Polycyclic aromatic hydrocarbons emission from cigar burner combustion system and comparison of their content in fly ashes

Agricultural biomass is considered a preferred RES in Serbia because of its availability and suitability to limit the use of fossil fuel resources and reduce GHG emissions. Therefore, constant work has been done to develop technologies that enable its utilization for energy purposes. As an example of these efforts, in the Agricultural Corporation PKB, the soybean straw cigarette-type combustion system has been applied for greenhouse heating for over a decade. However, many volatile and semivolatile organic compounds are emitted directly into the atmosphere or concentrated in ash particles during agricultural biomass combustion. Since some of the emitted compounds, such as polycyclic aromatic hydrocarbons (PAHs), are toxic, monitoring their concentrations in fly ash is recommended. Literature data regarding PAHs content in agricultural biomass ashes are insubstantial, especially in Serbia. For that purpose, PAHs contents in the cyclone and stack fly ashes of soybean straw were investigated and compared. In addition, the emission factors, toxicity, carcinogenicity and benzo[a]pyrene equivalence concentrations were determined and used to estimate the potential environmental impact of these ashes. As a result, stack ash has been shown to have a higher potential environmental risk than cyclone ash. Hence, an assessment of using soybean straw as a feed fuel in a real cigarette-type combustion plant regarding PAHs emission is given. These results provide important information for optimizing combustion conditions and assisting the local entities in managing air pollution and control policies in Serbia

Rapid laboratory method for the detection of chlorine in water

The possibility of chlorine detection in water by using of amperometric sensor with dialysis membrane was investigated. The sensor consists of platinum cathode and silver anode, which were immersed in electrolyte whose pH was controlled. The calibration diagrams were constructed for different electrolytes and polarization potentials. The detection limit of 0.1 mg/dm3 was obtained, middle value of sensor sensitivity was approximatelly 14 nA/mgdm'3 and response time was less than 1 s for designed amperometric sensor in laboratory conditions

Procena rizika za potencijalno opasne supstance iz letećih pepela dobijenih sagorevanjem uglja i otpadnog uglja

Lignite and coal waste used as feed fuels in thermal power plants (TPPs) and semi-industrial fluidized bed boiler (FBB), as well as their representative fly ashes (FAs), were examined. Fly ashes were compared employing anions and cations content in correspondent water extracts, trace elements and polycyclic aromatic hydrocarbon concentrations, as well as health risk assessments of substances known to be of concern for public health. Fluoride and sulfate contents in water extracted FAs are far below the legislation limits for waste, classifying all investigated FAs as non-hazardous. Among investigated trace elements, Cd content is the lowest, while Mn content is the highest. The highest enrichment ratios are noticed for As, Pb, Hg, Cu, V and Cr. The results indicate that total PAHs content is elevated in FA from the combustion of coal waste (AFB), with fluoranthene prevailing. The cancer risk of As and the non- -cancer risk of As and Ni in some FAs surpass their respective permissible limits. The incremental lifetime cancer risk of an adult population indicates a potential PAHs risk in AFB, whereas all other fly ashes are within safe limits.U ovom radu, ispitivana su goriva (lignit i otpadni ugalj) koja se koriste u termoelektranama i poluindustrijskom postrojenju sa fluidizovanim slojem, kao i leteći pepeli dobijeni njihovim sagorevanjem. Leteći pepeli su upoređeni na osnovu: sadržaja anjona i katjona u njihovim vodenim ekstraktima, koncentracije elemenata u tragovima i policikličnih aromatičnih ugljovodonika (PAH), kao i procene zdravstvenog rizika koji potiče od prethodno pomenutih potencijalno opasnih supstanci. Sadržaj fluorida i sulfata u vodenim ekstraktima letećih pepela daleko je ispod zakonski dozvoljenih granica za otpad, na osnovu čega se mogu svrstati u bezopasne. Od ispitivanih elemenata u tragovima, sadržaj Cd je najniži, dok je koncentracija Mn najviša. Najveće obogaćenje pepela u odnosu na odgovarajući ugalj, primećeno je za As, Pb, Hg, Cu, V i Cr. Na osnovu dobijenih rezultata pokazano je da je ukupni sadržaj PAH najveći za leteći pepeo dobijen sagorevanjem otpadnog uglja. Među ispitivanim PAH, najvišu koncentraciju ima fluoranten. Rizici koji potiču od arsena (među kancerogenim elementima), kao i arsena i nikla (među nekancerogenim elementima), premašuju dozvoljene granične vrednosti. Vrednost procenjenog rizika od raka kod odrasle populacije u slučaju PAH, pokazuje da za leteći pepeo dobijen sagorevanjem otpadnog uglja postoji potencijalni rizik, dok su vrednosti za ostale pepele unutar dozvoljenih granica

Determination of polycyclic aromatic hydrocarbons in biomass ash from cigar burner combustion systems

Biomass combustion has many advantages compared to fossil fuels due to reduction of carbon dioxide emissions, but several issues are present during biomass combustion. One that must always be considered is emission of nitrogen oxides (NOx), which have significant impact on the environment and health. At biomass combustion, main mechanism responsible for NOx emission is oxidation of fuel-bound nitrogen. Increased NOx emissions are particularly present at agricultural biomass combustion, due to its increased nitrogen content, which is further expressed by the use of nitrogen fertilizer. Denitrification methods are classified as pre-combustion, combustion control and post-combustion (flue gas treatment) methods. Aim of this paper is to provide insight in different flue gas denitrification methods (DeNOx measures) from the review of existing literature, with emphasis on post-combustion methods, since they have higher efficiency. Also, pre-combustion and combustion control methods at agricultural biomass combustion often do not provide reduction below emission standards. Selective catalytic (SCR) and selective noncatalytic reduction (SNCR), wet scrubbing, adsorption, electron beam, electrochemical method, non-thermal plasma and microbial approach were considered. For each method, mechanism of NOx reduction is given and discussed, alongside with efficiency that could be achieved. Overall comparison of advantages and disadvantages for these methods is provided. Further research of denitrification and optimization of described methods, to overcome NOx emission problem is required. Application of these methods in commercial use and increasing their efficiency, while solving cost and methods disadvantages, is key for biomass to be used as a renewable energy source and fossil fuel replacement

Biochemical characterization of soluble nucleotide pyrophosphatase/phosphodiesterase activity in rat serum

Biochemical properties of nucleotide pyrophosphatase/phosphodiesterase (NPP) in rat serum have been described by assessing its nucleotide phosphodiesterase activity, using p-nitrophenyl-5'-thymidine monophosphate (p-Nph-5'-TMP) as a substrate. It was demonstrated that NPP activity shares some typical characteristics described for other soluble NPP, such as divalent cation dependence, strong alkaline pH optimum (pH 10.5), inhibition by glycosaminoglycans, and K (m) for p-Nph-5'-TMP hydrolysis of 61.8 +/- A 5.2 mu M. In order to characterize the relation between phosphodiesterase and pyrophosphatase activities of NPP, we have analyzed the effects of different natural nucleotides and nucleotide analogs. ATP, ADP, and AMP competitively inhibited p-Nph-5'-TMP hydrolysis with K (i) values ranging 13-43 mu M. Nucleotide analogs, alpha,beta-metATP, BzATP, 2-MeSATP, and dialATP behaved as competitive inhibitors, whereas alpha,beta-metADP induced mixed inhibition, with K (i) ranging from 2 to 20 mu M. Chromatographic analysis revealed that alpha,beta-metATP, BzATP, and 2-MeSATP were catalytically degraded in the serum, whereas dialATP and alpha,beta-metADP resisted hydrolysis, implying that the former act as substrates and the latter as true competitive inhibitors of serum NPP activity. Since NPP activity is involved in generation, breakdown, and recycling of extracellular adenine nucleotides in the vascular compartment, the results suggest that both hydrolyzable and non-hydrolyzable nucleotide analogs could alter the amplitude and direction of ATP actions and could have potential therapeutic application.Serbian Ministry of Science and Technology [E143005

Na+/K+-ATPase: Activity and inhibition

The aim of the study was to give an overview of the mechanism of inhibition of Na+/K+-ATPase activity induced by some specific and non specific inhibitors. For this purpose, the effects of some ouabain like compounds (digoxin, gitoxin), noble metals complexes ([PtCl2DMSO2], [AuCl4](-), [PdCl4](2-), [PdCl(dien)](+), [PdCl(Me(4)dien)](+)), transition metal ions (Cu2+, Zn2+, Fe2+, Co2+), and heavy metal ions (Hg2+, Pb2+, Cd2+) on the activity of Na+/K+-ATPase from rat synaptic plasma membranes (SPM), porcine cerebral cortex and human erythrocytes were discussed.9th International Conference on Fundamental and Applied Aspects of Physical Chemistry, Sep 24-26, 2008, Belgrade, Serbi

Biochemical characterization of soluble nucleotide pyrophosphatase/phosphodiesterase activity in rat serum

Biochemical properties of nucleotide pyrophosphatase/phosphodiesterase (NPP) in rat serum have been described by assessing its nucleotide phosphodiesterase activity, using p-nitrophenyl-5'-thymidine monophosphate (p-Nph-5'-TMP) as a substrate. It was demonstrated that NPP activity shares some typical characteristics described for other soluble NPP, such as divalent cation dependence, strong alkaline pH optimum (pH 10.5), inhibition by glycosaminoglycans, and K (m) for p-Nph-5'-TMP hydrolysis of 61.8 +/- A 5.2 mu M. In order to characterize the relation between phosphodiesterase and pyrophosphatase activities of NPP, we have analyzed the effects of different natural nucleotides and nucleotide analogs. ATP, ADP, and AMP competitively inhibited p-Nph-5'-TMP hydrolysis with K (i) values ranging 13-43 mu M. Nucleotide analogs, alpha,beta-metATP, BzATP, 2-MeSATP, and dialATP behaved as competitive inhibitors, whereas alpha,beta-metADP induced mixed inhibition, with K (i) ranging from 2 to 20 mu M. Chromatographic analysis revealed that alpha,beta-metATP, BzATP, and 2-MeSATP were catalytically degraded in the serum, whereas dialATP and alpha,beta-metADP resisted hydrolysis, implying that the former act as substrates and the latter as true competitive inhibitors of serum NPP activity. Since NPP activity is involved in generation, breakdown, and recycling of extracellular adenine nucleotides in the vascular compartment, the results suggest that both hydrolyzable and non-hydrolyzable nucleotide analogs could alter the amplitude and direction of ATP actions and could have potential therapeutic application.Serbian Ministry of Science and Technology [E143005

Interaction of the [PtCl2(DMSO)(2)] Complex with L-Cysteine

The reaction between [PtCl,(DMSO)(2)] and L-cysteine (L-Cys) has been investigated in the presence of micelles of sodium dodecyl sulfate (SDS) - as a model for biological membranes. Additionally, the inhibitory effect of [PtCl2(DMSO)(2)] on the Na+,K+-ATPise activity and its partial prevention with 10 mM L-Cys were demonstrated. The interaction of L-Cys with [Ptcl(2)(DMSO)(2)] resulted in the formation of a [Pt(DMSO)(2)L-Cys)(2)](2+) (DMSO)(2)] Complex, which most probably occurs through stepwise replacement of Cl- with L-Cys. It has also been demonstrated that neither the pH value nor SDS affects the composition of the new complex. On the other hand, the pH value and SDS do affect the reaction rate, most probably due to electrostatic interactions with reactants. In Summary, this study can be used as a simple model approach for the investigation of reaction mechanisms between platinum complexes and various biomolecules, and for the determination of potential toxicity and/or side effects of antitumour platinum drugs