Prenzel, Jürgen

[["dc.bibliographiccitation.firstpage","447"],["dc.bibliographiccitation.issue","4"],["dc.bibliographiccitation.journal","Journal of plant nutrition and soil science"],["dc.bibliographiccitation.lastpage","454"],["dc.bibliographiccitation.volume","160"],["dc.contributor.author","Ludwig, Bernard"],["dc.contributor.author","Hölscher, Dirk"],["dc.contributor.author","Khanna, Partap"],["dc.contributor.author","Prenzel, Jürgen"],["dc.contributor.author","Fölster, Horst"],["dc.date.accessioned","2017-09-07T11:45:46Z"],["dc.date.available","2017-09-07T11:45:46Z"],["dc.date.issued","1997"],["dc.description.abstract","The results of physico-chemical investigations of an Ultisol subsoil under a 2-year old fallow in eastern Amazonia are presented. Subsoil chemistry was studied using 4 different approaches: i) concentrations of H, Na, K, Ca, Mg, Mn, Al, and Fe in seepage water were measured under field conditions, ii) the equilibrium soil chemistry was studied in sequential batch experiments where the soil was treated with different solutions, iii) results of batch experiments were simulated with a chemical equilibrium model, and iv) the seepage data were calculated using selectivity coefficients obtained by modelling the batch experiments. The model included multiple cation exchange, precipitation/dissolution of Al(OH)3 and inorganic complexation. Cation selectivity coefficients were pKx/Casel: X = Na: 0.3, K: 0.8, Mg: −0.1, and Al: 0.4. The amount of cations sorbed ranged from −0.2 to 2.0 (K), −0.7 to 2.3 (Mg), −1.6 to 1.8 (Ca), −4.8 to 3.6 (Al) and 0.0 to 8.5 (Na) mmolc kg−1. The model predictions were good with values lying within 0.3 pH units (for the pH range 3.7 to 7.2), and 3% of CEC for individual cations. The most important proton buffer reaction seemed to be the dissolution of gibbsite and a large release of Al into the soil solution. When selectivity coefficients obtained by the modelling procedure were used to predict the field data for cation concentrations in the seepage water, they decreased in the following order: Na > K > Ca > Mg > Al. These calculated values were similar to the measured order: Na > Ca > K ≈ Mg > Al. Thus the options for managing these soils should be carefully chosen to avoid soil acidification which may result from inappropriate use of fertilizer during the cropping period."],["dc.identifier.doi","10.1002/jpln.19971600403"],["dc.identifier.gro","3149090"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/5737"],["dc.language.iso","en"],["dc.notes.intern","Hoelscher Crossref import"],["dc.notes.status","final"],["dc.notes.submitter","chake"],["dc.relation.issn","0044-3263"],["dc.title","Modelling of sorption experiments and seepage data of an Amazonian Ultisol subsoil under cropping fallow"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","87"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Journal of Geochemical Exploration"],["dc.bibliographiccitation.lastpage","95"],["dc.bibliographiccitation.volume","73"],["dc.contributor.author","Ludwig, B."],["dc.contributor.author","Prenzel, J."],["dc.contributor.author","Obermann, P."],["dc.date.accessioned","2018-11-07T08:36:05Z"],["dc.date.available","2018-11-07T08:36:05Z"],["dc.date.issued","2001"],["dc.description.abstract","Secondary reactions occurring in pyrite-containing sediments from open cut coal mines are complex and not fully understood. In this study, the changes in seepage water composition in a column experiment with a sediment containing pyrite (5.6 g kg(-1)) were evaluated using a chemical equilibrium model. A column experiment with artificial irrigation (730 mm water yr(-1)) was carried out for 2 yr with a sediment from the open pit mine Garzweiler, Germany, at the Institute of Applied Geology. Tracer (LiCl) was added to the sediment. Seepage water composition at 52 cm depth was sampled weekly. Redox potential and the water potential were also recorded weekly. Sulphate and Fe(II) were the dominant ions in the seepage water with concentration maxima of 500 and 350 mmol l(-1) after 50 days (0.7 pore volumes (PV)). Minimum pH values were around 0.8 after 100 days (1.4 PV), but increased subsequently and reached 2.4 after 700 days (9.5 PV). Ion activity product calculations indicated the intermediate formation of gypsum (19th-480th day of the experiment). Solutions were undersaturated with respect to alunite, jarosite, jurbanite, schwertmannite, melanterite, gibbsite and goethite during the whole experiment. The model of coupled equilibria which included inorganic complexation, precipitation/dissolution of gypsum and multiple cation exchange was tested. Pyrite oxidation and pH-dependent silicate weathering were considered using simple input functions. Transport was modelled using a field capacity cascade submodel. Model results showed satisfactory agreement with measured values for pH and concentrations of SO4, Fe, Mg, Ca and Al. Correlation coefficients lay between 0.7 and 0.9 and linear regression coefficients (modelled against measured) were 1.5 (Ca), 1.0 (Fe, SO4), 0.8 (Mg), 0.7 (pH) and 0.6 (Al). The results showed that the protons produced during pyrite oxidation (94 mmol(c) H+ kg(-1)) were mainly released into seepage water (as HSO4- and H+). Cation exchange reactions buffered 20 mmol, of H+ kg(-1) sediment, and Al released by silicate weathering accounted for 3.6 mmol, H+ kg(-1). Modelling was useful to further understand the significance of different pH buffer reactions. (C) 2001 Elsevier Science B.V. All rights reserved."],["dc.identifier.doi","10.1016/S0375-6742(01)00190-X"],["dc.identifier.isi","000171650900004"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/18227"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Bv"],["dc.publisher.place","Amsterdam"],["dc.relation.conference","International Symposium on the Ecology of Post-Mining Landscapes"],["dc.relation.eventlocation","BRANDENBURG UNIV TCHNOL, COTTBUS, GERMANY"],["dc.relation.issn","0375-6742"],["dc.title","Modelling ion composition in seepage water from a column experiment with an open cut coal mine sediment"],["dc.type","conference_paper"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1055"],["dc.bibliographiccitation.issue","10"],["dc.bibliographiccitation.journal","Waste Management"],["dc.bibliographiccitation.lastpage","1066"],["dc.bibliographiccitation.volume","25"],["dc.contributor.author","Ludwig, Bernard"],["dc.contributor.author","Khanna, Partap"],["dc.contributor.author","Prenzel, Jürgen"],["dc.contributor.author","Beese, Friedrich"],["dc.date.accessioned","2018-11-07T08:49:12Z"],["dc.date.available","2018-11-07T08:49:12Z"],["dc.date.issued","2005"],["dc.description.abstract","Most ashes contain a significant amount of heavy metals and when released from disposed or used ash materials, they can form a major environmental concern for underground waters. The use of water extracts to assess the easily mobilisable content of heavy metals may not provide an appropriate measure. This study describes the patterns of heavy metal release from ash materials in context with results from the German standard extraction method DIN-S4 (DIN 38 414 S4). Samples of four different ashes (municipal solid waste incineration ash, wood ash, brown coal ash and hard coal ash) were subjected to a number of serial batch tests with liquid renewal, some of which involved the addition of acid to neutralize carbonates and oxides. Release of heavy metals showed different patterns depending on the element, the type of material, the method of extraction and the type of the extractant used. Only a small fraction of the total heavy metal contents occurred as water soluble salts; of special significance was the amount of Cr released from the wood ash. The reaction time (1, 24 or 72 h between each extraction step with water) had only a small effect on the release of heavy metals. However, the release of most of the heavy metals was governed by the dissolution processes following proton inputs, indicating that pH-dependent tests such as CEN TC 292 or others are required to estimate long-term effects of heavy metal releases from ashes. Based on the chemical characteristics of ash materials in terms of their form and so] ability of heavy metals, recommendations were made on the disposal or use of the four ash materials. (c) 2005 Elsevier Ltd. All rights reserved."],["dc.identifier.doi","10.1016/j.wasman.2005.01.007"],["dc.identifier.isi","000233176100008"],["dc.identifier.pmid","15979297"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/21402"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Pergamon-elsevier Science Ltd"],["dc.relation.issn","0956-053X"],["dc.title","Heavy metal release from different ashes during serial batch tests using water and acid"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Journal of Inorganic Biochemistry"],["dc.bibliographiccitation.volume","86"],["dc.contributor.author","Ludwig, Bernard"],["dc.contributor.author","Khanna, P."],["dc.contributor.author","Prenzel, J."],["dc.date.accessioned","2018-11-07T08:49:26Z"],["dc.date.available","2018-11-07T08:49:26Z"],["dc.date.issued","2001"],["dc.format.extent","68"],["dc.identifier.isi","000170467300613"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/21455"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Inc"],["dc.publisher.place","New york"],["dc.relation.issn","0162-0134"],["dc.title","Modelling environmentally important chemical processes in soils"],["dc.type","conference_abstract"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]