems of the 21st century due to its massive production every year and requires immediate attention from all stakeholders to protect the environment. Since the introduction of nanotechnology, bismuth-based nanomaterials have been used in variety of applications. Various techniques, such as hydrothermal, solvo-thermal and biosynthesis, have been reported for synthesizing these materials, etc. Among these, biosynthesis is eco-friendly, cost-effective, and less toxic than conventional chemical methods. The prime focuses of this review are to elaborate biosynthesis of bismuth-based nanomaterials via bio-synthetic agents such as plant, bacteria and fungi and their application in wastewater treatment as anti-pathogen/photocatalyst for pollutant degradation. Besides this, future perspectives have been presented for the upcoming research in this field, along with concluding remarks.

Hydrothermal synthesis of Bi2Se3 nanosheets by using gallic acid as a reductant

In this work, a simple and reproducible hydrothermal synthesis was employed to synthesize two-dimensional Bi2Se3 nanosheets by using gallic acid as a reductant. Meanwhile, the effects of the amounts of gallic acid and sodium hydroxide and the surfactant Triton X-100 on phase composition and morphology of the obtained Bi2Se3 were also studied. The results reveal that gallic acid could effectively reduce Se4+ to Se2- and gave rise to the formation of Bi2Se3. Additionally, keeping the reaction conditions of molar ratio of gallic acid to the precursor elements (Bi + Se) at 1 to 1 (or higher) and using strong alkaline solutions were the key factors to synthesize high purity crystalline Bi2Se3 nanosheets. Furthermore, flower-like Bi2Se3 composed of nanosheets with a dozen nanometer thickness could be easily fabricated by adding appropriate amounts of Triton X-100. This work provides a novel approach for synthesis of ultra-thin Bi2Se3 nanosheets in a controllable manner.