Pyrolysis of Softwood Carbohydrates in a Fluidized Bed Reactor

In the present work pyrolysis of pure pine wood and softwood carbohydrates, namely cellulose and galactoglucomannan (the major hemicellulose in coniferous wood), was conducted in a batch mode operated fluidized bed reactor. Temperature ramping (5 °C/min) was applied to the heating until a reactor temperature of 460 °C was reached. Thereafter the temperature was kept until the release of non-condensable gases stopped. The different raw materials gave significantly different bio-oils. Levoglucosan was the dominant product in the cellulose pyrolysis oil. Acetic acid was found in the highest concentrations in both the galactoglucomannan and in the pine wood pyrolysis oils. Acetic acid is most likely formed by removal of O-acetyl groups from mannose units present in GGM structure.     

Land-use based stormwater pollutant load estimation and monitoring system design

Accurate quantification of the amount, quality and sources of urban stormwater runoff are a prerequisite for effective stormwater management. The goal of this study was to estimate city-scale stormwater pollutant export, examine the effect of data sources on export estimates, and develop an optimization method for stormwater monitoring. The results were presented for the city of Lahti in southern Finland, where site mean pollutant concentrations (SMCs), annual pollutant loads, and monitoring guidelines for specific land use types were determined for total suspended solids (TSS), nutrients (total nitrogen TN and total phosphorus TP), chemical oxygen demand (COD), and metals (Pb, Zn, Cu, Cr, and Ni). Depending on the data source, differences between estimated pollutant exports ranged from -89% to 215%. Lack of reference data for every urban land use type and differences in land use classification schemes were identified as key factors limiting the accuracy of pollutant load estimation.     

Chemical composition, mass size distribution and source analysis of long-range transported wildfire smokes in Helsinki

Special episodes of long-range transported particulate (PM) air pollution were investigated in a one-month field campaign at an urban background site in Helsinki, Finland. A total of nine size-segregated PM samplings of 3- or 4-day duration were made between August 23 and September 23, 2002. During this warm and unusually dry period there were two (labelled P2 and P5) sampling periods when the PM2.5 mass concentration increased remarkably. According to the hourly-measured PM data and backward air mass trajectories, P2 (Aug 23-26) represented a single, 64-h episode of long-range transported aerosol, whereas P5 (Sept 5-9) was a mixture of two 16- and 14-h episodes and usual seasonal air quality. The large chemical data set, based on analyses made by ion chromatography, inductively coupled plasma mass spectrometry, X-ray fluorescence analysis and smoke stain reflectometry, demonstrated that the PM2.5 mass concentrations of biomass signatures (i.e. levoglucosan, oxalate and potassium) and of some other compounds associated with biomass combustion (succinate and malonate) increased remarkably in P2. Crustal elements (Fe, Al, Ca and Si) and unidentified matter, presumably consisting to a large extent of organic material, were also increased in P2. The PM2.5 composition in P5 was different from that in P2, as the inorganic secondary aerosols (NO3-, SO4(2-), NH4+) and many metals reached their highest concentration in this period. The water-soluble fraction of potassium, lead and manganese increased in both P2 and P5. Mass size distributions (0.035-10 microm) showed that a large accumulation mode mainly caused the episodically increased PM2.5 concentrations. An interesting observation was that the episodes had no obvious impact on the Aitken mode. Finally, the strongly increased concentrations of biomass signatures in accumulation mode proved that the episode in P2 was due to long-range transported biomass combustion aerosol.     

Degradative hydrogen peroxide oxidation of chelates catalysed by metallophthalocyanines

Catalytic oxidation of various chelating agents in aqueous solutions, namely: diethylenetriaminepentakis(methylphosphonic acid) (DTPMP); diethylenediaminepentaacetic acid (DTPA); ethylenediamine tetraacetic acid (EDTA); nitrilotriacetic acid (NTA); and beta-alaninediacetic acid (beta-ADA) was studied. Hydrogen peroxide was used as oxidising agent in combination with five different metallotetrasulfophthalocyanines as catalysts. (Reaction temperature was set to 60 degrees C, which is expected to be the temperature of bleaching wastewaters of modern pulp mill in the near future. Among the uncomplexed chelating agents, EDTA was most readily degraded, while DTPMP and NTA were less degradable. beta-ADA and DTPA concentrations remained high. The metal speciation of these chelating agents has a significant effect on their chemical degradability. Iron, manganese and sodium complexes were most degradable, while zinc, copper and calcium complexes were more difficult to oxidise.     

The hindering effect of experimental strategies on advancement of alkaline front and electroosmotic flow during electrokinetic lake sediment treatment

The current study focused on the hindering of alkaline front during electrokinetic copper migration in artificially contaminated lake sediments and the effect of several experimental strategies on electroosmotic flow. Fourteen laboratory scale experiments in triplicates were performed using plastic container where the distance between electrodes was 30 cm at 40 mA, 60 mA and 120 mA electric currents (under density of 0.15 mA cm(-2), 0.23 mA cm(-2) and 0.53 mA cm(-2), respectively) with different Cu concentrations (500 mg kg(-1), 1000 mg kg(-1), 1500 mg kg(-1), 2000 mg kg(-1) and 2500 mg kg(-1)) for 14 days. Tests were conducted with/without electric current and with/without the employment of membranes or barriers. Selected membranes and barriers proved to be efficient in hindering the alkaline front and thus improving copper migration in the sediments. During electrokinetic treatment and the use of the nylon membrane 85% of Cu was removed from sediments. Additionally, 80% and 70% of Cu was removed when cation exchange membrane and filter paper barrier were used. During the electrokinetic treatment Cu as well as the electroosmotic flow was always directed towards the cathode. The highest electroosmotic flow was observed with the lowest (500 mg kg(-1)) Cu concentration. Moreover, the electroosmotic flow and electrical gradient increased with the increase in electric current and was found to be the highest at 120 mA. When there were no membranes, barriers or acid used, severe pH jump was observed at a normalized distance of 0.5-0.6 from the anode. However, when membranes or barriers were employed, there was no pH jump present in the sediments.     

Capture of Co(II) from its aqueous EDTA-chelate by DTPA-modified silica gel and chitosan

The adsorption of Co(II) by diethylenetriaminepentaacetic acid (DTPA)-modified silica gel and chitosan in the presence of EDTA and other interfering species was studied. Co(II) removal ranged from 93% to 96% from the solutions where Co(II) was totally chelated by EDTA. The amount of oxalate or Fe(II) did not affect the adsorption of Co(II) in the case of DTPA-chitosan. However, increasing the amount of oxalate enhanced the adsorption performance of DTPA-silica gel, probably due to the formation of new active sites on the silica gel surface. DTPA-chitosan was also effective in simulated decontamination solutions. For DTPA-silica gel, the rate of adsorption of free Co(II) was controlled by pore diffusion, but the rate of adsorption of Co(II)EDTA was controlled by the surface chelation reaction, which was attributed to the inhibited diffusion of Co(II)EDTA inside the silica gel mesopores. However, the macroporous structure of DTPA-chitosan enabled pore diffusion of both Co(II) and Co(II)EDTA. The equilibrium isotherms of DTPA-silica gel were best described by a BiLangmuir model, in which there are two different adsorption sites on the silica gel surface assigned to different speciations of DTPA. For DTPA-chitosan, the data fit best with a Sips model, which indicates system heterogeneity. Finally, measurements with capillary electrophoresis showed an increase in dissolved EDTA during adsorption, demonstrating the ability of DTPA-modified adsorbents to release Co(II) from its EDTA chelate. This promising result can provide a basis for applying the studied materials to the treatment of water effluents containing Co(II) chelated by EDTA by a simple one-step adsorption process.     

Characterization of the microbial community and its changes in liquid piglet feed formulations

The stability of the microbial populations in liquid piglet feed formulations was studied over a period of 3 months. Total aerobic bacteria, lactic acid bacteria, proteolytic bacteria, amylolytic bacteria, lipolytic bacteria, Bacillus cereus group and yeasts and moulds were monitored using selective media. The results demonstrated a tendency for slight increases in the numbers of total aerobic bacteria (p = 0.002), lactic acid bacteria (p = 0.014), proteolytic bacteria (p = 0.006) and lipolytic bacteria (p = 0.003). The numbers of amylolytic bacteria (p = 0.791) and yeasts and moulds (p = 0.620) were more variable, and Bacillus cereus‐like bacteria were nearly absent. Lactic acid bacteria, especially lactobacilli and leuconostocs, were the predominant population, indicating that a natural fermentation occurred, reducing the pH of the feeds to 4.7. The presence of proteolytic, lipolytic and amylolytic bacteria could theoretically lead to an improvement in the digestibility of the feeds. Copyright © 2004 Society of Chemical Industry     

Preparation and characterization of sodium iron titanate ion exchanger and its application in heavy metal removal from waste waters

The ion exchange properties of sodium iron titanates, namely, NaFeTiO(4), Na(2)Fe(2)Ti(6)O(16) and iron-doped sodium nonatitanate were investigated. Conventional solid state and sol-gel methods were used in the synthesis of the sodium iron titanates. Structural characterization of the materials was performed with powder X-ray diffraction (XRD), thermogravimetry (TG), scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS) and with inductively coupled plasma optical emission spectrometry (ICP-OES). Based on TG analyses, the novel iron-doped sodium nonatitanate was proven to be a member of the layered titanate family. The different sodium iron titanates were compared based on the efficiency in separating Ni from aqueous streams by conducting batch experiments with a batch factor of 1000 ml/g. Iron-doped sodium nonatitanate exhibited the best ion exchange performance compared to the other sodium iron titanates studied. It was found to be selective for nickel over potassium and showed 99% removal efficiency for Ni.     

Antimicrobial and cytotoxic knotwood extracts and related pure compounds and their effects on food-associated microorganisms

Knotwood or bark extracts prepared from 30 species of hard and soft wood trees as well as selected pure compounds (lignans, stilbenes and flavonoids) were assayed for their antimicrobial activity against a battery of both gram positive and negative bacteria, yeasts, and filamentous fungi (Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, Lactobacillus plantarum, Escherichia coli, Salmonella infantis, Pseudomonas fluorescens, Candida albicans, Saccharomyces cerevisiae, Aspergillus fumigatus and Penicillium brevicompactum). By far the most consistent antibacterial and antifungal properties were associated with extracts of Pinus species. These extracts showed also cytotoxicity against a mouse hepatoma cell line. Both antimicrobial and cytotoxic properties correlated with the stilbene content of the extracts. Purified stilbenes showed the most consistent antimicrobial and cytotoxic activities, while purified lignans had marginal effects, only. The results suggest that stilbenes account both for the antimicrobial and cytotoxic properties of Pinus knotwood extracts.