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Träfflista för sökning "LAR1:cth ;lar1:(gu);lar1:(cth);pers:(Blanck Hans 1950)"

Sökning: LAR1:cth > Göteborgs universitet > Chalmers tekniska högskola > Blanck Hans 1950

  • Resultat 1-10 av 20
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  • Andersson Trojer, Markus, 1981-, et al. (författare)
  • Imidazole and Triazole Coordination Chemistry for Antifouling Coatings
  • 2013
  • Ingår i: Journal of Chemistry. - 2090-9063. ; 2013
  • Tidskriftsartikel (refereegranskat)abstract
    • Fouling of marine organisms on the hulls of ships is a severe problem for the shipping industry. Many antifouling agents are based on five-membered nitrogen heterocyclic compounds, in particular imidazoles and triazoles. Moreover, imidazole and triazoles are strong ligands for Cu2+ and Cu+, which are both potent antifouling agents. In this review, we summarize a decade of work within our groups concerning imidazole and triazole coordination chemistry for antifouling applications with a particular focus on the very potent antifouling agent medetomidine. The entry starts by providing a detailed theoretical description of the azole-metal coordination chemistry. Some attention will be given to ways to functionalize polymers with azole ligands. Then, the effect of metal coordination in azole-containing polymers with respect to material properties will be discussed. Our work concerning the controlled release of antifouling agents, in particular medetomidine, using azole coordination chemistry will be reviewed. Finally, an outlook will be given describing the potential for tailoring the azole ligand chemistry in polymers with respect to Cu2+ adsorption and Cu2+ Cu+ reduction for antifouling coatings without added biocides.
  • Andersson Trojer, Markus, 1981-, et al. (författare)
  • Use of microcapsules as controlled release devices for coatings
  • 2015
  • Ingår i: Advances in Colloid and Interface Science. - 0001-8686. ; 222, s. 18-43
  • Tidskriftsartikel (refereegranskat)abstract
    • Biofouling of surfaces is a considerable problem in many industrial sectors and for the public community in general. The problem is usually approached by the use of functional coatings and most of such antifouling coatings rely on the effect of biocides. However, a substantial drawback is the poor control over the release of the biocide as well as its degradation in the paint. Encapsulation of the biocides in microcapsules is a promising approach that may overcome some of the problems associated with the more traditional ways of incorporating the antifouling agent into the formulation. In this review, we summarize more than a decade of microcapsule research from our lab as well as from other groups working on this topic. Focus will be on two coacervation-based encapsulation techniques; the internal phase separation method and the double emulsion method, which together enable the encapsulation of a broad spectrum of biocides with different physicochemical properties. The release of the biocide from core-shell particles and from encapsulated biocides in coatings is treated in detail. The release behaviour is interpreted in terms of the physicochemical properties of the core-shell particle and the coating matrix. In addition, special attention is given to the experimental release methodology and the implementation of proper diffusion models to describe the release. At the end of the review examples of antifouling properties of some coatings against common biofoulers are presented.
  • Blanck, Hans, 1950-, et al. (författare)
  • New strategy for design of optimised combinations of antifoulants: mixture efficacy predictions, risk weighting and microcapsule technology
  • 2008
  • Ingår i: 14th International Congress on Marine Corrosion and Fouling, July 2008, Kobe Japan.
  • Konferensbidrag (refereegranskat)abstract
    • Organisms differ in their sensitivity to toxicants, and each biocide will have its own efficacy profile. Whenever an antifoulant is used to affect organisms beyond its high-efficacy profile, an excess of biocides will be emitted to the environment. We propose an unprejudiced and rational design of efficacy-optimised combinations with minimum environmental risk. To control release of several antifoulants independently we use microcapsules bound to a polymer coating. The approach is based on three initial steps: Mixture toxicity concepts are used to predict efficacy of >100 000 combinations of 2-8 antifoulants. Predictions are based on full concentration-efficacy relationships with regard to prevention of settling of fouling model organisms (e.g. periphyton, sea lettuce, barnacles, sea squirt, blue mussel). Based on the predictions we will identify a set of > 100 000 combinations that are efficacious to all model organisms, and define their mixture concentrations and mixture ratios. Risk ratios (e.g. PEC/ PNEC) for the individual antifoulants are then used as weighing factors to rank the combinations according to their estimated relative risk to the environment. This results in a set of promising antifoulant combinations defined by their constituents, mixture ratios and total concentrations in water. The release rate from each of the individual mixture components will be regulated by microcapsule numbers, chemical and physical properties, to deliver the expected combination at the surface of the ship hull. The flexibility of the paint formulation ・with one antifoulant only in each capsule ・suggests that the coating can easily be reformulated to adjust to more demanding conditions. This study is a part of the Marine Paint Research Programme funded by MISTRA, the Foundation for Strategic Environmental Research, Sweden.
  • Dahlbäck, Björn, et al. (författare)
  • The Challenge to Find New Sustainable Antifouling Approaches for Shipping
  • 2010
  • Ingår i: Coastal Marine Science. - 1349-3000. ; 34:1, s. 212-215
  • Tidskriftsartikel (övrigt vetenskapligt)abstract
    • Fouling of ships and its counter measure – antifouling – is receiving justified attention as a serious marine environmental problem. If the ship is fouled its fuel consumption will increase radically. If a ship is fouled its emissions to air will increase, its manoeuvrability will be affected and it will contribute to the spreading of aliens. The present antifouling strategies seem to be non-sustainable, either environmentally or technically/commercially. The large amounts of biocides used in antifouling paints constitute a marine pollution problem. Research for more sustainable solutions, biocidal as well as non-biocidal, is ongoing. Optimisation of new antifoulant combinations combined with microcapsule technology will offer the possibility to decrease the exposure of the marine environment to antifouling biocides.
  • Dahllöf, Ingela, 1963-, et al. (författare)
  • Long-term effects of tri-n-butyltin on the function of a marine sediment system
  • 1999
  • Ingår i: Marine Ecology Progress Series. ; 188, s. 1-11
  • Tidskriftsartikel (refereegranskat)abstract
    • The effect of tri-n-butyl-tin (TBT) was studied in a 5 mo experiment using intact coastal sediment communities in a boxcosm system. TBT-spiked sediment was added in a geometrical series between 0.0065 and 300 mu mol TBT m(-2) to a sediment that already had a background TBT concentration. Fluxes of ammonium, nitrate, phosphate, silicate and oxygen were used as effect indicators for the entire sediment system, integrating the function of all fauna and micro-organisms present. Changes in flux patterns were analysed in order to evaluate the effect of TBT on the whole sediment system using a non-parametric analysis of similarities (ANOSIM), based on Bray-Curtis similarity indices. Effects were seen at the lowest additions of 6.5 nmol TBT m(-2) as changes in flux pattern compared to the control sediments. The separate nutrient fluxes were also evaluated, showing an early response in a reduced ammonium flux and a stimulated nitrate flux for most of the TBT additions. The initial response indicated immediate effects on the microbial part of the sediment community. The fluxes changed with time in all sediment boxes, but the changes were different in sediments with added TBT compared to the control sediment. These changes showed that the heterotrophic capability to degrade organic matter and autotrophic nitrification was reduced during the 5 mo of the experiment. In the 3 highest additions, the abundance of macrofauna was reduced at the very beginning of the experiment, whereas fauna in the intermediate additions seemed to become stressed with time as indicated by an increased oxygen consumption. This study shows that minute additions of fresh TBT to an already contaminated sediment have effects on the function of the sediment system at nominal concentrations of nmol of TBT added per square metre. These additions were well below the current detection limits for TBT in sediments.
  • Eriksson, Karl Martin, 1970-, et al. (författare)
  • Long-term effects of the antibacterial agent triclosan on marine periphyton communities
  • 2015
  • Ingår i: Environmental Toxicology and Chemistry. - 0730-7268. ; 34:9, s. 2067-2077
  • Tidskriftsartikel (refereegranskat)abstract
    • Triclosan is a widely used antibacterial agent that has become a ubiquitous contaminant in freshwater, estuary, and marine environments. Concerns about potential adverse effects of triclosan have been described in several recent risk assessments. Its effects on freshwater microbial communities have been well studied, but studies addressing effects on marine microbial communities are scarce. In the present study, the authors describe short- and long-term effects of triclosan on marine periphyton (microbial biofilm) communities. Short-term effects on photosynthesis were estimated after 60min to 210min of exposure. Long-term effects on photosynthesis, chlorophyll a fluorescence, pigment content, community tolerance, and bacterial carbon utilization were studied after exposing periphyton for 17d in flow-through microcosms to 0.316nM to 10000nM triclosan. Results from the short-term studies show that triclosan is toxic to periphyton photosynthesis. Half maximal effective concentration (EC50) values of 1080nM and 3000nM were estimated using (CO2)-C-14-incorporation and pulse amplitude modulation (PAM) fluorescence measurements, respectively. After long-term triclosan exposure in flow-through microcosms, photosynthesis estimated using PAM fluorometry was not inhibited by triclosan concentrations up to 1000nM but instead increased with increasing triclosan concentration. Similarly, at exposure concentrations of 31.6nM and higher, triclosan caused an increase in photosynthetic pigments. At 316nM triclosan, the pigment amounts were increased by a factor of 1.4 to 1.9 compared with the control level. Pollution-induced community tolerance was observed for algae and cyanobacteria at 100nM triclosan and higher. Despite the widespread use of triclosan as an antibacterial agent, the compound did not have any effects on bacterial carbon utilization after long-term exposure.
  • Gustafsson, Mikael, 1965-, et al. (författare)
  • Benthic foraminiferal tolerance to tri-n-butyltin (TBT)
  • 2000
  • Ingår i: Marine Pollution Bulletin. ; 40, s. 1072-1075
  • Tidskriftsartikel (refereegranskat)abstract
    • Tri-n-butyltin (TBT) has been used in the marine environment as a toxic agent in antifouling paints, but unfortunately it also has negative effects on non-target organisms in the environment. In this study, intact coastal sediment was exposed for seven months to three levels of TBT corresponding to nominal additions of 0.00, 0.02 and 2.00 nmol TBT per g dry sediment. This paper presents the first attempt to find out how living benthic foraminifera respond to TBT, Increased foraminiferal abundance in the 0.02 nmol mesocosm could be an effect of decreased predation (competition), since other representatives of meiofauna and macrofauna tended to be less tolerant to TBT, Increasing toxicity in the most contaminated mesocosm group (2.00 nmol) resulted in a less abundant foraminiferal population suggesting that TBT affects the foraminiferal community.
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