Acta Hydrochimica Et Hydrobiologica最新文献

{"title":"Festkontaktierte potentiometrische Elektroden fr Sulfatbestimmungen in wssrigen Lsungen","authors":"M. Berthold, H. Jahn, H. Kaden","doi":"10.1002/1521-401X(200111)29:4<219::AID-AHEH219>3.0.CO;2-N","DOIUrl":"https://doi.org/10.1002/1521-401X(200111)29:4<219::AID-AHEH219>3.0.CO;2-N","url":null,"abstract":"Es wurde eine festkontaktierte Elektrode fur die potentiometrische Messung von Sulfationen in wassrigen Losungen entwickelt und untersucht. Die Elektrode basiert auf einer PVC-Membran, die das Ionophor 3-Decyl-1,5,8-triazacyclodecan-2,4-dion (DTADD) enthalt. Anstatt der ublichen inneren Flussigableitung wurde als Festkontakt eine Polypyrrolschicht verwendet, die auf der inneren Seite der PVC-Membran aufgebracht wurde. Die Eigenschaften dieser Elektrode wurden mit denen von Sulfatelektroden mit dem Ionophor α,α′-Bis(N′-phenylthioureylen)-m-xylen (BTH) und von Coated-wire-Elektroden verglichen. Fur die Parameter Sensitivitat, Selektivitat und Langzeitstabilitat ergeben Elektroden mit dem Ionophor DTADD verbesserte Eigenschaften. Im Konzentrationsbereich 5·10–5...10–2 mol L–1 SO42– wurde eine Steilheit von –(26.8 ± 0.5) mV/Dekade gefunden. Die Ansprechzeit t95 betragt ungefahr 10 s bei der Anderung der Sulfatkonzentration von 10–4 mol L–1 auf 10–3 mol L–1. Die neuen Sulfatelektroden weisen uber einen Zeitraum von 150 Tagen eine sehr niedrige Drift des Elektrodenpotentials auf. Die Selektivitat der Elektrode mit DTADD als Ionophor gegenuber dem Storion Nitrat ist hoher als bei Verwendung von BTH. Auch im Vergleich mit in der Literatur beschriebenen, andere Ionophore enthaltenden sulfatselektiven Elektroden mit flussigen inneren Referenzelektrolyten werden Verbesserungen erreicht. \u0000 \u0000 \u0000 \u0000Solid-contacted Potentiometric Electrodes for Measurements of Sulfate Ions in Aqueous Solutions \u0000 \u0000 \u0000 \u0000A solid-contact electrode for potentiometric measurement of sulfate ions in aqueous solutions was developed and examined. The electrode is based on a PVC membrane which contains the ionophore 3-decyl-1,5,8-triazacyclodecan-2,4-dione (DTADD). Instead of the usual inner fluid junction, a polypyrrole layer applied on the inner side of the PVC membrane was employed as inner solid contact. The performance of this electrode was compared to solid-state sulfate-selective electrodes with the ionophore α,α′-bis(N′-phenylthioureylene)-m-xylene (BTH) and to electrodes in the coated-wire configuration. For the parameters sensitivity, selectivity, and long-term stability, electrodes with the DTADD ionophore show improved properties. In the sulfate concentration range of 5·10–5...10–2 mol L–1 the slope of the response is –(26.8 ± 0.5) mV/decade. The new solid contact sulfate electrodes showed a very low drift of the electrode potential within a period of 150 days when the electrode was stored in 10–2 M Na2SO4. In Na2SO4 solutions of the pH range of 4...9 the electrode potentials were constant. The 95% response time was about 10 s when the sulfate concentration was changed from 10–4 mol L–1 to 10–3 mol L–1. The selectivity with DTADD ionophore relating to the nitrate ions is higher than the selectivity with BTH. Improvements are also made in comparison with sulfate-selective electrodes described in the literature which contain other ionophores with fluid inner reference electrolytes","PeriodicalId":7010,"journal":{"name":"Acta Hydrochimica Et Hydrobiologica","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86954881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dissolved humic substances can directly affect freshwater organisms","authors":"S. Pflugmacher, Linda Fay Tidwell, C. Steinberg","doi":"10.1002/1521-401X()29:1<34::AID-AHEH34>3.0.CO;2-8","DOIUrl":"https://doi.org/10.1002/1521-401X()29:1<34::AID-AHEH34>3.0.CO;2-8","url":null,"abstract":"Direct effects of pure humic substance (BS1 FA) on three different aquatic organisms (Ceratophyllum demersum, Dreissena polymorpha, and Chaetogammarus ischnus) were demonstrated in this study. Exposure to environmentally relevant concentrations (0.5 mg/L) of this humic substance led to the activation of the microsomal and soluble glutathione S-transferase (GST) in Ceratophyllum demersum. Exposure to 3-chlorobiphenyl showed also an elevation of GST activity, which is due to the proposed detoxication metabolism of these chlorinated biphenyl. Coexposure to a mixture of 3-chlorobiphenyl and BS1 FA showed a reduction of enzyme elevation, but still significant over an untreated control. The direct impact of humic substances seems not to be restricted to a specific class of organisms.","PeriodicalId":7010,"journal":{"name":"Acta Hydrochimica Et Hydrobiologica","volume":"28 1","pages":"34-40"},"PeriodicalIF":0.0,"publicationDate":"2001-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78313712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Adjustment of a Formulated Sediment for Sediment Testing with Caenorhabditis elegans (Nematoda)","authors":"Hermann Glatzer, W. Ahlf","doi":"10.1002/1521-401X()29:1<41::AID-AHEH41>3.0.CO;2-O","DOIUrl":"https://doi.org/10.1002/1521-401X()29:1<41::AID-AHEH41>3.0.CO;2-O","url":null,"abstract":"The OECD soil, which is standardised for use in the sediment toxicity with the midge Chironomus riparius revealed inhibition of the nematode Caenorhabditis elegans in body growth length and egg production of 41.0% and 84%, respectively. 18 formulated sediments were tested to optimise the sediment composition for growth and reproduction of C. elegans. Their components were chosen to simulate native sediments, whereby different quantities and different clay minerals were tested. The mixture that we found to be optimal in our experiments consisted of 5% sphagnum peat, 70% calcitic sand, 0.5% dolomite limestone, 4.5% iron(III) oxide, and a clay combination of 1.5% chlorite and 18.5% aluminium(III) oxide. When applying this mixture to C. riparius, the new formulated sediment improved also growth in comparison to the OECD sediment. \u0000 \u0000 \u0000 \u0000Anpassung der Zusammensetzung eines kunstlichen Sedimentes fur den Toxizitatstest mit Caenorhabditis elegans (Nematoda) \u0000 \u0000 \u0000 \u0000Der OECD-Boden, welcher fur Toxizitatstests mit Chironomus riparius auch als Sediment standardisiert ist, erzeugt eine Verminderung des Langenwachstums von 41% und eine Hemmung der Reproduktionsleistung von 84% bei dem Nematoden Caenorhabditis elegans gegenuber einem optimierten kunstlichen Sediment. 18 aus einzelnen Bestandteilen gemischte Sedimente wurden getestet, um eine optimale Zusammensetzung fur das Wachstum und die Reproduktion von C. elegans zu finden. Die Komponenten wurden so gewahlt, dass ein naturliches Sediment mit seinen Bestandteilen nachgebildet werden sollte. Die optimale Mischung, die wir durch Toxizitatstests fanden, besteht aus 5% Sphagnumtorf, 70% Sand, 0.5% Dolomit, 4.5% Eisen(III)-oxid sowie einer Tonkombination von 1.5% Chlorit and 18.5% Aluminium(III)-oxid. Dieses kunstliche Sediment verbesserte auch das Wachstum von C. riparius im Vergleich zu dem Wachstum im OECD-Sediment.","PeriodicalId":7010,"journal":{"name":"Acta Hydrochimica Et Hydrobiologica","volume":"7 1","pages":"41-46"},"PeriodicalIF":0.0,"publicationDate":"2001-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78887316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spectroscopic Characterization of Fulvic Acid Fractions of a Contaminated Groundwater","authors":"M. Kumke, C. Zwiener, G. Abbt-Braun, F. Frimmel","doi":"10.1002/(SICI)1521-401X(199912)27:6<409::AID-AHEH409>3.0.CO;2-V","DOIUrl":"https://doi.org/10.1002/(SICI)1521-401X(199912)27:6<409::AID-AHEH409>3.0.CO;2-V","url":null,"abstract":"Two fulvic acid (FA) samples taken from a former gas production facility in the Southwest of Germany were characterized using advanced fluorescence techniques. Steady-state fluorescence (fluorescence excitation, synchronous fluorescence) as well as time-resolved fluorescence were applied. Distinct differences between the sample B22 FA taken within the contamination plume and the sample B53 FA taken downstream were found. Comparison with a model compound for metabolites and humic substances revealed that due to the downstream passage the characteristics of the dissolved organic matter became more humic-like. The assignment of single classes of compounds in the sample B22 FA is discussed in terms of their synchronous fluorescence spectra and fluorescence decay time distribution.","PeriodicalId":7010,"journal":{"name":"Acta Hydrochimica Et Hydrobiologica","volume":"81 1","pages":"409-415"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79700152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Boron Isotopic Composition of Freshwater Lakes from Central Europe and Possible Contamination Sources","authors":"A. Vengosh, S. Barth, K. Heumann, S. Eisenhut","doi":"10.1002/(SICI)1521-401X(199912)27:6<416::AID-AHEH416>3.0.CO;2-2","DOIUrl":"https://doi.org/10.1002/(SICI)1521-401X(199912)27:6<416::AID-AHEH416>3.0.CO;2-2","url":null,"abstract":"The boron isotopic compositions of common synthetic boron products, municipal wastewaters from Switzerland, and three Swiss freshwater lakes were investigated. The δ11B values (δ11B values are normalized to the standard NIST SRM-951) of synthetic Na-borates (–0.4 to 7.6‰) and Ca-Na-borates (–13.4 to –4.9‰) overlap with those of natural borate minerals and hence suggest that the isotopic signal of anthropogenic boron is not modified during the manufacturing process. As a result it is possible to predict the isotopic composition of synthetic boron products and their potential impact upon contamination of water resources. The δ11B values of municipal wastewaters from two locations in northern Switzerland (–7.7 to –4.5‰) reflect utilization of Na/Ca- and/or Ca-borates depleted in 11B. Freshwater lakes from Switzerland (Lake Zurich, Greifensee, Lake Lugano) yielded a δ11B range of –1.7 to 7.1‰ and boron concentrations of 17 to 102 mg L–1. The boron isotopic ratios decrease with increasing boron concentrations, indicating mixing between anthropogenic boron with a low δ11B signature and meteoric boron with a heavier isotopic signal. We suggest that the isotopic composition of meteoric boron over central Europe has δ11B values in the range of ca. 10 to 20‰, whereas in coastal areas the marine component is larger with a higher 11B/10B ratio (δ11B ∼ 30‰). \u0000 \u0000 \u0000 \u0000Isotopenzusammensetzung des Bors in einigen zentraleuropaischen Suswasserseen und mogliche Kontaminationsquellen \u0000 \u0000 \u0000 \u0000Untersucht wurde die Isotopenzusammensetzung von verbreiteten synthetischen Borprodukten, von kommunalen Abwassern in der Schweiz und von drei Schweizer Suswasserseen. Die δ11B-Werte (bezogen auf den Standard NIST SRM-951) synthetischer Natriumborate (–0.4 bis 7.6‰) und Calciumborate (–13.4 bis –4.9‰) uberlappen mit denen naturlicher Boratminerale, was den Schlus nahelegt, das sich die Isotopensignatur bei der Verarbeitung zu kunstlichen Borprodukten beim Herstellungsprozes nicht verandert. Folglich ist es moglich, die Isotopenzusammensetzung synthetischer Borprodukte vorherzusagen bzw. aus der Isotopenzusammensetzung Bor-kontaminierter Gewasser auf den Eintragspfad zu schliesen. Die δ11BB-Werte des kommunalen Abwassers von zwei Orten in der Nordschweiz (–7.7 bis –4.5) spiegeln den Einsatz von δ11B-abgereicherten Natrium-Calcium- oder Calcium-Boraten wider. Die in dieser Arbeit untersuchten Schweizer Seen (Zurichsee, Greifensee, Luganer See) wiesen einen δ11B-Wert-Bereich von –1.7 bis 7.1‰ und Borkonzentrationen von 17 bis 102 μg L–1 auf. Das Isotopenverhaltnis des Bors sinkt mit steigender Borkonzentration, was auf einen Mischungsvorgang zwischen anthropogenem Bor mit niedriger δ11B-Signatur und Bor atmospharischen Ursprungs – meteorisches Bor τ mit einem groseren Anteil des schwereren Borisotops hinweist. Fur die isotopische Zusammensetzung des meteorischen Bors wird fur Zentraleuropa ein Bereich von 10 bis 20‰ zu Grunde gelegt, wahrend in Kustenbereichen die marine Komponente d","PeriodicalId":7010,"journal":{"name":"Acta Hydrochimica Et Hydrobiologica","volume":"4 1 1","pages":"416-421"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81970324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anwendung eines neuen Feldanalysenverfahrens zur Untersuchung der Stabilität von Arsen und seinen anorganischen Spezies in aquatischen Systemen","authors":"P. Volke, Broder J. Merkel","doi":"10.1002/(SICI)1521-401X(199907)27:4<230::AID-AHEH230>3.0.CO;2-E","DOIUrl":"https://doi.org/10.1002/(SICI)1521-401X(199907)27:4<230::AID-AHEH230>3.0.CO;2-E","url":null,"abstract":"The stability of arsenic species in aquatic systems is limited by the possibilities of chemical and biochemical reactions. Redox reactions and bioalkylation lead to changes of the species ratios. In this work, the stability of As(III) and As(V) was examined at storage of distilled, de-ionized, and drinking water at different conditions (refrigerator/room temperature; daylight/darkness) and additions (sulfuric acid; ascorbic acid). The determination ofthese species was carried out by a modified spectrophotometric method, suitable for laboratory analysis as well as for field analysis. The results show that chemical oxidation and biochemical reduction can occur. Sulfuric acid is favourable for the stabilization of total arsenic and of the inorganic species.","PeriodicalId":7010,"journal":{"name":"Acta Hydrochimica Et Hydrobiologica","volume":"41 1","pages":"230-238"},"PeriodicalIF":0.0,"publicationDate":"1999-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77842366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Adsorbed and Bound Residues in Fulvic Acid Fractions of a Contaminated Groundwater – Isolation:, Chromatographic and Spectroscopic Characterization","authors":"C. Zwiener, M. Kumke, G. Abbt-Braun, F. H. Frimel","doi":"10.1002/(SICI)1521-401X(199907)27:4<208::AID-AHEH208>3.0.CO;2-V","DOIUrl":"https://doi.org/10.1002/(SICI)1521-401X(199907)27:4<208::AID-AHEH208>3.0.CO;2-V","url":null,"abstract":"Humic substances (HS) were isolated from two contaminated groundwater samples (B22 and B53) from a site of a former gas facility. The isolation yielded almost only the fulvic acid fractions (FA). For characterization spectroscopic (UV, fluorescence) and chromatographic techniques (hydrophobic interaction chromatography – HIC as well as size-exclusion chromatography – SEC) were applied. The sample designated B22 FA was collected from the contamination plume whereas the sample B53 FA was collected downstream. Distinct differences were exhibited by these samples. The UV and fluorescence spectra as well as the HIC and SEC chromatograms of the B53 FA sample resemble those of the FA fraction obtained from natural water (groundwater, bog). The HIC and SEC chromatograms reveal the presence of organic compounds in B22 FA which can be derived from coal tar contaminants or their metabolites. Some of the compounds can be extracted from the FA fraction with non-polar organic solvents indicating adsorptive forces between the contaminants and the FA fraction. \u0000 \u0000 \u0000 \u0000Adsorbierte und gebundene Ruckstande in den Fulvinsaurefraktionen eines kontaminierten Grundwassers – Isolierung:, chromatographische und spektroskopische Charakterisierung \u0000 \u0000 \u0000 \u0000Von den zwei kontaminierten Grundwasserproben B22 und B53 eines ehemaligen Gaswerksgelandes wurden Huminstoffe (HS) isoliert. Dabei wurde jeweils vorwiegend die Fulvinsaurefraktion (FA) erhalten. Zur Charakterisierung der FA-Fraktionen wurden spektroskopische (UV, Fluoreszenz) und chromatographische Methoden (hydrophobe Wechselwirkungschromatographie HIC auf Umkehrphasen und Grosenausschluschromatographie SEC) angewandt. Die Proben zeigen deutliche Unterschiede, wobei B22 FA direkt aus der Schadstoffahne und B53 FA aus dem Abstrombereich stammt. Berucksichtigt man die UV- und Fluoreszenzspektren sowie die Chromatogramme der HIC- und SEC-Trennung, so ist B53 FA sehr gut mit FA-Fraktionen naturlicher Gewasser (Grund- bzw. Braunwasser) vergleichbar. Die Anwesenheit von organischen Verbindungen in der Probe B22 FA wird besonders in den Chromatogrammen nach HIC- und SEC-Trennung deutlich. Diese Verbindungen konnen auf Kohleteerruckstande oder deren Metaboliten zuruckgefuhrt werden. Ein Teil der organischen Verbindungen last sich mit unpolaren organischen Losemitteln aus der FA-Fraktion extrahieren, was auf Sorptionswechselwirkungen zwischen den Kontaminanten und der FA-Fraktion hinweist.","PeriodicalId":7010,"journal":{"name":"Acta Hydrochimica Et Hydrobiologica","volume":"30 1","pages":"208-213"},"PeriodicalIF":0.0,"publicationDate":"1999-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82747677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of a SPME-GC method for the determination of organic compounds in wastewater","authors":"C. Grote, E. Belau, K. Levsen, G. Wünsch","doi":"10.1002/(SICI)1521-401X(199907)27:4<193::AID-AHEH193>3.0.CO;2-J","DOIUrl":"https://doi.org/10.1002/(SICI)1521-401X(199907)27:4<193::AID-AHEH193>3.0.CO;2-J","url":null,"abstract":"A manual SPME method is presented for the analysis of organic compounds in industrial wastewater. 24 compounds commonly found in the wastewater of a chemical plant in northern Germany have been selected as reference compounds. Precision, linearity, and detection limits have been determined. Moreover, the effect of methanol content, pH value, salt content, and an excess of compounds on the extraction process have been studied. Several compounds have been investigated for their applicability as internal standards to quantify the compounds of interest. Since the method will later be transferred to a fully automated SPME-GC system, which will be operated directly on-site at an industrial wastewater purification plant, special attention has been paid to the analysis of real wastewater samples. In this context, the fibre stability has been studied by performing 53 extraction/desorption cycles from one wastewater sample. Neither a decrease in fibre performance nor in precision has been observed indicating that the proposed method is suitable for the analysis of real wastewater. \u0000 \u0000 \u0000 \u0000Entwicklung einer SPME-GC-Methode fur die Bestimmung von organischen Schadstoffen in Abwasser \u0000 \u0000 \u0000 \u0000Es wird eine manuelle SPME-Methode zur Analyse organischer Verbindungen in industriellem Abwasser prasentiert. 24 Verbindungen, die haufig im Abwasser eines norddeutschen Chemiebetriebes vorkommen, wurden als Referenzverbindungen ausgewahlt. Prazision, Linearitat und Nachweisgrenzen der Methode wurden ermittelt. Auserdem wurde der Effekt verschiedener Parameter wie Methanolgehalt, pH-Wert, Salzgehalt und der Einflus von Uberschuskomponenten auf die Extraktion untersucht. Mehrere Verbindungen wurden im Hinblick auf ihre Anwendbarkeit als interne Standards zur Quantifizierung der Wasserinhaltsstoffe untersucht. Da die vorgestellte Methode spater auf ein vollautomatisiertes SPME-GC-System ubertragen werden soll, das direkt an einer industriellen Abwasseraufbereitungsanlage betrieben wird, wurde insbesondere die Analytik realer Abwasserproben erprobt. In diesem Zusammenhang wurde die Faserstabilitat untersucht, indem mit einer Abwasserprobe 53 Zyklen aus Extraktion und Desorption durchgefuhrt wurden. Hierbei waren weder ein Abfall der Extraktionseffizienz der Faser noch Einbusen in der Prazision zu beobachten, so das die vorgestellte Methode zur Analyse industrieller Abwasser geeignet ist.","PeriodicalId":7010,"journal":{"name":"Acta Hydrochimica Et Hydrobiologica","volume":"13 1","pages":"193-199"},"PeriodicalIF":0.0,"publicationDate":"1999-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87809911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The carbonate radical (hco3·/co3–·) as a reactive intermediate in water chemistry: kinetics and modelling","authors":"Th. Umschlag, H. Herrmann","doi":"10.1002/(SICI)1521-401X(199907)27:4<214::AID-AHEH214>3.0.CO;2-6","DOIUrl":"https://doi.org/10.1002/(SICI)1521-401X(199907)27:4<214::AID-AHEH214>3.0.CO;2-6","url":null,"abstract":"Results from kinetic laboratory studies of reactions of the carbonate radical anion (CO - 3 .) with aromatic compounds in aqueous solution at T = 298 K are presented. Data were obtained in using a laser photolysis laser long-path absorption (LP-LPLA) apparatus which was designed for direct time-resolved studies of radical reactions. For the reactions of CO - 3 . with hydroquinone dimethyl ether (2), methyl anisole (3), benzene (4), p-xylene (5), toluene (6), chlorobenzene (7), nitrobenzene (8), and benzonitrile (9), rate coefficients of k 2 = (3.0 ± 0.6). 10 7 M-' s -1 , k 3 = (9.7 ± 1.7). 10 5 M -1 s -1 , k 4 = (3.2 ± 0.7). 10 5 M -1 s -1 , k 5 = (3.8 ± 0.9). 10 4 M -1 s -1 , k 6 = (6.8 ± 2.3). 10 4 M -1 s -1 , k 7 = (2.7 ± 0.6). 10 5 M -1 s -1 , k 8 = (1.4 ± 0.5). 10 4 M -1 s -1 , and k 9 < 1.3. 10 2 M -1 s -1 were obtained. In further studies the effect of temperature on the reactions (2), (4), and (5) has been studied. The kinetic data obtained for the reaction of the carbonate radical anion with aromatic compounds were compared to the corresponding reactions of the hydroxyl radical. Finally, these kinetic data were used within a simple model system to investigate the implications of carbonate radical anion kinetics within water treatment processes. It is shown that the degradation of organic pollutants in. OH-radical based water treatment may proceed via the CO - 3 ./HCO 3 . radical under certain conditions.","PeriodicalId":7010,"journal":{"name":"Acta Hydrochimica Et Hydrobiologica","volume":"27 1","pages":"214-222"},"PeriodicalIF":0.0,"publicationDate":"1999-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86331461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of 24 h and Long-term pHstat Leaching Tests for Heavy Metal Mobilization from Solid Matrices","authors":"A. Paschke, R. Wennrich, P. Morgenstern","doi":"10.1002/(SICI)1521-401X(199907)27:4<223::AID-AHEH223>3.0.CO;2-6","DOIUrl":"https://doi.org/10.1002/(SICI)1521-401X(199907)27:4<223::AID-AHEH223>3.0.CO;2-6","url":null,"abstract":"The dynamic leaching behaviour of environmentally relevant heavy metals makes it difficult to fix a suitable elution time of leaching tests. With ten different solid materials which were characterized by wavelength-dispersive X-ray fluorescence analysis and by the determination of aqua regia soluble amounts of heavy metals we performed 24 h and long-term leaching tests using the pHstat procedure at pH 4 to be able to compare the resulting acid neutralization capacities (ANC) and heavy metal mobilization. This comparison demonstrates firstly the limitations in predicting the extent of heavy metal release after a longer (geological) time period only from the leached amounts after 24 hours and the ratio of the ANC values measured in the 24 h test and in a long-term experiment, respectively. Secondly, the effect of elution time on the leachability is not uniform but element specific and matrix dependent. Hence, the pHstat leaching test performed in the usual manner does not seem to be suitable particularly for assessing long-term mobilization of heavy metals under acidic conditions. Additional experiments under variation of shaking frequency and time clearly demonstrate the dominant influence of the first parameter on the resulting ANC and support the necessity of further studies to optimize the pHstat leaching procedure before the test can be recommended in regulations for environmental protection. \u0000 \u0000 \u0000 \u0000Vergleich von 24-h- und Langzeit-pHstat-Schutteltests zur Schwermetall-Mobilisierung aus festen Matrices \u0000 \u0000 \u0000 \u0000Das dynamische Auslaugverhalten umweltrelevanter Schwermetalle macht es schwierig, eine geeignete Zeitdauer von Auslaugtests festzulegen. Mit zehn verschiedenen Feststoffen, die mittels wellenlangendispersiver Rontgenfluoreszenzanalyse und durch Bestimmung der konigswasserloslichen Schwermetallanteile charakterisiert wurden, haben wir 24-h- und Langzeit-Auslaugtests mit der pHstat-Prozedur bei pH = 4 durchgefuhrt, um die resultierenden Saureneutralisationskapazitaten (ANC) und die Mobilisierung der Schwermetalle vergleichen zu konnen. Dieser Vergleich zeigt erstens, das es nicht moglich ist, das Ausmas der Schwermetallfreisetzung nach langerer Kontaktzeit nur aus den ausgelaugten Mengen nach 24 Stunden und dem Verhaltnis der im 24-h- und Langzeit-Test gemessenen ANC-Werte vorherzusagen. Zweitens ist der Effekt der Elutionszeit auf die Auslaugbarkeit nicht einheitlich, sondern sehr elementspezifisch und matrixabhangig. Somit scheint der pHstat-Auslaugtest, in der ublichen Weise durchgefuhrt, wenig geeignet fur die Abschatzung der Langzeit-Mobilisierung von Schwermetallen unter sauren Bedingungen. Zusatzliche Experimente unter Variation der Schuttelfrequenz und Zeit zeigen klar den dominanten Einflus der ersteren auf die ermittelten ANC-Werte und unterstreichen die Notwendigkeit weiterer Untersuchungen zur Optimierung der pHstat-Auslaugprozedur, bevor diese fur das Regularium empfohlen werden kann.","PeriodicalId":7010,"journal":{"name":"Acta Hydrochimica Et Hydrobiologica","volume":"73 1","pages":"223-229"},"PeriodicalIF":0.0,"publicationDate":"1999-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73931619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}