δ13C and δD measurements of volatile organic compounds in a variety of emissions by thermal desorption compound specific isotope analysis

Volatile organic compounds (VOCs) can be related to different compound classes but they all have a distinct vapour pressure allowing them to enter the atmosphere under ambient conditions. VOCs can undergo various reactions in the atmosphere and are emitted by various processes (anthropogenic and natural). Compound specific isotope analysis (CSIA) has been used in many other research studies to track the fate and source of compounds in the environment and the geological record. The majority of CSIA has been applied to extracts from soil, sediment or crude oils requiring entirely different sampling techniques compared to atmospheric samples. Applying CSIA to atmospheric compounds is a growing research field but has mainly being restricted to stable isotopes of carbon.This PhD thesis presents a novel application for adsorptive sampling on TenaxTA to analyse compound specific δ13C and δD of a range of atmospheric VOCs (C6 - C10). For the first time a 2-stage thermal desorption (TD) unit was linked to gas chromatography isotope ratio mass spectrometry (GC-irMS) and instrumental conditions were thoroughly investigated and optimised. Results obtained by using a standard mix of eleven VOCs confirmed reliability of TD-GCirMS analyses with standard deviations (SD) below instrument precision. δ values showed negligible isotopic fractionation compared to results obtained from traditional GC-irMS analysis (without TD unit) demonstrating the suitability of TD for CSIA.The technique was applied to analyse VOCs from various emission sources, e.g. car exhaust, biomass combustion and an industry stack. The results obtained have provided some insight into the formation processes of the VOCs investigated. δ13C values from an alumina refinery emission support a natural origin for the VOCs (organic material in bauxite ore). The δD values (21 to - 137 ‰) of the industry emission were consistently more enriched in D compared to δD values of VOCs previously reported making the δ values of VOCs in the industrial stack unique. Car exhaust emission from a petrol engine showed significant differences in δ values for VOCs up to 2 ‰ and 25 ‰ (δ13C and δD, respectively) at different tank fuel levels when using the same fuel batch. Car exhaust emission samples from a diesel engine showed a high content of highly complex mixture of unresolved compounds thus chromatographic baseline separation of VOCs was not achieved for stable hydrogen isotope analysis and led to unreliable δ values. The results from different biomass combustion emissions (including 5 species of C3 plants and 3 species of C4 plants) confirmed significant differences in δ13C of VOCs between C3 and C4 plants due to their specific metabolic pathways for carbon fixation in photosynthesis. The δD of VOCs derived from dicotyledons were less depleted in D compared to δD of VOCs derived from grasses (differences >27 ‰) indicating that the VOCs are derived mainly from lignin/cellulose rather than from lipids since dicotyledons contain higher amounts of lignin/cellulose.Due to the unique isotopic signatures of the VOCs from the different emission sources it was possible to distinguish their origins. Furthermore, TD-GC-irMS shows great potential to establish other emission sources in the environment and may help to gain some insight into their modes of formation

δD and δ13C analyses of atmospheric volatile organic compounds by thermal desorption gas chromatography isotope ratio mass spectrometry.

This paper describes the establishment of a robust method to determine compound specific δD and δ13C values of volatile organic compounds (VOCs) in a standard mixture ranging between C6 and C10 and was applied to various complex emission samples, e.g. from biomass combustion and car exhaust. A thermal desorption (TD) unit was linked to a gas chromatography isotope ratio mass spectrometer (GC-irMS) to enable compound specific isotope analysis (CSIA) of gaseous samples. TenaxTA was used as an adsorbent material in stainless steel TD tubes. We determined instrument settings to achieve a minimal water background level for reliable δD analysis and investigated the impact of storage time on δD and δ13C values of collected VOCs (176 days and 40 days of storage, respectively). Most of the standard compounds investigated showed standard deviations (SD) < 6‰ (δD) when stored for 148 days at 4°C. However, benzene revealed occasionally D depleted values (21‰ SD) for unknown reasons. δ13C analysis demonstrated that storage of 40 days had no effect on VOCs investigated. We also showed that breakthrough (benzene and toluene, 37% and 7%, respectively) had only a negligible effect (0.7‰ and 0.4‰, respectively on δ13C values of VOCs on the sample tube. We established that the sample portion collected at the split flow effluent of the TD unit can be used as a replicate sample for isotope analysis saving valuable sampling time and resources. We also applied TD-GC-irMS to different emission samples (biomass combustion, petrol and diesel car engines exhaust) and for the first time δD values of atmospheric VOCs in the aboverange are reported. Significant differences in δD of up to 130‰ were observed between VOCs in emissions from petrol car engine exhaust and biomass combustion (Karri tree). However, diesel car emissions showed a high content of highly complex unresolved mixtures thus a baseline separation of VOCs was not achieved for stable hydrogen isotope analysis. The ability to analyse δD by TD-GC-irMS complements the characterisation of atmospheric VOCs and is maybe used for establishing further source(s)

Exposure of grapes to smoke of vegetation with varying lignin composition and accretion of lignin derived putative smoke taint compounds in wine

Smoke taint in wines from bushfire smoke exposure has become a concern for wine producers. Smoke taint compounds are primarily derived from pyrolysis of the lignin component of fuels. This work examined the influence of the lignin composition of pyrolysed vegetation on the types of putative smoke taint compounds that accrue in wines. At véraison, Merlot vines were exposed to smoke generated from five vegetation types with differing lignin composition. Smoke was generated under pyrolysis conditions that simulated bushfire temperature profiles. Lignin and smoke composition of each fuel type along with putative smoke taint compounds in wines were determined. The results showed that, regardless of fuel type, the commonly reported guaiacyl lignin derived smoke taint compounds, guaiacol and 4-methylguaiacol, represented about 20% of the total phenols in wines. Quantitatively, syringyl lignin derived compounds dominated the total phenol pools in both free and bound forms. The contributions of p-hydroxyphenyls were generally similar to the guaiacyl sources. A further unexpected outcome of the study was that pine smoke affected wines had significantly elevated levels of syringols compared to the controls although pine fuel and its smoke emission lacked syringyl products

KULTUROWE ZRÓśNICOWANIE JAKO PODSTAWA. UWAGI DO (STAREJ) NOWEJ TRANSNARODOWEJ KONCEPCJI MUZYCZNO-PEDAGOGICZNEJ

W odniesieniu do tematu „Znaczenie kształcenia muzycznego na tle zróŜnicowanej historii naszych narodów w Europie” do rangi zagadnienia naukowego urasta problem: Jak funkcjonują transkulturowe konstrukcje toŜsamościowe oraz jak w czasach globalizacji tworzy się kulturowa toŜsamość? Jako przykład posłuŜyć tu moŜe muzyczna socjalizacja we (wschodnio-)Ŝydowskiej kulturze, której istotnym wyznacznikiem toŜsamościowym jest muzyka, jaka od dawien dawna tworzona jest z uwzględnieniem historycznej zmienności w przestrzeni pomiędzy kulturami: synkretycznie i transkulturowo. śydowska, czterojęzyczna pieśń Dem sejdns nign opisuje np. historię róŜnorodnych migracji poprzez kilka generacji i ujmuje tematycznie konieczność międzypokoleniowego przekazywania muzycznego dziedzictwa. Wreszcie poprzez tę pieśń doświadcza się dramatycznej przemiany od tradycyjnej liturgii po polkę i swing, przez co utwór ten nie traci niczego ze swoich pierwotnych właściwości. Na przykład powstanie muzyki klezmerskiej antycypuje zglobalizowane formy kulturowe i Ŝydowskie wyznaczniki identyfikacyjne. Ze współdziałania tradycji, zinstytucjonalizowanego wychowania, włączenia nastolatka w codzienną praktykę muzyczną, muzyczno-immanentnego wsparcia indywidualnej muzycznej zdolności do wyraŜania i specyficznej tradycyjnej pedagogiki Ŝydowskiej wynikają liczne uwarunkowania tej przestrzeni, które umoŜliwiają kształtowanie się osobistych znaczeń muzycznych i transkulturowych konstrukcji toŜsamościowych

Novel process of biochemical ammonia removal from air streams using a zeolite (clinoptilolite) filter system

Ammonia (NH3) in air is of major health and environmental concern, i.e. contribution to the greenhouse effect when NH3 is converted to nitrous oxide (N2O) in the atmosphere. Another important concern for ammonia in the atmosphere, is the possible conversion to secondary fine particulate matter in the presence of SOx or NOx. The main sources of NH3 in air are waste and food processing industries as well as animal livestock production. The increase in environmental litigation, coupled with rising environmental awareness and a focus on quality of life, has resulted in an increase in the investigation and implementation of new technologies for the treatment of ammonia. In addition, existing methods are cost intensive, unreliable or complex and difficult to control. In this research, a novel biochemical ammonia removing process has been developed and operated for 300 days. This process involves a sequence of biological, physical and chemical processes initiated by the dissolution of the introduced ammonia into the water of the filter system to make the ammonium available for biological degradation (nitrification). A spontaneous reaction of the intermediate nitrification product, nitrite, and ammonium to nitrogen takes place as soon as both compounds are present. This reaction is known to be catalysed by zeolite (clinoptilolite). Water from the discharged moisture of the filter system was condensed on top of the reactor by employing a novel moisture control mechanism. The clean condensate percolated by gravity through the reactor bed and forced the accumulated compounds to the bottom of the reactor. This led to a gradient distribution of compounds across the reactor depth with the highest concentrations at the bottom (140 mM ammonium, 1 M nitrite and 350 mM nitrate), favouring the chemical reaction of NH4+ + NO2

Pilot scale trials of biofilters using zeolite and coir as filter media treating odour compounds from a composting facility

This study investigates odour removal of pilot-scale biofilters treating volatile organic compounds (VOCs) produced during composting of organic fraction of municipal solid wastes (OFMSW). Four biofilters, containing non-biodegradable zeolite, biodegradable coir fibre, and the mixture of both materials, with and without inoculum, were set up onsite to treat the exhaust gases from a local composting facility. Odour-removal efficiencies of the biofilters were monitored by sensory concentration measurement using olfactometry and analytical measurement using gas chromatography-mass spectrometry (GC-MS) on three occasions, at start-up, 3 months and 9 months of operation. At feeding rate of 1 L/L/min and feed concentration of 9,000-10,000 OU, odour removal efficiencies of the biofilters were over 90% right from start up through to 9-month period of monitoring. Inoculation of biofilter was found to be beneficial but not essential. Based on detailed analysis of odour compounds using GC-MS, zeolite biofilter was effective in adsorbing polar compounds (such as alcohol and volatile acids) while coir biofilter was found to be particularly effective in capturing non-polar VOCs, such as monoterpenes (the main component in the feed stream). The combination of coir and zeolite complemented one another providing very effective removal of both polar and non-polar volatile compounds

Design and development of a novel biofilter

The design and development of a novel biofilter is described in this paper. Moisture control is a key aspect of the design. Moisture from the gas stream leaving the biofilter is condensed and returned to the top of biofilter as reflux of pure water. The refluxed water maintains a moist environment for the bacteria throughout the total biofilter column. It also washes down microbial product/s (nitrite and nitrate in the case of ammonia oxidation) that may be toxic to microorganism at a high concentration. This allows microbial activity to be maintained at its most favorable level in the top section of the biofilter. Optimization of moisture balance between evaporation and condensation can result in a system whereby water level on the media surface is sufficient for microbes to thrive while no leachate is produced. In a proof-of-concept study, a laboratory-scale computer controlled biofilter system employing the reflux process was operated to remove ammonia from an air stream (2.05 μmol /L= 50 ppmv) at a volume load of 1 L/L/min. Inoculated zeolite (clinoptilolite) was used as filter media. Depth profile analysis of the filter bed showed the development of a steep gradient of ammonia, nitrite and nitrate from the top layer to the bottom layer of filter media in the biofilter. Aside from the well-known ammonium adsorption on zeolite, consistent microbial nitrification continued to take place. Nitrite and nitrate level at the bottom of the biofilter continued to increase over 180 day period of experiment. As a result, ammonia removal efficiency remained close to 100% in the leachate-free biofilter