Solvent Extractable Material Research Articles

A comparison between laboratory and industrial fouling of reverse osmosis membranes used to concentrate milk

Reverse osmosis with polyamide spiral wound membranes is used to concentrate milk to reduce its volume before transport to processing facilities. The main aim of this work was to identify the cause of unusually low flux through a membrane that had been used in an industrial facility. The fluxes of new and used industrial membranes were measured using a flat-sheet cross-flow laboratory system. It was found that the fouling characteristics of laboratory fouled membranes were entirely different from the industrial membrane. The laboratory membranes could be restored to a high flux with a regime of water flushing, caustic and acid. FTIR showed no significant build-up on the membrane. In contrast the industrial membrane could not be cleaned in this manner. FTIR and FT-Raman showed species associated with milk lipids. Cleaning by solvent extraction using a two-phase mixture of water, isopropanol and cyclohexane increased the flux from 1% to almost 50% of the value of a new membrane. Analysis of the solvent-extracted material indicated the presence of phospholipids with a relatively high concentration of sphingomyelin. It was concluded that the laboratory experiments did not mimic industrial processes and an effective industrial cleaning system was not found.

Study on the structural evolution of semi-chars and their solvent extracted materials during pyrolysis process of a Chinese low-rank coal

The structural evolution of coal during pyrolysis process has been studied for a long time but remains unclear, mainly due to the extraordinary complexity of coal structure. The present study aimed to further identify the chemical structural evolution of different parts in the semi-chars obtained by low-temperature pyrolysis of a Chinese low-rank coal (Shenfu coal). Semi-chars and their solvent extracted materials (oil, resin, asphaltene and preasphaltene) were analyzed by 13C nuclear magnetic resonance (NMR) mass spectrometry, diffuse reflectance Fourier transform-infrared spectroscopy (DRIFTs) and ultraviolet (UV) fluorescence spectroscopy, separately. The results showed that 23.8% weight loss occurred during the whole pyrolysis process at 435 °C and half of the weight loss was achieved in the initial five minutes. By contrast, amount of the extracts in semi-chars (solvent extracted metaplast materials) decreased more dramatically in the initial stage of the pyrolysis, and 51.8% of the extracts disappeared in the initial one minute. Oil and preasphaltene showed higher thermal sensitivity than asphaltene and resin. Considerable content of metaplast materials with 1–2 rings (especially in oil and/or asphaltene) were produced along with the pyrolysis process. Condensed aromatic structures in semi-chars were relatively stable and mainly decomposed in the initial stage of pyrolysis which could be attributed to the dramatically decomposition of some active aromatic structures with ≥ 4 rings (especially the components in extracts such as preasphaltene). The results provided a new insight into the structural evolution of coal during low-temperature pyrolysis process, which specially considered the detailed information of the solvent extractable metaplast materials in semi-chars.

Characterisation of bioavailability of Surat Basin Walloon coals for biogenic methane production using environmental microbial consortia

The study sets out to characterise the bioavailability of six Surat Basin Walloon coals from different stratigraphic layers in a single borehole to environmental methanogenic consortia. Factors that control bioavailability have also been investigated on grounds of coal petrographic composition and the organic composition of solvent-extractable matter. Finely crushed coal core samples were inoculated with digested sludge culture from domestic wastewater treatment in serum bottles kept anoxically before incubation at mesophilic temperature over 30days for biomethane production. Degradation of coal compounds was demonstrated via GC–MS characterisation of methanol and dichloromethane (DCM) extracts, in combination with aqueous volatile fatty acids and alcohols and total organic carbon (TOC) analysis on fresh and microbially-digested coal samples. The resulting methane yields ranged from 14 to 33μmol/g, with an average of 21μmol/g (0.515m3/t), comparable to those previously reported for subbituminous coals. Organic solvent-extractable materials that accounted for 3.8 to 12% of coal weight were generally dominated by aliphatic compounds, composed of mainly medium-long-chain n-alkanes, n-alcohols and esters. Aromatics were detected up to three fused rings, and are rich in dibenzofuran, alkyl benzene, diphenyls and alkyl PAH (polymeric aromatic hydrocarbon). The abundance of solvent-extractable matter was found to be positively associated with liptinite content, particularly suberinite, sporinite and liptodetrinite. Preservation of these compounds was thought to rely on vitrinite, such as telinite and collotelinite that are rich in micropores, serving as storage for the hydrocarbons. Environmental factors, such as microbe-carrying groundwater might compromise coal extractability by converting coal hydrocarbons to biogas. Bioavailability of coal was shown to be controlled by three factors: 1) Water solubility - Bioassay eliminated an average 98% of aqueous compounds (based on TOC), which were dominated by volatile fatty acids and alcohols, and to a lesser degree, medium-chain (primarily C10 to C20) n-alcohols, esters and aliphatic amine; 2) Solvent extractability – 34.5% of solvent-extractable compounds were shown to be biodegraded (based on peak intensity in GC–MS), with methanol extracts being more bioavailable than DCM's; 3) Heterogeneous moieties, particularly aliphatic hydroxyl group, ester bond, ether bond and CN bond in aliphatic amine - These functional groups present heteroatoms that can lower the activation energy of nearby bonds, making them vulnerable for microbial cleavage. Compound degradation in bioassays was shown to be clearly associated with methane yield, but only a small proportion degraded was converted to methane. Further improvement may be achieved via proper adaptation of the current microbial community.

Impacts of Mild Pyrolysis and Solvent Extraction on Coking Coal Thermoplasticity

The thermoplastic development of a coking coal was studied before and after treatment to study the impacts on thermoswelling and volatiles release. The treatment process consisted of two consecutive steps, namely mild pyrolysis and solvent extraction. The intention was to characterize the thermally generated and solvent extractable material produced immediately prior to swelling onset and to study the impact of its removal. The heating step removed ∼5% of the coal volatiles and reduced its swelling extent from 83% to 25%. Subsequent solvent extraction with tetrahydrofuran (THF) on the heated coal removed up to 21% of material on a dry basis. The residue after extraction showed little swelling extent and significantly altered volatiles release profile on heating, indicating the role of extracted materials in thermoplastic development and tar formation. The molecular weight distributions of volatile tars collected after pyrolysis shared a similar molecular weight distribution spanning between 200 and 600 Da...

Radiation- and self-ignition induced alterations of Permian uraniferous coal from the abandoned Novátor mine waste dump (Czech Republic)

The effects of uranium mineralization and self-burning processes on inorganic and organic components of coal have been studied at a waste pile of the former Novátor coal and uranium mine at Bečkov (Intrasudetic Basin, Czech Republic) in order to characterize physical and chemical properties of wastes as a basis for further environmental studies. Unaltered bituminous coal was composed predominantly of vitrinite with random reflectance values between 0.72% and 0.86%, and inertinite, less common liptinite macerals, and a low level of organic solvent-extractable material (0.01–1.33wt.%). Uranium minerals caused local radioactive alterations in the uranium-enriched coal matrix. The diameter of rounded radiation-induced haloes ranged from 0.35 to 100μm with higher reflectance (0.84–3.44%) compared with bulk coal. Structural changes in radiation induced altered organic coal matter were characterized by low values of Raman band disorder, fewer aliphatic CH bonds and higher levels of oxygenated functional groups in micro-infrared spectra. Zones of higher reflectance were also confined to veinlets of epigenetic chalcopyrite, galena, and sphalerite mineralization, oriented perpendicularly to the coal bedding. The methylnaphthalene ratios (MNR) of extracted organic matter correlated with uranium concentrations in individual samples.In self-ignition-affected samples, the higher reflectance (1.31–1.71%), and values of Raman band disorder mirrored the intensity of burning processes. Organic matter samples located at unburnt- and burnt coal interfaces were composed of a mixture of coal macerals, char and solid bitumens. In the waste heap burning zone, coal and claystone were transformed to “clinkers” composed of plagioclase, pyroxenes, tremolite, hematite, magnetite, anatase, and aluminosilicate glass or to “paralava”, formed by porous cordierite and hematite. Organic components in the burnt-out zone were represented by small dense and massive coke particles with reflectance of 4.48%, fusinite with reflectance of 3.05% and rare coke droplets of solid bitumen (R=1.90%). Only traces of phenanthrene and alkanes were identified in organic extracts of burnt-out rock.

Evaluation of Total Petroleum Hydrocarbons (TPH) Measurement Methods for Assessing Oil Contamination in Soil

The most commonly used total petroleum hydrocarbons (TPH) analysis method measures petroleum hydrocarbon concentrations in soil by carbon range that can be detected by gas chromatography/flame ionization detection (GC/FID). Different cleanup procedures have been performed for removing some naturally occurring organics from petrogenic hydrocarbons prior to GC/FID analysis. To evaluate the different pre-treatment methods, more than 60 samples (including background soil and plant samples, as well as oil contaminated soil samples) were sampled from 2008 to 2010 in Canada. TPH values without cleanup (TPH-T), with column cleanup (TPH-F 3) and with in-situ cleanup (TPH-F) were compared to evaluate the effects of different pre-treatment methods on the TPH analysis values. Different total solvent extractable materials (TSEM) loading amounts were applied for in-situ silica gel cleanup method to evaluate the effect of the TSEM loading amount on the measured TPH-F values. The column cleanup method was evaluated by comparing the representative polar biogenic organic compounds (BOCs) and TPH in polar fraction (designated as TPH-F 4). Qualitatively, cleanup procedures removed most of the BOCs for background samples with high content of BOCs, but the GC/FID chromatograms did not show significant alteration for samples with heavy oil contamination. The quantified TPH-T, TPH-F 3 and TPH-F showed good agreement for oil contaminated samples, even though the loading dosage exceeded the maximum TSEM limits of silica gel (16.7 mg TSEM on per gram silica gel). For background samples, the measured TPH values were ranked as: TPH-T > TPH-F > TPH-F 3 when the TSEM loading amount exceeded 16.7 mg/g of silica gel, but no obvious difference was observed when the TSEM loading amount was less than 16.7 mg/g. Therefore, the TSEM loading capacity played an important role for the cleanup of background samples. The comparison of the measured TPH-T and TPH-F 3 obtained from background soil and plant samples did not show an obvious relationship, thus TPH values of soil samples can not be replaced by those from plants grown in the soil sampled area. The evaluation of column cleanup method showed that this method can effectively remove most of the BOCs, but the removal of the hydrocarbons which contribute to the measured TPH-F 3 can be negligible.

Oil Weathering after the Deepwater Horizon Disaster Led to the Formation of Oxygenated Residues

Following the Deepwater Horizon disaster, the effect of weathering on surface slicks, oil-soaked sands, and oil-covered rocks and boulders was studied for 18 months. With time, oxygen content increased in the hydrocarbon residues. Furthermore, a weathering-dependent increase of an operationally defined oxygenated fraction relative to the saturated and aromatic fractions was observed. This oxygenated fraction made up >50% of the mass of weathered samples, had an average carbon oxidation state of -1.0, and an average molecular formula of (C(5)H(7)O)(n). These oxygenated hydrocarbon residues were devoid of natural radiocarbon, confirming a fossil source and excluding contributions from recent photosynthate. The incorporation of oxygen into the oil's hydrocarbons, which we refer to as oxyhydrocarbons, was confirmed from the detection of hydroxyl and carbonyl functional groups and the identification of long chain (C(10)-C(32)) carboxylic acids as well as alcohols. On the basis of the diagnostic ratios of alkanes and polycyclic aromatic hydrocarbons, and the context within which these samples were collected, we hypothesize that biodegradation and photooxidation share responsibility for the accumulation of oxygen in the oil residues. These results reveal that molecular-level transformations of petroleum hydrocarbons lead to increasing amounts of, apparently recalcitrant, oxyhydrocarbons that dominate the solvent-extractable material from oiled samples.

Study on the relation of solvent extractable material and resistivity of pyrolysed coal

Changes in electrical and dielectric properties along with yield of the material extracted with pyridine and chloroform depending on the temperature of pyrolysis were analyzed for the two samples of coals with different ranks. The material soluble in pyridine but insoluble in chloroform and the material soluble in chloroform were investigated with Fourier transform infrared spectroscopy (FT-IR) method using attenuated total reflection techniques (ATR). It was stated that an anomalous course of the changes in resistivity of pyrolysates, which were separated from the zones of the charge being plasticized, was related with the existence of low molecular compounds in the supramolecular structure of pyrolysates. These low molecular compounds functionate as dielectrics and block the transport of electric charge in the carbon matrix.

A simplified screening procedure for determination of total N–NO groups (TNG) and nitrite (NO2−) in commercial low-molecular-weight heparins (LMWH) by selective chemical denitrosation followed by high-sensitivity chemiluminescence detection (NO-analyzer, NOA)

Aim of this work was to set up a method for the sensitive and selective determination of nitrite (NO2−) and total N-nitroso groups (TNG) in dalteparin and nadroparin, commercial low- molecular-weight heparins (LMWH), prepared by deaminative depolymerization of heparin with nitrous acid. The European Pharmacopoeia VI ed. indicates respectively 5ppm as the maximum content for contaminant NO2− in the former and 0.25ppm for TNG in the latter and no clear indication is given for N–NO groups in dalteparin, i.e. TNG must be absent because of the specific manufacturing process.The proposed technique is based on the development of a pre-analytical device, coupled to a chemiluminometer, constituted by three sequentially connected and commercially available purge vessels, where selective reagents are employed for the conversion of NO2− and N–NO to nitric oxide (NO). In detail, NO2− was determined in the first chamber and non-volatile and volatile TNG in the second and third. This method was validated for selectivity, sensitivity, linearity, accuracy and precision. The method was shown to be selective, with a quantitative linear range of 1–1000ppb). The bias, intra- and inter-day percent relative error was lower than 1%. The contamination of NO2− and TNG in nadreparin was below the limits; for dalteparin NO2− fell within the limit, but there was a huge amount of TNG (15.80±0.05ppm–6.69±0.02ppm). Preliminary investigation on the solvent-extractable material from dalteparin showed the majority of chemiluminescence retained in the aqueous residue to indicate that this N–NO groups may belong to solvent unextractable material or be tightly bound to the dalteparin backbone.

Molecular markers, essential oils and diagnostic parameters as indicators for assessing the origin and constitution of organic matter in atmospheric aerosols

Atmospheric particulate matter was collected at two sites: an Abies boressi forest in central Greece and in Giesta, a coastal-rural site in the centre of Portugal. The extractable organic material consisted primarily of aliphatic hydrocarbons, acids, alcohols, and ketones, with a predominance of molecular weights >C20, derived from vascular plant waxes. Biomarkers for vegetation sources such as phytosterols, triterpenic compounds and essential oils were also detected. Microbial components (>C20), pyrogenic aromatic hydrocarbons and petroleum residues, including hopanes, steranes and cyclic and branched hydrocarbons, were present in the various aerosol extracts. In the apportionment of the various organic fractions to sources, vegetation waxes dominated, contributing to 50?60% of the solvent-extractable material in the aerosols. Petroleum residues and microbial components comprise 25?30% and 15?25% of the organic matter, respectively.

Thermal stability of foamed polysiloxane rubbers: Headspace analysis using solid phase microextraction and analysis of solvent extractable material using conventional GC–MS

The thermal stability of a condensation cured polysiloxane rubber (RTV5370) has been investigated using both solid phase microextraction (SPME) for headspace analysis of volatiles and conventional gas chromatography–mass spectrometry (GC–MS) for the assessment of toluene extractable fraction. In each case, the chemical composition and distribution of dimethylsiloxane cyclic species were assessed. Of particular interest is how the levels of the species change with age and the likely degradation processes that contribute to their production. Such studies are important as they help identify potential compatibility issues relating to the use of this material. SPME studies show typically that headspace volatile species consist primarily of a range of cyclic polydimethylsiloxanes (D 3–D 8, where D refers to the dimethylsiloxane unit and the subscript refers to the number of Si–O bonds making up the cyclic). 2-Ethylhexanoic acid, a by-product from hydrolysis of the tin catalyst used in the synthesis of the rubber, was also detected in the headspace. The toluene extractable fractions typically showed a wide range of cyclic polydimethylsiloxane (D 4–D 18) species, as well as 2-ethylhexanoic acid and a number of phthalate-based plasticisers. Our studies on thermally aged samples show significant increases in the octamethylcyclotetrasiloxane (D 4) cyclic both within the polymer matrix and in the headspace. These effects have been attributed to thermally activated depolymerisation reactions leading to the production of octamethylcyclotetrasiloxane (D 4) cyclic monomer. Quantification studies, to establish the likely levels of silicone cyclics present in the polymer matrix, were conducted by calibration of the gas chromatography column using silicone standards. The concentration of octamethyltetrasiloxane (D 4) and dodecamethylcyclohexasiloxane (D 6) in pristine, thermally aged and real-time aged samples (from field trials) were all found to be within a few parts per million concentration range.

A study of different soots using pyrolysis–GC–MS and comparison with solvent extractable material

This paper presents characterisation data for a range of soots produced by combustion from ethylene, benzene and kerosene, and soot from the biomass materials willow coppice and oat straw. Soot samples from laminar flames burning the hydrocarbons have been characterised using heated probe mass spectrometry (MS) and gas chromatography (GC)–MS. In some cases fractional pyrolysis–GC–MS was performed at 400 °C/1000 °C. Solvent extraction of samples in toluene or methanol was also employed. Three main categories of material are found for each soot sample: loosely bound solvent extractable material, more strongly bound higher molecular weight material that is difficult to resolve, and highly developed soot. Biomass soot also shows this three component composition although a much wider range of polycyclic aromatic and of oxygenated compounds are present.

LC-MS/MS and FT-IR analyses of stones from a patient with Crohn’s disease: a case report

This report describes the unusual case of a patient affected by Crohn’s disease suffering from intestinal obstruction with recurrent occlusive symptoms not due to the intestinal disease, but to the presence of two calcified foreign bodies in the pelvis. The stones were surgically removed and analysed by reverse-phase liquid chromatography coupled to UV diode array detection and mass spectrometry (LC-UV-DAD-MS/MS), Chromatoprobe-MS/MS and by Fourier-transform-infrared spectroscopy (FT-IR) techniques. The combined mass spectrometric approaches allowed unequivocally to identify 5-aminosalicylic acid (5-ASA) in stone 1, and to demonstrate that its formation was due to an unmodified 5-ASA tablet, a formulation that must undergo complete dissolution in the small bowel. The second stone was constituted by a solid layer (no solvent-extractable material) identified by FT-IR as a polystyrene fragment. This indicates that accidental ingestion of a plastic material, followed by its calcification, was responsible for its formation.

Lipids and their modes of occurrence in two surface sediments from the Danube delta and northwestern Black Sea: implications for sources and early diagenetic alteration: I. Carboxylic acids

Two surface sediments from the Danube delta and an adjacent area of the northwestern Black Sea were subjected to sequential treatment in order to obtain comprehensive qualitative and quantitative information on carboxylic acid moieties. Four acid fractions, corresponding to distinct pools, were thus obtained from each sample: (1) an organic solvent-extractable fraction corresponding to the “unbound” acids, (2) an “OH −-labile” fraction (released by classical alkaline hydrolysis of the solvent-extracted material) corresponding to the ester-bound acids, (3) a “H +-labile” fraction (obtained via subsequent acid hydrolysis of extracted and base-hydrolysed material) corresponding to amide- and/or ether-bound acids, (4) the “tightly-bound” acids released by TMAH thermochemolysis of the insoluble, non-hydrolysable and HF/HCl-resistant material. The existence of these four pools of acids reflects differences in the mode of linkage of the acid moieties and/or in the protection provided by the (macro)molecular structures into which they are incorporated. Considerable qualitative and quantitative differences were observed, for a given sample, depending on the particular pool, and large differences were also noted, for a given pool, between the two samples. The biogeochemical investigation of the carboxylic acids according to their modes of occurrence in these two surface sediments with contrasting locations provides information on (i) the relative importance of microalgal, bacterial and terrestrial contributions in surface sediments, as well as the types of species implicated and (ii) the extent of early diagenetic alteration.

Chemical–structural characterization of solvent and thermal extractable material from perhydrous vitrinites

In this work, the characterization of the non-covalently bonded compounds present in a set of perhydrous coals of different age and geographical location (Cretaceous coals: UCV and TCV and Jurassic coals: AJV, PGJV, WJVh and WJVl) was carried out by means of a combination of the analyses of the material soluble in chloroform and the thermal extract. The extract in chloroform was studied through GC/MS and NMR and the thermovaporized fraction was obtained by means of flash pyrolysis at the Curie temperature of 350 °C and quantified by on-line GC-MS. The results obtained for the Cretaceous coals confirm that the substances responsible for the hydrogenation are those covalently bonded to the vitrinite network as a result of the modifications undergone by the botanical precursors. Despite the striking similarity in the global characteristics of these two coals (TCV and UCV) significant differences between the material non-covalently bonded to their coal matrices were found. These differences are attributed to the type of resins present in the coals and/or to their different degree of evolution. With respect to the Jurassic coals, the present study allows the process by which the hydrogenated substances were assimilated into their structure to be established. The characterization of the assimilated substances in the WJVl coal reveals an unexpectedly high incorporation of alkanes given the humic origin of this sample. From these results the assimilation of hydrogen-rich substances from the decomposition of the organic remains in the sedimentary environment in which WJVl precursor were deposited, is proposed. The incorporation of products derived from the primary decomposition of organic material is not evident for the WJVh and AJV coals. The substances assimilated into the coal matrices show a higher aromaticity, the aromatic structures of WJVh being more condensed than those found in AJV. The compositional differences between them probably arise from the different source of the hydrogen-rich material. In the case of AJV coal the source was the adsorption of hydrocarbons generated and migrated from the Pliensbachian source-rocks whereas in WJVh, assimilated compounds come from the material generated by the thermal transformation (coalification) of the adjacent organic rocks of similar age. Finally, PGJV shows two types of non-covalently bonded compounds. Solvent extractable material is mainly composed of the first type of compounds, which is predominantly aliphatic in nature with a preponderance of alkanes. The second type of compounds is more aromatic and they are probably located in the close porosity of this coal. They are not accessible to chloroform but they are the most abundant in the thermal extract.

Comparative study of the compositional characteristics of liquids derived by hydrotreating of Nigerian tar sand bitumen. I. Simulated distillation : Ukwuoma, O. Petroleum Science and Technology, 2002, 20 (5 & 6), 525–534

Ultracentrifugation was investigated as a means to obtain solvent-free bitumen from oil sand. The bitumen from three oil sands of varying grades was separated by placing the sands in specially designed tubes and centrifuging for 2 h at 198 000 g at 20 °C. For all grades of oil sand, approximately 70% of the bitumen was recovered. The recovered bitumen was compared to the residual remaining on the sand, and to that extracted by the conventional Soxhlet technique. The ultracentrifuged bitumen contained some emulsified water and a small amount of fine solids. The solvent-extracted material was water-free, but contained a small amount of residual solvent and fine solids. The ultracentrifuge caused some fractionation of the bitumen, resulting in a product slightly enriched in asphaltene components compared to the solvent-extracted material. The residual bitumen remaining on the sand was correspondingly slightly depleted in asphaltenes. However, as evidenced by gas Chromatographic simulated distillation data, ultracentrifugation did retain the light (180–220 °C) components of the bitumen which were lost during the solvent removal step following solvent extraction. Other analyses such as density, viscosity and elemental composition verified that ultracentrifugation resulted in some fractionation of bitumen components.

Mass balance of organic carbon fractions in atmospheric aerosols

Total suspended particulate matter was collected in two Portuguese urban areas (Lisbon and Aveiro) and in a Finnish forested site. Samples were sequentially extracted with dichloromethane and water. The solvent extract was separated by flash chromatography into aliphatics, aromatics, carbonyls, alcohols, and an acidic fraction, and analyzed by gas chromatography‐mass spectrometry. An organic/black carbon analyzer was used to evaluate the carbonaceous matter in filters, the water‐soluble fraction, solvent extractable material, and the content of different organic classes. Results showed that the common simple extraction with dichloromethane is able to dissolve less than 50% of the particulate organic material. The successive extraction with water removes an important quantity of the leftover organic polar compounds. The sum of both extractions recovers between 70% and 90% of the organic carbon present. The amount of oxygenated compounds is frequently more than 70% of the extracted material, with a large predominance of organic acids and alcohols, especially for particles with diameters less than 0.49 μm. The organic compounds identified in the extractable atmospheric particulate matter are represented by primary compounds with both anthropogenic and biogenic origin, which mainly derive from vegetation waxes and from petrogenic sources. Secondary products resulting from the oxidation of volatile organic compounds were also detected. The water‐soluble fraction contains essentially oxocarboxylic and dicarboxylic acids, and cellulosic constituents. In accordance with the anthropogenic characteristics of the sampling sites, nonpolar fractions constitute up to 24% of the extracted organic carbon in Lisbon and present high levels of petroleum markers, while in the forested station these compounds represent 8%. The oxygenated organic compounds account for 76–92% of the extracted carbon in samples from Aveiro and Finland. Owing to favorable photochemical conditions during the sampling campaign, secondary organic constituents present higher levels in Aveiro. The forested site is the one where the water‐soluble components show greater variability and concentrations.

Movement and fate of residual mineral oil contaminants in bioremediated soil.

After the bioremediation of soils contaminated with mineral oil products, residual contaminants (designated as total solvent extractable material [TSEM]) remain therein. Since limited information is available about the movement and fate of these residual contaminants in the environment, the potential environmental hazards are difficult to assess. The aim of this study was to identify and quantify the relevant transport and transformation processes of the residual contaminants in bioremediated soil such as volatilization, leaching, and further biodegradation and to conduct a mass flow analysis for the TSEM in bioremediated soil for the first year after application as top soil. The results indicate that after 1 year, the major portion (93%) of the TSEM can be recovered in the top soil and 7% of the TSEM was lost. The majority of the total losses (>98%) was due to transformation processes (biodegradation and aging effects), while small amounts escaped into the atmosphere (0.08%), plant uptake was negligible, (<0.001%) and leaching, identified as the major transport process, accounted for only small effects (1.7%).

Monocarboxylic, dicarboxylic and hydroxy acids released by sequential treatments of suspended particles and sediments of the Black Sea

Highly variable mixtures of free and bound monocarboxylic, dicarboxylic and hydroxy acids are present in particulate matter from oxic and anoxic zones of the water column and underlying sediments of the Black Sea. Three pools of acids were obtained by sequential treatment: (1) an organic solvent-extractable free fraction, (2) an OH −-labile fraction released by alkaline hydrolysis of the solvent-extracted material, and (3) a H +-fraction obtained by acid hydrolysis of extracted and base-hydrolysed material. Monocarboxylic acids quantitatively dominated acid distributions in particles and sediments, but hydroxy [α-, β-, ω- and (ω-1)] acids were relatively enriched in particles from the anoxic zone and in sediments, reaching nearly 30% of total acids. β-Hydroxy acids were the most abundant hydroxy acids, being present in all particulate and sediment samples. α-, ω- and (ω-1)-Hydroxy acids were found only in sediments and then at low relative abundances. Distributions of carboxylic and hydroxy acids varied considerably between the three treatments and between oxic-zone particles, anoxic-zone particles, and sediment. Results are discussed in terms of biogeochemical mechanisms of differential production, degradation and preservation.

Biological treatment of chemically flocculated agro-industrial waste from the wool scouring industry by an aerobic process without sludge recycle

A new agro-industrial effluent known as Sirolan CF effluent is the aqueous phase remaining after the chemical flocculation of wool scouring effluent by the Sirolan CF process. This effluent has been characterized, and shown to be effectively treated by biological degradation. It has a high concentration of organic material (5750 mg/L COD), with a low BOD 5/COD ratio (0.29). Aerobic biological treatment was tested using laboratory and pilot scale reactors, and shown to remove essentially all BOD 5, solvent extractable material and detergent activity. Maximum removal of the COD was 65% leaving a 2000 mg/L residual component of nonbiodegradable organic material. The combined processes of Sirolan CF and biological treatment removed over 90% of the COD and all solvent extractable material from raw wool scouring effluent. This compares favourably to existing treatment systems, and represents a viable and attractive alternative to treat this extremely polluted wastewater.