Showing papers by "Thalappil Pradeep published in 2021"
TL;DR: In this article, the formulation and periodic self-assembly of different noble metal nanoclusters are focused upon, and their potential applications in molecular recognition, sensing, gas storage, device fabrication, bioimaging, therapeutics, and catalysis are discussed.
Abstract: Ligand protected noble metal nanoparticles are excellent building blocks for colloidal self-assembly. Metal nanoparticle self-assembly offers routes for a wide range of multifunctional nanomaterials with enhanced optoelectronic properties. The emergence of atomically precise monolayer thiol-protected noble metal nanoclusters has overcome numerous challenges such as uncontrolled aggregation, polydispersity, and directionalities faced in plasmonic nanoparticle self-assemblies. Because of their well-defined molecular compositions, enhanced stability, and diverse surface functionalities, nanoclusters offer an excellent platform for developing colloidal superstructures via the self-assembly driven by surface ligands and metal cores. More importantly, recent reports have also revealed the hierarchical structural complexity of several nanoclusters. In this review, the formulation and periodic self-assembly of different noble metal nanoclusters are focused upon. Further, self-assembly induced amplification of physicochemical properties, and their potential applications in molecular recognition, sensing, gas storage, device fabrication, bioimaging, therapeutics, and catalysis are discussed. The topics covered in this review are extensively associated with state-of-the-art achievements in the field of precision noble metal nanoclusters.
61 citations
TL;DR: This concept, recent advancements in the cocrystallization of atomically precise noble metal clusters and their potential future directions are presented, and different strategies to create coassemblies of thiolate-protected noble metal nanoclusters are presented.
Abstract: Cocrystallization is a phenomenon involving the assembly of two or more different chemical entities in a lattice, occurring typically through supramolecular interactions. In this concept, recent advancements in the cocrystallization of atomically precise noble metal clusters and their potential future directions are presented. Different strategies to create coassemblies of thiolate-protected noble metal nanoclusters are presented first. An approach is the simultaneous synthesis, and cocrystallization of two clusters having similar structures. A unique pair of clusters found recently, namely Ag40 and Ag46 with same core but different shell are taken to illustrate this. In another category, the case of the same core is presented, namely Ag116 with different shells, as in a mixture of Ag210 and Ag211 . Next, an intercluster reaction is presented to create cocrystals through selective crystallization of the reaction products. The coexistence of competing effects, magic sizes, and magic electron shells in a coassembly of alloy nanoclusters is discussed next. Finally, an assembly strategy for nanoclusters using electrostatic interactions is described. This concept is concluded with a future perspective on the emerging possibilities of such solids. Advancements in this field will certainly help the development of novel materials with exciting properties.
22 citations
12 Jan 2021
TL;DR: In this paper, various synthetic methodologies have been developed so far for the controlled synthesis of alloy metal nanoclusters (NCs), which are considered as intermediates between the atomic/molecular regime and the bulk.
Abstract: Atomically precise metal nanoclusters (NCs), protected by a monolayer of ligands, are regarded as potential building blocks for advanced technologies. They are considered as intermediates between the atomic/molecular regime and the bulk. Incorporation of foreign metals in NCs enhances several of their properties such as catalytic activity, luminescence, and so on; hence, it is of high importance for tuning their properties and broadening the scope of applications. In most of the cases, enhancement in specific properties was observed upon alloying due to the synergistic effect. In the past several years, many alloy clusters have been synthesized, which show a tremendous change in the properties than their monometallic analogs. However, controlling the synthesis and tuning the structures of alloy NCs with atomic precision are major challenges. Various synthetic methodologies have been developed so far for the controlled synthesis of alloy NCs. In this perspective, we have highlighted those diverse synthetic routes to prepare alloys, which include co-reduction, galvanic reduction, antigalvanic reduction, metal deposition, ligand exchange, intercluster reaction, and reaction of NCs with bulk metals. Advancement in synthetic procedures will help in the preparation of alloy NCs with the desired structure and composition. Future perceptions concerning the progress of alloy nanocluster science are also provided.
21 citations
TL;DR: In this article, the rate constants of the corresponding reactions were fitted to the experimental data, and good agreement was obtained with exchange rate constants which scale with the probability of finding a silver or gold atom in the respective monomeric subunit of the dimer, reflecting an entropic driving force for alloying.
Abstract: The kinetics of intercluster metal atom exchange reactions between solvated [Ag25(DMBT)18]- and [Au25(PET)18]- (DMBT and PET are 2,4-dimethylbenzenethiol and 2-phenylethanethiol, respectively, both C8H10S) were probed by electrospray ionization mass spectrometry and computer-based modeling. Anion mass spectra and collision induced dissociation (CID) measurements show that both cluster monomers and dimers are involved in the reactions. We have modeled the corresponding kinetics assuming a reaction mechanism in which metal atom exchange occurs through transient dimers. Our kinetic model contains three types of generic reactions: dimerization of monomers, metal atom exchange in the transient dimers, and dissociation of the dimers to monomers. There are correspondingly 377 discrete species connected by in total 1302 reactions (i.e., dimerization, dissociation and atom exchange reactions) leading to the entire series of monomeric and dimeric products [AgmAu25-m]- (m = 1-24) and [AgmAu50-m]2- (m = 0-50), respectively. The rate constants of the corresponding reactions were fitted to the experimental data, and good agreement was obtained with exchange rate constants which scale with the probability of finding a silver or gold atom in the respective monomeric subunit of the dimer, i.e., reflecting an entropic driving force for alloying. Allowing the dimerization rate constant to scale with increasing gold composition of the respective reactants improves the agreement further. The rate constants obtained are physically plausible, thus strongly supporting dimer-mediated metal atom exchange in this intercluster reaction system.
19 citations
TL;DR: Directing the assembly of plasmonic nanoparticles into chiral superstructures has diverse applications including, chiroptical sensing, nonlinear optics, and biomedicine.
Abstract: Directing the assembly of plasmonic nanoparticles into chiral superstructures has diverse applications including, chiroptical sensing, nonlinear optics, and biomedicine Though soft template-mediat
19 citations
TL;DR: In this article, a ligand-exchange induced structural transformation reaction starting from [Ag18H16(TPP)10]2+ (shortly Ag18) was confirmed using UV-vis optical absorption features, which exhibit characteristic patterns, confirmed its molecular nature.
Abstract: Noble metal nanoclusters protected with carboranes, a 12-vertex, nearly icosahedral boron-carbon framework system, have received immense attention due to their different physicochemical properties. We have synthesized ortho-carborane-1,2-dithiol (CBDT) and triphenylphosphine (TPP) coprotected [Ag42(CBDT)15(TPP)4]2- (shortly Ag42) using a ligand-exchange induced structural transformation reaction starting from [Ag18H16(TPP)10]2+ (shortly Ag18). The formation of Ag42 was confirmed using UV-vis absorption spectroscopy, mass spectrometry, transmission electron microscopy, X-ray photoelectron spectroscopy, infrared spectroscopy, and multinuclear magnetic resonance spectroscopy. Multiple UV-vis optical absorption features, which exhibit characteristic patterns, confirmed its molecular nature. Ag42 is the highest nuclearity silver nanocluster protected with carboranes reported so far. Although these clusters are thermally stable up to 200 °C in their solid state, light-irradiation of its solutions in dichloromethane results in its structural conversion to [Ag14(CBDT)6(TPP)6] (shortly Ag14). Single crystal X-ray diffraction of Ag14 exhibits Ag8-Ag6 core-shell structure of this nanocluster. Other spectroscopic and microscopic studies also confirm the formation of Ag14. Time-dependent mass spectrometry revealed that this light-activated intercluster conversion went through two sets of intermediate clusters. The first set of intermediates, [Ag37(CBDT)12(TPP)4]3- and [Ag35(CBDT)8(TPP)4]2- were formed after 8 h of light irradiation, and the second set comprised of [Ag30(CBDT)8(TPP)4]2-, [Ag26(CBDT)11(TPP)4]2-, and [Ag26(CBDT)7(TPP)7]2- were formed after 16 h of irradiation. After 24 h, the conversion to Ag14 was complete. Density functional theory calculations reveal that the kernel-centered excited state molecular orbitals of Ag42 are responsible for light-activated transformation. Interestingly, Ag42 showed near-infrared emission at 980 nm (1.26 eV) with a lifetime of >1.5 μs, indicating phosphorescence, while Ag14 shows red luminescence at 626 nm (1.98 eV) with a lifetime of 550 ps, indicating fluorescence. Femtosecond and nanosecond transient absorption showed the transitions between their electronic energy levels and associated carrier dynamics. Formation of the stable excited states of Ag42 is shown to be responsible for the core transformation.
18 citations
TL;DR: In this paper, the authors developed a highly cost-effective and sustainable method of gold extraction in which gold recovery using a sustainable and inexpensive method has tremendous environmental and economic implications, which has been shown to be more efficient than conventional methods.
Abstract: Gold recovery using a sustainable and inexpensive method has tremendous environmental and economic implications. We developed a highly cost-effective and sustainable method of gold extraction in wh...
14 citations
TL;DR: The authors in this paper proposed a framework to guide and trigger advances in sustainable chemistry and engineering, in a way similar to the 12 principles of Green Chemistry and the 12 Principles of Green Engineering, in order to assess reported discoveries in a uniform and easily recognizable way.
Abstract: I 2015, the United Nations (UN) unveiled an ambitious plan, the Sustainable Development Goals (SDGs), aimed at providing guidelines, applicable universally to all nations, for equitable and responsible development, respectful of humans and ecosystems. The SDGs plan sets a clear agenda to be achieved by 2030 (Agenda 2030), composed of 17 goals and 169 targets, that promotes economic growth, environmental protection, social inclusion, and human well-being. This framework has been adopted by many governmental agencies, foundations, and companies in order to articulate specific actions in the broader context of sustainable development. The global scientific community has also established connections to the SDGs, highlighting the central role that sustainable chemistry and engineering must play to realize them. In particular, the SDGs are a powerful way to focus on how chemicals are used. The central role and impact of advanced technologies on global well-being and sustainability are further recognized by the declaration of a United Nations International Year of Basic Sciences for Sustainable Development in 2022. Time-bound action based on specific policies in different regions is critical for achieving Agenda 2030. For example, the successes of India, China, and Brazil, among the most populous countries, in achieving the SDGs will hugely contribute to the global outcomes. Efforts are underway to quantify progress, such as the SDG India Index. Directed actions to achieve the SDGs will be region specific. For example, it has been suggested that combating environmental pollution will be key in achieving the SDGs in China. Advances in science, technology, and education are critical to successfully address the various challenges and achieve the SDGs. Within ACS Sustainable Chemistry & Engineering (ACS SCE), we encourage authors to connect their research to the SDGs (Figure 1), identifying societal, environmental, and healthrelated benefits within submitted manuscripts where appropriate. The editors of ACS SCE are currently publishing a series of editorials on effective practices to incorporate sustainability assessments in submitted papers. We believe that the SDGs offer an opportunity to assess reported discoveries in a uniform and easily recognizable way. Specifically, sustainability advances reported in manuscripts can be used to benchmark progress against published 2030 SDG targets. This approach provides a framework to guide and trigger advances in sustainable chemistry and engineering, in a way similar to the 12 Principles of Green Chemistry and the 12 Principles of Green Engineering. It must be noted that all these frameworks call for a holistic view of sustainability, whereby advances should lead to progress in all criteria, not in just one or a few at the expense of others. We encourage authors to adopt such an approach when critically assessing their reported advances. We also welcome perspective-type manuscripts on the topic of the SDGs in the context of chemistry and engineering research, education, chemistry enterprise, public agencies, etc. While several such articles have appeared since the launch of the SDGs, the global crisis caused by the COVID-19 pandemic is reinforcing the urgency to work toward these goals. COVID19 has had a major impact on human health and well-being (Goal 3) globally, yet the difference in the abilities of nations to effectively respond to the pandemic is revealing disparities across the globe in a number of SDG areas such as poverty (Goal 1), hunger (Goal 2), education (Goal 4), clean water and sanitation (Goal 6), and economic growth (Goal 8). Our ability to produce and consume responsibly has been drastically affected by disrupted supply chains, impaired mobility for people and goods, and increased reliance on disposables (Goal 12). The use of disposable masks, alongside already widespread use of single use plastics, is impacting habitats both on land and in the ocean (Goals 14 and 15). Some governments have seized this opportunity to cast ambitious plans for a post pandemic economic recovery to provide a boost to clean and affordable energy (Goal 7),
13 citations
TL;DR: Atomically precise noble metal nanoclusters protected with proteins have emerged as a new research frontier in nanoscience due to their unique optical and chemical properties as well as promising a promising future as mentioned in this paper.
Abstract: Atomically precise noble metal nanoclusters protected with proteins have emerged as a new research frontier in nanoscience due to their unique optical and chemical properties as well as promising a...
13 citations
TL;DR: In this article, the authors synthesize an effective cellulose-based adaption method to produce clean water in resource-limited settings, which is shown to be an extremely affordable and sustainable way of producing clean water.
Abstract: Adsorption is shown to be an extremely affordable and sustainable way of producing clean water, particularly in resource-limited settings. In this paper, we sought to synthesize an effective cellul...
12 citations
TL;DR: In this article, the formation of a versatile luminescent organo-inorganic layered hybrid material, composed of bovine serum albumin (BSA)-protected Au30 clusters and aminoclay sheets, was demonstrated.
Abstract: We demonstrate the formation of a versatile luminescent organo-inorganic layered hybrid material, composed of bovine serum albumin (BSA)-protected Au30 clusters and aminoclay sheets. X-ray diffraction revealed the intercalation of Au30@BSA in the layered superstructure of aminoclay sheets. Coulombic attraction of the clusters and the clay initiates the interaction, and the appropriate size of the clusters allowed them to intercalate within the lamellar aminoclay galleries. Electron microscopy measurements confirmed the hierarchical structure of the material and also showed the cluster-attached clay sheets. Zeta potential measurement and dynamic light scattering probed the gradual formation of the ordered aggregates in solution. The hybrid material could be stretched up to 300% without fracture. The emergence of a new peak in the luminescence spectrum was observed during the course of mechanical stretching. This peak increased in intensity gradually with the degree of elongation or strain of the material. A mechanochromic luminescence response was further demonstrated with a writing experiment on a luminescent mat of the material, made by electrospinning.
TL;DR: In this paper, the formation of hexagonal ice from clathrate hydrates is investigated and the most common and highly studied crystalline form of ice is shown to be hexagonal.
Abstract: Although hexagonal ice (ice Ih) is the most common and highly studied crystalline form of ice, its nucleation from clathrate hydrates is poorly understood. Here, we report the formation of ice Ih t...
TL;DR: Capacitive deionization (CDI) is an emerging technology which involves adsorption and desorption of ions on the electrode surface by application of low potential difference (≈1.2-1.8 V) across a pair of porous carbon electrodes, thereby making it both energy and cost-efficient compared to other existing desalination methods as discussed by the authors.
Abstract: DOI: 10.1002/admi.202001998 terms of equipment and energy consumption.[6,8–11] Capacitive deionization (CDI) is an emerging technology which involves adsorption and desorption of ions on the electrode surface by application of low potential difference (≈1.2–1.8 V) across a pair of porous carbon electrodes, thereby making it both energy and cost-efficient compared to other existing desalination methods. When a flowing water stream is passed across a CDI system, cations and anions move toward oppositely charged electrodes and get adsorbed on them, thereby generating deionized and ‘drinkable’ water, starting from brackish water. Subsequently, adsorbed ions can be removed from the electrode by reversing the polarity, thereby regenerating the electrode surface, ready for reuse for next adsorption cycle.[5] Thus, clean water can be produced continuously by repeating the adsorption and desorption cycles. CDI is a cost-effective, point-of-use method with a high theoretical desalination efficiency.[5] However, its practical applications for desalination are yet to be recognized at a large scale, and research is being carried out to synthesize new materials with improved adsorption capacities.[5,12–14] Related technologies such as Faradaic deionization and the use of different 2D materials in CDI are also explored intensely.[15–17] Various carbonaceous materials and their composites are being used as CDI electrodes because of their high salt adsorption capacities in the range of several mg g−1.[18–25] Graphene, and graphene-derivatized materials, such as, graphene-like nanoflakes,[26] activated carbon,[27] activated carbon nanofiber (ACF),[28] reduced graphene oxide (rGO),[27,29] carbon nanotubes (CNT),[29] graphene–CNT composites,[29,30] rGO–ACF,[28] 3D macroporous graphene architectures,[31] sponge-templated graphene,[14] graphene–Fe3O4, graphene chitosan–Mn3O4, rGO–activated carbon composites,[27] and functionalized graphene nanocomposite,[34] have been used as CDI electrodes. The adsorption capacities of graphenic composites, such as graphene/carbon nanotube, CO2 activated rGO, sulfonic functional graphite nanosheets, SO3H/NH2 graphene/activated carbon, MgAl-Ox/G nanohybrids, 3D-graphene architecture, and graphene sponge measured were 1.4, 6.26, 8.6, 10.3, 13.6, Capacitive deionization (CDI) is an emerging, cost-effective alternative for energy-efficient desalination technology. Efficient electrode materials based on individual reduced graphene oxide (rGO) nanosheets are produced by functionalizing them with polystyrene (rGO–PS) through an in situ polymerization process involving rGO, styrene monomer, and divinylbenzene. The rGO–PS-integrated composite nanostructures are subsequently functionalized with sulfonate and quaternary amine functionalities to achieve positively and negatively charged electro-adsorbent ion-exchange resins (EAIERs), respectively. These EAIERs ‘molecular constructs’ are used to fabricate CDI electrodes, and deionization is performed to remove various ions. These molecular constructs promote faster charge transfer at the electrode–electrolyte interface and maintained the electrical conductivity of the active rGO. This leads to a high electroadsorption capacity of 15.93 mg g−1 of Cl− using NaCl solution with a conductivity of 802 μS in laboratory batch experiments, which is approximately five times higher than the adsorption capacity of rGO electrodes reported earlier (≈2–3 mg g−1) in comparable experimental conditions. No significant Faradaic redox reactions or chemical changes are observed on the electrode surface, which make these electrodes exhibit excellent electrochemical stability even after multiple adsorption/desorption cycles.
18 Feb 2021
TL;DR: Active cooling-based atmospheric water generators, despite their growing demand, continue to be energy intensive and offer poor collection efficiencies (energy consumption per liter of water produc... as mentioned in this paper...
Abstract: Active cooling-based atmospheric water generators, despite their growing demand, continue to be energy intensive and offer poor collection efficiencies (energy consumption per liter of water produc...
TL;DR: It is shown that ambient electrospray of preformed polydisperse nanoparticles makes them monodisperse and the product nanoparticles self-assemble spontaneously to form organized films, all within seconds, which may be extended for the creation of advanced materials of many kinds.
Abstract: Conversion of polydisperse nanoparticles to their monodisperse analogues and formation of organized superstructures using them involve post synthetic modifications, and the process is generally slow. We show that ambient electrospray of preformed polydisperse nanoparticles makes them monodisperse and the product nanoparticles self-assemble spontaneously to form organized films, all within seconds. This phenomenon has been demonstrated with thiol-protected polydisperse silver nanoparticles of 15 ± 10 nm diameter. Uniform silver nanoparticles of 4.0 ± 0.5 nm diameter were formed after microdroplet spray, and this occurred without added chemicals, templates, and temperature, and within the time needed for electrospray, which was of the order of seconds. Well organized nanoparticle assemblies were obtained from such uniform particles. A home-made and simple nanoelectrospray set-up produced charged microdroplets for the generation of such nanostructures, forming cm2 areas of uniform nanoparticles. A free-standing thin film of monodisperse silver nanoparticles was also made on a liquid surface by controlling the electrospray conditions. This unique method may be extended for the creation of advanced materials of many kinds.
TL;DR: In this paper, the authors proposed a method to detect contamination of groundwater by arsenic (As(III/V) and phosphate (P(V)) using adsorption-based remediation methods.
Abstract: Contamination of groundwater by arsenic (As(III/V)) is a serious global issue, and phosphate (P(V)) is known to be the biggest interference in adsorption-based remediation methods. The present stud...
TL;DR: Traditional black rice varieties with their nutraceutical properties had considerably greater protein, thiamin, riboflavin, pantothenic acid, pyridoxine, and antimicrobial activities compared to the two selected white rice varieties.
Abstract: The present investigation aims to explore the importance of some traditional black rice varieties with their nutraceutical properties. The beneficial properties of these varieties remain unknown to the majority of the population due to the inadequate data. Decorticated rice grains of four black rice varieties were evaluated and compared with two commonly consumed white rice varieties - Gobindabhog (traditional aromatic) and BPT 5204 (modern high yielding variety). The sugars and total lipid levels were similar in Gobindabhog and BPT 5204. The black rice varieties, however, had considerably greater protein, thiamin, riboflavin, pantothenic acid, pyridoxine, and antimicrobial activities compared to the two selected white rice varieties. The ICPMS analysis of black rice grains showed that the former also had higher levels of Mn, Fe, and Zn than the white rice varieties. However, BPT 5204 contained a greater amount of Cu than the black rice varieties. Total flavonoid and phenolic content, as well as antioxidant potentiality of black rice varieties were also considerably higher than those of the white rice varieties.
TL;DR: In this article, the authors explored changes in binding modes of the most common ligand, citrate on silver nanoparticles (AgNPs) using single-particle surface-enhanced Raman scattering (SP-SERS) single AgNPs of 50
Abstract: This study explored changes in binding modes of the most common ligand, citrate on silver nanoparticles (AgNPs) using single-particle surface-enhanced Raman scattering (SP-SERS) Single AgNPs of 50
TL;DR: In this article, an aminoclay-graphene oxide composites was incorporated into thin-film composite (TFC)-reverse osmosis membranes to improve the desalination efficiency of brackish water.
Abstract: DOI: 10.1002/admi.202100533 (RO) has emerged as a promising method to eradicate the drinking water crisis.[1–7] An RO membrane generally consists of a polyester non-woven fabric upon which a polysulfone layer is casted. These two layers are porous, highly permeable, and provide mechanical support to the topmost layer. The polysulfone side of the membrane is coated with a cross-linked aromatic polyamide thin film by interfacial polymerization between the organic molecules (e.g., trimesoyl chloride, TMC) and aqueous (e.g., m-phenylene diamine, MPD) phases.[8–11] The presence of the active layer of polyamide improves the salt rejection, and antifouling properties of the membrane.[11,12] Additives including camphor sulfonic acid (CSA), triethylamine (TEA), and sodium lauryl sulfate (SLS) are also frequently used to enhance the membrane preparation by aiding the absorption of MPD on the polysulphone support.[12] Despite copious advantages of membrane filtration systems, such as easy operation and high flexibility in technologies, they present some limitations, including chlorine sensitivity, and susceptibility to fouling, which impedes their large-scale applications.[13–15] In some cases, deposition of extra-cellular polymeric substances (EPS), soluble microbial products (SMP), and microbial cells in the pores resulting in a drop in flux and salt rejection capacity. The amide groups in the polyamide skin layer are also vulnerable to chlorine attack, even at a low chlorine dosage in the feed water.[16] The polyamide chains allegedly undergo ring chlorination in the presence of chlorine, which disrupts hydrogen bonding between the chains and degrades the polymer matrix.[17] The disruption leads to a dramatic decline in the permeation flux, membrane life, and selectivity, which increases the required pressure for operation. Modification of the thin-film composite (TFC) membranes by adding different hydrophilic nanomaterials like carbon, alumina, silica zeolites, 2D materials, and their derivatives is common in order to combat these problems and improve water permeation characteristics.[8,18–28] Recently, several nanocomposites-based RO membranes have been explored extensively, as synergy of components enhances the physicochemical properties and increases thermal and Present work attempts to incorporate aminoclay-graphene oxide composites into thin-film composite (TFC)-reverse osmosis membranes to improve the desalination efficiency of brackish water. The composite is coated on a polysulfone substrate as a result of interfacial polymerization of m-phenylene diamine and trimesoyl chloride, at different time durations. The prepared membranes are analyzed for their water permeation and salt rejection efficiencies using brackish feed water. The results indicated that the membrane loaded with 0.015 wt% of the composite delivered maximum flux at 20 bar pressure for 2000 ppm feed. Moreover, the water flow rate increased by ≈3.27 times (from 15.62 ± 0.36 to 50.28 ± 1.69 Lm–2 h–1), compared to the unmodified TFC membrane. An enhancement in the salt rejection from 97.03 ± 1.07 to 99.51 ± 0.10% is also observed for the same feed water at 20 bar as compared to the unmodified membrane. Furthermore, antifouling tests with model bio-foulant humic acid revealed better stability and antifouling performance of the prepared membranes than the unmodified membranes under identical operating conditions. The membrane, therefore, assures high performance and lifetime owing to its mechanical and chemical stability, and hence suggests energy-efficient desalination.
TL;DR: In this article, the authors identify chemistry and engineering challenges associated with advanced and sustainable recycling technologies and management of E-waste, focusing on areas where ACS Sustainable Chemistry & Engineering (ACS SCE) would welcome manuscripts.
Abstract: E and electrical products, such as mobile phones, personal computers, printers, and television sets, are ubiquitous in modern society. It has been estimated that more than 50 million tons of end-of-life electronic waste (E-waste) is generated by these products annually and that these waste streams are growing rapidly. Recycling infrastructures are becoming available as product take-back programs and other means of collecting end-of-life electronic products emerge. However, fundamental challenges associated with the deconstruction of electronic products and establishment of complex systems required for sustainable resource recovery continue to exist. Typically, deconstruction and recycling of Ewaste is conducted where the market price for manual labor is low, and in many scenarios, the level of environmental monitoring and control is minimal. E-waste is a critical material flow that must be managed to deliver circularity in terms of maximizing value and resource utilization; however, this must not compromise human health and other sustainable development goals. The opportunities associated with E-waste flow, together with the potential environmental and human impacts of unrecovered E-waste materials, have led many in the sustainable chemistry and engineering communities to develop environmentally friendly technologies to treat and recycle Ewaste. This editorial is intended to identify chemistry and engineering challenges associated with advanced and sustainable recycling technologies and management of E-waste, focusing on areas where ACS Sustainable Chemistry & Engineering (ACS SCE) would welcome manuscripts. Measurements of the output and distribution of electronic products are important steps in mapping and quantifying potential E-waste production. Data on the production, composition, and recycling of electronic products coupled with the application of big data and active materials tracking in E-waste management will play increasingly important roles in this objective. Effective data collection and modeling systems need to be developed to accurately predict production, stock, and flow of E-waste. Manuscripts describing innovations in the material flow analysis (MFA) and life cycle assessment (LCA) will be welcomed by ACS SCE. Once E-waste is generated, and possibly mapped, resource recycling requires a complex system of technologies, in part due to the heterogeneous composition of the waste. Metals, recyclable plastics with brominated flame retardants (BFRs), liquid crystals, and other organic materials are commonly found in E-waste. Resource recovery technologies can involve principles of metallurgy, electrochemistry, and physics, as well as the use of innovative dissolution and reaction methods. Identifying synergies that lead to the recovery of multiple materials is a major opportunity. ACS SCE welcomes contributions that advance novel and synergistic sustainable recycling technologies. Pollution control in the recycling of E-waste is important. Data on the distribution of pollutants, release mechanisms, and ecosystem impacts associated with recycling processes including their consequences on health are important in order to make more objective evaluations of recycling technologies. For example, in recycling processes that employ mechanical/physical separation methods (dismantling, crushing, and physical separation), fine particles and organic pollutants (BFRs, polybrominated diphenyl ethers (PBDEs), polychlorinated dibenzo-p-dioxins, and dibenzofurans (PCDD/Fs)) can be released. Plasma and similar energyintensive chemistries will have emissions associated with their energy use, and these types of emissions need to be accounted for in sustainability assessments of E-waste recycling processes. ACS SCE welcomes contributions that use innovative methods to identify and quantify pollutants and impacts associated with E-waste processing. Finally, the sustainability of recycling processes of E-waste should be evaluated, including energy consumption, risk assessment of environment and human health, and economic feasibility. Separation of complex components in E-waste requires new cost-effective processes. In addition, secondary pollution and health risks to people during recycling must be minimized. Therefore, E-waste recovery strategies must use methods and tools to quantitatively measure overall sustainability. ACS SCE welcomes manuscripts on advances and uses of such systems approaches to ensure that a green circular economy of E-waste recycling does not result in unintended harm and is environmentally, economically, and socially desirable. Broadly, (i) mapping electronic product and E-waste flows, (ii) innovations in recycling processes, (iii) synergistic recycling of multiple resources, and (iv) quantitative assessment of recycling technologies (energy consumption, risk assessment of health, environmental impact, and economic
TL;DR: Reflection absorption infrared spectroscopic investigations of multilayer films of acetonitrile and water in an ultrahigh vacuum under isothermal conditions showed the emergence of cubic (ice Ic) and hexagonal (ice Ih) ices depending on the composition of the film.
Abstract: Reflection absorption infrared spectroscopic investigations of multilayer films of acetonitrile (ACN) and water in an ultrahigh vacuum under isothermal conditions showed the emergence of cubic (ice Ic) and hexagonal (ice Ih) ices depending on the composition of the film. The experiments were conducted with a mixed film of 300 monolayers in thickness and the ACN : H2O monolayer ratios were varied from 1 : 5 to 5 : 1. Mixed films were deposited at 10 K and warmed to 130–135 K, where ACN desorbed subsequently and IR spectral evolution was monitored continuously. While the emergence of ice Ic at 130 K has been reported, the occurrence of ice Ih at this temperature was seen for the first time. Detailed investigations showed that ice Ih can form at 125 K as well. Crystallization kinetics and activation energy (Ea) for the emergence of ice Ih were evaluated using the Avrami equation.
TL;DR: In this paper, an ambient electrospray deposition (AESD) process was used to transform nanodiamond (ND) into OLCs (50 ± 13 nm in size) in water.
Abstract: Onion-like carbons (OLCs) are a class of fullerene-like circular nanoallotropes of carbon, typically synthesized from nanodiamond (ND) via thermal annealing, plasma spraying, and laser ablation. These methods require high temperature, high vacuum, or inert gas. Here, we report an ambient electrospray deposition (AESD) process to transform NDs (11 ± 1 nm in size) into OLCs (50 ± 13 nm in size) in water. Transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) were used for the characterization of NDs and OLCs. High-resolution TEM images showed an increased interplanar spacing from ND (0.23 nm) to OLC (0.39 nm). Raman spectra showed a shift in the ND peak from 1336 cm−1 to D-band at 1349 cm−1, and XPS quantitatively estimated an increase in the graphitization ratio (sp/sp) from 0.95 to 3.16 after AESD. Comparison of electrospray with sonic spray confirmed that such a transformation required an external voltage as well. AESD was also performed for NDs dispersed in ethanol and acetonitrile, which showed a solvent-dependent transformation.
TL;DR: In this paper, the authors used a catalyst-free chemical approach to tailor both the mechanical property and water wettability at ambient conditions for sustainable waste management and controlling the relevant environmental pollution.
Abstract: Controlled tailoring of mechanical property and wettability is important for designing various functional materials. The integration of these characteristics with waste materials is immensely challenging to achieve, however, it can provide sustainable solutions to combat relevant environmental pollutions and other relevant challenges. Here, the strategic conversion of discarded and valueless waste paper into functional products has been introduced following a catalyst-free chemical approach to tailor both the mechanical property and water wettability at ambient conditions for sustainable waste management and controlling the relevant environmental pollution. In the current design, the controlled and appropriate silanization of waste paper allowed to modulate both the a) porosity and b) compressive modulus of the paper-derived sponges. Further, the association of 1,4-conjugate addition reaction between amine and acrylate groups allowed to obtain an unconventional waste paper-derived chemically 'reactive' sponge. The appropriate covalent modification of the residual reactive acrylate groups with selected alkylamines at ambient conditions provided a facile basis to tailor the water wettability from moderate hydrophobicity, adhesive superhydrophobicity to non-adhesive superhydrophobicity. The embedded superhydrophobicity in the waste paper-derived sponge was capable of sustaining large physical deformations, severe physical abrasions, prolonged exposure to harsh aqueous conditions, etc. Further, the waste paper-derived, extremely water-repellent sponges and membranes were successfully extended for proof-of-concept demonstration of a practically relevant outdoor application, where the repetitive remediation of oil spillages has been demonstrated following both selective absorption (25 times) of oils and gravity-driven filtration-based (50 times) separation of oils from oil/water mixtures at different harsh aqueous scenarios.
TL;DR: In this paper, a surface anchoring-induced enhanced luminescence of AuQC@BSA clusters on high surface area dendritic fibrous nanosilica of 800 nm diameter enabled their luminecence imaging at a single particle level.
Abstract: We report a hybrid material in which surface anchoring-induced enhanced luminescence of AuQC@BSA clusters on high surface area dendritic fibrous nanosilica of 800 nm diameter enabled their luminescence imaging at a single particle level. The photophysical and structural properties of the hybrid material were characterized by various spectroscopic and microscopic techniques. Concomitant imaging using scattering and luminescence of such mesostructures and their response to analytes have been used to develop a chemical sensor. The hybrid material was found to be catalytically active in silane to silanol conversion, and 100% conversion was observed in 4 h when the reaction was carried out at 30 °C in the presence of light. Such materials at submicron dimensions with enhanced surface area, emission in the solid state along with a high quantum yield of 12% in water along with enhanced scattering, and surface functionalities present numerous benefits for the creation of multifunctional materials.
TL;DR: Microdroplet impact-induced spray ionization (MISI) is demonstrated involving the impact of microdroplets produced from a paper and their impact on another, leading to the ionization of analytes deposited on the latter, which ionize and get detected by a mass spectrometer.
TL;DR: In this article, isotopic exchange reactions of atomically precise silver nanoclusters (NCs) with materials of different dimensions, namely, NCs, plasmonic nanoparticles (NPs), and bulk metals, all made of silver.
Abstract: We present isotopic exchange reactions of atomically precise silver nanoclusters (NCs) with materials of different dimensions, namely, NCs, plasmonic nanoparticles (NPs), and bulk metals, all made of silver. Isotopically pure Ag25(DMBT)18 − and Ag25(DMBT)18 − (DMBT is 2,4dimethyl benzene thiol) were reacted with Ag NPs of different sizes in the range of ∼2−11 nm, protected with the same ligand. The exchange of Ag/Ag atoms in the NC was monitored using electrospray ionization mass spectrometry. The reaction kinetics was analyzed by fitting the temporal evolution of the reactant concentration to a kinetic model. The reaction timescales of NC−NP reactions were significantly longer compared to those of the NC−NC exchange process under similar conditions. Differences between NC−NC exchange and NC−NP exchange highlighted the importance of the structure in controlling the reaction. Moreover, isotopic exchanges of the NC were also studied with the bulk metal to obtain a complete understanding of how the kinetics of atom transfer varies upon changing the size of the reacting partner from nanoscale to bulk.
TL;DR: In this paper, an assessment of physio-chemical studies were carried out in erode city and samples of groundwater were collected from different locations and water quality parameters such as pH, Electrical conductivity, Chlorides, Alkalinity, Total Hardness, TDS, Sulphates and Turbidity were analyzed.
TL;DR: In this article, a simple method whereby lattice planes in single crystals of nanoclusters can be observed using a conventional transmission electron microscope, enabling further expansion of cluster research has been presented.
TL;DR: In this paper, the authors demonstrate a sustainable, fast, and facile room temperature synthesis of plasmonic nanoparticles and luminescent nanoclusters of gold using an affordable, easy to build, and robust triboelectric generator.
Abstract: In this letter, we demonstrate a sustainable, fast, and facile room temperature synthesis of plasmonic nanoparticles and luminescent nanoclusters of gold. The synthesis was performed using an affordable, easy to build, and robust triboelectric generator (TG). The electricity generated by the TG was transferred to the solution continuously to synthesize gold nanoclusters (AuNCs). The obtained AuNCs had extremely narrow size distributions with mean particle sizes of ∼2 nm and showed bright pink luminescence under UV light. The approach was also extended to synthesize plasmonic gold nanoparticles (AuNPs). With this method, the synthesis time could be reduced from hours to several minutes without requiring any reducing agents. Tunability in size by simple variation of synthetic conditions and the consequent change in properties make this method usable for diverse applications.