Higher Uptake Of Copper Research Articles

Biogenic copper nanoparticles from Avicennia marina leaves: Impact on seed germination, detoxification enzymes, chlorophyll content and uptake by wheat seedlings.

Biogenic copper nanoparticles (Cu NPs) were synthesized using the aqueous crude extract of mangrove leaves, Avicennia marina (CE). GC-MS metabolite profiling of CE showed that their carbohydrates are mainly composed of D-mannose (29.21%), D-fructose, (18.51%), L-sorbose (12.91%), D-galactose (5.47%) and D-Talose (5.21%). Ultra-fine nanoparticles of 11.60 ±4.65 nm comprising Cu2O and Cu(OH)2 species were obtained with a carbohydrate and phenolic content of 35.6±3.2% and 3.13±0.05 mgGA/g, respectively. The impact of the biogenic Cu NPs on wheat seedling growth was dose-dependent. Upon treatment with 0.06 mg/mL of Cu NPs, the growth was promoted by 172.78 ± 23.11 and 215.94 ± 37.76% for wheat root and shoot, respectively. However, the lowest relative growth % of 81.94 ± 11.70 and 72.46 ± 18.78% were recorded for wheat root and shoot, respectively when applying 0.43 mg/mL of Cu NPs. At this concentration, peroxidase activity (POX) of the germinated wheat seeds also decreased, while ascorbic acid oxidase (AAO) and polyphenol oxidase (PPO) activities increased. Higher uptake of copper was observed in the root relative to the shoot implying the accumulation of the nanoparticles in the former. The uptake was also higher than that of the commercial Cu NPs, which showed an insignificant effect on the seedling growth. By treating the wheat leaves in foliar application with 0.06 mg/mL of Cu NPs, their contents of Chlorophyll a, Chlorophyll b, and total chlorophyll were enhanced after 21 days of application. Meanwhile, the high concentration (0.43 mg/mL) of Cu NPs was the most effective in reducing the leaf content of chlorophyll (a, b, and total) after the same time of application. The findings of this study manifest the potential of utilizing controlled doses of the prepared biogenic Cu NPs for inhibition or stimulation of seedling growth.

Nano zero valent iron (nZVI) particles for the removal of heavy metals (Cd2+, Cu2+ and Pb2+) from aqueous solutions.

For the past 15 years, nanoscale metallic iron (nZVI) has been investigated as a new tool for the treatment of heavy metal contaminated water. The removal mechanisms depend on the type of heavy metals and their thermodynamic properties. A metal whose redox potential is more negative or close to the reduction potential of Fe(0) is removed by the reduction process, while the others will be mediated by precipitation, complexation or other sorption processes. This review summarises our contemporary knowledge of nZVI aqueous chemistry, synthesis methods, mechanisms and actions (practical experiences) of heavy metal (Cd, Cu and Pb) removal and challenges of nZVI practical applications. Its inner core (iron(0)) has reducing ability towards pollutants, while the iron oxide (FeO) outer shell provides reaction sites for chemisorption and electrostatic interactions with heavy metals. Emerging studies highlighted that nZVI surfaces will have negatively charged species at higher pH and have good affinity for the removal of positively charged species such as heavy metals. Different sizes, shapes and properties of nZVI have been produced using various methods. Ferric salt reduction methods are the most common methods to produce stable and fine graded nZVI. Higher uptake of copper(ii), lead(ii) and cadmium(ii) has also been reported by various scholars. Practical pilot tests have been conducted to remove heavy metals, which gave highly satisfactory results. Challenges such as agglomeration, sedimentation, magnetic susceptibility, sorption to other fine materials in aqueous solution and toxicity of microbiomes have been reported. Emerging studies have highlighted the prospects of industrial level application of nano zero valent particles for the remediation of heavy metals and other pollutants from various industries.

Integrated Metabolomic and Proteomic Approaches Dissect the Effect of Metal-Resistant Bacteria on Maize Biomass and Copper Uptake

Marginal soils arise due to various industrial and agricultural practices reducing crop productivity. Pseudomonas sp. TLC 6-6.5-4 is a free-living multiple-metal-resistant plant-growth-promoting bacteria (PGPB) isolated from Torch Lake sediment that promotes maize growth and nutrient uptake. In this study, we examined both PGPB-soil and PGPB-plant interactions. PGPB inoculation resulted in significant increase in maize biomass. Soil inoculation before sowing seeds and coating seeds with the PGPB resulted in higher copper uptake by maize compared to other methods. The PGPB-soil interaction improved phosphorus uptake by maize and led to significant decrease in organic bound copper in marginal soil and a notable increase in exchangeable copper. PGPB improved soil health based on soil enzyme activities. Metabolomic analysis of maize revealed that PGPB inoculation upregulated photosynthesis, hormone biosynthesis, and tricarboxylic acid cycle metabolites. Proteomic analysis identified upregulation of proteins related to plant development and stress response. Further, the activity of antioxidant enzymes and total phenolics decreased in plants grown in marginal soil suggesting alleviation of metal stress in presence of PGPB. The ability of PGPB to modulate interconnected biochemical pathways could be exploited to increase crop productivity in marginal soils, phytoremediation of metal contaminated soils, and organic agriculture.

Interaction between copper and radiocesium in Indian mustard and sunflower grown in the hydroponic solution

Both Indian mustard and sunflower were grown in a hydroponic solution treated with different concentration activities of 134Cs or with different amounts of copper or with both in order to investigate the interaction between copper and radiocesium. It was found that 134Cs activity concentration applied in the nutrient solution exerted more influence on the uptake and translocation of copper by Indian mustard than by sunflower. Indian mustard grown in hydroponic solution containing certain levels of copper and being treated with higher 134Cs activity concentration showed higher uptake of copper than sunflower. However, in the case of root copper concentrations, sunflower showed significantly higher copper immobilization by roots than Indian mustard. It was also found that the presence of copper in the hydroponic solution did modify radiocesium uptake by both species. The application of 1 mg/l in the growth medium could greatly increase the uptake of 134Cs by both species. With 3 mg/l concentration of copper amended to the solution, the accumulation of 134Cs by both species was decreased compared to the 1 mg/l copper treatment. These lines of evidence show that there is stronger interaction between copper and radiocesium in Indian mustard than in sunflower during the root uptake through nutrient solution.

Surface and Texture Characterization of Alumina-Supported Copper and Mixed Copper–Manganese Oxide Catalysts and Their Formate Precursors

Alumina-supported copper and copper–manganese oxide catalysts as well as the parent formates were characterized by means of FTIR spectroscopy in situ and nitrogen physisorption. The IR spectroscopic results are discussed on the basis of the deposition scheme proposed recently by Kapteijn et al. (J. Catal.150, 94 (1994). The infrared bands in the high-frequency region (OH stretches) indicate that the aqueous copper species formed in the solutions are deposited on the basic and neutral surface OH groups, while as our previous studies show the aqueous manganese species are deposited on the basic and acidic OH groups. However, the aqueous manganese species are deposited on the basic and neutral OH groups in the presence of copper ions (pH 4.6–4.7). The deposition of the aqueous metal species on the protonated basic OH groups occurs as a result of the “ion-pairing” process. The driving forces resulting in the deposition of the aqueous metal species on the neutral OH groups are considered to be hydrogen bonds. The deposition of the formate ions is also discussed. The higher uptake of copper as compared to manganese is discussed in terms of the metal ion properties (electronic configuration, the ability to form hydrogen bonds of different strength, metal species–support interaction). The nitrogen physisorption shows that the initial mesoporous character of γ-Al2O3 structure does not change during impregnation. The rFHH values which characterized the adsorbent–adsorbate interaction forces are calculated. The comparative analysis of the pore size distribution curves of the oxide-supported samples and their parent formates proves to be a useful tool to elucidate the metal species–support interaction strength.

Surface functional groups on acid-activated nutshell carbons

Nutshells from agriculturally important nut crops (almond, black walnut, English walnut, macadamia nut and pecan) were converted to granular activated carbon using phosphoric acid activation in nitrogen or air. Surface functional groups (carbonyl, phenols, lactones, carboxyl) were quantified by titration with bases of different ionization potential. The degree of copper uptake was correlated with the presence of various functional groups on these carbons. The results indicate that acid-activation strategies which provide the greatest contact of nutshells with air during carbonization and activation also have the greatest quantity of surface functional groups and the highest copper uptake. Also, the type of nutshell used for activated carbon production has little effect on the types of surface functional groups produced and subsequent copper adsorption. This study demonstrates that a judicious choice of activation strategy for nutshell precursors can produce activated carbons with numerous surface functional groups and high copper adsorption activity.

Synergistic physiological effects of low copper and various oxygen concentrations on Macoma balthica

The negative effects of copper on Macoma balthica are significantly increased when this bivalve is simultaneously exposed to low oxygen concentrations. This might be explained by the fact that low oxygen concentrations (oxygen deficiency) are combined with a slightly lower pH and thus with a different copper speciation, resulting in a higher bio-availability of copper and, consequently, in a higher copper uptake by M. balthica. Symptomatic for the increased negative effects of copper on M. balthica at low oxygen concentrations is an increased oxygen demand, which in turn reflects an increased consumption of energy. Consequently, at low oxygen levels, low copper concentrations (8–15 μg dm-3) greatly affect the glycogen content of the tissues, and finally (at 15 μg Cu dm-3) result in a heavy loss of dry weight and a drastic reduction of the adenylate energy charge (AEC). Generally, it might be concluded that dry weight, glycogen content and AEC are more affected by a combination of oxygen deficiency and a low copper concentration (2.5 cm3 O2 dm-3, 15 μg Cu dm-3) than by higher copper concentrations (up to 86 μg dm-3) at high oxygen levels (5.0 cm3 dm-3).

The comparison of soy-bean wastes, used tea-leaves and sewage sludge for growing Chlorella pyrenoidosa

Aqueous extracts of sewage sludge, used tea-leaves and soy-bean residues have been used as culture media for the cultivation of a unicellular green alga, Chlorella pyrenoidosa. Bristol medium was employed as a control medium for comparison. A preliminary experiment was conducted to search for the most suitable concentration of each culture medium for the growth of C. pyrenoidosa. The following concentrations of the waste materials were chosen for the subsequent cultivation: sludge, 2%; used tea-leaves, 1% and soy-bean residue, 2%. It was discovered that 2% soy-bean residue extract produced the highest growth rate, followed by 2% sludge and Bristol medium, with the used tea-leaves producing the lowest. The cells of C. pyrenoidosa cultivated in sludge extract had a higher uptake of copper, manganese and iron than those cultivated in other media. It was also demonstrated that the acidic condition of the used tea-leaves and the relatively high concentration of copper and lead at the higher concentration of sludge extract (3%) inhibited the growth of C. pyrenoidosa.