Hans Chr. Bruun Hansen

Short presentation

Hans Christian Bruun Hansen, Professor in Environmental Chemistry. PhD 1991 – University of Copenhagen. I have my main interest in solid-solution processes in soils and sediments governing pollutant fate and with applications in soil and water cleaning. I have been working with many topics in in terrestrial environmental chemistry, but three fields have particular focus: i) Engineering and reactivity of iron(II)iron(III) hydroxides (“green rusts”) particles, ii) phosphate bonding in anoxic soils, and iii) fate of natural toxins.  We were among the first to explore the strong reducing capacity of green rusts, e.g.  reduction of nitrate to ammonium, and reductive dehalogenation of chlorinated alkanes. Recently, we have found that green rusts can be used as precursor for formation of single sheet iron oxides – 1 nm thick. These particles have interesting uses as photo- and electrocatalysts.  I am teaching environmental chemistry from BSc to PhD level .

CV

Born 12 April 1959 (Denmark, Danish)

Higher education

PhD 1987 – 91            Chemistry Dept., Royal Veterinary and Agricultural University, Copenhagen

MSc 1981 – 87            Cand. silv., Royal Veterinary and Agricultural University, Copenhagen

Appointments

2007 -            Professor in Environmental Chemistry, Dept. Plant and Environmental Sciences (previously Dept. Basic Sciences and Environment) , University of Copenhagen

1999 - 2007   Professor in Environmental Chemistry, Chemistry Department, Royal Veterinary and Agricultural University

1994 – 1998   Associate Professor, Chemistry Dept., Royal Veterinary and Agricultural University

1990 – 1994   Assistant Professor, Chemistry Dept., Royal Veterinary and Agricultural University

1989 – 1990   Teaching assistant, Chemistry Dept., Royal Veterinary and Agricultural University

Duties and positions of trust

2005 -            Head, Section of Environmental Chemistry and Physics (40 persons)

2007 - 2009   Head of Water Research Initiative (VIVA)

2005 - 2007   Board of Danish Environmental Research Institute

2005 - 2008   Member of the Danish Water Research Platform

2004 – 2012   Member of Academic Council and Research Committee at Royal Veterinary and Agriculturual University, later University of Copenhagen

2003 - 2012   Head of PhD research school in Environmental Chemistry, Microbiology and Toxicology (RECETO)

2002 - 2005   Member of Research Council for Development Research

2002 – 2004   Øresund Environment Board

2001 - 2006   Member of Danish Research Councils (SJVF, FTP; vice head)

2000 -            Referee for more than 20 journals, e.g. Environmental Science and Technology, Environmental Toxicology and Chemistry, Nanoscale, Clays and Clay Minerals, Geochimica et Cosmochimica Acta,

2000 -            5  10 annual tasks in relation to assessment of proposals (5 countries), PhD theses (7 countries), and and job applications (4 countries) abroad.

Memberships

Society of Environmental Toxicology and Chemistry (SETAC), European Clay Groups Association (EGGA), Mineralogical Society, European Association of Geochemistry (EAG), International Soil Science Society (ISSS), and Danish Chemical Society

Research area

Research with focus on chemical reactions of inorganic and organic pollutants at solid-solution interfaces in geoenvironments with implications for soil and water quality: i) Reactions of metal hydroxide/oxide particles with particular emphasis on reduction/oxidation, hydrolysis, and photodegradation of priority pollutants, including synthesis of nanocomposites for remediation of polluted soils and groundwater,  ii) Thermodynamics and kinetics of sorption processes important for applications in soil and water cleaning technology and with main focus on surface complexation reactions, and iii) Organic environmental chemistry with main focus on biotoxins and pesticides. In this field main focus has been on carcinogenic indanones, glucosinolates-isothiocyanates, and cyanogenic glucosides.

Current research projects

• Sustainable phosphorus remediation and recycling technologies in the landscape (SupremeTech). Danish Research Council for Strategic Research, 2010 – 2015, xx mill DKr.

• Iron hydroxide intercalates for degradation of halogenated solvents in sediment and groundwater (Iron-X). Danish Research Council for Technology and Production, 2011 – 2014, xx mill Dkr.

• Innovative cleaning technologies for production of drinking water during flooding episodes. DANIDA, 2012 – 2015, xx mill Dkr

• Sino-Danish Research Center Beijing – Water and Environment. Post Doc and PhD projects. Danish Ministery for Science, Technology and Innovation, 2011 - , 1 mill Dkr/year

• From soil to streamwater – fate and toxicity of insecticides in surfacewater. Danish Environmental Protection Agency, 2011 – 2013, 0.4 mill Dkr

• From surface to drinking water by combined filtration and electrochemical disinfection. Danish Environmental Protection Agency, 2013 – 2014, ??

• High-affinity double porous filter materials – from physical chemistry to industrial coating with iron oxides (Ultrasorb). Danish Research Council for Strategic Research, 2012 – 2013, 0.5 mill DKr.

Completed more than 15 projects within the last 10 years covering external funding of approximately 35 mill DKr.

Teaching

Since 1990 taught 19 different courses from BSc to PhD level, and supervised 69 MSc thesis projects and 25 PhD projects – all experimental. Current supervisor for 5 PhD students and 3 MSc students. Initiated (2005) a European MSc study programme: “Environmental Science: Soil, Water and Biodiversity (EnvEuro)” (3 European Universities), and co-initiator (2005) of international MSc programme in Environmental Chemistry and Health at University of Copenhagen. Partner (2000 – 2006) in SLUSE educational network with South Africa, Thailand and Malaysia. Partner (2011) in the Sino-Danish programme “Water and Environment”.

The following two lines of research have been pioneering and also have had significant impact : i) formation and reactivity of mixed-valence iron hydroxides (so called green rusts), and ii) analysis and fate of natural plant-produced toxins and other organic pollutants in soil.

Green rusts: Hansen et al. (1994) demonstrated that previously published data for mixed-valence iron hydroxides in soil were wrong and that the precipitate forming when amorphous iron(III)hydroxide reacts with iron(II) is an iron(II)iron(III) hydroxide-sulphate (green rust) with a distinct structure. This work was followed by Hansen et al. (1996) who for the first time showed that green rusts can reduce nitrate with stoichiometric formation of ammonium – a study which was followed by a suite of other studies. Three years later Erbs et al. (1999) showed that green rusts are also capable to dehalogenate chlorinated alkanes – an extremely interesting observation with huge perspectives. Green rusts can be engineered, and Ayala-Luis et al. (2012) showed that an organo-intercalated green rust reduced tetrachloremethane much faster and with complete dehalogenation compared with parent green rusts. Finally, Huang et al. (2013) made a fantastic observation: oxidation of organo-intercalated green rusts followed by delamination leads to formation of 1 nm thick single-sheets of iron oxide – with huge perspectives for sorption and catalysis and as templates for surface-chemical reactions.

Natural toxins: Rasmussen et al. (2003) for the first time documented the presence of carcinogenic ptquiloside in soil below bracken stands. This work was followed by many other works focusing on the kinetics of degradation in soil, in particular Ayala-Luis et al (2006) made a breakthrough. As for ptaquiloside glucosinolates was shown to be weakly sorbed, and rather quickly transformed (Gimsing et al., 2006), but generating high concentrations of toxic isothiocyanates. More than 30 publications have been made on fate and toxicity of natural toxins in soil environments – with significance for risk assessment of crop plants incl. GMO crops.

Other surprising observations have been made on other topics in environmental chemistry, and the work by Fang et al. (2010) is a classical and beautiful example of sorption of variable charged pollutant species sorb to variable charged surfaces and the modelling hereof.