Influence of Wooden Sawdust Treatments on Cu(II) and Zn(II) Removal from Water

Organic waste materials and semi-products containing cellulose are used as low-cost adsorbents that are able to compete with conventional sorbents. In addition, their capacity to bind heavy metal ions can be intensified by chemical treatments using mineral and organic acids, bases, oxidizing agents, and organic compounds. In this paper, we studied the biosorption capacity of natural and modified wooden sawdust of poplar, cherry, spruce, and hornbeam in order to remove heavy metals from acidic model solutions. The Fourier transform infrared spectroscopy (FTIR) spectra showed changes of the functional groups due to the alkaline modification of sawdust, which manifested in the considerably increased intensity of the hydroxyl peaks. The adsorption isotherm models clearly indicated that the adsorptive behavior of metal ions in treated sawdust satisfied not only the Langmuir model, but also the Freundlich model. The adsorption data obtained for studied sorbents were better fitted by the Langmuir isotherm model for both metals, except for spruce sawdust. Surface complexation and ion exchange are the major mechanisms involved in metal ion removal. We investigated the efficiency of the alkaline modified sawdust for metal removal under various initial concentrations of Cu(II) and Zn(II) from model solutions. The highest adsorption efficiency values (copper 94.3% at pH 6.8 and zinc 98.2% at pH 7.3) were obtained for poplar modified by KOH. For all types of sawdust, we found that the sorption efficiency of modified sorbents was higher in comparison to untreated sawdust. The value of the pH initially increased more in the case of modified sawdust (8.2 for zinc removal with spruce NaOH) and then slowly decreased (7.0 for Zn(II) with spruce NaOH).This research was funded by Scientific Grant Agency of the Ministry of Education, Science, Research, and Sport of the Slovak Republic and the Slovak Academy of Sciences, grant number 1/0419/19 and grant number 1/0326/18

Synthesis of Gold Nanoparticles by Blue-Green Algae Spirulina Platensis

The synthesis of gold nanoparticles by one of the many popular microorganisms – blue-green algae Spirulina platensis was studied. The complex of optical and analytical methods was applied for investigation of experimental samples after exposure to chloroaurate (HAuCl4) solution at different doses and for different time intervals. To characterize formed gold nanoparticles UV-vis Spectrometry, Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Energy-dispersive analysis of X-rays (EDAX) were used. It was shown that after 1.5 – 2 days of exposure the extracellular formation of nanoparticles of spherical form and the distribution peak within the interval of 20-30 nm took place. To determine gold concentrations in the Spirulina platensis biomass neutron activation analysis (NAA) was applied. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3496

Microbial synthesis of silver nanoparticles by streptomyces glaucus and spirulina platensis

Microbial synthesis of nanoparticles has a potential to develop simple, costeffective and eco-friendly methods for production of technologically important materials. In this study, for the first time a novelactinomycete strain Streptomyces glaucus71 MD isolated from a soy rhizosphere in Georgiais for the first time extensively characterized and utilized for the synthesis of silver nanoparticles. Scanning Electron Microscope (SEM) allowed observing extracellular synthesis of nanoparticles, which has many advantages from the point of view of applications. Production of silver nanoparticles proceeded extracellularlywith the participation of another microorganism, bluegreen microalgae Spirulinaplatensis (S. platensis). In this study it is shown that the production rate of the nanoparticles depends not only on the initial concentration of AgNO3 but also varies with time in a nonmonotonic way. SEM study of silver nanoparticles remaining on the surface of microalgae revealed that after 1 day of exposure to 1 mM AgNO3 nanoparticles were arranged as long aggregates along S. platensiscells strongly damaged by silver ions. However, after 5 days of exposure to silver S. platensiscells looked completely recovered and the nanoparticles were distributed more uniformly on the surface of the cells. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2067

Tough Sprouting – Impact of Cadmium on Physiological State and Germination Rate of Soybean Seeds

Seed germination is the earliest process in plant development and is crucial for further plant growth and fitness. The process is regulated by various internal and external factors, including soil pollutants such as nonessential metals. In the present study, we examined in detail the impact of short-term imbibition in Cd solutions at several concentrations (5, 10, and 25 mg/L) on germination rate and physiological state of soybean seeds. The results showed that although Cd was readily absorbed by the seeds, the metal had no effect on seeds cell viability, oxidative stress intensity, or germination percentage. In contrast, imbibition in Cd solution led to slight reduction in antioxidant capacity of seeds. Seedlings grown from seeds pretreated with metal showed no differences in growth in relation to the control. Taken together, the results indicate that soybean seeds are relatively tolerant even to high Cd concentration (up to 25 mg/L)

Comparison of non-destructive techniques and conventionally used spectrometric techniques for determination of elements in plant samples (coniferous leaves)

Conventionally used spectrometric techniques of inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma optical emission spectrometry (ICP-MS) usually involve time-consuming sample preparation procedure of a sample dissolution which requires the usage of aggressive and toxic chemicals. The need for suitable and sustainable analytical methods for direct multi-elemental analysis of plant samples has been increased in recent years. Spectrometric techniques for direct sample analysis, instrumental neutron activation analysis (INAA) and X-ray fluorescence (XRF) have been applied in environmental studies and various fields of screening tests. Nevertheless, these techniques are not commonly used for plant sample analysis and their performances need to be evaluated. This research aimed to assess how reliable non-destructive techniques are in the determination of elements in plants compared to conventionally used spectrometric techniques. A total of 49 plant samples of four conifer species (Pinus nigra, Abies alba, Taxus baccata and Larix decidua) were measured using two conventionally applied (ICP-MS, ICP-OES) and two non-destructive techniques (wavelength dispersive XRF (WD-XRF), INAA). The comparison was performed by investigation of relative ratios of concentrations and by correlation analysis. Moreover, precision of the techniques was examined and compared. The quality control included analysis of NIST pine needles certified reference material (1575a) using all examined techniques. Our results suggest that additional analytical and quality control steps are necessary for reaching the highest accuracy of multi-elemental analysis

Soybean Seedlings Enriched with Iron and Magnesium - Impact on Germination, Growth and Antioxidant Properties

Abstract Iron (Fe) and magnesium (Mg) deficiency in human diets is a widespread problem observed in various regions of the world. Insufficient Fe uptake results in the development of iron dependent anaemia and depressed physical and intellectual performance. In turn Mg deficiency is associated with alterations in neuromuscular and cardiovascular systems. An emerging alternative to traditional supplementation of these elements in the form of pills, liquids or effervescent tablets, is introduction of fortified food products. In present study we show that preincubation of soybean seeds in Fe and Mg solutions leads to elevated content of these elements in the seedlings. Importantly the pretreatment did not affect germination rate, seedlings growth or, with an exception of Fe supplementation at highest concentration, antioxidant capacity. The obtained results indicate that preincubation of seeds in Fe and Mg solutions may be a promising method of obtaining enriched soybean sprouts

Revised Pourbaix diagrams for the vanadium – water system

The forms of occurrence of vanadium metal are determined by the major chemical reactions in the aquatic environment such as hydrolysis, oxidation, reduction, and precipitation. Depending on pH, potential and total concentration of inorganic ions and organic ligands, vanadium compounds may undergo various transformations to produce a whole range of chemical forms in aqueous systems. In this paper, a novel approach has been applied for calculating potential-pH (Pourbaix) diagrams, based on the developed thermodynamic analysis of chemical equilibria in the V–H2O system. On the basis of currently revised thermodynamic data for V(III), V(IV) and V(V) hydrolysis and original thermodynamic and graphical approach used, the repartition of their soluble and insoluble chemical species has been investigated. By means of ΔG–pH diagrams, the areas of thermodynamic stability of V(IV) and V(V) hydroxides have been established for a number of analytical concentrations of vanadium in heterogeneous mixtures. The obtained results, based on the thermodynamic analysis and graphic design of calculated data, are in good agreement with available experimental data

Comparison of ICP-MS, ICP-OES, INAA, and WDXRF Techniques in Measuring Elements in Coniferous Needles Samples

The elemental composition of plant matrices has been conventionally determined by spectrometric techniques such as Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) [1]. Wet mineralization (digestion) of samples requires time, equipment, and usage of aggressive and toxic chemicals which are the main drawbacks of those routinely used techniques [2]. The need for suitable analytical methods for direct and multi-elemental analysis of plant samples has been increased in recent years [3]. Instrumental Neutron Activation Analysis (INAA) is one of the techniques for direct analysis which has been previously applied in environmental studies, nevertheless it is not a commonly used technique for plant samples. X-ray fluorescence (XRF) is another technique with the possibility of performing multi-element analysis directly on solid samples with numerous advantages. Although non-destructive techniques (INAA and XRF) are widely accepted in various fields of screening tests regarding the analytical approach, their performance needs to be evaluated in plant sample analysis. The main aim of this research was to assess how reliable non-destructive techniques are in detecting elements in conifer needles regarding routinely used spectrometric techniques. A total of 49 plant samples of four conifer species (Pinus nigra, Abies alba, Taxus baccata, and Larix decidua) were measured using two routinely used (ICPMS and ICP-OES) and two non-destructive instrumental techniques (WD-XRF and INAA). A quality control program included NIST pine needles certified reference material (1575a) analysis using all examined techniques. The techniques were compared by examination of relative ratio (element concentration measured using investigated analytical techniques divided by concentration determined by ICP-MS (figure 1)) and by correlation. Precision of all examined techniques was additionally investigated. This study confirmed that non-destructive spectroscopic techniques can be successfully applied on plant samples since sample preparation for these techniques is fast and in good accordance with the principles of green chemistry. Investigated standardless XRF method can also produce well-correlated results, compared to other techniques based on calibration standards. Obtained results suggest that the high accuracy of the analysis can be ensured by additional analytical and quality control steps (the use of internal standards, standard addition, etc.)

On the Geochemistry of the Danube River Sediments (Serbian Sector)

To determine the nature and origin of the unconsolidated bottom sediments, as well as to demonstrate and quantify the presence of Presumably Contaminating Elements (PCE) in the Serbian Danube River, as a novelty, the mass fractions on nine major elements as oxides—SiO2, TiO2, Al2O3, FeO, MnO, MgO, CaO, Na2O, and K2O, as well as Sc, V, Cr, Co, Ni, Cu, Zn, As, Rb, Sr, Zr, Sb, Cs, Ba, La, Hf, Ta, W, Th, and U were determined by Instrumental Neutron Activation Analysis (INAA) in 13 sediment samples collected between Belgrade and Iron Gate 2 dam. INAA was chosen for its ability to perform elemental analysis without any preliminary sample treatment that could introduce systematic errors. The distribution of major elements was relatively uniform, with the sampling locations having less influence. Concerning the trace elements, excepting the PCE Cr, Ni, Cu, Zn, As, and Sb, their distributions presented the same remarkable similarity to the Upper Continental Crust (UCC), North American Shale Composite (NASC), Average Bottom Load (ABL), and Average Dobrogea Loess (AVL), and were in good concordance with the location of the Serbian Danube River in the Pannonian Plain. In the case of considered PCE, both Enrichment Factor and Pollution Load Index showed values higher than the pollution threshold, which pointed towards a significant anthropogenic contamination, and rising concern to what extent the water quality and biota could be affected

NADPH oxidase is involved in regulation of gene expression and ROS overproduction in soybean (Glycine max L.) seedlings exposed to cadmium

Cadmium-induced oxidative burst is partially mediated by NADPH oxidase. The aim of the present research was to evaluate the role of NADPH oxidase in soybeans’ response to short-term cadmium stress. The application of an NADPH oxidase inhibitor, diphenyleneiodonium chloride (DPI), affected expression of two Cd-inducible genes, encoding DOF1 and MYBZ2 transcription factors. This effect was observed after 3 h of treatment. Interestingly, Cd-dependent increases in NADPH oxidase activity occurred only after a period of time ranging from 6 and 24 h of stress. Stimulation of the enzyme correlated in time with a significant accumulation of reactive oxygen species (ROS). Further analysis revealed that pharmacological inhibition of NADPH oxidase activity during 24 h of Cd stress does not affect Cd uptake, seedling growth, or the level of lipid peroxidation. The role of NADPH oxidase in the response of soybean seedlings to short-term Cd exposure is discussed