Symbiosis is commonly present in marine invertebrates. Many corals and sponges have symbiotic algae or bacteria. In the previous studies of the sponge Cinachyra australiensis, 85% of the bacteria associated with the sponge have high similarity (88.65%) with the symbiotic chemoautotrophic sulfur-oxidizing bacteria of the deep-sea hydrothermal vent mussel, Solemya reidi. This study aims to investigate the localization of the chemoautotrophic sulfur-oxidizing bacteria associated with Cinachyra australiensis. The Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase (RubisCO) large-subunit genes for autotrophic organisms were amplified by polymerase chain reaction from the sponge samples. The phylogenetic relationship of the RubisCO large subunit genes was analyzed. A total of 26 clones were selected and sequenced. They could be divided into two groups. One (9 clones) belongs to form I type IB (cynobacteria and green algae). The other (17 clones) belongs to form II type IA (chemoautotrophic symbiotic bacteria). The location of the sulfur-oxidizing chemoautotrophic bacteria was shown to be intracellular symbiosis within the mesoglial cells by fluorescence in situ hybridization.

This study investigated the fuel properties, engine performances, and emissions of two biodiesels and diesel. The fuels examined were D100 (ultra-low sulfur diesel), B20 (20% palm biodiesel +80% ultra-low sulfur diesel) and B100 (palm biodiesel). The fuel properties analysis results showed that the benefits of biodiesel were high cetane value, extremely low sulfur and aromatic contents, and good lubricity. While the defects of biodiesel were high pour point. The particulates emitted from the burning of D100, B100, B20 were mainly fine particulates, also known as young aerosols. Particles smaller than 2.5 µm easily enter the trachea and bronchus via the upper respiratory tract, finally deposit on the alveolus, which could cause severe injury to human health. The emission of soluble organic fraction (SOF) from diesel engine using D100, B100 and B20 were 23.2%, 19.9% and 20.2%, respectively. The SOF of D100 is slightly higher than B100 and B20. It suggested that adding biodiesel into diesel can decrease SOF and thus reduce the potential danger to human health. The original total PAHs concentration of tail gas emitted from engines using D100, B100 and B20 were 241, 50.6 and 98.8 µg/m3, respectively. Adding 20% biodiesel into D100 could reduce 59.0% of PAHs emission. Moreover, the original total BaPeq concentration of tail gas emitted from diesel engines using D100, B100 and B20 were 0.714, 0.509 and 0.570 µg/m3, respectively. Adding 20% biodiesel into D100 could also reduce 20.2% of total BaPeq emission. Hence, adding biodiesel into diesel can effectively reduce the emission of PAHs and the potential danger to human health. The emission factors of carbonyl compounds from diesel engines using D100, B100 and B20 were 395, 1,170 and 326 mg/BHP-hr, respectively. carbonyl compounds of B100 were obviously higher than D100 and B20. The results indicated that using pure palm biodiesel in diesel engine can increased the emission of carbonyl compounds. However, adding 20% biodiesel into D100 can effectively reduce 17.5% of carbonyl compounds emission. Keyword: ultra-low sulfur diesel, palm biodiesel, fuel properties¡BThe emission of soluble organic fraction (SOF)¡BPAHs¡Bcarbonyl compounds¡C

This study investigated the production of powdered activated carbon derived from carbon black of pyrolyzed waste tires, and their adsorptive capacity on vapor-phase mercury chloride (HgCl2) using both adsorption column and thermogravimetric adsorption systems. The adsorption isotherms and kinetic models were further simulated in the study. In addition, an innovative compositive impregnation process was developed to increase the sulfur content of powdered activated carbon derived from waste tires. The activation of carbon black to form powdered activated carbon was performed in a tubular oven. The operating parameters including activation temperatures, activation time, and water feed rates were investigated in this study. Experimental results indicated that the yield of carbon-black derived powdered activated carbon (CBPAC) decreased with the increase of activation temperature, activation time, and water feed rate, while the BET surface area and pore volume decreased. In the comparison of activation time and water feed rate in the activation process, activation time had an important impact on the production of specific surface area than water feed rate. The optimal operating parameters included activation temperature of 900¢J, activation time of 180min, water feed rate of 0.5 mLH2O/gC-sec, and water injection behind activation process of 17.5 min. From the analysis of carbon surface, the carbon contents of powdered carbon black (PCB), CBPAC, commercial powdered activated carbon (CPAC) were 89.5%, 87.6%, and 88%, respectively. The C (1s) peak region of PCB consisted of 49.8% C-C, 38.9% C-O, 10.5% C=O or O-C-O. Similar analysis results showed that the total area of the C (1s) peak region of CBPAC consisted of 57.5% C-C, 26.8% C-O, 8.1% C=O or O-C-O, and 7.6% O-C=O. Similar to CPAC, the C (1s) peak region consisted of 42.6% C-C, 41.8% C-O, and 15.6% O-C=O. Furthermore, the sulfur contents of PCB and CBPAC were both 0.5%. The S (2p) peak region of PCB consisted of 58.9% ZnS (zinc sulfide) and 41.1% S=C=S. For CBPAC, the S (2p) peak region solely contained S=C=S. The comparison of two sulfur impregnation processes revealed that the innovative compositive impregnation process could simultaneously increased the sulfur content and the BET surface area of powdered activated carbon (PAC), however, the direct impregnation process increased the sulfur content while the BET surface area of PAC decreased linearly. Without the disadvantages of time and energy consumption associated with direct impregnation, the compositive impregnation is an efficient and energy-saving process for producing sulfurized PAC with a high BET surface area and high sulfur content. Experimental results obtained from the adsorption column tests indicated that the influence of the adsorption depth on the adsorptive capacity of CBPAC did not vary much, while the adsorptive capacity of CBPAC increased with HgCl2 concentration. Furthermore, the adsorptive capacity of CBPAC on vapor-phase HgCl2 was less than that of CPAC at the adsorption temperatures of 25~150¢J and high humidity of 12.3 wt %. The difference of adsorptive capacity for CBPAC and CPAC correlated closely with BET surface area and sulfur content. Results form the thermogravimetric adsorption analysis indicated that the adsorptive capacity of CBPAC and initial adsorption rate on vapor-phase HgCl2 increased with HgCl2 concentration and decreased with adsorption temperature. In the kinetic modeling, the deviation of experimental and simulated values simulated by the pseudo-first-order model was lower than those of pseudo-second-order models. Furthermore, the r (correlation coefficient) of pseudo-first-order and pseudo-second-order models were 0.9745~0.9977 and 0.9217~0.9780, respectively. It suggested that the pseudo-first-order model could simulate the adsorption of HgCl2 onto CBPAC better than pseudo-second-order model.

The reaction of potassiumtetrachloroplatinate with 2-aminothiophenol, yielded a dark blue solid product. This work is about the characterization of this dark blue solid and the investigation of its binding interaction to DNA and enzyme activity. The blue solid product or the &ldquo / blue complex&rdquo / (as we called it in this work) is soluble in acetone, acetonitrile and DMSO yielding a blue solution. It is stable in solution and has a very strong absorption band at 724 nm. The product is paramagnetic and displays one kind of platinum in XPS (platinum binding energies were obtained at 71.1 and 74.6 eV, respectively). The elemental (C, H, N, S, Pt) analysis indicated that the platinum to ligand (2- aminothiophenolate) mole ratio is 1:2. The interpretation of the data collected from elemental analysis and ESR, XPS, NMR, CV measurements leads to conclude that the blue complex prepared in this work is a new platinum blues. This is the first example of platinum blues, in which the bridging ligand is a nitrogen and sulfur donor one. The proposed structure can be visualized as a dimer of binuclear head-tohead isomer of the green product, with C2h symmetry. The band at 724 nm is assigned to an allowed electronic transition from a metal-5dz orbitals based MO to metal-6pz orbitals based MO in tetranuclear core. In order to determine the binding mode of the blue complex to ct-DNA, electronic absorption spectroscopy is employed and hyperchromism about 17.5 percent is observed, which indicates a weak binding of the blue complex to DNA, such as electrostatic interaction of metal ions or H-bonding through the hydroxyl group of the complex. Voltammetric titration carried out in solution suggested the preferential stabilization of Pt(III) to Pt(II) on binding to DNA. The blue complex inhibits the GSTs activity between 45-200 micromolar, in sheep liver GST enzyme. The GST enzymes causes drug resistance, therefore inhibition of this enzyme suggests that this complex can be used in combined chemotherapy.

The objective of this study was to remove mercury vapor from municipal waste incinerator (MWI) by the adsorption of powder activated carbon (PAC) prepared from the pyrolysis of waste tire. The study focused on the measurement of mercury concentration in flue gas emitted from municipal waste incinerator, the preparation of PAC from the pyrolysis of the waste tire and impregnated with sulfur, and the adsorption capacity of mercury by the self-made PAC. The measurement of heavy metals in flue gas emitted from four typical MWIs was conducted in this study. Experimental results obtained from the measurement of mercury from flue gas indicated that the removal efficiency of mercury ranged from 83.71%~96.22%for the tested MWIs. This study revealed that the injection of PAC in flue gas would enhance the removal efficiency of mercury. Besides, oxided mercury (Hg2+) can be removed much more easily than elemental mercury (Hg0). Experimental results obtained from the pyrolysis of waste tires indicated that the pyrolysis temperature of waste tire was approximately 400~500¢J, and the percentage of carbon residue is 35~37%. With higher temperature and water feed rate and longer activation time, the specific surface area and total pore volume of PAC increased while the average pore radius decreased. The highest specific surface area of PAC obtained in this study was 996 m2/g. In addition, experimental results obtained from sulfur impregnation process indicated that the specific surface area of PAC decreased dramatically as sulfur was added to PAC. Experiment results obtained from the adsorption capacity of HgCl2 on PAC by column test indicated that PAC with higher specific surface area could adsorb more HgCl2 at room temperature (25¢J). The adsorption capacity of sulfur impregnated PAC decreased at 25¢J was due to the decrease of specific surface area of PAC. However, results from the comparison of two PAC with similar specific surface area indicated that the PAC with higher sulfur content had higher adsorption capacity. It suggested that the addition of sulfur to PAC could enhance the adsorption of HgCl2 at 25¢J. Experimental results obtained from column tests at 150¢J showed that the adsorption capacity of PAC increased as sulfur content of PAC increased. These results suggested that the adsorption mechanism of HgCl2 by PAC was mainly physical adsorption at lower temperature and it was chemisorption at higher temperature. Besides, the self-made PAC demonstrated the similar adsorption capacity of HgCl2 with commercial PAC used in MWIs.

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This study investigated the adsorptive and desorption capacity of HgCl2 onto powdered activated carbon derived from carbon black of pyrolyzed waste tires (CPBAC) via thermogravimetric analysis (TGA). Due to incomplete classification and recycling of municipal solid wastes (MSW), they still mix with a lot of hazardous materials, which unfortunately can not be removed by incinerators and air pollution control devices(APCDs). Among them, mercury and its pollutants attract more attention by people. Mercury and its pollutants emitted from the incineration of municipal solid wastes could cause severely adverse effects on human health and ecosystem since they exist mainly in vapor phase due to high vapor pressure. If they can not be remove by the air pollution control devices, they will be emitted to the atmosphere and cause serious effects on environmental ecology via various routes. Activated carbon has been widely applied to the treatment of organic compounds and heavy metals in wastewater and waste gas stream. However, the adsorptive capacity of activated carbon decreases with adsorption temperature. The low adsorptive capacity of activated carbon at high temperature (>150 oC) can be overcome by impregnated activated carbons. Previous study reported that sulfur impregnated powdered activated carbons could effectively remove the vapor-phase elemental mercury (Hgo) emitted from MSW incinerators and utility power plants. However, the impregnated typically used is sulfur (S) which is solely applied for the adsorption of elemental mercury (Hgo). Besides, these studies seldom investigate the distribution of impregnated sulfur in the inner pores of activated carbon and its effects on the specific surface area and pore size distribution. Thus, this study was to investigate the fundamental mechanisms for the adsorption/desorption of HgCl2 by/from sulfur impregnated PAC. Experimental results indicated that the sulfur content of sulfur impregnated CBPAC decreased with increasing impregnation temperatures form 400 to 650 oC; while the surface area of sulfur impregnated CBPAC increased with impregnation temperatures. In this study, TGA was applied to obtain the adsorptive capacity of HgCl2 onto CBPAC with adsorption temperature (150oC) and influent HgCl2 concentration (100~500 £gg/m3). Experimental results indicated that the adsorptive capacity of CBPAC increased with the increase of influent HgCl2 concentration and surface area of the activated carbon. This study revealed that the impregnation of sulfur on CBPAC could increase its adsorption capacity at high temperatures. Desorption experimental parameters included desorption temperature (400, 500, and 600 oC), heating rate (10, 15, and 20 oC /min) and regeneration cycle (1~7 cycles). In probing into the regeneration efficiency of CBPAC, experiments were conducted at the desorption times of 60 and 30 min. The results suggested the regeneration efficiency of carbon under 30 min was generally highter than that under 60 min. Because the desorption time was more longer and the sulfur content was lesser. Therefore, the regeneration times was reduce. Experimental results indicated that the mechanism of HgCl2 desorption from the spent CPBAC was strongly affected by desorption temperature. Both the desorption efficiency and the desorption rate of HgCl2 increased dramatically with desorption temperature. The desorption heat of HgCl2 (823 KJ/mole) was much higher than the vaporization heat of HgCl2 (59.2 KJ/mole), indicating that the adsorption of HgCl2 on sulfur impregnated CBPAC was chemical adsorption. Consequently, raising desorption temperature could enhance the desorption of HgCl2 and shorten the duration for HgCl2 desorption. Moreover, the formation of HgS during the desorption of HgCl2 from activated carbons can be proved by the surface characteristics of sulfur impregnated activated carbons. Results obtained from the regeneration of sulfur impregnated activated carbons indicated that the regeneration cycles decreased as the desorption duration increased. It was attributed to the potential desorption of sulfur from actived carbons, which thus decreased the adsorptive capacity and the regeneration cycles.

Methane is a greenhouse gas and a major contributor to climate change. Methanogenic Archaea produce more than 1 billion tons of this gas each year through methanogenesis, the anaerobic reduction of CO₂ to methane. Coenzyme B (CoB) is one of eight coenzymes required for methanogenesis and it is unique to methanogens. Therefore, this coenzyme is a potential target for inhibiting methanogenesis. To further elucidate the CoB biosynthetic pathway, genes from Methanocaldococcus jannaschii were cloned and expressed in an effort to identify the CoB homoaconitase. From this study, the MJ0499-MJ1277 pair of proteins was identified as the methanogen isopropylmalate isomerase involved in leucine and isoleucine biosynthesis. The MJ1003-MJ1271 pair of proteins was characterized as the homoaconitase required for CoB biosynthesis. This enzyme exhibited broad substrate specificity, catalyzing the isomerization of cis-unsaturated tri-carboxylates with [gamma]-chains of 1-5 methylenes in length. Previously characterized homoaconitases only catalyzed half of the predicted reactions in the isomerization of homocitrate. The MJ1003-MJ1271 proteins function as the first homoaconitase described to catalyze the full isomerization of homocitrate to homoisocitrate. Also, the CoB homoaconitase was identified as specific for (R)-homocitrate and cis-unsaturated intermediates, contrary to a previous study that suggested the substrate specificity of this enzyme included (S)-homocitrate and trans-homoaconitate. The M. jannaschii isopropylmalate isomerase and homoaconitase share more than 50% sequence identity and catalyze analogous reactions. Site directed mutagenesis of the MJ1271 protein was used to identify residues involved in substrate specificity. Arg26 of MJ1271 was critical for the specificity of the CoB homoaconitase. Mutation of this residue to the analogous residue in the M. jannaschii isopropylmalate isomerase, Val28, altered the substrate specificity of the homoaconitase to include the substrates of isopropylmalate isomerase. These homologs of aconitase require a [4Fe-4S] cluster for coordinating their respective substrates at the enzyme active site. However, methanogens lack most of the proteins required for iron-sulfur cluster assembly. Therefore, genes homologous to the Salmonella enterica ApbC iron-sulfur scaffold protein were characterized from methanogens. The MMP0704, MJ0283, and SSO0460 proteins from Methanococcus maripaludis, M. jannaschii, and Solfolobus solfataricus, respectively, were identified as scaffold proteins involved in methanogen iron-sulfur cluster biosynthesis. / text

Development of alternative cathodes that have high capacity and long cycle life at an affordable cost is critical for next generation rechargeable batteries to meet the ever-increasing requirements of global energy storage market. Lithium-sulfur batteries, employing sulfur cathodes, are increasingly being investigated due to their high theoretical capacity, low cost, and environmental friendliness. However, the practicality of lithium-sulfur technology is hindered by technical obstacles, such as short shelf and cycle life, arising from the shuttling of polysulfide intermediates between the cathode and the anode as well as the poor electronic conductivity of sulfur and the discharge product Li2S. This dissertation focuses on overcoming some of these problems. The sulfur cathode involves an electrochemical conversion reaction compared to the conventional insertion-reaction cathodes. Therefore, modifications in cell-component configurations/structures are needed to realize the full potential of lithium-sulfur cells. This dissertation explores various custom and functionalized cell components that can be adapted with pure sulfur cathodes, e.g., porous current collectors in Chapter 3, interlayers in Chapter 4, sandwiched electrodes in Chapter 5, and surface-coated separators in Chapter 6. Each chapter introduces the new concept and design, followed by necessary modifications and development. The porous current collectors embedded with pure sulfur cathodes are able to contain the active material in their porous space and ensure close contact between the insulating active material and the conductive matrix. Hence, a stable and reversible electrochemical-conversion reaction is facilitated. In addition, the use of highly porous substrates allows the resulting cell to accommodate high sulfur loading. The interlayers inserted between the pure sulfur cathode and the separator effectively intercept the diffusing polysulfides, suppress polysulfide migration, localize the active material within the cathode region, and boost cell cycle stability. The combination of porous current collectors and interlayers offers sandwiched electrode structure for the lithium/dissolved polysulfide cells. By way of integrating the advantages from the porous current collector and the interlayer, the sandwiched electrodes stabilize the dissolved polysulfide catholyte within the cathode region, resulting in a high discharge capacity, long-term cycle stability, and high sulfur loading. The novel surface-coated separators have a polysulfide trap or filter coated onto one side of a commercial polymeric separator. The functional coatings possess physical and/or chemical polysulfide-trapping capabilities to intercept, absorb, and trap the dissolved polysulfides during cell discharge. The functional coatings also have high electrical conductivity and porous channels to facilitate electron, lithium-ion, and electrolyte mobility for reactivating the trapped active material. As a result, effective reutilization of the trapped active material leads to improved long-term cycle stability. The investigation of the key electrochemical and engineering parameters of these novel cell components has allowed us to make progress on (i) understanding the materials chemistry of the applied functionalized cell components and (ii) the electrochemical performance of the resulting lithium-sulfur batteries. / text

Hydrogen production is dependent on natural gas, 90% in the U.S. and 48% of the world's production. Natural gas supply is dwindling and it's price is increasing. Greenhouse gases and air pollutants are emitted when natural gas is used. In a single product production facility, coal is not competitive with natural gas for hydrogen production at current prices. Hydrogen production by direct electrochemical dissociation of water requires a relatively high voltage.Techniques have been developed for manufacturing hydrogen as a lucrative byproduct of IGCC electric power generation, refinery sulfur production and sulfuric acid production for fertilizer production. Laboratory experiments have been conducted on small systems to advance the technology and full size commercial plants have been conceptualized and analyzed to establish economic viability.In this thesis, a low voltage electrochemical hydrogen production technique has been developed that entails scavenging of the anode with sulfur dioxide. In an electrochemical cell hydrogen is produced at the negative electrode while the positive electrode is bathed in sulfur dioxide which is oxidized with water to sulfuric acid. The presence of SO2 substantially reduces the equilibrium voltage relative to that required for the direct dissociation of water into hydrogen and oxygen. Also sulfuric acid is a more valuable byproduct than oxygen. More sulfuric acid is produced than any other chemical commodity in the U.S. and is a major economic indicator. Hydrogen produced by the electrochemical route being discussed in this thesis illustrates industrial possibilities for large scale-up, economical hydrogen production.In an electrochemical cell, an equilibrium voltage of 1.23 volts is required to decompose water into hydrogen and oxygen. The presence of sulfur dioxide to scavenge the anode can reduce the equilibrium voltage from 1.23 volts to 0.17 volts. The equations shown below are reactions showing the energy requirements.2H2Oâ?? 2H2 + O2 - 4 Faradays @ 1.2Vâ?? 2SO2 + 4H2O 2H2SO4 + 2H2 - 4 Faradays @ 0.17V The thermochemical free energy is reduced from 113kcal/mole to 15kcal/mole if sulfur dioxide is used as a scavenger.In this work, extensive studies to determine the most effective electrodes and catalysts have been carried out. The possibilities for photo electrochemical implementation have been investigated and cell design optimization has been performed Experimental methods and results will be presented and discussed.