Green Synthesis Route Research Articles

Green Colloidal Synthesis of MoS2 Nanoflakes.

Currently, two approaches dominate the large-scale production of MoS2: liquid-phase exfoliation, referred to as the top-down approach, and bottom-up colloidal synthesis from molecular precursors. Known colloidal synthesis approaches utilize toxic precursors. Here, an alternative green route for the bottom-up synthesis of MoS2 nanoflakes (NFs) is described. The NFs were synthesized by colloidal synthesis using [Mo(CH3COO)2]2 and a series of sulfur (S)-precursors including thioacetamide (TAA), 3-mercaptopropionic acid (3-MPA), l-cysteine (L-CYS), mercaptosuccinic acid (MSA), 11-mercaptoundecanoic acid (MUA), 1-dodecanethiol (DDTH), and di-tert-butyl disulfide (DTBD). While TAA, an S-precursor most commonly used for MoS2 NF preparation, is a known carcinogen, the other investigated S-precursors have low or no known toxicity. High-resolution scanning transmission electron microscopy (HR-STEM) and grazing incidence wide-angle X-ray scattering (GIWAXS) confirmed that in all cases, the syntheses yielded single-layer MoS2 NFs with lateral sizes smaller than 15 nm and a well-defined crystal structure. Electronic absorption and Raman spectra showed characteristic features associated with the MoS2 monolayers. The evolution of the absorption spectra of the growth solution during the syntheses reveals how the kinetics of the NF formation is affected by the S-precursor as well as the nature of the coordinating ligands.

Biogenic one-step synthesis of silver nanoparticles using Quisqualis indica linn flower extract: Characterization, molecular docking, and DFT studies

The present study reports a one-step, eco-friendly, and green synthesis route of silver nanoparticles (AgNPs) from the flower extract of Quisqualis indica Linn. Analytical techniques like Ultraviole-visible (UV–Vis), Field emission scanning electron microscope (FESEM), and X-ray diffraction (XRD) were used to investigate different physicochemical characteristics of AgNPs. The UV–Vis spectrum revealed the maximum absorption at 455 nm and FESEM images confirmed that the synthesis produces stable, polydisperse with a spherical, rod-shaped, triangular, and hexagon shape. XRD analysis at 2θ degrees of 38.1o, 44.3o, 64.7o, and 77.7o corresponding to the (111), (200), (220), and (311) planes, respectively, Bragg’s reflections of the face-centered cubic crystalline structure. Fourier transform infrared spectroscopy (FTIR) analysis suggested that the carbonyl and alcoholic groups of the different compounds of the extract of Quisqualis indica Linn flowers were majorly responsible for being the stabilizer and a capping agent of AgNPs. Furthermore, the quantum chemical parameters of β-Sitosterol (1), Brinzolamide (2), Gallic Acid (3), L-Asparagine (4), L-Proline (5), Quisqualic Acid (6), Quinoline-4-Carbonitrile (7), Quercetin (8), and Rutin (9) compounds present in the flowers of Quisqualis indica Linn are also calculated based on density functional theory (DFT). In silico study, a method such as molecular docking was carried out to determine the binding affinity of compounds (1–9) with presentations of Gram-positive bacteria (PDB ID: 2MLM) and Gram-negative bacteria (PDB ID-1KZN). Compounds (1), (2), (7) and (8) had a better score of binding toward the selected proteins. Overall, our findings shed light on the green synthesis of silver nanoparticles and it could be a potential candidate for the pharmaceutical industry against topical pathogens.

Microwave energized preparation and electrochemical performance of Ag added NiO/CeO2ternary nanocomposites for energy storage applications

Noble metal incorporated nanocomposites are extensively useful in supercapacitor applications owing to the nature of higher specific capacity and good rate capability. We have prepared Ag added NiO/CeO2 ternary mixed oxides through green synthesis route. The influence of Ag concentration on the structural, morphological and electrochemical characteristics of NiO/CeO2 has been examined and reported. The microstructure analysis reveals that the ternary mixed oxides to consist of Ag nanoclusters, CeO2 rods and NiO flakes. The formation of ternary mixed oxides has promoted the diffusion rate of electrolyte ions resulting in superior electrochemical performance. A maximum capacity of 639 C g–1 was obtained at a current density of 2 mA cm–2 for the ternary nanocomposites containing 9 mol% of silver. Moreover, the incorporation of substantial amount of Ag has effectively improved the lifespan and reduced charge transfer resistance. The findings of the present study strongly indicate that the Ag incorporated NiO/CeO2 is a suitable candidate for supercapacitor electrode fabrication.

Antibacterial Activity of Green Synthesized Silver Nanoparticle using Banana Flower Extract

In recent years, due to unique physical and chemical properties of nanoparticles, its uses to disrupt biofilm of bacteria are revolutionary steps in antimicrobial research. To use in bioprocess the silver nanoparticles should be biocompatible and free from toxic chemicals. In the present study we report a cost effective and environment friendly route for green synthesis of silver nanoparticles using banana flower extract (BFE) as reducing as well as capping agent. This plant has been opted for the present study for its known medicinal properties and it is easily available. The biosynthesized silver nanoparticles are characterized by UV–Vis spectroscopy which showed a broad peak at around 450 nm, indicated the stability of synthesized silver nanoparticles. Antimicrobial potential of silver nanoparticles synthesized were tested against both Gram positive and Gram-negative bacteria. It was found to be effective against both of them and it showed maximum activity against Gram positive bacteria S. aureus. Silver nanoparticles (AgNPs) have been imposed as an excellent antimicrobial agent being able to combat bacteria in vitro and in vivo causing infections. The results show green synthesized silver nanoparticles, using BFE extract, have a potential to inhibit the growth of bacteria.

Polymer based on beta-cyclodextrin for the removal of bisphenol A, methylene blue and lead(II): Preparation, characterization, and investigation of adsorption capacity

A bioadsorbent was prepared by applying a green facile synthesis route, using water as solvent and beta-cyclodextrin (βCD), citric acid (CA), and polyethylene glycol (PEG) as raw materials. The synthesis parameters were optimized, and the prepared βCD-CA-PEG polymer was thoroughly characterized. With FT-IR analysis, the formation of the new polymeric structure based on a network with ester bonds between βCD, PEG, and citric acid was detected. The increase in thermal stability revealed by the TGA analysis confirmed further the polymerization. The XRD and SEM analyses demonstrated that the original structure of βCD was changed, and a new amorphous structure was formed. The results of the SEM and BET analyses showed that the polymer has relatively low surface area and porosity. The zeta potential study revealed that the polymer has a negative surface charge at a pH range of 3–10. The swelling test showed moderate water uptake, suggesting good hydrophilicity and flexibility of the polymer’s network, thus enhancing the interaction with pollutants’ molecules. Regarding the adsorption performance of the βCD-CA-PEG polymer, bisphenol A (BPA), methylene blue (MB), and lead (Pb(II)) were rapidly and efficiently removed from aqueous solutions. The adsorption processes followed the pseudo-second-order kinetic model for all pollutants in both mono-pollutant and multi-pollutant systems. Furthermore, BPA and Pb(II) adsorption equilibrium data were well simulated by the Langmuir model, while MB adsorption fitted well to the Sips model. The presence of natural organic matter (humic acid) or the increased ionic strength (addition of NaCl) did not significantly impact the adsorption capacity. Finally, the polymer could be easily regenerated at room temperature and retained its good adsorption performance even after five adsorption–desorption cycles. The prepared βCD-CA-PEG polymer can pose an efficient alternative adsorptive in water and wastewater treatment targeting several pollutant categories, including specific organic micropollutants, cationic dyes and heavy metals.

Electrochemical performance of ZnMgO photoanodes prepared by a green synthesis route

Electrochemical performance of ZnMgO photoanodes prepared by a green synthesis route

Engineering Radioactive Microspheres for Intra‐Arterial Brachytherapy Using Radiation‐Induced Graft Polymerization

AbstractIntravascular brachytherapy requires advances in radio‐embolization technologies that combine brilliant radiostability efficacy with a facile and green synthesis route. A hybrid‐integrated radioactive microsphere strategy using phosphorylcholine‐modified lutetium‐177 coordinated polymeric microspheres (177Lu‐PCMs) is reported that are fabricated via radiation‐induced graft polymerization for imaging‐guided locoregional intravascular brachytherapy. The underlying formation mechanism of 177Lu‐PCMs is elucidated using first‐principles computations and density functional theory calculations, and 177Lu loading mechanisms are investigated with Near‐edge and extended X‐ray absorption fine structure spectroscopy. The engineered 177Lu‐PCMs exhibit excellent mechanical properties, good hydrophilicity, and controlled sphere diameter. These features provide advantages of ultra‐stable embolic radio‐theranostics, which is demonstrated in different preclinical rodent models and isolated human liver tumor tissues. During locoregional intra‐arterial brachytherapy, 177Lu‐PCMs can be visualized via SPECT to validate the in vivo biodistribution and retention in real time, achieving precise delivery, effective anti‐cancer treatment, and a distinguished safety profile without degradation, ectopic embolization, and adverse reactions. Therefore, this study offer a new avenue for the development of a highly innovative and translational approach for precision intra‐arterial brachytherapy.

A Green Synthesis Route to Derive Carbon Quantum Dots for Bioimaging Cancer Cells.

Carbon quantum dots (CQDs) are known for their biocompatibility and versatile applications in the biomedical sector. These CQDs retain high solubility, robust chemical inertness, facile modification, and good resistance to photobleaching, which makes them ideal for cell bioimaging. Many fabrication processes produce CQDs, but most require expensive equipment, toxic chemicals, and a long processing time. This study developed a facile and rapid toasting method to prepare CQDs using various slices of bread as precursors without any additional chemicals. This fast and cost-effective toasting method could produce CQDs within 2 h, compared with the 10 h process in the commonly used hydrothermal method. The CQDs derived from the toasting method could be used to bioimage two types of colon cancer cells, namely, CT-26 and HT-29, derived from mice and humans, respectively. Significantly, these CQDs from the rapid toasting method produced equally bright images as CQDs derived from the hydrothermal method.

Biosorption of Escherichia coli Using ZnO-Trimethyl Chitosan Nanocomposite Hydrogel Formed by the Green Synthesis Route.

In this study, we tested the biosorption capacity of trimethyl chitosan (TMC)-ZnO nanocomposite (NC) for the adsorptive removal of Escherichia coli (E. coli) in aqueous suspension. For the formation of ZnO NPs, we followed the green synthesis route involving Terminalia mantaly (TM) aqueous leaf extract as a reducing agent, and the formed ZnO particles were surface-coated with TMC biopolymer. On testing of the physicochemical characteristics, the TM@ZnO/TMC (NC) hydrogel showed a random spherical morphology with an average size of 31.8 ± 2.6 nm and a crystal size of 28.0 ± 7.7 nm. The zeta potential of the composite was measured to be 23.5 mV with a BET surface area of 3.01 m2 g-1. The spectral profiles of TM@ZnO/TMC NC hydrogel on interaction with Escherichia coli (E. coli) revealed some conformational changes to the functional groups assigned to the stretching vibrations of N-H, C-O-C, C-O ring, and C=O bonds. The adsorption kinetics of TM@ZnO/TMC NC hydrogel revealed the pseudo-second-order as the best fit mechanism for the E. coli biosorption. The surface homogeneity and monolayer adsorption of the TM@ZnO/TMC NC hydrogel reflects majorly the entire adsorption mechanism, observed to display the highest correlation for Jovanovic, Redlich-Peterson, and Langmuir's isotherm models. Further, with the use of TM@ZnO/TMC NC hydrogel, we measured the highest adsorption capacity of E. coli to be 4.90 × 10 mg g-1, where an in-depth mechanistic pathway was proposed by making use of the FTIR analysis.

An economical green route synthesis of carbon spheres derived from kitchen biowastes for supercapacitor application

An economical green route synthesis of carbon spheres derived from kitchen biowastes for supercapacitor application

Sustainable and Green Synthesis of Carbon Nanofibers from Date Palm Residues and Their Adsorption Efficiency for Eosin Dye

This work investigates the prospective usage of dried date palm residues for eosin Y and eosin B (ES-Y and ES-B) dye removal from an aqueous solution. A green synthesis route is utilized to prepare carbon nanofibers (CNFs) from date palm residues. We study the characteristics of carbon nanomaterials based on their composition and morphology. The characterization includes different types of instruments such as a Fourier-Transform Infrared Spectroscopy (FTIR), Brunauer Emmett Teller (BET), and Scanning Electron Microscopy (SEM). Batch mode experimentations are conducted and studied utilizing various significant factors such as the dose of the adsorbent, solution pH, contact time, and the initial quantity of eosin molecules as a pollutant. The dye adsorption capability improves with an increasing adsorbent dose of up to 40 mg of CNFs. The adsorption of dyes onto CNFs achieves equilibrium in around 60 h, whereas the optimal starting dye concentration in this study is 50 ppm. Further, to study the under-investigated toxic molecules’ adsorption process mechanism on the nanomaterials’ active sites, we introduce kinetic models involving pseudo-first-order, pseudo-second-order, and models based on intra-particle diffusion. Langmuir and Freundlich’s isotherms are considered to study the equilibrium isotherms, and the Langmuir isotherm model deals considerably with the attained experimentation results.

Green synthesis routes for spinel ferrite nanoparticles: a short review on the recent trends

Green synthesis routes for spinel ferrite nanoparticles: a short review on the recent trends

Facile synthesis of carbon layered TiO2 nanocomposite for high photocatalytic activity

A green synthesis route was designed to develop a visible-light-driven thin carbon layered titanium dioxide (CLT) nanocomposite using ascorbic acid as carbon precursor. The presence of a thin layer of carbon (CLT) on the TiO2 surface was observed from HR-TEM. The thickness of CLT is directly proportional to the concentration of carbon precursor, where this CLT acts a photosensitizer for harvesting the broad band of visible light spectrum. CLT nanocomposite (15.485 m2/g) showed an improved surface area of 1.4 times that of a commercial TiO2 (7.461 m2/g). The photocatalytic activity of CLT nanocomposite was investigated for the volatile organic compound destruction using p-xylene pollutant in a standard ISO photocatalytic oxidation reactor under daylight. The mechanism pathway of CLT nanocomposite was followed by the adsorption of chemical contaminants in the pores of CLT that precisely capture the contaminants capture and destruction on its surface. The electron-hole pair recombination rate of CLT nanocomposite was lower than the pristine TiO2 was evident from photoluminescence spectra. The antibacterial activity of CLT was also studied using E. coli as a model pathogen. This environmentally friendly photocatalyst CLT offers a novel route for good industrial utilization because of its low cost and mass production.

Layered Magnesium Phosphate as an Environmentally Friendly Solid Lubrication Additive: Morphology Control and Tribological Properties

To develop a new type of environmentally friendly solid lubricant and expand the high-value utilization of salt lake resources, we prepared a layered magnesium phosphate (MgHPO4·1.2H2O) eco-friendly lubricant using an improved green hydrothermal synthesis route in which particle size and morphology were controlled. The tribological properties of the layered magnesium phosphate samples as additives in PAO8 calcium-based grease were evaluated using an Optimol SRV-V oscillating reciprocating tester (hereafter referred to as SRV tester). Products exhibited excellent friction behavior when added to grease. When added at 3.0 wt %, the tribological properties of the grease were improved significantly; the highest operating load was raised from 400 to 600 N, the wear volume was decreased from 44.98 to 7.50 (10–4 mm3), and friction curves became more stable and smooth. A possible lubricating mechanism was proposed. Macro to micro analysis of rubbing surfaces showed that the MgP materials had a protective effect on the PAO8 calcium-based grease matrix, and lubricating films were clearly formed on the friction pair surface.

Grüne, wasserbasierte, und skalierbare Synthesen von porösen Salzen mit kationischen Al24‐Hydroxid‐Acetat‐Clustern

AbstractDie Chemie von Al3+‐Ionen in wässriger Lösung ist sehr komplex und führte bereits zu verschiedenen Polyoxokationen. In diesem Artikel wird die einfache Synthese von porösen Salzen der Zusammensetzung [Al24(OH)56(CH3COO)12]X4 (CAU‐55‐X, mit X=Cl−, Br−, I−, HSO4−) beschrieben, welche einen kationischen Al24‐Cluster enthalten. Die Kristallstrukturen wurden aus Elektronenbeugungsdaten bestimmt. Verschiedene Synthesewege wurden für das Chloridsalz [Al24(OH)56(CH3COO)12]Cl4 in Wasser entwickelt, die innerhalb von Minuten zu hohen Ausbeuten (>95 %, und bis zu 215 g pro Ansatz) führten. Die Verbindungen weisen spezifische Oberflächen und H2O‐Kapazitäten mit Maximalwerten von bis zu 930 m2 g−1 bzw. 430 mg g−1 auf. Die Partikelgröße von CAU‐55‐X kann zwischen 140 nm und 1250 nm eingestellt werden, wodurch die Herstellung stabiler Dispersionen oder hochkristalliner Pulver möglich ist. Die positive Oberflächenladung der Partikel ermöglicht eine schnelle und effektive Adsorption anionischer Farbstoffmoleküle und die Adsorption von per‐ und polyfluorierten Alkylverbindungen (PFAS).

Porous Salts Containing Cationic Al24 -Hydroxide-Acetate Clusters from Scalable, Green and Aqueous Synthesis Routes.

The solution chemistry of aluminum is highly complex and various polyoxocations are known. Here we report on the facile synthesis of a cationic Al24 cluster that forms porous salts of composition [Al24 (OH)56 (CH3 COO)12 ]X4 , denoted CAU-55-X, with X=Cl- , Br- , I- , HSO4 - . Three-dimensional electron diffraction was employed to determine the crystal structures. Various robust and mild synthesis routes for the chloride salt [Al24 (OH)56 (CH3 COO)12 ]Cl4 in water were established resulting in high yields (>95 %, 215 g per batch) within minutes. Specific surface areas and H2 O capacities with maximum values of up to 930 m2 g-1 and 430 mg g-1 are observed. The particle size of CAU-55-X can be tuned between 140 nm and 1250 nm, permitting its synthesis as stable dispersions or as highly crystalline powders. The positive surface charge of the particles, allow fast and effective adsorption of anionic dye molecules and adsorption of poly- and perfluoroalkyl substances (PFAS).

An integrated life cycle assessment and techno-economic analysis: Evaluation on the production of polymers of intrinsic microporosity (PIM-1) and UiO-66-NH2 as membrane materials

Material synthesis requires an enormous amount of organic solvents which leads to huge environmental burdens. Being so, the necessity to utilize non-toxic chemicals is of growing interest in the global market. Harnessing a green fabrication strategy could be a sustainable remedy. Herein, life cycle assessment (LCA) and techno-economic assessment (TEA) using a cradle-to-gate approach to select the green synthesis route for the production of main components in mixed matrix membranes such as polymer and fillers were studied. Five representative synthesis routes of polymers of intrinsic microporosity (PIM-1) and fillers such as UiO-66-NH2 (UiO: University of Oslo) were conducted. Our findings revealed that the tetrachloroterephthalonitrile (TCTPN) synthesized PIM-1 using a novel approach (e.g., P5-Novel synthesis) and solvent-free synthesized UiO-66-NH2 (e.g., U5-Solvent-free) demonstrated the least environmental impact and are most economically feasible. The environmental burden and cost of PIM-1 synthesized by P5-Novel synthesis route decreased by 50 % and 15 %, respectively, while that of UiO-66-NH2 produced via U5-Solvent-free route reduced by 89 % and 52 %, respectively. Additionally, solvent reduction was found to have an apparent effect on cost-saving, whereby the production cost declined 13 % with a 30 % solvent reduction. Alleviation of environmental burdens could also be found through recovering solvents or substituting with a greener alternative (e.g., water). The fundamentals gained on the environmental impacts and economic feasibility of PIM-1 and UiO-66-NH2 production from this LCA-TEA study may provide a preliminary evaluation for the development of green and sustainable materials.

Biogenic synthesis of copper oxide (CuO) NPs exploiting Averrhoa carambola leaf extract and its potential antibacterial activity

Herein, we report our assiduous endeavor to meet one of the demands of 21st century, the green route of synthesis, for copper (II) oxide nanoparticles (CuO NPs) using Averrhoa carambola leaf extract for the first time. The synthesized CuO NPs was characterized by XRD, XPS, FESEM, FTIR, DLS, zeta (ζ)-potential and UV–Vis spectroscopic techniques. XRD revealed the monoclinic crystalline phase of the CuO NPs with crystallite size of 24.84 nm. XPS confirmed the surface elemental composition and Cu2+ oxidation state of CuO NPs. The formation of NPs was confirmed by the surface plasmon resonance (SPR) spectra based on the sharp absorption at 220 nm. FESEM images showed assorted shapes albeit spherical shapes were the dominant ones. The calculative particle size based on the FESEM images was 98 ± 26 nm whereas DLS analysis showed larger particle size (117 nm) because of hydro-dynamic volume. Zeta-potential of the synthesized CuO NPs was found to be −13.65 mV at neutral pH. FTIR analysis confirmed the presence of metal-oxide (Cu–O) bond. The synthesized CuO NPs were exploited as an antibacterial agent against 2 gram positive (Bacillus megaterium and Staphylococcus aureus) and 3 gram negative bacteria (Escherichia coli, Salmonella typhi and Pseudomonas aeruginosa). Salmonella typhi and Escherichia coli were found to be highly vulnerable to CuO NPs with the highest zone of inhibition of 26 mm and 24 mm respectively. Bio-resource based green synthesized CuO can be a potential candidate in the array of nanomedicine considering its fascinating activity against broad spectrum bacterial strains.

Facile synthesis of novel Z-scheme GO-modified ternary composite as photocatalyst for enhanced degradation of bisphenol-A under sunlight

BackgroundPhotocatalytic degradation using sunlight as a light source has attracted increasing attention because of low operating cost, high degradation efficiency, and environmental friendliness. Metal oxide decorated graphene oxide-based composites as Z-scheme photocatalysts are highly efficient in degrading bisphenol-A (BPA), but such studies are scarce. MethodsThis work employed a facile and green synthesis route for Z-scheme GO-modified ternary composite (ZnO/GO/Mn2O3) photocatalyst. FTIR, FESEM, RAMAN spectra, EDX, BET, XRD, UV–Vis DRS, and PL spectra characterized the synthesized materials. Significant findingsThe results indicate that the catalyst's bandgap energy and surface area were 1.69 eV and 75.35 m2/g. The synthesized ZnO/GO/Mn2O3 composite degrade BPA under sunlight irradiation and completely degraded within 20 min reaction time, pH 7, and using 10 mg/100 mL catalyst dosage. Free radical capturing experiments established that the dominant reactive species for degradation were •O2− and h+ having 95.16 and 91.23% degradation efficiency. The kinetic study show that the pseudo-first-order best presents the kinetic model, and the rate constant (0.201 min−1) was 22.22, 14.28, and 4.08 times higher than Mn2O3, GO, and ZnO/GO, respectively. The enhanced catalytic activity occurred due to the development of an efficient Z-scheme heterojunction, which facilitates the separation of charge carriers, thereby increasing the number of reactive species in the solution. The recycling experiments showed only 10.85% degradation was reduced after five consecutive cycles. Finally, a plausible BPA degradation mechanism was proposed.

Two-dimensional Pd-Cellulose with optimized morphology for the effective solar to steam generation

Nanosized plasmonic metallic nanoparticles such as Pd have gained significant attention due to their diverse applications in catalysis, sensing, and light-to-heat conversion. However, the development of scalable and environmentally friendly synthesis routes for such nanoparticles is crucial for the sustainable development of industrial applications. In this work, we address this challenge by synthesizing Pd-nanoparticles on the cellulose filter paper (Pd-Cellulose) via two scalable green synthesis routes: low-temperature thermal and plasma synthesis. We found that adjusting synthesis conditions allowed us to achieve an optimum morphology that maximizes light absorptance. The nature of the reduction species during synthesis significantly impacts the morphology and heat-transfer properties of the resulting material. Compared to thermally synthesized Pd-Cellulose, the absorbers synthesized with plasma have smaller particles size and higher coverage, which leads to higher broadband light absorptance and more intense heat transfer to the surroundings. The optimized Pd-based light absorbers were utilized in a solar-to-steam desalination system, resulting in an evaporation rate of 1.30 kg/m2h for the open system and a filtration rate of 0.7 kg/m2h for the closed system. Our findings provide insights into the green and scalable synthesis and optimization of Pd-based light absorbers and their potential application in sustainable renewable energy systems.