Ottimizzazione dei processi depurativi di reflui ad elevato carico organico a fini di recupero energetico

L���attuale condizione che caratterizza il settore energetico richiede un necessario processo di riconversione che, oltre a favorire il risparmio energetico, riduca la dipendenza dai combustibili fossili ed accresca l���impiego di fonti energetiche rinnovabili, dando un contributo fondamentale alla riduzione delle emissioni di gas serra come diversi accordi internazionali richiedono. Si rende pertanto necessario accelerare i processi che da alcuni anni stanno favorendo l���utilizzo di energia da fonti rinnovabili. Tra queste, le fonti legate ai processi di trattamento biologico dei reflui stanno avendo un interessante sviluppo. Esistono numerosi processi biologici che consentono la produzione di energia in maniera indiretta, quali ad esempio i processi di digestione anaerobica finalizzati alla produzione di biogas e/o produzione biologica di idrogeno. In tale contesto si inserisce la tecnologia delle Microbial Fuel Cell, che consente la produzione diretta di energia elettrica, finalizzata al recupero energetico inteso al miglioramento dell���efficienza energetica e alla riduzione dei costi d���esercizio di impianti di trattamento biologico dei reflui. Il presente lavoro di Tesi di Dottorato sperimentale, svoltosi in collaborazione al laboratorio PROT.-IDR. della sede ENEA di Bologna, riporta i risultati dell���attivit�� di ricerca condotta su una MFC (Microbial Fuel Cell) a doppio stadio biologico per il trattamento di reflui ad elevato carico organico e produzione continua di energia elettrica. E��� stata provata l���applicabilit�� della MFC con entrambi i comparti biotici utilizzando elettrodi di grafite non trattata ottenendo, con un carico organico in ingresso di circa 9 gd-1, valori di potenza massima prodotta che si attestano su 74 mWm-2, corrente elettrica massima generata di 175 mAm-2 ad una tensione di 421 mV, ed una conversione di COD in elettricit�� pari a 1,2 gCODm-2d-1. I risultati sono stati molto positivi per quanto riguarda le prestazioni depurative ottenute dalla MFC. L���efficienza di depurazione misurata ha raggiunto un valore massimo del 98% di rimozione del COD in ingresso, mentre e la concentrazione di azoto ammoniacale nell���effluente raccolto all���uscita del sedimentatore �� sempre stata inferiore a 1 mgN-NH4+l-1. Tra gli obiettivi posti all���inizio della sperimentazione si �� rivelata di notevole interesse la valutazione del possibile utilizzo della MFC come sistema per il monitoraggio on-line del COD e degli acidi grassi volatili (VFA) prodotti all���interno di un digestore anaerobico, attraverso la definizione di una correlazione tra i dati elettrici registrati in continuo e le concentrazioni di CODanaer e VFA misurate in diversi periodi della sperimentazione. L���analisi DGGE della biomassa catodica ha fornito uno strumento analitico utile allo studio della diversit�� della comunit�� microbica sospesa ed adesa al catodo e ha confermato la forte similarit�� delle specie batteriche riconosciute nei campioni analizzati. In particolare, le bande di sequenziamento ottenute sono affiliate ai gruppi batterici Firmicutes, ���-Proteobacteria, ��� -Proteobacteria, ���-Proteobacteria e Bacteroidetes. Da quanto emerso dalla sperimentazione condotta si pu�� pertanto concludere che ad oggi le MFC sono in fase di evoluzione rispetto ai primi prototipi utilizzati per lo studio delle comunit�� microbiali e per la comprensione dei meccanismi di trasferimento elettronico. Sfruttarne la potenza prodotta in maniera commerciale diviene una grande sfida per il futuro, ed �� opinione comune che le prime applicazioni pratiche delle MFC saranno come fonte di recupero energetico per i dispositivi utilizzati per il monitoraggio dell���ambiente e per il trattamento delle acque reflue.

Tropospheric carboxylic acids in tropical rainforest environments

Der ��bergang der Grenzschicht von stark ozeanisch auf kontinental beeinflusst wurde in 2 tropischen K��stenwaldgebieten Amerikas untersucht, wo Luftmassen vom Meer kommend ��ber den Kontinent transportiert werden.Zwei Feldkampagnen wurden durchgef��hrt; in Costa Rica (CR; 07.1996) und in Surinam (04.1998). In CR wurde im nord��stlichen Flachgebiet (etwa 10��25' N; 84��W) Regenwasser gesammelt, in dem sp��ter Carboxylate, anorganischen Anionen, Ca2+, K+, NH4+ und Mg2+ gemessen wurden. Die Proben wurden an 5 verschiedenen Stellen entlang der Windrichtung 1, 20, 60, 60 und 80 km von der K��ste gesammelt. In Surinam (Sipaliwini, 2��02' N, 56��08' W) wurden organischen S��uren aus der Gasphase gesammelt etwa 550 km von der K��ste entfernt, sowohl wie O3 und CO. Die Proben wurden mittels Ionenchromatographie und Kapillarelektrophorese analysiert. Morgendliche Einmischung der n��chtlichen residualen Schicht und Luft der unteren freien Troposph��re war Hauptquelle f��r HCOOH und CH3COOH in der Tagesmischschicht. Es wurde gezeigt, dass lokale Produktion dieser S��uren durch chemische Reaktionen eine kleine Rolle gespielt hat und dass direkte Emission vernachl��ssigbar war.Aus den beiden Feldkampagnen folgt, dass die Konzentrationen der sekund��ren Verbindungen HCOOH, CH3COOH, Ozon und CO in der Tagesmischschicht von Importen bestimmt wurden, was gilt f��r Regen- und Trockenzeit bis zu Entfernungen von 550 km zur K��ste.

Isolierung, Reinigung und Expression zentraler Enzyme der Biosynthese des pflanzlichen Antiarrhythmikums Ajmalin

Zusammenfassung In der vorliegenden Arbeit wurden im Zuge derAjmalinbiosynthese in Rauvolfia serpentina die NADPH2abh��ngigen Reduktionsschritte des Alkaloids Vomilenin zu 17O Acetylnorajmalin genauer untersucht.Dabei konnte erstmals die exakte Reaktionsreihenfolgeaufgedeckt und die daran beteiligten Enzyme ausPflanzenzellsuspensionskulturen isoliert und aufgereinigtwerden. Die ausgearbeiteten, optimierten Reinigungsprotokollef��hrten in wenigen Stufen gezielt zu den voneinandergetrennten Reduktase Fraktionen. Durch die Trennung derReduktase Aktivit��ten war der Grundstein gelegt, dasZwischenprodukt der Reaktion anzureichern und mitverschiedenen analytischen Verfahren als 2?-(R)-1.2Dihydrovomilenin zu identifizieren. Die daraufhin vergebenenBezeichnungen Vomilenin Reduktase (EC.1.5.1.32) und 1.2Dihydrovomilenin Reduktase (EC.1.3.1.73) zielen auf dasumzusetzende Substrat ab.F��r die Vomilenin Reduktase konnte eine 4 stufige Reinigung��ber (NH4)2SO4 F��llung, Anionen-austauschchromatographie mitSOURCE 30Q, Hydrophobe Interaktionschromatographie an SOURCE15Phe und Affinit��tschromatographie mit 2��,5�� ADP Sepharoseausgearbeitet werden. Hierbei konnte die 1.2Dihydrovomilenin Reduktase schon nach dem erstens��ulenchromatogra-phischen Schritt (S 30Q) abgetrenntwerden. Das am Ende der Proteinreinigung angefertigte SDSGel zeigte nur noch 3 Banden, von denen die beiden bei ca.40 und 43 kDa gelegenen Banden mit dem Aktivit��tsverlaufder Vomilenin Reduktase korrelierten. Diese wurden einempartiellen Verdau mit der Endoproteinase LysC unterworfen,wobei jeweils 2 Spaltpeptide erhalten werden konnten.Die 1.2 Dihydrovomilenin Reduktase Reinigung umfa��te 6Reinigungsschritte mit (NH4)2SO4-F��llung, SOURCE 30QAnionenaustauschchromatographie, HydroxylapatitChromatographie, 2��,5�� ADP Sepharose-Chromatographie,Anionenaustausch an DEAE Sepharose und abschlie��en-denAnionenaustausch ��ber MonoQ. Die resultierendeProteinfraktion wies eine ca. 200 fache Anreicherung an 1.2Dihydrovomilenin Reduktase auf. Auch hierbei wurde die nachSDS Gelelek-trophorese als 1.2 Dihydrovomilenin Reduktasebestimmte Proteinbande (bei ca. 48 kDa) sequen-ziert. Eskonnten vier Peptidfragmente erhalten werden, die ebenso wiedie sequenzierten Peptidst��cke der 40 und 43 kDa Bande einehohe Homologie zu Oxidoreduktasen, im einzelnen zuCinnamoylalcohol- und Mannitol Dehydrogenasen, aufwiesen.Um die Identit��t der sequenzierten Proteinbanden zubest��tigen, wurde ��ber ��reverse genetics�� die jeweilscodierende cDNA eruiert. Daf��r wurden - ausgehend von denPeptidst��cken der Mikro-sequenzierung - degenerierte Primerentwickelt und ��ber PCR Teilbereiche der cDNA amplifiziert.Diese konnten f��r eine radioaktive Durchmusterung einerRauvolfia cDNA Bank herangezogen werden. Alternativ botallein die Kenntnis der spezifischen Nukleotidabfolge dieM��glichkeit der Gewinnung von 5�� und 3�� Ende derVoll��ngenklone durch RACE PCR.Nach Abschlu�� dieser Arbeiten konnten f��r die 40 und 48 kDaBande je ein Voll��ngenklon und f��r die 43 kDa Bande 2Voll��ngenklone (Isoformen) gefunden werden. S��mtlicheVoll��ngenklone besitzen einen offenen Leserahmen, der durchnicht zu translatierende Bereiche am 5�� und 3�� Endeeingefa��t wird. Um die entsprechenden Proteine produzierenzu k��nnen, mu��ten die daf��r codierenden cDNA Bereiche dereinzelnen Klone in ein geeignetes Vektor Wirt-System(Expressionssystem) eingebracht werden.Nach erfolgreicher Umklonierung wurde die Expression durchIPTG Zugabe kontrolliert und Proteinrohextrakte aus denBakterienst��mmen isoliert. Als Substrate wurden Vomilenin,das strukturisomere Alkaloid Perakin und aufgrund derHomologien zu Cinnamoylalcohol und Mannitol Dehydrogenasen Zimtaldehyd, Dihydrozimtaldehyd und D(-)Fructose getestet. In allen E. coli St��mmen konnte ein unspezifischesReduktionspotential nachgewiesen werden, ohne da�� jedochVomilenin reduziert wurde. Die Testung der 1.2Dihydrovomilenin Reduktase Klone mu��te wegen Substratmangelentfallen.Die weitere Charakterisierung der pflanzlichen Enzymeerbrachte eine enorm hohe Substratspezifit��t mit einer sichauf Rauvolfia beschr��nkenden taxonomischen Verbreitung.Die Molekulargewichtsbestimmung f��r die Vomilenin Reduktaseergab nach Gr����enausschlu��-chromatographie an Superdex 75ein Gewicht von etwa 43 kDa. Das ebenfalls ��ber Superdex 75ermittelte Molekulargewicht f��r die 1.2 DihydrovomileninReduktase lag bei ca. 49.8 kDa. Weiterhin wurde eine Metallionenabh��ngigkeit f��r dieVomilenin Reduktase aufgezeigt und die Cofaktorspezifit��tsowie die pH und Temperatur Optima f��r beide Reduktasenbestimmt.

Synthesis and characterization of metal-chalcogenide MQ 2-Nanoparticles (M = Mo, W, Zr; Q = S, O)

Here, we present the adaptation and optimization of (i) the solvothermal and (ii) the metal-organic chemical vapor deposition (MOCVD) approach as simple methods for the high-yield synthesis of MQ2 (M=Mo, W, Zr; Q = O, S) nanoparticles. Extensive characterization was carried out using X-ray diffraction (XRD), scanning and transmission electron micros��copy (SEM/TEM) combined with energy dispersive X-ray analysis (EDXA), Raman spectroscopy, thermal analyses (DTA/TG), small angle X-ray scattering (SAXS) and BET measurements. After a general introduction to the state of the art, a simple route to nanostructured MoS2 based on the decomposition of the cluster-based precursor (NH4)2Mo3S13���xH2O under solvothermal conditions (toluene, 653 K) is presented. Solvothermal decomposition results in nanostructured material that is distinct from the material obtained by decomposition of the same precursor in sealed quartz tubes at the same temperature. When carried out in the presence of the surfactant cetyltrimethyl��ammonium bromide (CTAB), the decomposition product exhibits highly disordered MoS2 lamellae with high surface areas. The synthesis of WS2 onion-like nanoparticles by means of a single-step MOCVD process is discussed. Furthermore, the results of the successful transfer of the two-step MO��CVD based synthesis of MoQ2 nanoparticles (Q = S, Se), comprising the formation of amorphous precursor particles and followed by the formation of fullerene-like particles in a subsequent annealing step to the W-S system, are presented. Based on a study of the temperature dependence of the reactions a set of conditions for the formation of onion-like structures in a one-step reaction could be derived. The MOCVD approach allows a selective synthesis of open and filled fullerene-like chalcogenide nanoparticles. An in situ heating stage transmission electron microscopy (TEM) study was employed to comparatively investigate the growth mechanism of MoS2 and WS2 nanoparticles obtained from MOCVD upon annealing. Round, mainly amorphous particles in the pristine sample trans��form to hollow onion-like particles upon annealing. A significant difference between both compounds could be demonstrated in their crystallization conduct. Finally, the results of the in situ hea��ting experiments are compared to those obtained from an ex situ annealing process under Ar. Eventually, a low temperature synthesis of monodisperse ZrO2 nanoparticles with diameters of ~ 8 nm is introduced. Whereas the solvent could be omitted, the synthesis in an autoclave is crucial for gaining nano-sized (n) ZrO2 by thermal decomposition of Zr(C2O4)2. The n-ZrO2 particles exhibits high specific surface areas (up to 385 m2/g) which make them promising candidates as catalysts and catalyst supports. Co-existence of m- and t-ZrO2 nano-particles of 6-9 nm in diameter, i.e. above the critical particle size of 6 nm, demonstrates that the particle size is not the only factor for stabilization of the t-ZrO2 modification at room temperature. In conclusion, synthesis within an autoclave (with and without solvent) and the MOCVD process could be successfully adapted to the synthesis of MoS2, WS2 and ZrO2 nanoparticles. A comparative in situ heating stage TEM study elucidated the growth mechanism of MoS2 and WS2 fullerene-like particles. As the general processes are similar, a transfer of this synthesis approach to other layered transition metal chalcogenide systems is to be expected. Application of the obtained nanomaterials as lubricants (MoS2, WS2) or as dental filling materials (ZrO2) is currently under investigation.

Physiological and Biochemical Aspects of Iron Nutrition in Grapevine

The objective of this thesis was to study the response mechanisms of grapevine to Fe-deficiency and to potential Fe chlorosis prevention strategies. The results show that the presence of bicarbonate in the nutrient solution shifted the activity of PEPC and TCA cycle enzymes and the accumulation/translocation of organic acids in roots of Fe-deprived plants. The rootstock 140 Ruggeri displayed a typical behavior of calcicole plants under bicarbonate stress. The Fe chlorosis susceptible rootstock 101-14 reacted to a prolonged Fe-deficiency reducing the root activity of PEPC and MDH. Noteworthy, it accumulates high levels of citric acid in roots, indicating a low capacity to utilizing, transporting and/or exudating organic acids into the rhizosfere. In contrast, 110 Richter rootstock is capable to maintain an active metabolism of organic acids in roots, accumulating them to a lesser extent than 101-14. Similarly to 101-14, SO4 genotype displays a strong decrease of mechanisms associated to Fe chlorosis tolerance (PEPC and MDH enzymes). Nevertheless it is able to avoid excessive accumulation of citric acid in roots, similar as 110 Richter rootstock. Intercropping with Festuca rubra increased leaf chlorophyll content and net photosynthesis. In addition, intercropping reduces the activity of PEPC in roots, similary to Fe-chelate supply. Applications of NH4+ with nitrification inhibitor prevents efficiently Fe-deficiency, increases chlorophyll content, and induces similar root biochemical responses as Fe-EDDHA. Without the addition of nitrification inhibitors, the effectiveness of NH4+ supply on Fe chlorosis prevention resulted significantly lower. The aspects intertwined in this investigation highlight the complexity of Fe physiology and the fine metabolic tuning of grapevine genotypes to Fe availability and soil-related environmental factors. The experimental evidences reveal the need to carry out future researches on Fe nutrition maintaining a continous flow of knowledge between theoretical and agronomical perspectives for fully supporting the efforts devoted to convert science into practice.

Sulfur isotope analysis of aerosol particles by NanoSIMS

A new method to measure the sulfur isotopic composition of individual aerosol particles by NanoSIMS has been developed and tested on several standards such as barite (BaSO4), anhydrite (CaSO4), gypsum (CaSO4��2H2O), mascagnite ((NH4)2SO4), epsomite (MgSO4��7H2O), magnesium sulfate (MgSO4��xH2O), thenardite (Na2SO4), boetite (K2SO4) and cysteine (an amino acid). This ion microprobe technique employs a Cs+ primary ion beam and measures negative secondary ions permitting the analysis of sulfur isotope ratios in individual aerosol particles down to 500 nm in size (0.001-0.5 ng of sample material). The grain-to-grain reproducibility of measurements is typically 5��� (1��) for micron-sized grains, <5��� for submicron-sized grains, and <2��� for polished thin sections and ultra microtome sections which were studied for comparison. The role of chemical omposition (matrix effect) and sample preparation techniques on the instrumental mass fractionation (IMF) of the 34S/32S ratio in the NanoSIMS has been investigated. The IMF varies by ~15��� between the standards studied here. A good correlation between IMF and ionic radius of the cations in sulfates was observed. This permits to infer IMF corrections even for sulfates for which no isotope standards are available. The new technique allows to identify different types of primary and secondary sulfates based on their chemical composition and to measure their isotopic signature separately. It was applied to marine aerosol samples collected in Mace Head and urban aerosol samples collected in Mainz. It was shown that primary sulfate particles such as sulfate in NaCl or gypsum particles precipitated from ocean water retain the original isotopic signature of their source. The isotopic composition of secondary sulfate depends on the isotopic composition of precursor SO2 and the oxidation pathway. The 34S/32S fractionation with respect to the precursor SO2 is -9��� for homogeneous oxidation and +16.5��� for heterogeneous oxidation. This large difference between the isotopic fractionation of both pathways allows identifying the oxidation pathway from which the SO42- in a secondary sulfate particle is derived, by means of its sulfur isotope ratio, provided that the isotopic signature of the precursor SO2 is known. The isotopic composition of the precursor SO2 of secondary sulfates was calculated based on the isotopic composition of particles with known oxidation pathway such as fine mode ammonium sulfate.

Laboruntersuchungen zur Aufnahme von NH 3 durch Eiskristalle bei Gleichgewicht und beim Wachstum

In dieser Arbeit wurde in Laborexperimenten die Aufnahme von NH3 durch wachsende Eiskristalle und Eiskristalle, die in eisges��ttigter Umgebung mit ihrer mittleren Fallgeschwindigkeit angestr��mt wurden, untersucht. So sollten die Verh��ltnisse innerhalb der Wolke beim Wachstum der Eiskristalle ���in cloud scavenging��� und unterhalb der Wolke beim Anstr��men mit eisges��ttigter NH3 - Luftmischung simuliert werden. Bei l��ngerer Exposition dendritischer Eiskristalle mit eisges��ttigter NH3 - Luftmischung ist die Diffusion des gebildeten NH4+ in den Eiskristall hinein, entscheidend f��r den Anteil an NH3, der aus der Gasphase nach der Adsorption als NH4+ im Eis zur��ckbleibt. Die experimentellen Daten konnten mit einer einfachen Annahme zur Diffusion in einen ���halb unendlichen��� Festk��rper beschrieben werden. In weiteren Experimenten konnte gezeigt werden, dass die Aufnahme des NH3 durch nicht wachsende Eiskristalle von anderen Spurenstoffen im Eis beeinflusst wird. Eiskristalle, die im Vorfeld des Str��mungsadsorptionsexperiments mit NH3, mit SO2 exponiert wurden, zeigten eine deutliche Zunahme der NH3 - Aufnahme aus der Gasphase. Die Aufnahme von NH3 durch nicht wachsende Eiskristalle ist f��r typische atmosph��rische NH3 - Volumenmischungsverh��ltnisse nicht relevant. Dagegen zeigten die Experimente zur NH3 Aufnahme beim Eiskristallwachstum, dass dieser Prozess in der Atmosph��re nicht vernachl��ssigt werden kann.

Corrosione atmosferica in area urbana-costiera di un acciaio Cor-Ten: studio del rilascio in ambiente dei metalli di lega

Cor-Ten is a particular kind of steel, belonging to low-alloyed steel; thanks to his aesthetic features and resistance to atmospheric corrosion, this material is largely used in architectural, artistic and infrastructural applications. After environmental exposure, Cor-Ten steel exhibits the characteristic ability to self-protect from corrosion, by the development of a stable and adherent protective layer. However, some environmental factors can influence the formation and stability of the patina. In particular, exposure of Cor-Ten to polluted atmosphere (NOx, SOx, O3) or coastal areas (marine spray) may cause problems to the protective layer and, as a consequence, a release of alloying metals, which can accumulate near the structures. Some of these metals, such as Cr and Ni, could be very dangerous for soils and water because of their large toxicity. The aim of this work was to study the corrosion behavior of Cor-Ten exposed to an urban-coastal site (Rimini, Italy). Three different kinds of commercial surface finish (bare and pre-patinated, with or without a beeswax covering) were examined, both in sheltered and unsheltered exposure conditions. Wet deposition brushing the specimens surface (leaching solutions) are monthly collected and analyzed to evaluate the extent of metal release and the form in which they leave the surface, for example, as water-soluble compounds or non-adherent corrosion products. Five alloying metals (Fe, Cu, Cr, Mn and Ni) and nine ions (Cl-, NO3-, NO2-, SO42-, Na+, Ca2+, K+, Mg2+, NH4+) are determined through Atomic Absorption Spectroscopy and Ion Chromatography, respectively. Furthermore, the evolution and the behaviour of the patina are periodically followed by surface investigations (SEM-EDS and Raman Spectroscopy). After two years of exposure, the results show that Bare Cor-Ten, cheaper than the other analyzed specimens, even though undergoes the greater mass variation, his metal release is comparable to the release of the pre-patinated samples. The behavior of pre-patinated steel, with or without beeswax covering, do not show particular difference. This exposure environment doesn���t allow a completely stabilization of the patina; nevertheless an estimate of metal release after 10 years of exposure points out that the environmental impact of Cor-Ten is very low: for example, the release of chromium in the soluble fraction is less than 10 mg if we consider an exposed wall of 10 m2.

External drivers of biogeochemical cycles in a tropical montane forest in Ecuador

Successful conservation of tropical montane forest, one of the most threatened ecosystems on earth, requires detailed knowledge of its biogeochemistry. Of particular interest is the response of the biogeochemical element cycles to external influences such as element deposition or climate change. Therefore the overall objective of my study was to contribute to improved understanding of role and functioning of the Andean tropical montane forest. In detail, my objectives were to determine (1) the role of long-range transported aerosols and their transport mechanisms, and (2) the role of short-term extreme climatic events for the element budget of Andean tropical forest. In a whole-catchment approach including three 8-13 ha microcatchments under tropical montane forest on the east-exposed slope of the eastern cordillera in the south Ecuadorian Andes at 1850-2200 m above sea level I monitored at least in weekly resolution the concentrations and fluxes of Ca, Mg, Na, K, NO3-N, NH4-N, DON, P, S, TOC, Mn, and Al in bulk deposition, throughfall, litter leachate, soil solution at the 0.15 and 0.3 m depths, and runoff between May 1998 and April 2003. I also used meteorological data from my study area collected by cooperating researchers and the Brazilian meteorological service (INPE), as well as remote sensing products of the North American and European space agencies NASA and ESA. My results show that (1) there was a strong interannual variation in deposition of Ca [4.4-29 kg ha-1 a-1], Mg [1.6-12], and K [9.8-30]) between 1998 and 2003. High deposition changed the Ca and Mg budgets of the catchments from loss to retention, suggesting that the additionally available Ca and Mg was used by the ecosystem. Increased base metal deposition was related to dust outbursts of the Sahara and an Amazonian precipitation pattern with trans-regional dry spells allowing for dust transport to the Andes. The increased base metal deposition coincided with a strong La Ni��a event in 1999/2000. There were also significantly elevated H+, N, and Mn depositions during the annual biomass burning period in the Amazon basin. Elevated H+ deposition during the biomass burning period caused elevated base metal loss from the canopy and the organic horizon and deteriorated already low base metal supply of the vegetation. Nitrogen was only retained during biomass burning but not during non-fire conditions when deposition was much smaller. Therefore biomass burning-related aerosol emissions in Amazonia seem large enough to substantially increase element deposition at the western rim of Amazonia. Particularly the related increase of acid deposition impoverishes already base-metal scarce ecosystems. As biomass burning is most intense during El Ni��o situations, a shortened ENSO cycle because of global warming likely enhances the acid deposition at my study forest. (2) Storm events causing near-surface water flow through C- and nutrient-rich topsoil during rainstorms were the major export pathway for C, N, Al, and Mn (contributing >50% to the total export of these elements). Near-surface flow also accounted for one third of total base metal export. This demonstrates that storm-event related near-surface flow markedly affects the cycling of many nutrients in steep tropical montane forests. Changes in the rainfall regime possibly associated with global climate change will therefore also change element export from the study forest. Element budgets of Andean tropical montane rain forest proved to be markedly affected by long-range transport of Saharan dust, biomass burning-related aerosols, or strong rainfalls during storm events. Thus, increased acid and nutrient deposition and the global climate change probably drive the tropical montane forest to another state with unknown consequences for its functions and biological diversity.

Sintesi e propriet�� di biochar da biomasse residuali

Il termine biochar definisce il prodotto solido derivante dalla pirolisi di un qualsiasi materiale organico, con lo specifico scopo di essere applicato nei suoli sia per fini agronomici che di gestione ambientale. Un suo utilizzo in maniera "responsabile" richiede per�� una piena comprensione delle sue propriet�� e dei meccanismi che controllano la sua attivit�� nel terreno, che dipendono dalla biomassa di partenza e dalle condizioni di sintesi tramite pirolisi. Infatti le condizioni di pirolisi, in particolare la temperatura di processo e il tempo di residenza, determinano biochar con caratteristiche differenti. In questo lavoro di tesi sono stati prodotti biochar da due diverse tipologie di biomassa residuale ampiamente disponibili (stocchi di mais e pollina). Per ciascuna biomassa sono state scelte tre condizioni di pirolisi (400��C x 20 minuti, 500��C x 10 minuti e 600��C x 5 minuti). Sui biochar ottenuti sono state effettuate le seguenti determinazioni: analisi elementare, Pirolisi���GC���MS, idrocarburi policiclici aromatici (IPA), acidi grassi volatili (VFA), azoto ammoniacale (N���NH4 +), pH, conduttivit�� elettrica e ritenzione idrica. Infine i biochar sintetizzati sono stati utilizzati per fare due test di germinazione per valutare l'effetto sulla formazione delle prime strutture di crescita delle plantule, tramite test di tossicit�� brevi con piastre Petri. Il primo test �� stato condotto a concentrazione crescente di miscele acqua/biochar (2, 5, 40 e 100 g/L sulla base delle quantit�� di biochar utilizzate come ammendante nel suolo), sulla germinazione seguendo la metodologia normata dalla ISO 11269:2012. I semi utilizzati nel primo test sono stati quelli del crescione (Lepidium sativum L.) come specie dicotiledone, e del sorgo (Sorghum saccharatum M.) come monocotiledone. Il secondo saggio di tossicit�� eseguito �� stato quello descritto dalla normativa in materia UNI 11357, valutando l'eventuale effetto di tossicit�� alla massima concentrazione delle varie tipologie di biochar, utilizzando come specie dicotiledoni il cetriolo (Cucumis sativus L.) ed il crescione (Lepidium sativum L.), come monocotiledone il sorgo (Sorghum saccharatum M.). Per i biochar da stocchi di mais, rappresentativi di biomasse erbacee e con diverso grado di carbonizzazione, non si osservano effetti apprezzabili alle condizioni di uso agricolo. Nel caso dei biochar da pollina si osservano invece inibizioni alla germinazione sin dalle concentrazioni pi�� basse. In particolare, quello pirolizzato a 400��C mostra un potenziale effetto tossico pi�� marcato, probabilmente associato ad un contenuto di IPA e VFA superiore a quello degli altri biochar.

Exchange of nitrogen dioxide (NO 2) between plants and the atmosphere under laboratory and field conditions

Nitrogen is an essential nutrient. It is for human, animal and plants a constituent element of proteins and nucleic acids. Although the majority of the Earth���s atmosphere consists of elemental nitrogen (N2, 78 %) only a few microorganisms can use it directly. To be useful for higher plants and animals elemental nitrogen must be converted to a reactive oxidized form. This conversion happens within the nitrogen cycle by free-living microorganisms, symbiotic living Rhizobium bacteria or by lightning. Humans are able to synthesize reactive nitrogen through the Haber-Bosch process since the beginning of the 20th century. As a result food security of the world population could be improved noticeably. On the other side the increased nitrogen input results in acidification and eutrophication of ecosystems and in loss of biodiversity. Negative health effects arose for humans such as fine particulate matter and summer smog. Furthermore, reactive nitrogen plays a decisive role at atmospheric chemistry and global cycles of pollutants and nutritive substances.rnNitrogen monoxide (NO) and nitrogen dioxide (NO2) belong to the reactive trace gases and are grouped under the generic term NOx. They are important components of atmospheric oxidative processes and influence the lifetime of various less reactive greenhouse gases. NO and NO2 are generated amongst others at combustion process by oxidation of atmospheric nitrogen as well as by biological processes within soil. In atmosphere NO is converted very quickly into NO2. NO2 is than oxidized to nitrate (NO3-) and to nitric acid (HNO3), which bounds to aerosol particles. The bounded nitrate is finally washed out from atmosphere by dry and wet deposition. Catalytic reactions of NOx are an important part of atmospheric chemistry forming or decomposing tropospheric ozone (O3). In atmosphere NO, NO2 and O3 are in photosta��tionary equilibrium, therefore it is referred as NO-NO2-O3 triad. At regions with elevated NO concentrations reactions with air pollutions can form NO2, altering equilibrium of ozone formation.rnThe essential nutrient nitrogen is taken up by plants mainly by dissolved NO3- entering the roots. Atmospheric nitrogen is oxidized to NO3- within soil via bacteria by nitrogen fixation or ammonium formation and nitrification. Additionally atmospheric NO2 uptake occurs directly by stomata. Inside the apoplast NO2 is disproportionated to nitrate and nitrite (NO2-), which can enter the plant metabolic processes. The enzymes nitrate and nitrite reductase convert nitrate and nitrite to ammonium (NH4+). NO2 gas exchange is controlled by pressure gradients inside the leaves, the stomatal aperture and leaf resistances. Plant stomatal regulation is affected by climate factors like light intensity, temperature and water vapor pressure deficit. rnThis thesis wants to contribute to the comprehension of the effects of vegetation in the atmospheric NO2 cycle and to discuss the NO2 compensation point concentration (mcomp,NO2). Therefore, NO2 exchange between the atmosphere and spruce (Picea abies) on leaf level was detected by a dynamic plant chamber system under labo��ratory and field conditions. Measurements took place during the EGER project (June-July 2008). Additionally NO2 data collected during the ECHO project (July 2003) on oak (Quercus robur) were analyzed. The used measuring system allowed simultaneously determina��tion of NO, NO2, O3, CO2 and H2O exchange rates. Calculations of NO, NO2 and O3 fluxes based on generally small differences (���mi) measured between inlet and outlet of the chamber. Consequently a high accuracy and specificity of the analyzer is necessary. To achieve these requirements a highly specific NO/NO2 analyzer was used and the whole measurement system was optimized to an enduring measurement precision.rnData analysis resulted in a significant mcomp,NO2 only if statistical significance of ���mi was detected. Consequently, significance of ���mi was used as a data quality criterion. Photo-chemical reactions of the NO-NO2-O3 triad in the dynamic plant chamber���s volume must be considered for the determination of NO, NO2, O3 exchange rates, other��wise deposition velocity (vdep,NO2) and mcomp,NO2 will be overestimated. No significant mcomp,NO2 for spruce could be determined under laboratory conditions, but under field conditions mcomp,NO2 could be identified between 0.17 and 0.65 ppb and vdep,NO2 between 0.07 and 0.42 mm s-1. Analyzing field data of oak, no NO2 compensation point concentration could be determined, vdep,NO2 ranged between 0.6 and 2.71 mm s-1. There is increasing indication that forests are mainly a sink for NO2 and potential NO2 emissions are low. Only when assuming high NO soil emissions, more NO2 can be formed by reaction with O3 than plants are able to take up. Under these circumstance forests can be a source for NO2.

Biochar in perennial crops: nutritional, agronomical and environmental implications

Biochar is the solid C-rich matrix obtained by pyrolysis of biomasses, currently promoted as a soil amendment with the aim to offset anthropogenic C emissions, while ameliorating soil properties and growth conditions. Benefits from biochar seem promising, although scientific understandings are beginning to be explored. In this project, I performed a suite of experiments in controlled and in field conditions with the aims to investigate the effect of biochar on: a) the interaction with minerals; b) Fe nutrition in kiwifruit; c) soil leaching, soil fertility, soil CO2 emissions partitioning, soil bacterial profile and key gene expression of soil nitrification-involved bacteria; d) plant growth, nutritional status, yield, fruit quality and e) its physical-chemical changes as affected by long-term environmental exposure. Biochar released K, P and Mg but retained Fe, Mn, Cu and Zn on its surface which in turn hindered Fe nutrition of kiwifruit trees. A redox reaction on the biochar surface exposed to a Fe source was elucidated. Biochar reduced the amount of leached NH4+-N but increased that of Hg, K, P, Mo, Se and Sn. Furthermore, biochar synergistically interacted with compost increasing soil field capacity, fertility, leaching of DOC, TDN and RSOC, suggesting a priming effect. However, in field conditions, biochar did not affect yield, nutritional status and fruit quality. Actinomadura flavalba, Saccharomonospora viridis, Thermosporomyces composti and Enterobacter spp. were peculiar of the soil amended with biochar plus compost which exhibited the highest band richness and promoted gene expression levels of Nitrosomonas spp., Nitrobacter spp. and enzymatic-related activity. Environmental exposure reduced C, K, pH and water infiltration of biochar which instead resulted in a higher O, Si, N, Na, Al, Ca, Mn and Fe at%. Oxidation occurred on the aged biochar surface, it decreased progressively with depth and induced the development of O-containing functional groups, up to 75nm depth.

Metodologie "green" per l'ottenimento di biopolimeri da colture microbiche

Sono stati studiati ed applicati metodi ���green��� per l���estrazione di poliidrossialcanoati (PHA) da colture microbiche singole (Cupriavidus necator) e miste. Sono stati effettuati esperimenti che prevedono l���utilizzo di surfattanti anionici switchable (SAS) per l���estrazione del polimero, al fine di arrivare ad un protocollo ottimale per l���estrazione di PHB da C.necator che prevede l���uso di NH4 laurato come SAS (100 wt% rispetto al peso dei batteri) per tre ore a 90��C. La sostanza ambifilica agisce distruggendo la membrana cellulare esponendo cos�� i granuli di PHB. Il SAS utilizzato si caratterizza per la possibilit�� di essere recuperabile tramite aggiunta di CO2 al sistema con una resa del 98%. Per le colture microbiche miste, pi�� refrattarie all���impiego dei surfattanti, sono stati utilizzati dei pre-trattamenti, meccanici e fotocatalitici, al fine di indebolire la membrana batterica. Per il trattamento meccanico sono stati impiegati un omogeneizzatore e un sonicatore ad ultrasuoni; mentre per il trattamento fotocatalitico �� stata sperimentata l���azione del nano biossido di titanio (sospensione 1% nano-TiO2) in miscela con i batteri, esposti a radiazioni UV. Dai risultati ottenuti sia il trattamento meccanico che quello fotocatalitico non sono risultati adeguati per i batteri misti. Infine il PHB estratto dalla biomassa batterica �� stato purificato con un trattamento fotocatalitico che prevede l���utilizzo di nano-TiO2 1% supportato in tessuti, esposti a luce UV. I risultati di questo post-trattamento mostrano che, anche utilizzando diverse tipologie di tessuto, il PHB viene in parte adsorbito dal tessuto, con la seguente perdita di campione. In conclusione il trattamento del C. necator con i SAS risulta essere un ottimo metodo di estrazione di PHB considerando sia la qualit�� del polimero estratto sia il riciclo e il riutilizzo del surfattante, mentre per il trattamento delle colture microbiche miste ancora non �� stato trovato un protocollo soddisfacente.

Species specific nitrogen isotope analysis by NanoSIMS

Der atmosph��rische Kreislauf reaktiver Stickstoffverbindungen besch��ftigt sowohl die Naturwissenschaftler als auch die Politik. Dies ist insbesondere darauf zur��ckzuf��hren, dass reaktive Stickoxide die Bildung von bodennahem Ozon kontrollieren. Reaktive Stickstoffverbindungen spielen dar��ber hinaus als gasf��rmige Vorl��ufer von Feinstaubpartikeln eine wichtige Rolle und der Transport von reaktivem Stickstoff ��ber lange Distanzen ver��ndert den biogeochemischen Kohlenstoffkreislauf des Planeten, indem er entlegene ��kosysteme mit Stickstoff d��ngt. Die Messungen von stabilen Stickstoffisotopenverh��ltnissen (15N/14N) bietet ein Hilfsmittel, welches es erlaubt, die Quellen von reaktiven Stickstoffverbindungen zu identifizieren und die am Stickstoffkeislauf beteiligten Reaktionen mithilfe ihrer reaktionsspezifischen Isotopenfraktionierung genauer zu untersuchen. rnIn dieser Doktorarbeit demonstriere ich, dass es m��glich ist, mit Hilfe von Nano-Sekund��rionenmassenspektrometrie (NanoSIMS) verschiedene stickstoffhaltige Verbindungen, die ��blicherweise in atmosph��rischen Feinstaubpartikeln vorkommen, mit einer r��umlichen Aufl��sung von weniger als einem Mikrometer zu analysieren und zu identifizieren. Die Unterscheidung verschiedener stickstoffhaltiger Verbindungen erfolgt anhand der relativen Signalintensit��ten der positiven und negativen Sekund��rionensignale, die beobachtet werden, wenn die Feinstaubproben mit einem Cs+ oder O- Prim��rionenstrahl beschossen werden. Die Feinstaubproben k��nnen direkt auf dem Probenahmesubstrat in das Massenspektrometer eingef��hrt werden, ohne chemisch oder physikalisch aufbereited zu werden. Die Methode wurde Mithilfe von Nitrat, Nitrit, Ammoniumsulfat, Harnstoff, Aminos��ren, biologischen Feinstaubproben (Pilzsporen) und Imidazol getestet. Ich habe gezeigt, dass NO2 Sekund��rionen nur beim Beschuss von Nitrat und Nitrit (Salzen) mit positiven Prim��rionen entstehen, w��hrend NH4+ Sekund��rionen nur beim Beschuss von Aminos��uren, Harnstoff und Ammoniumsalzen mit positiven Prim��rionen freigesetzt werden, nicht aber beim Beschuss biologischer Proben wie z.B. Pilzsporen. CN- Sekund��rionen werden beim Beschuss aller stickstoffhaltigen Verbindungen mit positiven Prim��rionen beobachtet, da fast alle Proben oberfl��chennah mit Kohlenstoffspuren kontaminiert sind. Die relative Signalintensit��t der CN- Sekund��rionen ist bei kohlenstoffhaltigen organischen Stickstoffverbindungen am h��chsten.rnDar��ber hinaus habe ich gezeigt, dass an reinen Nitratsalzproben (NaNO3 und KNO3), welche auf Goldfolien aufgebracht wurden speziesspezifische stabile Stickstoffisotopenverh��ltnisse mithilfe des 15N16O2- / 14N16O2- - Sekund��rionenverh��ltnisses genau und richtig gemessen werden k��nnen. Die Messgenauigkeit auf Feldern mit einer Rastergr����e von 5��5 ��m2 wurde anhand von Langzeitmessungen an einem hausinternen NaNO3 Standard als �� 0.6 ��� bestimmt. Die Differenz der matrixspezifischen instrumentellen Massenfraktionierung zwischen NaNO3 und KNO3 betrug 7.1 �� 0.9 ���. 23Na12C2- Sekund��rionen k��nnen eine ernst zu nehmende Interferenz darstellen wenn 15N16O2- Sekund��rionen zur Messung des nitratspezifischen schweren Stickstoffs eingesetzt werden sollen und Natrium und Kohlenstoff im selben Feinstaubpartikel als interne Mischung vorliegt oder die natriumhaltige Probe auf einem kohlenstoffhaltigen Substrat abgelegt wurde. Selbst wenn, wie im Fall von KNO3, keine derartige Interferenz vorliegt, f��hrt eine interne Mischung mit Kohlenstoff im selben Feinstaubpartikel zu einer matrixspezifischen instrumentellen Massenfraktionierung die mit der folgenden Gleichung beschrieben werden kann: ���15Nbias = (101 �� 4) ��� f ��� (101 �� 3) ���, mit f = 14N16O2- / (14N16O2- + 12C14N-). rnWird das 12C15N- / 12C14N- Sekund��rionenverh��ltnis zur Messung der stabilen Stickstoffisotopenzusammensetzung verwendet, beeinflusst die Probematrix die Messungsergebnisse nicht, auch wenn Stickstoff und Kohlenstoff in den Feinstaubpartikeln in variablen N/C���Verh��ltnissen vorliegen. Auch Interferenzen spielen keine Rolle. Um sicherzustellen, dass die Messung weiterhin spezifisch auf Nitratspezies eingeschr��nkt bleibt, kann eine 14N16O2- Maske bei der Datenauswertung verwendet werden. Werden die Proben auf einem kohlenstoffhaltigen, stickstofffreien Probennahmesubstrat gesammelt, erh��ht dies die Signalintensit��t f��r reine Nitrat-Feinstaubpartikel.

Comparison of Model Chemistry and Density Functional Theory Thermochemical Predictions with Experiment for Formation of Ionic Clusters of the Ammonium Cation Complexed with Water and Ammonia; Atmospheric Implications

The G2, G3, CBS-QB3, and CBS-APNO model chemistry methods and the B3LYP, B3P86, mPW1PW, and PBE1PBE density functional theory (DFT) methods have been used to calculate ��H�� and ��G�� values for ionic clusters of the ammonium ion complexed with water and ammonia. Results for the clusters NH4+(NH3)n and NH4+(H2O)n, where n = 1���4, are reported in this paper and compared against experimental values. Agreement with the experimental values for ��H�� and ��G�� for formation of NH4+(NH3)n clusters is excellent. Comparison between experiment and theory for formation of the NH4+(H2O)n clusters is quite good considering the uncertainty in the experimental values. The four DFT methods yield excellent agreement with experiment and the model chemistry methods when the aug-cc-pVTZ basis set is used for energetic calculations and the 6-31G* basis set is used for geometries and frequencies. On the basis of these results, we predict that all ions in the lower troposphere will be saturated with at least one complete first hydration shell of water molecules.