Recent Patents on Nanotechnology - Volume 15, Issue 3, 2021

Background: Environmental pollution has been a recognized problem for human health and the ecosystem. Remediation is usually costly and time-consuming, so researchers' attention has been drowning to develop and use new materials. This review aims to summarize the recent development of carbon-based materials used for environmental management. Methods: We conducted a detailed analysis of available literature based on the Web of Science database. In the third part of the manuscript are given some of the recent patents on carbon-based materials. The corresponding papers were carefully evaluated. Results: More than one hundred and ninety papers were included in section literature. Based on the available literature it an increasing trend in carbon-based material usage can be observed. These materials are used in resolving environmental issues: adsorbents in water and wastewater treatment; precursor of catalysts, soil improvement, waste management, climate change mitigation, electrochemical energy storage and soil remediation adsorption processes. Although it is a mainly new approach considered as environmentally friendly, there are finding, observation, negative aspects, and conclusion that must be taken into consideration. Conclusion: The findings of this review confirm that many factors must be considered when carbon- based materials are used. At the same time, this review aims to emphasize development trends in providing a useful guide to design and fabricate high-efficiency and low-cost carbon materials.

Background: Globally, around 150 million people are still supplied with arsenic contaminated drinking water. The groundwaters effected often contain problematic concentrations of natural organic matter (NOM), which plays an important role in releasing As into the aquifer. Thus, this review explores the recent literature relating to the application of various nanomaterials to solve these drinking water supply problems and highlights the work that still needs to be done. Methods: After an extensive initial search patent papers were selected based on their quality and relevance to the topic of this review: the use of magnetic nanomaterials based on pure magnetic materials, magnetic composites of carbon/graphene/biochars, polymeric matrices, metal-organic frameworks and mixed-oxide magnetic nanocomposites, as As adsorbents and as photocatalysts for NOM removal. Results: 160 papers relating to the application of nanomaterials for As removal were reviewed and 38 papers covering photocatalysts for NOM removal. These papers were organised by type of nanomaterial, and their important findings summarised. Although many authors have demonstrated effective solutions in the laboratory, the following areas still need to be addressed: the challenges posed by larger pilot and full scale continuously operated processes; the treatment of complex natural water matrices; which technologies will be required to economically separate nanoparticles from the treated water; whether the nanoparticles will be more economically and environmentally sustainable than other techniques available. Conclusion: Despite these significant gaps in the literature, the body of work carried out thus far, as summarised in this review paper, strongly suggests that full scale treatment solutions applying (magnetic) nanomaterials may prove highly effective in the future for both arsenic and NOM removal.

Background: Over the last two decades, thousands of scientific papers and many patents have been written relating to applications of ionic liquids, a family of compounds that garnered such huge interest due to their reputation as "green chemicals". This work reviews the recent literature to investigate the progress ionic liquids have made in their transition from academia to full-scale application in a variety of industries. Methods: For this review, keywords related to ionic liquids and their possible applications were used to search patent databases such as Google patents. The recent patents thus discovered were tabulated and sorted by application, and the most significant patents were identified. For each application of ionic liquids identified in the patent search, an additional review of the recent scientific literature was carried out, focussing on the relevant ionic liquids and their potential environmental impact. Results: Patents involving ionic liquids were found for various industrial applications, including in chemical industry production technologies, nanotechnology, gas storage and environmental remediation. Despite the widespread interest of the chemical industry, which hopes to improve the environmental sustainability of their technologies by utilising ionic liquids, to date, only a handful of full-scale processes which utilise ionic liquids have been successfully commercialised. That said, a large number of pilot studies have been carried out in recent years, and 62 patents and 270 scientific texts are summarised herein and other industrial applications are also approaching the market. Conclusion: The properties of ionic liquids inhibit their entry into the atmosphere. However, their annual production is expected to increase drastically, raising urgent questions about their environmental impact, especially in water bodies. More research is thus required to identify and mitigate any risks ionic liquids might pose to the environment.

Background: The application of zero-valent iron nanoparticles (nZVI) to remediate soil and groundwater has gained increased attention within the last decade, primarily due to their high reactivity, cost-effectiveness and potential to treat a broad range of contaminants (e.g., chlorinated organic solvents, inorganic anions, or metals). Objective: In this paper, the state of the art of applicability of nanomaterials, especially the most frequently used nZVI in soil and groundwater, is presented. The purpose of this article is to give an overview of the current knowledge pertaining to the synthesis, employment, limitations, and risk of iron nanoparticles. Methods: Therefore, the authors have reviewed and discussed the recent patents and papers related to the developments and approaches made on the synthesis of iron nanoparticles, emphasizing the justification of green synthesis methods. The studies related to the effective use of nanoparticles in remediating organic and inorganic contaminants are addressed. The potential limitations, challenges, and risks of this innovative nanoremediation technology are also discussed. Results: Studies suggest that nZVI have successfully been applied in nanoremediation; however, little is known about the particles’ fate and impacts. Additionally, it has already been proven that synthesis and modification can largely determine the physicochemical and biological properties of the particles. Conclusion: This review corroborates the suitability of nanoparticles in the remediation of contaminated media, simultaneously highlighting the work still needed to optimize the syntheses and careful use of such materials, concluding that comprehensive screenings should be performed prior to nZVI applications to assess their behavior and impact on the environment and living systems.

Background: Reuse of waste materials present in the technosphere, such as the metal mining tailings is becoming a more economical and energy-efficient method for obtaining the raw materials than the classical mining. Number of patents are presenting methods for tailings recycling, often in construction industry and metallurgy. At the same time, world market for metallic nanomaterials is rapidly increasing with numerous new applications and these two subjects should be connected. Methods: Paper presents the hypothesis that fine sludge from the metal mining tailings could be dominant source of the raw material for the nanotechnology. The idea is based on the fact that most of the usual publications present methodologies for synthesis of nanomaterials only from high-quality chemicals which is often expensive and unsustainable. Proposition here says, that it would be more economical to use the tailings as one of the technospheric wastes, directly by extracting the metal ions, selectively precipitating their cations and subsequently using them in nanotechnologies. Arguments are given by cross-comparison of the literature and patents on iron, bauxite, lead/zinc, copper, tailings and also the extraction of rare earth elements from tailing resources. Results: Metal mining tailings are shown to be an emerging subject in various research papers and patents together with other secondary raw materials. Conclusions: Use of the metal mining tailings as the resources in nanotechnology, is a large energysaving potential. Taking advantage of this readily available technospheric waste which contains mostly micrometer particles, should contribute also to the zero-metal waste goals.

Background: In past years, nanomaterials have been actively studied and developed and successfully used in many fields. Due to water scarcity, the application of nanomaterials in water and wastewater treatment has drawn significant attention. Due to their superior features, they represent functional materials with great potential for pollution removal and environmental applications. Objective: This literature review aims to summarize and present the metal nanoparticles used for dye wastewater treatment. The discussion subject is metallic nanoparticles for mentioned use, with a special focus on iron-based, bimetallic, and photocatalytic nanomaterials. Methods: Reference search of “metal nanoparticles in dye wastewater treatment” was conducted in detail through the Serbian Library Consortium for Coordinated Acquisition (KoBSON). Published papers search was mainly based on Web of Science and ScienceDirect database focusing on the latest research on this topic. The corresponding literature was carefully read, analyzed, and evaluated. Results: Two hundred and twenty-four scientific and review articles, thesis, and book chapters, patents were evaluated in order to summarise current trends in metal nanoparticle use in wastewater treatment. An increasing trend in scientific research regarding metal nanoparticles can be observed for the removal of different inorganic and organic pollutants. Among the most extensively tested are dye molecules, representing challenging species in terms of degradation and consequent removal. Modification, layering, combination, and green synthesis of metal nanoparticles result in materials capable of efficient and environmentally sustainable wastewater treatment. Conclusion: In this paper, an extensive review of metal nanoparticles in dye wastewater treatment is presented. With rapid water demand, the development of sustainable materials and technology is necessary. The use of these materials represents eco-friendly, energy-efficient, and sustainable water purification solutions. However, the matter of usage commercialization is still to be addressed.