Selective Reduction of Nitrogen Oxides In Combustion Flue Gases

The body of Information presented in this paper is directed to those Individuals concerned with the removal of NO_x in combustion flue gases. A catalytic process for the selective reduction of nitrogen oxides by ammonia has been investigated. Efforts were made toward the development of catalysts resistant to SO_x poisoning. Nitrogen oxides were reduced over various metal oxide catalysts in the presence or absence of SO_x(SO₂ and SO₃). Catalysts consisting of oxides of base metals (for example, Fe₂O₃) were easily poisoned by SO₃, forming sulfates of the base metals. A series of catalysts which are not susceptible to the SO_x poisoning has been developed. The catalysts possess a high activity and selectivity over a wide range of temperatures, 250—450°C. The catalysts were tested in a pilot plant which treated a flue gas containing 110-150 ppm NO_x, 660-750 ppm SO₂, and 40-90 ppm SO₃. The pilot plant was operated at 350°C and at a space velocity of 10,000 h^-1. The removal of nitrogen oxides was more than 90% for several months.

A mechanism of the NO-NH₃ reaction has also been investigated. It is found that NO reacts with NH₃ at a 1:1 mole ratio in the presence of oxygen and the reaction is completely inhibited by the absence of oxygen. The experimental data show that the NO-NH₃ reaction in the presence of oxygen is represented byNO + NH₃ + 1/4 O₂ = N₂ + 3/2 H₂O.     

The pyrolysis of sawdust and polyethylene in TG and U-shape tube reactor

The co-pyrolysis of sawdust and polyethylene was carried out in a TG-DTG system and a U-shape tube reactor. This research was focused on the interaction between sawdust and polyethylene during the pyrolysis process. The results showed that the interaction between the sawdust particles and polyethylene particles could be ignored during the devolatile process, but there was interaction among the volatile components in the co-pyrolysis process.     

Persistent organic pollutants (POPs) in Caspian seals of unusual mortality event during 2000 and 2001

Persistent organic pollutants including organochlorine pesticides, PCBs, and PCDDs/DFs were determined in the blubber of Caspian seals, which died during an outbreak of canine distemper virus in 2000 and 2001. DDTs were the predominant contaminants that ranged from 3.1 to 560 microg/g lipid. A negative correlation was observed between concentration of contaminants and blubber thickness. During spring, as the blubber layer becomes thin after breeding and moulting, seals may face higher risk due to the increased concentration of organochlorines in their bodies. TEQs in the blubber of Caspian seals (10-340 pg TEQ/g) were lower than those in seals from other locations, suggesting that toxic effects of these contaminants are a deal less in the present population and they are unlikely to be linked to mass mortality. The levels of PCBs and pesticides in Caspian seals, however, comparable to those in other aquatic mammals that have suffered from epizootics, might pose a risk of immunosuppression.     

Perfluorooctanesulfonate and perfluorooctanoate in raw and treated tap water from Osaka, Japan

Perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) have been recognized as emerging environmental pollutants because of their ubiquitous occurrence in the environment, biota, and humans. PFOS and PFOA have been detected in water in Japan. Nevertheless, occurrence of PFOS and PFOA in potable water from municipal water treatment plants is not clearly known. We analyzed PFOS and PFOA in raw and tap water samples collected from 14 drinking water treatment plants in winter and summer seasons in Osaka to determine the concentrations of PFOS and PFOA in raw and potable tap water samples. PFOS and PFOA were detected in all raw water samples. Concentration ranges of PFOS and PFOA in raw water were 0.26-22 ng/l and 5.2-92 ng/l, respectively. Whereas the concentrations PFOS in raw water from Osaka were similar to those in other areas in Japan, the concentrations of PFOA were higher than in other areas. Concentration ranges of PFOS and PFOA in potable tap water were 0.16-22 ng/l and 2.3-84 ng/l, respectively. There were positive correlations between PFC concentrations in raw water and tap water samples. Therefore, the removal efficiency of PFCs by the present water treatment may be low. Based on the current action value reported by U.S. Environmental Protection Agency, PFOA concentrations found in tap water in Osaka is not expected to pose health risks.     

Nematomorph parasites drive energy flow through a riparian ecosystem

Parasites are ubiquitous in natural systems and ecosystem-level effects should be proportional to the amount of biomass or energy flow altered by the parasites. Here we quantified the extent to which a manipulative parasite altered the flow of energy through a forest-stream ecosystem. In a Japanese headwater stream, camel crickets and grasshoppers (Orthoptera) were 20 times more likely to enter a stream if infected by a nematomorph parasite (Gordionus spp.), corroborating evidence that nematomorphs manipulate their hosts to seek water where the parasites emerge as free-living adults. Endangered Japanese trout (Salvelinus leucomaenis japonicus) readily ate these infected orthopterans, which due to their abundance, accounted for 60% of the annual energy intake of the trout population. Trout grew fastest in the fall, when nematomorphs were driving energy-rich orthopterans into the stream. When infected orthopterans were available, trout did not eat benthic invertebrates in proportion to their abundance, leading to the potential for cascading, indirect effects through the forest-stream ecosystem. These results provide the first quantitative evidence that a manipulative parasite can dramatically alter the flow of energy through and across ecosystems.     

Biosorption of uranium from aqueous solutions by Azolla sp. and Limnobium laevigatum

Environmental Science and Pollution Research - The main goal of this study was to assess alternatives to the current challenges on environmental quality and circular economy. The former is here...     

Molecular structure of extracellular poly(3-hydroxybutyrate) depolymerase fromAlcaligenes faecalis T1

The amino acid sequence of a peptide containing an active serine was examined with poly(3-hydroxybutyrate) (PHB) depolymerase ofAlcaligenes faecalis T1. The sequence Cys-Asn-Ala-Trp-Ala-Gly-Ser-Asn-Ala-Gly-Lys was obtained. This amino acid sequence around the active serine does not fit any reported sequence of other esterases and proteases. On the other hand, a segment of the amino acid sequence of PHB depolymerase ofA. faecalis was homologous to the type III sequence of fibronectin. Similar sequences have been reported in some type of bacterial chitinase and cellulases, and PHB depolymerase seems to have an overall similarity to these bacterial extracellular hydrolases.