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Biosorption of lead ions by cyanobacteria Spirulina platensis: kinetics, equilibrium and thermodynamic study

Abstract

The potential use of dry Spirulina platensis biomass to remove lead ions from aqueous solution was investigated. Effects of various parameters such as contact time, temperature, dosage of biosorbent, initial pH, and initial concentration of lead were investigated in the batch adsorption mode. The highest lead removal of 5.7 mg/g was obtained at pH 5, biomass dosage of 0.5 g, initial lead concentration of 60 mg/L. The Langmuir and Freundlich models fit the experimental data (R2 > 0.99), while the kinetic data was best described using the pseudo second-order kinetic model (R2 > 0.99). FTIR spectra indicated that the metal removal takes place through binding to OH, C=O and P=O groups. Lead was efficiently recovered from biomass by mineral acids, while using CH3COOH and NaOH as eluents the biomass maintained high biosorption capacity during three cycles. This study demonstrates the potential of using Spirulina platensis as biosorbent to remove lead from industrial wastewater.

Open access
Diamagnetic cobalt(III)tris(o-ethylxanthate) and nickel(II)bis(o-ethylxanthate)

Abstract

Diamagnetic [Co(xanth)3] and [Ni(xanth)2] complexes have been prepared by reaction of Co(II) and Ni(II) salts with potassium O-ethyl xanthate (Kxanth). The isolated Co(III) and Ni(II) complexes have been characterized by single-crystal X-ray crystallography, UV-VIS and IR spectroscopy, computational methods, and magnetic measurements.

Open access
Distinguishing between juniper-flavoured spirit drinks from different producers

Abstract

A simple method for classifying juniper-flavoured spirit drinks is proposed based on the ratio of fluorescence intensity values in synchronous fluorescence spectra. Receiver operating curves (ROC) and linear discriminant analysis (LDA) were used to compute the performance of the classification. Significant differences in the fluorescence intensity ratios (I316/I287 and I324/I287) observed in the spectra recorded using wavelength difference 10 nm were evaluated by ROC analysis to identify cutoff values that gave ideal AUCs equal to one, thus allowing for 100% correct classification of the samples according to producer criteria. LDA showed that drinks of different producers could be distinguished (100% correct classification) on the basis of their differences in the fluorescence intensity ratios (I323/I287, I324/I287, I316/I287 and I325/I287). These results show that complete synchronous spectra are not required to discriminate between producers. Instead of them, fluorescence intensity could be measured at selected wavelengths.

Open access
Investigation of genotoxicity in river sediments

Abstract

The purpose of the present study was to develop a useful screening method to assess genotoxic effect of polluted bottom sediments from the water reservoir Ružin No.I. The Hornád and Hnilec Rivers drained a former mining area, have been polluted in the long-term by heavy metals (Cu, As, Sb, Hg), which significantly contributed to environmental degradation. Genotoxicity of bottom sediment was evaluated by test SOS-ChromoPadTM 3.0 for solid samples without extraction. The mentioned test represents simple, quick and direct sediment phase toxicity testing procedure. In this test bacterial strain Escherichia coli K12 PQ37 was used. The results of SOS-ChromoPadTM 3.0 showed that sample Hornád has low potential genotoxic effect on the environment. It was determined on the basis of slight blue colouration of chromogenic paper at the point of sediment application. The sample Hnilec was negative. This test allows significantly reduce the time for obtaining information about sediments genotoxicity and accept necessary security proceeding in time.

Open access
Microextraction based on solidified floating organic drop coupled with ETAAS for the determination of lead in herbs

Abstract

A rapid, inexpensive and practical solidified of floating organic droplet microextraction (SFODME) prior to electrothermal atomic absorption spectrometry (ETAAS) was proposed for lead (Pb) determination in herb samples. For SFODME procedure, 1-(2-pysidylazo)-2-naphthol was used as a complexing agent. Analytical parameters influencing the extraction efficiency, i.e. types and volume of extracting solvent, concentration of 1-(2-pyridylazo)-2-naphthol, pH, extraction temperature and time were optimized. Under the optimized conditions, LOD and LOQ were 0.064 and 0.214 μg L−1, respectively, and an enrichment factor was achieved at 18.71 with the relative standard deviation ranging from 1.3 to 2.5% (n=6). The proposed method was effectively applied to the determination of lead in Spinach leaves (SRM-1570a) and Thai herb samples with acceptable results.

Open access
NMR spectroscopic properties of furo[2′,3′:4,5]pyrrolo[1,2-d][1,2,4]triazine derivatives

Abstract

The 1H and 13C NMR spectroscopic properties of a series of furo[2′,3′:4,5]pyrrolo[1,2-d][1,2,4]triazin-8(7H)-ones and -thiones were investigated. The influence of various electron donating as well as electron withdrawing substituents at C-5 or N-7 on 1H NMR chemical shifts as well as 13C chemical shifts at C8 were observed. The 5-chloromethyl group had a little influence on the chemical shift of H-7 proton and the 8-thione group causes deshielding of H-7 as well as H-5 protons in comparison with the C-8 carbonyl group.

Open access
The optimization of propagation medium for the increase of laccase production by the white-rot fungus Pleurotus ostreatus

Abstract

The lignocellulolytic enzymes are routinely produced by submerged fermentation using lignocellulosic material, but for more effective production, it would be suitable to precede the production phase on the lignocellulose by propagation phase in the nutrition medium suitable for growth of the fungi. Therefore, the aim of this study was to increase the laccase production by the white-rot fungus Pleurotus ostreatus by two-step cultivation strategy. In the first step, propagation medium was optimized for the maximal biomass growth, the second step included the laccase production by produced fungal biomass in media with the selected lignocellulosic material (pine sawdust, alfalfa steam and corn straw). From our experiments, parameters such as glucose concentration, yeast extract concentration and pH of propagation medium were selected as key factors affecting growth of P. ostreatus. The optimal conditions of propagation medium for maximal fungal growth determined by response surface methodology were: glucose concentration 102.68 g/L, yeast extract concentration 43.65 g/L and pH of propagation medium 7.24. These values were experimentally verified and used statistical model of biomass production prediction was appropriate adjusted. Thus prepared fungal biomass produced in the media with lignocellulose approximately 9-16 times higher concentrations of the laccase in 3 times shorter time than the fungal biomass without propagation phase in optimized propagation medium.

Open access
Plant stress activated by chlorine from disinfectants prepared on the base of sodium hypochlorite

Abstract

In this study, the phytotoxicity of disinfectants prepared on the base of sodium hypochlorite was determined. For our tests two commercial products, Savo and Dom Amor, as well as 10% NaClO solution were used. While Savo contained only NaClO, Dom Amor contained NaClO and earthworm enzymes. Products on the base of NaClO are used in households for cleaning and disinfection of floors, furniture, sanitary and kitchen equipment. Savo may be used for the disinfection of drinking waters as well. Products with NaClO are also used for bacteria, algae and pathogens reduction in irrigation waters. As a subject, young seedlings of mustard Sinapis alba L. were used for the study of chronic toxicity. The observed parameters of the inhibition of roots and shoots growth, dry (DM) and fresh (FM) mass as well as photosynthetic pigments production (chlorophyll a, b, carotenoids) and water content in the plants were determined. The results point out that Dom Amor was the most toxic for S. alba seedlings growth and the rank order of the FAC contents for both plant parts was arranged as: Dom Amor > Savo > NaClO. All disinfectants reduced the DM and FM of roots; however, they stimulated biomass production in the shoots. On the basis of the obtained results it could be concluded, that disinfectants stimulated photosynthetic pigments production and reduced water content mainly in the roots. Dom Amor did not significantly reduced the water content in the shoots and for this parameter the following rank orders of inhibition for roots and shoots could be arranged as NaClO > Dom Amor > Savo and NaClO > Savo > Dom Amor, respectively. All commercial products increased chlorophyll a (Chla) and the carotenoids (Car) content in the shoots. As significant increase was confirmed first for Chla whose content in the presence of NaClO at concentration 24 mL/L overextended that in the control by 3.5 times. The rank orders of stimulation for Chla and Car were NaClO > Savo > Dom Amor and Dom Amor > NaClO > Savo, respectively.

Open access
Responses of Aspergillus niger to selected environmental factors

Abstract

Four wild type strains of A. niger were collected from soil and stream sediments representing environments with variable level of As, Sb, Al, Fe, Cd, Cu, and Zn contamination. Banská Štiavnica-Šobov (S), Pezinok-Kolársky vrch (P) and Slovinky (Sl) represent contaminated localities. Locality Gabčíkovo (G) was as a control site. The influence of toxic elements in these substrates on fungal growth, colony size, enzymatic activity, production of organic acids and their pelletization in water suspensions with montmorillonite was studied. The aim of our study was to find out how the wild type strains from (contaminated) environment will behave in different model solutions. We also wanted to add some new information in this area of study, because that there is some gap in the available knowledge.

Open access
Variable dynamics of cadmium uptake and allocation in four soybean cultivars

Abstract

Cadmium is a serious environmental pollutant and its uptake by plant represents a serious health risk. Uptake, accumulation as well as sensitivity of soybean plants to metals have been shown to vary with genotype, while the dynamics of this uptake has rarely been studied. Here we studied the uptake and accumulation of Cd2+ ions in different parts of soybean plants of four cultivars Moravians, Gallec, Kent and Cardiff. The plants at early developmental stage were immersed in Hoagland nutrient solution in the presence or absence of 50 mg.L−1 and the isotope of 109Cd2+ to monitor its accumulation continuously at 24 h intervals for 10 days. Our results showed that the uptake rate varied among the cultivars, being the highest in roots of the cv. Moravians and the lowest in the cv. Gallec. We also observed a non-even distribution of radioactivity within the entire plants of individual cultivars. The most of Cd2+ isotope was translocated into primary leaves and leaves in the cvs. Kent and Moravians; on the contrary, relatively less in the cvs. Cardiff and Gallec. The results were fitted with genetic potential, growth as well as defense parameters such as proline accumulation. Combining uptake dynamics and biochemical data are indicative for different tolerance strategies of soybeans.

Open access