Green synthesis of copper nanoparticles for the efficient removal (degradation) of dye from aqueous phase

A review of physical, chemical and biological synthesis methods of bimetallic nanoparticles and applications in sensing, water treatment, biomedicine, catalysis and hydrogen storage

This article provides an in-depth analysis of various fabrication methods of bimetallic nanoparticles (BNP), including chemical, biological, and physical techniques. The review explores BNP's diverse uses, from well-known applications such as sensing water treatment and biomedical uses to less-studied areas like breath sensing for diabetes monitoring and hydrogen storage. It cites results from over 1000 researchers worldwide and >300 peer-reviewed articles. Additionally, the article discusses current trends, actionable recommendations, and the importance of synthetic analysis for industry players looking to optimize manufacturing techniques for specific applications. The article also evaluates the pros and cons of various fabrication methods, highlighting the potential of plant extract synthesis for mass production of capped BNPs. However, it warns that this method may not be suitable for certain applications requiring ligand-free surfaces. In contrast, physical methods like laser ablation offer better control and reactivity, especially for applications where ligand-free surfaces are critical. The report underscores the environmental benefits of plant extract synthesis compared to chemical methods that use hazardous chemicals and pose risks to extraction, production, and disposal. The article emphasizes the need for life cycle assessment (LCA) articles in the literature, given the growing volume of research on nanotechnology materials. This article caters to researchers at all stages and applies to various fields applying nanomaterials.

Synthesis of Cu and CuO nanoparticles from e-waste and evaluation of their antibacterial and photocatalytic properties

Waste printed circuit boards (WPCBs) contain a plethora of valuable metals, considered an attractive secondary resource. In the current research, a hydrometallurgical process combined ammonia/ammonium chloride leaching and reduction (using L-ascorbic acid) to recover copper and its oxide (CuO) as nanosized particles from WPCBs was investigated. The results of leaching indicated that 96.7% of copper could be recovered at a temperature of 35 °C for a leaching duration of 2 h with ammonium chloride and ammonia concentration of 2 mol/L at a solid:liquid ratio of 1:10 g/cm3. The synthesized particles exhibit spherical and distorted sphere morphology with average particle size of 460 nm and 50 nm for Cu and CuO NPs, respectively. The antibacterial activity of Cu, CuO, and a (1:1) blend of both (Cu/CuO) has been examined against five different bacterial and fungal strains. The highest zone of inhibition was measured as 21.2 mm for Cu NPs toward Escherichia coli and 16.7 mm for Cu/CuO blend toward Bacillus cereus bacteria. The highest zone of inhibition was measured as 13 mm and 13.8 mm for Cu/CuO blend toward Fusarium proliferatum and Penicillium verrucosum fungi. Cu/CuO blend showed notable photocatalytic activity towards Rhodamine B dye under visible light irradiation with 96% degradation rate within 120 min. Using the process developed in this study, copper and its oxide as nanoparticles can be produced from WPCBs and used for multifunctional applications.

Enhancing Photocatalytic Efficiency of Spent Tea Leaf Powder on ZnIn2S4 Incorporation: Role of Surface Charge on Dye Degradation

Photocatalytic degradation of dye contaminants using nanocomposite adsorbents has emerged as a promising solution for wastewater treatment. Owing to its abundant availability, eco-friendly composition, biocompatibility, and strong adsorption activity, spent tea leaf (STL) powder has been extensively explored as a viable dye-adsorbent material. In this work, we report spectacular enhancement in the dye-degradation properties of STL powder on incorporation of ZnIn₂S₄ (ZIS). The STL/ZIS composite was synthesized using a novel, benign, and scalable aqueous chemical solution method. Comparative degradation and reaction kinetics studies were performed onto an anionic dye, Congo red (CR), and two cationic dyes, Methylene blue (MB) and Crystal violet (CV). The degradation efficiencies of CR, MB, and CV dyes were obtained to be 77.18, 91.29, and 85.36%, respectively, using the STL/ZIS (30%) composite sample after the 120 min experiment. The spectacular improvement in the degradation efficiency of the composite was attributed to its slower charge transfer resistance (as concluded by the EIS study) and optimized surface charge (as concluded by ζ potential study). Scavenger tests and reusability tests deciphered the active species (^•O₂^-) and reusability of the composite samples, respectively. To the best of our knowledge, this is the first report to demonstrate improvement in the degradation efficiency of STL powder on ZIS incorporation.

Toxicological assessment of Phormidium sp. derived copper oxide nanoparticles for its biomedical and environmental applications

Driven by the need to biosynthesized alternate biomedical agents to prevent and treat infection, copper oxide nanoparticles (CuONPs) have surfaced as a promising avenue. Cyanobacteria-derived synthesis of CuONPs is of substantive interest as it offers an eco-friendly, cost-effective, and biocompatible route. In the present study biosynthesized CuONPs were characterized and investigated regarding their toxicity. Morphological analysis using TEM, SEM and AFM showed the spherical particle size of 20.7 nm with 96% copper that confirmed the purity of CuONPs. Biogenic CuONPs with IC₅₀ value of 64.6 µg ml^-1 showed 90% scavenging of free radicals in superoxide radical scavenging assay. CuONPs showed enhanced anti-inflammatory activity by 86% of protein denaturation with IC₅₀ value of 89.9 µg ml^-1. Biogenic CuONPs exhibited significant toxicity against bacterial strains with lowest MIC value of 62.5 µg ml^-1 for B. cereus and fungal strain with a MIC value of 125 µg ml^-1 for C. albicans. In addition CuONPs demonstrated a high degree of synergistic interaction when combined with standard drugs. CuONPs exhibited significant cytotoxicity against non-small cell lung cancer with an IC₅₀ value of 100.8 µg ml^-1 for A549 and 88.3 µg ml^-1 for the H1299 cell line with apoptotic activities. Furthermore, biogenic CuONPs was evaluated for their photocatalytic degradation potential against methylene blue dye and were able to removed 94% dye in 90 min. Free radical scavenging analysis suggested that CuONPs assisted dye degradation was mainly induced by hydroxide radicals. Biogenic CuONPs appears as an eco-friendly and cost effective photocatalyst for the treatment of wastewater contaminated with synthetic dyes that poses threat to aquatic biota and human health. The present study highlighted the blend of biomedical and photocatalytic potential of Phormidium derived CuONPs as an attractive approach for future applications in nanomedicine and bioremediation.

Durian Shell-Mediated Simple Green Synthesis of Nanocopper against Plant Pathogenic Fungi

The synthesis of fungicides in eco-friendly and cost-effective ways is significantly essential for agriculture. Plant pathogenic fungi cause many ecological and economic issues worldwide, which must be treated with effective fungicides. Here, this study proposes the biosynthesis of fungicides, which combines copper and Cu₂O nanoparticles (Cu/Cu₂O) synthesized using durian shell (DS) extract as a reducing agent in aqueous media. Sugar and polyphenol compounds contained in DS, as the main phytochemicals acting in the reduction procedure, were extracted under different temperatures and duration conditions to obtain the highest yields. We confirmed the extraction process performed at 70 °C for 60 min to be the most effective in extracting sugar (6.1 g/L) and polyphenols (22.7 mg/L). We determined the suitable conditions for Cu/Cu₂O synthesis using a DS extract as a reducing agent for a synthesis time of 90 min, a volume ratio of DR extract/Cu²⁺ of 15:35, an initial pH solution of 10, a synthesis temperature of 70 °C, and a CuSO₄ concentration of 10 mM. The characterization results of as-prepared Cu/Cu₂O NP showed a highly crystalline structure of Cu₂O and Cu with sizes estimated in the range of 40-25 nm and 25-30 nm, respectively. Through in vitro experiments, the antifungal efficacy of Cu/Cu₂O against Corynespora cassiicola and Neoscytalidium dimidiatum was investigated by the inhibition zone. The green-synthesized Cu/Cu₂O nanocomposites, which are potential antifungals against plant pathogens, exhibited excellent antifungal efficacy against both Corynespora cassiicola (MIC = 0.25 g/L, the diameter of the inhibition zone was 22.00 ± 0.52 mm) and Neoscytalidium dimidiatum (MIC = 0.0625 g/L, the diameter of the inhibition zone was 18.00 ± 0.58 mm). Cu/Cu₂O nanocomosites prepared in this study could be a valuable suggestion for the control of plant pathogenic fungi affecting crop species globally.

Biosynthesis and chemical composition of nanomaterials in agricultural soil bioremediation: a review

Nanomaterials (NMs) are currently being used in agricultural soils as part of a new bioremediation (BR) process. In this study, we reviewed the biosynthesis of NMs, as well as their chemical composition and prospective strategies for helpful and sustainable agricultural soil bioremediation (BR). Different types of NMs, such as nanoparticles, nanocomposites, nanocrystals, nano-powders, and nanotubes, are used in agricultural soil reclamation, and they reflect the toxicity of NMs to microorganisms. Plants (Sargassum muticum, Dodonaea viscose, Aloe Vera, Rosemarinus officinalis, Azadirachta indica, Green tea, and so on) and microorganisms (Escherichia coli, Shewanella oneidensis, Pleurotus sp., Klebsiella oxytoca, Aspergillus clavatus, and so on) are the primary sources for the biosynthesis of NMs. By using the BR process, microorganisms, such as bacteria and plants, can immobilize metals and change both inorganic and organic contaminants in the soil. Combining NMs with bioremediation techniques for agricultural soil remediation will be a valuable long-term solution.

Biologically Synthesized Copper Nanoparticles Show Considerable Degradation of Reactive Red 81 Dye: An Eco-Friendly Sustainable Approach

Diospyros kaki leaf extract was used in this study as a favorable basis for the synthesis of copper nanoparticles (Cu NPs). X-ray diffraction (XRD) and UV-visible spectroscopy approaches were used to characterize the biologically synthesized copper nanoparticles. The XRD analysis showed that copper nanoparticles were face-centered cubic structure. Various experimental levels like conc. of dye, concentration of Cu NPs, pH, reaction time, and temperature were optimized to decolorize reactive red 81 dye using the synthesized Cu NPs. Reactive red 81 dye was decolorized maximum using Cu NPs of 0.005 mg/L. Additionally, reactive red 81 dye was decolorized at its maximum at pH = 6, temperature = 50°C. Our study reported that chemical oxidation demand (COD) and total organic carbon (TOC) deduction efficacies were 74.56% and 73.24%. Further degradation study of reactive red 81 dye was also carried out. Cu NPs have the ability and promising potential to decolorize and degrade reactive red 81 dye found in wastewater.

Facile fabrication of green nano pure CeO2 and Mn-decorated CeO2 with Cassia angustifolia seed extract in water refinement by optimal photodegradation kinetics of malachite green

To eradicate the aquatic pollution caused by dyes, trendily the global researchers provide dedication to dye degradation using nanostructured photocatalyst. This research work is dedicated to explore an advanced, facile, bio-compact green fabricated nanostructure for water refinement. In this regard, plant-mediated syntheses of pure CeO₂ and Mn-decorated CeO₂ nano-powders have been inspected using seed extract of Cassia angustifolia. Investigations through UV-diffuse reflectance spectroscopy explored the significantly tuned band gap of Mn:CeO₂. FT-IR spectroscopy shows the existing functional groups of high-potential phenolic compounds, proteins, and amino acids in Cassia angustifolia act as reducing and capping agents involved in the green fabricated nanostructured samples. X-ray diffraction pattern has been exposed to crystalline cubic fluorite morphology in a single phase and it leads to a regulated optimized amount of Mn on CeO₂ nanostructure. The FESEM analysis predicts the morphology of CeO₂ in spherical and Mn:CeO₂ in flower-like structure. The HRTEM analysis has portrayed particle size of CeO₂ is 11 nm and tuned Mn:CeO₂ nanostructure is 9 nm. The HRTEM images revealed the average particle size in the range 10-12 nm in CeO₂ and 8-9 nm in 5 mol% Mn:CeO₂ nanoparticles. It showed a decrease in average particle size with an increase in Mn concentration and the reduction in size may be due to the replacement of Ce(IV) with Mn(II) ions. The elemental composition in nanostructure was predicted using energy-dispersive X-ray analysis. The rapid photocatalytic degradation efficiency of malachite green was effectually performed and compared with the kinetics model of Mn:CeO₂ and pure CeO₂ nanostructures. From the augmented results, tuned Mn:CeO₂ was found to act as the finest green fabricated photocatalyst in the amputation of lethal and carcinogenic dye.

Photocatalytic, antiproliferative and antimicrobial properties of copper nanoparticles synthesized using Manilkara zapota leaf extract: A photodynamic approach

Copper nanoparticles were synthesized using Manilkara zapota leaf extract. The synthesis of the nanoparticle was primarily visualized when the colour of the reaction mixture turned into reddish-brown. Biosynthesized nanoparticles were characterized by UV-vis, FT-IR, XRD, SEM and EDX. The UV spectra showed maximum absorption at 584 nm. FT-IR studies showed stretching frequency at 592.76 cm^-1, which is the fingerprint region for Cu-O bond. The crystallinity of the synthesized copper nanoparticles (Mz-Cu NPs) was revealed through XRD analysis. The synthesized Mz-Cu NPs were spherical with an average size of 18.9-42.5 nm and it was shown by SEM analysis. EDX analysis displayed that the nano sample contains 58 % of copper. The antimicrobial property of the synthesized nanoparticles was evaluated against fungal plant pathogens Rhizoctonia solani (MTCC 12232), Sclerotium oryzae (MTCC 12230) and bacterial species, namely Bacillus subtilis (ATCC 23857), Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 25923), Vibrio harveyi (ATCC 35084), Vibrio parahaemolyticus (ATCC 33845). In in-vitro haemolytic assay, the particle showed 5.73, 3.34, 0.5 % hemolysis at 100, 50, 25 μg/mL concentration respectively. In the antiproliferative assay, the IC₅₀ values of MCF7 and Vero cells were found to be 53.89 and 883.69 μg/μl. The particle degraded Methyl violet, Malachite green and Coomassie brilliant blue by 92.2, 94.9 and 78.8 %, within 50, 40 and 60 min, respectively, through its photocatalytic activity.

Green synthesis of copper nanoparticles using Celastrus paniculatus Willd. leaf extract and their photocatalytic and antifungal properties

This research aimed to explore the eco-friendly green synthesis of copper nanoparticles (CuNPs) using Celastrus paniculatus leaves extract. Primarily, the biosynthesized CuNPs characterized by UV-vis spectroscopy showed an absorption peak at 269 nm. Further, The SEM and TEM studies revealed the spherical shape of particles with size ranged between 2-10 nm with an average particle diameter of 5 nm. FT-IR analysis confirmed the presence of functional groups -OH, C[bond, double bond]C and C-H triggers the synthesis of CuNPs. The negative zeta potential -22.2 mV indicated the stability of CuNPs was confirmed by DLS and the composition and purity by EDS studies. Further, the photocatalytic property of the CuNPs was divulged by their methylene blue dye degradation potential. The reaction kinetics followed pseudo-first-order with k-values (rate constant) 0.0172 min-1. In addition, this material was found to be a good antifungal agent against plant pathogenic fungi Fusarium oxysporum showed 76.29 ± 1.52 maximum mycelial inhibition.

Waste-to-wealth: biowaste valorization into valuable bio(nano)materials

The waste-to-wealth concept aims to promote a future sustainable lifestyle where waste valorization is seen not only for its intrinsic benefits to the environment but also to develop new technologies, livelihoods and jobs.

Novel synthesis and characterization of pristine Cu nanoparticles for the non-enzymatic glucose biosensor

Non enzymatic electrochemical glucose sensing was developed based on pristine Cu Nanopartilces (NPs)/Glassy Carbon Electrode (GCE) which can be accomplished by simple green method via ocimum tenuiflorum leaf extract. Then, the affect of leaf extract addition on improving Structural, Optical and electrochemical properties of pristine cu NPs was investigated. The synthesized Cu NPs were characterized with X-ray diffraction (X-ray), Uv-Visible spectroscopy (Uv-Vis), Fourier transformation infrared spectroscopy (FTIR), Particle size distribution (PSA), Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDS), Transmission electron microscopy (TEM) for structural optical and morphological studies respectively. The synthesized Cu NPs were coated over glassy carbon electrode (GCE) to study the electrochemical response of glucose by cyclic voltammetry and ampherometer. The results indicates that the modified biosensor shows a remarkable sensitivity (1065.21 μA mM^-1 cm^-2), rapid response time (<3s), wide linear range (1 to 7.2 mM), low detection limit (0.038 μM at S/N = 3). Therefore, the prepared Cu NPs by the Novel Bio-mediated route were exploited to construct a non-enzymatic glucose biosensor for sustainable clinical field applications.

MoS2/Cu/TiO2 nanoparticles: synthesis, characterization and effect on photocatalytic decomposition of methylene blue in water under visible light

Photodegradation processes are of great interest in a range of applications, one of which is the photodecomposition of pollutants. For this reason, analysing nanoparticles that improve the efficiency of these processes under solar radiation are very necessary. Thus, in this study, TiO₂ was doped with Mo and Cu using low-temperature hydrolysis as the method of synthesis. Pure TiO₂ and x%MoS₂/Cu/TiO₂ nanoparticles were prepared, where x is the theoretical quantity of MoS₂ added (0.0%, 1.0%, 5.5%, 10.0%), setting the nominal quantity of Cu at 0.5 wt.%. The samples obtained were characterized by X-ray diffraction, Raman spectroscopy, X-ray electron spectroscopy and UV-Vis spectroscopy in diffuse reflectance mode. The results suggest that the TiO₂ structure was doped with the Mo⁶⁺ and Cu²⁺ ions in the position of the Ti⁴⁺. The x%MoS₂/Cu/TiO₂ samples presented lower band gap energy values and greater optical absorption in the visible region than the pure TiO₂ sample. Lastly, the photocatalytic activity of the samples was assessed by means of the photodegradation of methylene blue under visible light. The results show that when the quantity of Mo in the co-doped samples increased (x%MoS₂/Cu/TiO₂) there were significant increases of up to 93% in the photocatalytic activity.

Indigenous north eastern India fern mediated fabrication of spherical silver and anisotropic gold nano structured materials and their efficacy for the abatement of perilous organic compounds from waste water-A green approach

Herein, we presented a hitherto unexplored native fern of north eastern India; Diplazium esculentum mediated biogenic fabrication of spherical silver and anisotropic gold nano structured materials.