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Lövgren, Lars
Publications (10 of 42) Show all publications
Shtangeeva, I., Tesfalidet, S. & Lövgren, L. (2017). Comparison of nutrient concentrations in leaves of five plants. Journal of plant nutrition, 40(2), 239-247
Open this publication in new window or tab >>Comparison of nutrient concentrations in leaves of five plants
2017 (English)In: Journal of plant nutrition, ISSN 0190-4167, E-ISSN 1532-4087, Vol. 40, no 2, p. 239-247Article in journal (Refereed) Published
Abstract [en]

The paper describes investigation on bioaccumulation of mineral elementsand identification of plants based on the concentrations of the elements inthe plant leaves. Five native plant species (Elytrigia repens, Plantago major,Urtica dioica, Chelidonium majus, and Taraxacum officinale) were studied. Toexclude the effects from different growth conditions and developmentalstages, the plants were collected simultaneously from the same site (park inSt. Petersburg, Russia). It was found that for all plants high concentrations ofpotassium, sodium, phosphorus and magnesium (K, Na, P, and Mg) weretypical, while concentrations of zinc (Zn) and copper (Cu) were the lowest.The most significant difference was found between concentrations ofelements in monocots and eudicots. Among other species,T. officinalehadthe highest concentrations of almost all elements. Excellent separation of theplants into different groups which was due to different elementconcentrations in the plant leaves was demonstrated.

Place, publisher, year, edition, pages
Taylor & Francis Group, 2017
Keywords
Grass, leaf nutrient concentrations, monocots and eudicots, ICP-OES
National Category
Botany Other Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:umu:diva-128832 (URN)10.1080/01904167.2016.1237647 (DOI)000396825500011 ()2-s2.0-84999791362 (Scopus ID)
Available from: 2016-12-15 Created: 2016-12-15 Last updated: 2018-06-09Bibliographically approved
Kozyatnyk, I., Lövgren, L., Tysklind, M. & Haglund, P. (2017). Multivariate assessment of barriers materials for treatment of complex groundwater rich in dissolved organic matter and organic and inorganic contaminants. Journal of Environmental Chemical Engineering, 5(4), 3075-3082
Open this publication in new window or tab >>Multivariate assessment of barriers materials for treatment of complex groundwater rich in dissolved organic matter and organic and inorganic contaminants
2017 (English)In: Journal of Environmental Chemical Engineering, ISSN 2160-6544, E-ISSN 2213-3437, Vol. 5, no 4, p. 3075-3082Article in journal (Refereed) Published
Abstract [en]

This study focused on the challenges of treating groundwater rich in dissolved organic matter and contains both heavy metals and organic pollutants. Activated carbon, fly ash, lignite, peat, torrefied organic material and zero-valent iron were tested as prospective materials for permeable barriers. Removal of different pollutants was analyzed using coefficients of the Freundlich equation for adsorption isotherms. Principal components analysis was used to visualize similarities and differences in pollutant removal efficiency and sorbent capacity between barrier materials. Fly ash, iron (aerobic conditions) and activated carbon were found to be promising materials for dissolved organic matter removal. Fly ash was the most effective material for metal removal, and fly ash, activated carbon and peat were the most effective materials for removal of organic contaminants. Thus, fly ash shows the most potential for simultaneous removal of metals and organic pollutants. However, it has limited capacity for removing neutral halogenated aromatic compounds. For these, zero-valent iron (aerobic conditions) has greater capacity, probably because of the formation of a porous layer of iron oxyhydroxide. In summary, batch adsorption experiments followed by principal components analysis evaluation of the results are useful tools for selecting suitable materials for treatment of groundwater contaminated with multiple organic and inorganic pollutants.

Place, publisher, year, edition, pages
Elsevier, 2017
Keywords
Adsorption, Groundwater, Fulvic acids, Permeable barrier, Principal components analysis
National Category
Water Treatment
Identifiers
urn:nbn:se:umu:diva-140660 (URN)10.1016/j.jece.2017.06.011 (DOI)000411143200003 ()
Available from: 2017-10-16 Created: 2017-10-16 Last updated: 2019-04-09Bibliographically approved
diva2:946717
Open this publication in new window or tab >>On the leaching of mercury by brackish seawater from permeable barriers materials and soil
2015 (English)In: Journal of Environmental Chemical Engineering, ISSN 2160-6544, E-ISSN 2213-3437, Vol. 3, no 2, p. 1200-1206Article in journal (Refereed) Published
Abstract [en]

Soils at former pulp, paper and chemical plants in the subarctic (boreal) zone, including Canada, Scandinavia, Russia, and parts of the USA, are often contaminated with organic pollutants and heavy metals, of which mercury is one. The soil- and ground-water at these sites is often rich in dissolved organic matter (DOM), particularly fulvic substances. Permeable barriers are sometimes used to limit the migration of pollutants with groundwater and protect nearby aquatic environments. These are installed downstream of the source, generally close to the receiving water body. In cases when such barriers have been installed close to the sea, concerns have been raised that the seawater may back-flush the barrier and release mercury, often a key contaminant, in the form of stable chloride complexes.

Intrusion of seawater into coastal groundwater reservoirs has previously been shown to result in dissolution of mercury from soil. Less is known about the ability of brackish water, present in estuaries or brackish seas, to mobilize mercury from soil or from barrier materials. We therefore investigated the effect of artificial brackish seawater (6.3‰ salinity) on the sorption and desorption of mercury from different barrier materials (activated carbon, fly ash, lignite, torrified material, peat, and iron powder).

The mercury was found to be associated with the high molecular weight fraction of groundwater DOM and it was concluded that the mercury was removed (sorbed) as relatively strong DOM-complexes. Chloride ions did not seem to form aqueous complexes with mercury to any great extent and artificial brackish seawater did not desorb mercury from the contaminated soil or from the studied barrier materials.

Place, publisher, year, edition, pages
Elsevier, 2015
Keywords
Mercury, Dissolved organic matter, Chloride, Adsorption, Groundwater
National Category
Other Environmental Engineering
Identifiers
urn:nbn:se:umu:diva-123547 (URN)10.1016/j.jece.2015.04.017 (DOI)000217986800069 ()
Funder
The Kempe Foundations, JCK- 1142
Available from: 2016-07-05 Created: 2016-07-05 Last updated: 2019-04-09Bibliographically approved
Kozyatnyk, I., Haglund, P., Lövgren, L., Tysklind, M., Gustafsson, A. & Törneman, N. (2014). Evaluation of barrier materials for removing pollutants from groundwater rich in natural organic matter. Water Science and Technology, 70(1), 32-39
Open this publication in new window or tab >>Evaluation of barrier materials for removing pollutants from groundwater rich in natural organic matter
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2014 (English)In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 70, no 1, p. 32-39Article in journal (Refereed) Published
Abstract [en]

Permeable barriers are used for passive remediation of groundwater and can be constructed from a range of materials. The optimal material depends on the types of contaminants and physicochemical parameters present at the site, as well as the hydraulic conductivity, environmental safety, availability, cost and long-term stability of the material itself. The aim of the presented study was to test a number of materials for their ability to remove heavy metals and organic pollutants from groundwater with a high (140 mg L-1) content of natural organic matter (NOM). The following materials were included in the study: sand, peat, fly ash, iron powder, lignin and combinations thereof. Polluted water was fed into glass columns loaded with each sorbent and the contaminant removal efficiency of the material was evaluated through chemical analysis of the percolate. Materials based on fly ash and zero-valent iron were found to be the most effective for heavy metal removal, while fly ash and peat were the most effective for removing aliphatic compounds. Filtration through lignin and peat led to leaching of NOM. Although the leaching decreased over time, it remained high throughout the experiments. The results indicate that remediation of contaminated land at disused industrial sites is a complex task that often requires the use of mixed materials or a minimum of two sequential barriers.

Place, publisher, year, edition, pages
IWA Publishing, 2014
Keywords
adsorption, groundwater, heavy metals, natural organic matter, organic pollutants, permeable barriers
National Category
Environmental Sciences Water Treatment
Identifiers
urn:nbn:se:umu:diva-94176 (URN)10.2166/wst.2014.192 (DOI)000341181200005 ()
Available from: 2014-10-06 Created: 2014-10-06 Last updated: 2019-04-09Bibliographically approved
Dopson, M., Ossandon, F. J., Lövgren, L. & Holmes, D. S. (2014). Metal resistance or tolerance?: Acidophiles confront high metal loads via both abiotic and biotic mechanisms. Frontiers in Microbiology, 5, 157
Open this publication in new window or tab >>Metal resistance or tolerance?: Acidophiles confront high metal loads via both abiotic and biotic mechanisms
2014 (English)In: Frontiers in Microbiology, ISSN 1664-302X, E-ISSN 1664-302X, Vol. 5, p. 157-Article in journal (Refereed) Published
Abstract [en]

All metals are toxic at high concentrations and consequently their intracellular concentrations must be regulated. Extremely acidophilic microorganisms have an optimum growth of pH <3 and proliferate in natural and anthropogenic low pH environments. Some acidophiles are involved in the catalysis of sulfide mineral dissolution, resulting in high concentrations of metals in solution. Acidophiles are often described as highly metal resistant via mechanisms such as multiple and/or more efficient active resistance systems than are present in neutrophiles. However, this is not the case for all acidophiles and we contend that their growth in high metal concentrations is partially due to an intrinsic tolerance as a consequence of the environment in which they live. In this perspective, we highlight metal tolerance via complexation of free metals by sulfate ions and passive tolerance to metal influx via an internal positive cytoplasmic transmembrane potential. These tolerance mechanisms have been largely ignored in past studies of acidophile growth in the presence of metals and should be taken into account.

Place, publisher, year, edition, pages
Frontiers Media, 2014
Keywords
metal, acidophile, resistance, tolerance, homeostasis, biomining
National Category
Chemical Sciences Medical Biotechnology (with a focus on Cell Biology (including Stem Cell Biology), Molecular Biology, Microbiology, Biochemistry or Biopharmacy)
Identifiers
urn:nbn:se:umu:diva-88950 (URN)10.3389/fmicb.2014.00157 (DOI)000334278500001 ()
Available from: 2014-05-22 Created: 2014-05-19 Last updated: 2018-06-07Bibliographically approved
Mangold, S., Potrykus, J., Björn, E., Lövgren, L. & Dopson, M. (2013). Extreme zinc tolerance in acidophilic microorganisms from the bacterial and archaeal domains. Extremophiles, 17(1), 75-85
Open this publication in new window or tab >>Extreme zinc tolerance in acidophilic microorganisms from the bacterial and archaeal domains
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2013 (English)In: Extremophiles, ISSN 1431-0651, E-ISSN 1433-4909, Vol. 17, no 1, p. 75-85Article in journal (Refereed) Published
Abstract [en]

Zinc can occur in extremely high concentrations in acidic, heavy metal polluted environments inhabited by acidophilic prokaryotes. Although these organisms are able to thrive in such severely contaminated ecosystems their resistance mechanisms have not been well studied. Bioinformatic analysis of a range of acidophilic bacterial and archaeal genomes identified homologues of several known zinc homeostasis systems. These included primary and secondary transporters, such as the primary heavy metal exporter ZntA and Nramp super-family secondary importer MntH. Three acidophilic model microorganisms, the archaeon 'Ferroplasma acidarmanus', the Gram negative bacterium Acidithiobacillus caldus, and the Gram positive bacterium Acidimicrobium ferrooxidans, were selected for detailed analyses. Zinc speciation modeling of the growth media demonstrated that a large fraction of the free metal ion is complexed, potentially affecting its toxicity. Indeed, many of the putative zinc homeostasis genes were constitutively expressed and with the exception of 'F. acidarmanus' ZntA, they were not up-regulated in the presence of excess zinc. Proteomic analysis revealed that zinc played a role in oxidative stress in At. caldus and Am. ferrooxidans. Furthermore, 'F. acidarmanus' kept a constant level of intracellular zinc over all conditions tested whereas the intracellular levels increased with increasing zinc exposure in the remaining organisms.

Keywords
Acid mine drainage, Acidophile, Metal resistance, Modeling, Zinc
National Category
Microbiology
Identifiers
urn:nbn:se:umu:diva-60634 (URN)10.1007/s00792-012-0495-3 (DOI)000312779200007 ()23143658 (PubMedID)
Available from: 2012-10-22 Created: 2012-10-22 Last updated: 2018-06-08Bibliographically approved
Nelson, H., Sjöberg, S. & Lövgren, L. (2013). Surface complexation modelling of arsenate and copper adsorbed at the goethite/water interface. Applied Geochemistry, 35, 64-74
Open this publication in new window or tab >>Surface complexation modelling of arsenate and copper adsorbed at the goethite/water interface
2013 (English)In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 35, p. 64-74Article in journal (Refereed) Published
Abstract [en]

The co-adsorption of Cu(II) and arsenate onto the surface of goethite has been studied by performing adsorption experiments and potentiometric titrations, and a surface complexation model has been developed to describe the experimental results. Models for the binary systems, Cu-goethite and arsenate-goethite, were acquired separately and the model parameters were then included in the ternary system, together with the solubility products of solid Cu(II) arsenates reported in the literature. The adsorption of Cu(II) was described applying a model in which Cu(II) forms bidentate bridging mono- and binuclear surface complexes. According to recent interpretations of ATR-FTIR and EXAFS data the arsenate ions are assumed to be coordinated in a monodentate fashion to singly coordinated hydroxyl groups at the surface, and hydrogen-bonded to neighbouring triply coordinated surface oxide sites. In the case of co-adsorption of Cu(II) and arsenate, the adsorption could not be predicted by applying the combined model from the two binary systems. Two ternary Cu(II)-arsenate-goethite surface complexes must be included, one complex in which an arsenate ion is coordinating to surface Fe(III) (≡FeOAsO3Cu0.5-) and one complex in which arsenate is bound to the surface by coordinating to an adsorbed Cu(II) ion (≡(Fe3OFeOH)Cu2(OH)2HAsO41-). No solid Cu (II) arsenate phases were formed under the experimental conditions in the present study. From constructed predominance area diagrams, the significance of adsorption and precipitation processes are discussed. Furthermore, calculated solubility of Cu(II) and As(V) is used to indicate optimum conditions for the cleaning of contaminated natural waters.

Place, publisher, year, edition, pages
Oxford: Elsevier, 2013
Keywords
initio molecular geometries, solid solution interface, alpha-FeOOH, exafs spectroscopy, aqueous solution, oxide minerals, adsorption, (hydr)oxides, speciation, water
National Category
Chemical Sciences
Identifiers
urn:nbn:se:umu:diva-52960 (URN)10.1016/j.apgeochem.2013.03.007 (DOI)000322065800008 ()
Available from: 2012-03-07 Created: 2012-03-07 Last updated: 2018-06-08Bibliographically approved
Lützenkirchen, J., Preočanin, T., Kovačević, D., Tomišić, V., Lövgren, L. & Kallay, N. (2012). Potentiometric titrations as a tool for surface charge determination. Croatica Chemica Acta, 85(4), 391-417
Open this publication in new window or tab >>Potentiometric titrations as a tool for surface charge determination
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2012 (English)In: Croatica Chemica Acta, ISSN 0011-1643, E-ISSN 1334-417X, Vol. 85, no 4, p. 391-417Article in journal (Refereed) Published
Abstract [en]

This article summarizes methods for determining proton surface charge at mineral/water interfaces. It covers conventional experimental procedures and discusses problems with the techniques. Also it involves recommendations for obtaining reasonable and comparable results. The term "comparable results" refers to comparison between results for the same solid as obtained in different laboratories. The most important parameters for the surface titrations are discussed. We also propose a reference titration procedure that would allow direct, unbiased comparisons of experimental data. The article finally includes a check-list for researchers and reviewers which should allow limiting the amount of titration data that are not useful for future uses.

 

Keywords
surface charge, potentiometric titration, surface reaction, pH measurement
National Category
Chemical Sciences
Identifiers
urn:nbn:se:umu:diva-63739 (URN)10.5562/cca2062 (DOI)
Available from: 2013-01-07 Created: 2013-01-07 Last updated: 2018-06-08Bibliographically approved
Persson, P., Andersson, T., Nelson, H., Sjöberg, S., Giesler, R. & Lövgren, L. (2012). Surface complexes of monomethyl phosphate stabilized by hydrogen bonding on goethite (α-FeOOH) nanoparticles. Journal of Colloid and Interface Science, 386(1), 350-358
Open this publication in new window or tab >>Surface complexes of monomethyl phosphate stabilized by hydrogen bonding on goethite (α-FeOOH) nanoparticles
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2012 (English)In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 386, no 1, p. 350-358Article in journal (Refereed) Published
Abstract [en]

Typically, a significant fraction of phosphorus in soils is composed of organic phosphates, and this fraction thus plays an important role in the global phosphorus cycle. Here we have studied adsorption of monomethyl phosphate (MMP) to goethite (α-FeOOH) as a model system in order to better understand the mechanisms behind adsorption of organic phosphates to soil minerals, and how adsorption affects the stability of these molecules. The adsorption reactions and stability of MMP on goethite were studied at room temperature as a function of pH, time and total concentration of MMP by means of quantitative batch experiments, potentiometry and infrared spectroscopy. MMP was found to be stable at the water-goethite interface within the pH region 3-9 and over extended periods of time, as well as in solution. The infrared spectra indicated that MMP formed three predominating pH-dependent surface complexes on goethite, and that these interacted monodentately with surface Fe. The complexes differed in hydrogen bonding interactions via the auxiliary oxygens of the phosphate group. The presented surface complexation model was based on the collective spectroscopic and macroscopic results, using the Basic Stern approach to describe the interfacial region. The model consisted of three monodentate inner sphere surface complexes where the MMP complexes were stabilized by hydrogen bonding to a neighboring surface site. The three complexes, which had equal proton content and thus could be defined as surface isomers, were distinguished by the distribution of charge over the 0-plane and β-plane. In the high pH-range, MMP acted as a hydrogen bond acceptor whereas it was a hydrogen bond donor at low pH.

Place, publisher, year, edition, pages
Elsevier, 2012
Keywords
Monomethyl phosphate, Goethite, Adsorption, Surface complexation, Infrared spectroscopy Basic Stern Model, Hydrogen bonding, Surface isomers
National Category
Chemical Sciences
Identifiers
urn:nbn:se:umu:diva-58074 (URN)10.1016/j.jcis.2012.07.042 (DOI)22901376 (PubMedID)
Available from: 2012-08-24 Created: 2012-08-24 Last updated: 2018-06-08Bibliographically approved
Nelson, H., Shchukarev, A., Sjöberg, S. & Lövgren, L. (2011). Composition and solubility of precipitated copper(II) arsenates. Applied Geochemistry, 26(5), 696-704
Open this publication in new window or tab >>Composition and solubility of precipitated copper(II) arsenates
2011 (English)In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 26, no 5, p. 696-704Article in journal (Refereed) Published
Abstract [en]

Equilibrium reactions involving Cu(II) and As(V) have been studied with respect to formation of complexes in aqueous solutions as well as formation of solid phases. Potentiometric titrations performed at 25 °C (I = 0.1 M Na(Cl)) and at different Cu to As ratios gave no evidence for the existence of Cu(II) arsenate complexes in solution below the pH of the precipitation boundaries (pH ≈ 4), irrespective of the Cu to As ratio and pH. Mixing of solutions of Cu(II) and As(V) at different proportions and adjusting pH to values ranging from 4 to 9 resulted in precipitation of five different solid phases. The elemental composition of the solids was determined using X-ray Photoelectron Spectroscopy, and Environmental Scanning Microscopy–Field Emission Gun equipped with an energy dispersive spectroscopy detector. The average Cu/As ratio was determined by dissolving the solids. Total soluble concentrations of the components Cu(II) and As(V), as well as the basicity of the solid phases were determined by analysis of aqueous solutions. Based upon these experimental data the stoichiometric composition of the solid phases and their stability were determined. The resulting equilibrium model includes the solid phases Cu3(AsO4)2, Cu3(AsO4)(OH)3, Cu2(AsO4)(OH), Cu5Na(HAsO4)(AsO4)3 and Cu5Na2AsO4)4, where Cu5Na(HAsO4)(AsO4)3 and Cu5Na2(AsO4)4 have not been reported previously. In 0.1 M Na(Cl), Na+ was found to be a significant component in two of the solid phases. The Cu5Na2(AsO4)4 was formed in weakly alkaline conditions with pNa < 2.5. Stability constants for all solid phases have been determined. Distribution diagrams as well as predominance area (pNa–pH) diagrams are presented to illustrate stability fields of the different solid phases.

Place, publisher, year, edition, pages
Elsevier, 2011
National Category
Chemical Sciences
Identifiers
urn:nbn:se:umu:diva-51506 (URN)10.1016/j.apgeochem.2011.01.028 (DOI)
Available from: 2012-01-24 Created: 2012-01-24 Last updated: 2018-06-08Bibliographically approved
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