Ants accumulate heavy metals and respond to pollution with modification in species composition, community structure, altered behaviour and immunity. However, the levels of heavy metals in ants’ nests ...and explicit individual-level responses towards heavy metals have not been revealed. We found that red wood ants Formica lugubris accumulate high and correlated values of such heavy metals as Al, Cd, Co, Cu, Fe, Ni, Pb and Zn both in ants and nest material near cobalt smelter in Finland. Relative differences in metal concentrations were higher in nests than in ants. The highest values were obtained for elements such as Co (36.6), Zn (14.9), Cd (9.7), Pb (8.5), Cu (7.4), Ni (6.4), As (4.7), Cr (2.9) and Fe (2.4) in nest material, and Co (32.7), Cd (6.3), Pb (6), Fe (2.8), Ni (2.9) and Zn (2.1) in ants. In industrial and reference areas, ants have no differences in size, but differed in dry and residual body mass. In polluted areas, F. lugubris had less melanised heads, but not thoraxes. The sensitivity of cuticular colouration in red wood ants subjected to heavy metal pollution might be related to metal-binding properties of melanins. The overall results are useful for the improvement of biomonitoring techniques using ants as indicators of industrial contamination and for further discovery of novel ecotoxicological biomarkers.
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•Levels of Al, Cd, Co, Cu, Fe, Ni, Pb and Zn correlate in F. lugubris ants and nests.•Ants have lower size-related body mass in polluted area.•Ants from industrial area possess less melanised heads, but not thoraxes.
Levels of Al, Cd, Co, Cu, Fe, Ni, Pb and Zn correlate between F. lugubris ants and their nests. Ants have lower size-related body mass in polluted area and they were less melanised.
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•Novel magnetic SiO2@CoFe2O4-GO based nanocomposites were synthesized.•Adsorption capacity for AB1 and Cr(VI) was found to be 130.74 and 136.40mgg−1.•Desorption experiments revealed ...the stable reusable capacity of the nanocomposite.
In this study, magnetic nanocomposites viz. SiO2@CoFe2O4 nanoparticles decorated on graphene oxide were synthesized using solvothermal and sol-gel processes. The prepared nanocomposite materials were used as magnetic adsorbents for the removal of organic and inorganic pollutants (acid black 1 dye and Cr(VI) ions as model pollutants) from aqueous solution. The structure, morphology and other physico-chemical properties of nanocomposites were characterized by X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), high resolution-transmission electron microscopy (HR-TEM), vibrating sample magnetometer (VSM), X-ray photo spectroscopy (XPS), zeta potential and Fourier transform infrared (FT-IR) spectroscopy. Batch mode adsorption studies were conducted with the prepared nanocomposites to determine the maximum adsorption capacity of acid black 1 dye and Cr(VI) ions as a function of contact time, pH, adsorbent dosage and initial adsorbate concentrations. Different kinetic and isotherm models were tested to describe and elucidate the adsorption mechanisms. Based on the experimental results obtained, the synthesized materials proved to exhibit considerable potential for the removal of acid black 1 and Cr(VI) ions from aqueous solution.
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•Real mine effluents from the processing of uranium-bearing ore were treated.•Over 99% of uranium was separated from effluents using low-cost natural biopolymer.•Rapid adsorption was ...recorded, which is desirable in industrial-scale applications.•The process performance was dependent on pH, temperature, and solid–liquid ratio.•Recycling of the biopolymer was possible with 73% uranium recovery.
This study aimed to efficiently and cost-effectively recover uranium from real mine effluents derived from the processing of uranium-bearing ore. A natural bioactive polymer, chitosan, was applied as a low-cost material to separate uranium ions and characterised using a scanning electron microscope coupled with an energy dispersive spectrometer, and a Fourier transform infrared spectroscopy analysis. Rapid adsorption (over 90% within 10 min) was recorded in the examined batch-type system. The kinetics of the reactions were calculated, and the rate of uranium adsorption tended to follow a second-order equation. The maximum adsorption capacities of the biopolymer given by the Langmuir model were 17.44 mg/g and 7.51 mg/g for the flotation and Knelson tailings water, respectively. The results demonstrated that the separation of uranium ions from effluents was temperature- and pH-dependent. Studies have revealed an enhancement in uranium uptake at elevated water temperatures. As the pH increased from 2 to 10, the net charge on the biopolymer surface changed from positive to negative, which indicated the possible involvement of electrostatic interactions in the binding of the metal ions. In addition, interactions between uranyl ions and biopolymer functional groups were confirmed. The regeneration possibility and reusability of the biopolymer were investigated, and approximately 73% of the uranium was recovered by the fourth adsorption–desorption cycle.
Cellulose nanofibers (CNFs) tethered with sulphur as anionic ligand were synthesized from medical absorbent cotton by dissolution with NaOH, CO(NH2)₂ followed by mechanical intrusion of sulphur from ...SC(NH₂)₂ at an elevated temperature. The solid-phase CNFs embedded with sulphur complexes possessed negative sites which were used to remove cationic metals viz., Pb(II) and Cd(II) from synthetic and industrial wastewater. The physicochemical properties of the CNFs were analyzed by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), pH at point of zero charge (pHpzc) and X-ray photoelectron spectroscopy (XPS). Batch adsorption studies were conducted with synthetic wastewater to optimize the conditions for Pb(II) and Cd(II) removal by CNFs. Different adsorption kinetic models were applied to assess and define the adsorption mechanism. The maximum Langmuir adsorption capacity was found to be 1.16 and 0.82 mmol g−1 for Pb(II) and Cd(II) ions, respectively. Regeneration studies showed that the CNFs can be reused using 0.1 M NaOH as eluent. The percentage removal efficiency of different cationic metals by CNFs from untreated industrial wastewater ranged from ca. 90–98%.
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•S-ligand tethered cellulose nanofibers were synthesized for metals adsorption.•Adsorption capacity of S-CNFs was 1.16 mmol g−1 for Pb and 0.82 mmol g−1 for Cd.•Ligand exchange is suggested as possible mechanism for both metal ions.•Reusability studies revealed that synthesized adsorbent is resilient.•Synthesized CNFs can be effectively used in industrial wastewater treatment.
In this work, anionic sulphur tethered cellulose nanofibers were synthesized from absorbent cotton and used in the removal of cationic metals from synthetic and industrial wastewater.
Companies in the wood industry are constantly developing their outdoor products. The possibility of using bio-based chemicals as an alternative to traditional wood preservatives—regulated in Europe ...by The Biocidal Products Regulation No 528/2012—has been considered, but chemical leaching from the wood decreases its effectiveness and may negatively affect the environment. This study aims to compare the effectiveness of bio-based chemicals with potential use in wood preservation to commercially available preservatives, to investigate their fixation to wood and their ecotoxicity and to quantify the potentially toxic elements leached from the wood. Pyrolysis distillates of tree bark, organic acids found in distillates, Colatan GT10 tannin extract and log soaking liquid as a hardwood veneer process residue were tested and compared with commercial pine oil and a copper-based wood preservative. In the wood decay test of impregnated pine sapwood specimens, Colatan GT10 extract performed as well as the commercial wood preservatives. The same decay trial with leached specimens significantly reduced the performance of the bio-based chemicals. The results of the ecotoxicity test with photoluminescent Aliivibrio fischeri bacteria showed that many bio-based chemicals with potential use in wood preservation have markedly lower ecotoxicity than commercially available wood preservatives, but the ecotoxicity of some bio-based chemicals is higher, as in the case of some of the pyrolysis distillates. The wood preservation efficiency and the ecotoxicity of the studied chemicals had a poor correlation, implying that other factors besides treatment agent toxicity play a role in deterring fungal growth on treated wood. The amount of elemental toxins in the leachates was low. These results emphasize the importance of the chemical ecotoxicity of bio-based preservative compounds, as their detrimental effect on the environment can be higher than that of the traditional preservatives unless effectively linked to wood to prevent leaching.
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•Antifungal activity of bio-based preservatives decreased significantly after leaching.•Bio-based chemicals had generally lower ecotoxicity than the commercial products.•Some bio-based chemicals had higher ecotoxicity than the commercial products.•Fixation of preservative components to wood is needed to reduce their ecotoxicity.
Porous silicon (PSi) has attracted wide interest as a potential material for various fields of nanomedicine. However, until now, the application of PSi in photothermal therapy has not been successful ...due to its low photothermal conversion efficiency. In the present study, biodegradable black PSi (BPSi) nanoparticles were designed and prepared via a high-yield and simple reaction. The PSi nanoparticles possessed a low band gap of 1.34 eV, a high extinction coefficient of 13.2 L/g/cm at 808 nm, a high photothermal conversion efficiency of 33.6%, good photostability, and a large surface area. The nanoparticles had not only excellent photothermal properties surpassing most of the present inorganic photothermal conversion agents (PCAs) but they also displayed good biodegradability, a common problem encountered with the inorganic PCAs. The functionality of the BPSi nanoparticles in photothermal therapy was verified in tumor-bearing mice in vivo. These results showed clearly that the photothermal treatment was highly efficient to inhibit tumor growth. The designed PCA material of BPSi is robust, easy to prepare, biocompatible, and therapeutically extremely efficient and it can be integrated with several other functionalities on the basis of simple silicon chemistry.
A Novel approach to remove metals from aqueous solutions has been developed. The method is based on a resin free, solid, non-toxic, microcrystalline bisphosphonate material, which has very low ...solubility in water (59 mg/l to ion free Milli-Q water and 13 mg/l to 3.5% NaCl solution). The material has been produced almost quantitatively on a 1 kg scale (it has been prepared also on a pilot scale, ca. 7 kg) and tested successfully for its ability to collect metal cations from different sources, such as ground water and mining process waters. Not only was this material highly efficient at collecting several metal ions out of solution it also proved to be regenerable and reusable over a number of adsorption/desorption, which is crucial for environmental friendliness. This material has several advantages compared to the currently used approaches, such as no need for any precipitation step.
We investigated the common wasp,
Vespula vulgaris
as a bioindicator and biomonitor of metals in the industrial area. Using traps, we collected 257 yellowjackets along a pollution gradient in the ...Harjavalta
Cu
-
Ni
smelter in Southwest Finland. Our method detected metal elements such as arsenic (
As
), cobalt (
Co
), copper (
Cu
), iron (
Fe
), nickel (
Ni
), lead (
Pb
), zinc (
Zn
), and mercury (
Hg
) in wasps
.
The data analyses revealed
V. vulgaris
can be a proper indicator for
As
,
Cd
,
Co
,
Cu
,
Ni,
and
Pb
, rather than for
Fe
and
Zn
contamination. Body burdens of
As
,
Cd
,
Co
,
Cu
,
Ni
, and
Pb
decreased with an increase in distance from smelter. Enrichment factor (EF) followed the pattern
Pb
˃
Cd
˃
As
˃
Co
˃
Cu
˃
Ni
. The highest bioaccumulation (BAF) values were revealed for
Cd
(5.9) and the lowest for
Pb
(0.1). Specially designed software (
WaspFacer
) allowed revealing body burdens of
As
,
Cd
,
Co
,
Cu
,
Ni
, and
Pb
to be associated with rather smaller than more asymmetric facial colour markings in yellowjackets. These results add to the body of literature on how heavy metal contaminants can have tangible phenotypic effects on insects and open future opportunities for using wasps as indicators of metal pollution.
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•Low removal of Cd and other heavy metals following heat-treatment of ashes in air.•Cd, Pb, Tl, Bi and Zn removed from ashes by heat-treatment in reducing environments.•Cr (VI) ...contents reduced by heating bottom ash and fly ash in reducing environments.•>100-fold decrease in Cr leaching following treatment in reducing environments.•Negligible leaching of Cr and Cd above pH 4 from thermally detoxified bottom ash.
This study assesses the potential of thermal processing for detoxification of wood-combustion ashes that contain high levels of Cr and Cd. Thermal treatment (1000 °C) of bottom ash and fly ash in an oxidising gas (air) atmosphere resulted in: low volatilisation of Cd and most other heavy metals, oxidation of Cr in the ashes to Cr (VI), and, in the case of the fly ash, significantly increased leaching of Cr and Mo. Thermal treatment in a nitrogen atmosphere resulted in local reducing conditions due to oxidation of ash-derived carbon to CO (g). Thermal treatments in this atmosphere and in a reducing atmosphere consisting of 10 % H2 and the balance N2 detoxified the ashes in at least two ways: (i) by substantially removing Cd, Pb, Bi, Tl, and, in the case of the fly ash, Zn from the ashes by volatilisation; and (ii) by thermal reduction of Cr (VI) in the ashes. There was at least a 100-fold reduction in the leaching of total Cr from both the bottom ash and the fly ash following the thermal treatments in reducing conditions. Chromium only leached from the detoxified bottom ash to a significant extent in acidic conditions (pH < 4).
•The new innovative continuously compressing crushing (CCC) was tested for the first time for natural ore samples.•The basic idea of the new CCC method has been to implement the principle of the ...ideal comminution method as accurately as possible.•The liberation of ultra-coarse-grained graphite flakes (+300 µm) was most observed in the crushing product of pilot-scale CCC.•CCC enables the enrichment of coarser and cleaner graphite.
In this study the comminution methods of graphite bearing ore were compared by using five different crushing methods, namely a jaw crusher, a roll crusher, uniaxial compression tests, and a new type of continuously compressing crushers. These new continuously compressing crushers were available in laboratory and pilot scales. The particles in the + 1700 µm size class produced by continuously compressing crushing were coarser and rougher in texture compared to the rounded particles produced traditionally by a jaw crusher. In the size class −100 µm, most of the graphite flakes were observed independently in the products of each of these crushing methods. The liberation of ultra-coarse-grained graphite flakes in size class + 300 µm was most observed after pilot-scale continuously compressing crusher. The shape and enrichment of the graphite flakes were very similar after both laboratory and pilot scale continuously compressing crushers. In contrast, the graphite flakes produced by jaw crusher appeared as broken particles in the form of accumulation of several layered and non-independent graphite flake structures. The results of this study demonstrate that the new innovative continuously compressing crushing method enables the enrichment of coarser and cleaner graphite, which has a much higher value and wider industrial applications compared to amorphous and fine-grained graphite.