Microbial reduction of sulfur dioxide with pretreated sewage sludge and elemental hydrogen as electron donors

It has been demonstrated that heat- and alkali-pretreated sewage sludge may serve as an electron donor and carbon source for SO₂ reduction byDesulfovibrio desulfuricans. A continuousD. desulfuricans culture was operated for 6 mo with complete reduction of SO₂ to H₂S. The culture required only minor amounts of mineral nutrients in addition to pretreated sewage sludge. It has also been shown that the sulfate-reducing bacteriumDesulfotomaculum orientis can be grown on H₂ as an energy source, CO₂ as a carbon source, and SO₂ as a terminal electron acceptor. Complete reduction of SO₂ to H₂S was observed.     

Microbial removal of sulfur dioxide from a gas stream with net oxidation to sulfate

A study has been conducted of the feasibility of utilizing the sulfate reducing bacteriumDesulfovibrio desulfuricans and the chemoautotrophThiobacillus denitrificans as a basis of a microbial process for the removal of sulfur dioxide from a gas with net oxidation to sulfate. In reactors-in-series, SO₂ was reduced to H₂S in the first stage by D.desulfuricans. The H₂S was then stripped with nitrogen and sent to a second stage where it was oxidized to sulfate by T.denitrificans. A sulfur balance demonstrated complete reduction of SO₂ to H₂S in the first stage and complete oxidation of H₂S to sulfate in the second stage.     

Comparison of UPLC and HPLC for Determination of trans-10-Hydroxy-2-Decenoic Acid Content in Royal Jelly by Ultrasound-Assisted Extraction with Internal Standard

Two well-known derivatization procedures, H₂SO₄–butanol and H₂SO₄–methanol esterification, were compared for application to GC–MS identification of organic acids in Bayer process liquors. H₂SO₄–butanol and H₂SO₄–methanol derivatization must be combined for analysis of carboxylic acids. Twenty organic acids were identified by gas chromatography–mass spectrometry. Heptanedioic, 3-methylhexanedioic, octanedioic, 1,3-benzenedicarboxylic, nonanedioic, decanedioic, hexadecanoic, 9,12-octadecadienoic, octadecanoic, and phthalic acids were identified for the first time in Bayer liquors. The retention times (y) and carbon numbers (x) of these seven n-dicarboxylic acids (C₄–C₁₀) were fit to a linear relationship by use of Microsoft Excel. These dicarboxylic acids and two benzenedicarboxylic acids were quantified by use of the internal standard method.     

Tribochemistry and kinetics of Al2(SO4)3·xH2O decomposition

The thermal decomposition of tribochemically activated Al₂(SO₄)₃·xH₂O was studied by TG, DTA and EMF methods. For some of the intermediate solids, X-ray diffraction and IR-spectroscopy were applied to learn more about the reaction mechanism. Thermal and EMF studies confirmed that, even after mechanical activation of Al₂(SO₄)₃·xH₂O, Al₂O(SO₄)₂ is formed as an intermediate. Isothermal kinetic experiments demonstrated that the thermochemical sulphurization of inactivated Al₂(SO₄)₃·xH₂O has an activation energy of 102.2 kJ·mol^?1 in the temperature range 850–890 K. The activation energy for activated Al₂(SO₄)₃·xH₂O in the range 850–890 K is 55.0 kJ·mol^?1. The time of thermal decomposition is almost halved when Al₂(SO₄)₃·xH₂O is activated mechanically. The results permit conclusions concerning the efficiency of the tribochemical activation of Al₂(SO₄)₃·xH₂O and the chemical and kinetic mechanisms of the desulphurization process.     

The chemical reduction of small inorganic gases in an electrothermal plasma reactor

Chemical reduction of small inorganic gases is accomplished using an electro-thermal plasma reactor. This benchscale reactor maintains a highly reactive plasma zone in a fluidized bed of carbon particles through which an electrical current is discharged. The carbon particles function as current-controlling media, heat sinks and reaction sites. Chemicals introduced into this medium are subjected to a variety of energy sources and chemically reactive species, which result in chemical reduction. It is shown that the inorganic gases, H₂O, CO₂, NO, NO₂ and SO₂, are chemically reduced in the plasma zone of the reactor. The end products consist of hydrogen, carbon monoxide and nitrogen gases. Additionally, elemental sulfur is deposited onto the carbon particles.     

Synthesis, structure, and properties of chromium(III) sulfates

Reactions between CrO₃ and 50- are studied at temperatures up to the boiling point of the acid. Depending on the H₂SO₄ concentration and synthesis temperature, Cr₂(SO₄)₃, CrH(SO₄)₂, (H₃O)[Cr(SO₄)₂], Cr₂(SO₄)₃·H₂SO₄·4H₂O (gross formula), and (H₅O₂)[Cr(H₂O)₂(SO₄)₂], are obtained as identified reaction products in addition to the incompletely characterized chromic-sulfuric acid. The Cr^III-based sulfates are characterized by X-ray powder diffraction, thermogravimetric, and magnetic susceptibility measurements. The nuclear and magnetic structures of Cr₂(SO₄)₃ at are determined, the structure type of (H₃O)[Cr(SO₄)₂] is established, and the crystal structure of (H₅O₂)[Cr(H₂O)₂(SO₄)₂] is firmly stipulated. Magnetic susceptibility data suggest that the samples of CrH(SO₄)₂ are in a micro-crystalline rather than in an amorphous state. All Cr^III-based sulfates synthesized in this study appear to undergo paramagnetic-to-antiferromagnetic transitions at around .     

A biological process for the reclamation of flue gas desulfurization gypsum using mixed sulfate-reducing bacteria with inexpensive carbon sources

A combined chemical and biological process for the recycling of flue gas desulfurization (FGD) gypsum into calcium carbonate and elemental sulfur is demonstrated. In this process, a mixed culture of sulfate-reducing bacteria (SRB) utilizes inexpensive carbon sources, such as sewage digest or synthesis gas, to reduce FGD gypsum to hydrogen sulfide. The sulfide is then oxidized to elemental sulfur via reaction with ferric sulfate, and accumulating calcium ions are precipitated as calcium carbonate using carbon dioxide. Employing anaerobically digested municipal sewage sludge (AD-MSS) medium as a carbon source, SRBs in serum bottles demonstrated an FGD gypsum reduction rate of 8 mg/L/h (10⁹ cells)^-1. A chemostat with continuous addition of both AD-MSS media and gypsum exhibited sulfate reduction rates as high as 1.3 kg FGD gypsum/m³d. The increased biocatalyst density afforded by cell immobilization in a columnar reactor allowed a productivity of 152 mg SO₄ ^-2/Lh or 6.6 kg FGD gypsum/m³d. Both reactors demonstrated 100% conversion of sulfate, with 75–100% recovery of elemental sulfur and chemical oxygen demand utilization as high as 70%. Calcium carbonate was recovered from the reactor effluent on precipitation using carbon dioxide. It was demonstrated that SRBs may also use synthesis gas (CO, H₂, and CO₂ in the reduction of gypsum, further decreasing process costs. The formation of two marketable products—elemental sulfur and calcium carbonate—from FGD gypsum sludge, combined with the use of a low-cost carbon source and further improvements in reactor design, promises to offer an attractive alternative to the landfilling of FGD gypsum.

     

Removal of SO2 from Gas Streams by Oxidation using Plasma-Generated Hydroxyl Radicals

The key problem for the removal of SO₂ by electrical discharge methods is how to obtain the hydroxyl radicals at high concentration and large production rates. With the micro-gap discharge method, O₂ and H₂O in simulated gas streams (N₂/O₂/H₂O/SO₂) are ionized into a large number of OH^. radicals to oxidize SO₂ into SO₃ which reacts with H₂O forming H₂SO₄ droplets at 120 °C in the absence of any catalyst or absorbent. The droplets are captured with an electrostatic precipitator. As a result, conversion of SO₂ to primarily H₂SO₄ is limited by the generation of OH^. radicals. By increasing the reduced field and concentrations of O₂ and H₂O, the amount of OH^. radicals increase resulting in more removal of SO₂ from gas streams. The removal efficiency of SO₂ reaches 100% when the residence time is only 0.74 s. Therefore, a new gas-phase oxidation method for removal of SO₂ without NH₃ additive is found.     

Comparison of the fermentability of enzymatic hydrolyzates of sugarcane bagasse pretreated by steam explosion using different impregnating agents

Sugarcane bagasse is a potential lignocellulosic feedstock for ethanol production, since it is cheap, readily available, and has a high carbohydrate content. In this work, bagasse was subjected to steam explosion pretreatment with different impregnation conditions. Three parallel pretreatments were carried out, one without any impregnation, a second with sulfur dioxide, and a third with sulfuric acid as the impregnating agent. The pretreatments were performed at 205°C for 10 min. The pretreated material was then hydrolyzed using celluloytic enzymes. The chemical composition of the hydrolyzates was analyzed. The highest yields of xylose (16.2 g/100 g dry bagasse), arabinose (1.5 g/100 g), and total sugar (52.9 g/100 g) were obtained in the hydrolysis of the SO₂-impregnated bagasse. The H₂SO₄-impregnated bagasse gave the highest glucose yield (35.9 g/100 g) but the lowest total sugar yield (42.3 g/100 g) among the three methods. The low total sugar yield from the H₂SO₄-impregnated bagasse was largely due to by-product formation, as the dehydration of xylose to furfural. Sulfuric acid impregnation led to a three-fold increase in the concentration of the fermentation inhibitors furfural and 5-hydroxymethylfurfural (HMF) and a two-fold increase in the concentration of inhibitory aliphatic acids (formic, acetic, and levulinic acids) compared to the other two pretreatment methods. The total content of phenolic compounds was not strongly affected by the different pretreatment methods, but the quantities of separate phenolic compounds were widely different in the hydrolyzate from the H₂SO₄-impregnated bagasse compared with the other two hydrolyzates. No major differences in the content of inhibitors were observed in the hydrolyzates obtained from SO₂-impregnated and non-impregnated bagasse. The fermentability of all three hydrolyzates was tested with a xylose-utilizing Saccharomyces cerevisiae strain with and without nutrient supplementation. The hydrolyzates of SO₂-impregnated and nonimpregnated bagasse showed similar fermentability, whereas the hydrolyzate of H₂SO₄-impregnated bagasse fermented considerably poorer.     

Oxidation of some catecholamines by sodium N-chloro-p-toluenesulfonamide in acid medium: A kinetic and mechanistic approach

The kinetics of the oxidation of five catecholamines viz., dopamine (A), L-dopa (B), methyldopa (C), epinephrine (D) and norepinephrine (E) by sodium N-chloro-p-toluenesulfonamide or chloramine-T (CAT) in presence of HClO₄ was studied at 30±0.1 °C. The five reactions followed identical kinetics with a first-order dependence on [CAT] _o , fractional-order in [substrate] _o , and inverse fractional-order in [H⁺]. Under comparable experimental conditions, the rate of oxidation of catecholamines increases in the order D>E>A>B>C. The variation of ionic strength of the medium and the addition of p-toluenesulfonamide or halide ions had no significant effect on the reaction rate. The rate increased with decreasing dielectric constant of the medium. The solvent isotope effect was studied using D₂O. A Michaelis-Menten type mechanism has been suggested to explain the results. Equilibrium and decomposition constants for CAT-catecholamine complexes have been evaluated. CH₃C₆H₄SO₂NHCl of the oxidant has been postulated as the reactive oxidizing species and oxidation products were identified. An isokinetic relationship is observed with β=361 K, indicating that enthalpy factors control the reaction rate. The mechanism proposed and the derived rate law are consistent with the observed kinetics.     

一系列由柔性N,N'-双(3-吡啶甲基)胺构筑的螺旋配合物的合成、结构和性质

合成和表征了5个螺旋配位聚合物{[Cu(Hbpma)(H₂O)₄]₂(SO₄)₃·3.5H₂O}_n (1)、{[Ni(Hbpma)(H₂O)₄]₄(SO₄)₆·10.75H₂O}_n (2)、{[Mn(Hbpma)(H₂O)₄](SO₄)_1.5·3H₂O}_n (3)、{[Zn(Hbpma)(H₂O)₄]₄(SO₄)₆·4H₂O·4CH₃OH}n (4)和{[Cu(Hbpma)2(H₂O)₂](SO₄)₂·9H₂O}_n (5), 其中bpma代表N,N'-双(3-吡啶甲基)胺。晶体结构分析表明配合物1~4为一维链状结构, 配合物5为二维层状结构, 其中金属离子由质子化的bpma配体桥连。值得注意的是, 采取反-反式构象的柔性bpma配体使得配合物1和2为假螺旋链结构, 配合物3和4为螺旋链结构, 配合物5为螺旋层结构。同时研究了配合物的磁性和热稳定性。     

Thermotropic Liquid Crystals of Double-Chain Zwit-terionic Surfactants (C16)2NCnS

A series of double-chain sulfobetain zwitterionic surfactants with varying carbon number of the intercharge group (spacer), (C₁₆H₃₃)₂NCH₃(CH₂)_nSO₃, where n=2, 3, 4, and 6, referred to as (C₁₆)₂NC_nS, were synthesized. The influence of the spacer length on the thermal behaviors of (C₁₆)₂NC_nS in their pure state was studied using thermogravimetry (TG), differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and X-ray diffraction (XRD). Thermogravimetric analysis (TGA) showed that the thermal stability of (C₁₆)₂NC_nS lowered with increasing the spacer length. All compounds showed a complex polymorphism. Only for (C₁₆)₂NC₄S and (C₁₆)₂NC₆S, thermotropic liquid crystals were observed using POM. The former exhibited a smectic A (SmA) phase, whereas the latter formed a hexagonal columnar phase. These liquid crystals obtained both in the cooling and the second heating scans provided compelling evidence for the thermal stability of these compounds.     

Cellulose production based on hemicellulose hydrolysate from steam-pretreated willow

The production cost of cellulolytic enzymes is a major contributor to the high cost of ethanol production from lignocellulosics using enzymatic hydrolysis. The aim of the present study was to investigate the cellulolytic enzyme production ofTrichoderma reesei Rut C 30, which is known as a good cellulase secreting micro-organism, using willow as the carbon source. The willow, which is a fast-growing energy crop in Sweden, was impregnated with 1–4% SO₂ and steam-pretreated for 5 min at 206°C. The pretreated willow was washed and the wash water, which contains several soluble sugars from the hemicellulose, was supplemented with fibrous pretreated willow and used for enzyme production. In addition to sugars, the liquid contains degradation products such as acetic acid, furfural, and 5-hydroxy-methylfurfural, which are inhibitory for microorganisms. The results showed that 50% of the cellulose can be replaced with sugars from the wash water. The highest enzyme activity, 1.79 FPU/mL and yield, 133 FPU/g carbohydrate, was obtained at pH 6.0 using 20 g/L carbon source concentration. At lower pHs, a total lack of growth and enzyme production was observed, which probably could be explained by furfural inhibition.     

A general solution-chemistry route to the synthesis LiMPO4 (M=Mn, Fe, and Co) nanocrystals with [010] orientation for lithium ion batteries

A general and efficient solvothermal strategy has been developed for the preparation of lithium transition metal phosphate microstructures (LiMnPO₄, LiFePO₄, and LiCoPO₄), employing ethanol as the solvent, LiI as the Li source, metal salts as the M sources, H₃PO₄ as the phosphorus source, and poly(vinyl pyrrolidone) (PVP) as the carbon source and template. This route features low cost, environmental benign, and one-step process for the cathode material production of Li-ion batteries without any complicated experimental setups and sophisticated operations. The as-synthesized LiMPO₄ microstructures exhibit unique, well-shaped and favorable structures, which are self-assembled from microplates or microrods. The b axis is the preferred crystal growth orientation of the products, resulting in a shorter lithium ion diffusion path. The LiFePO₄ microstructures show an excellent cycling stability without capacity fading up to 50 cycles when they are used as a cathode material in lithium-ion batteries.     

Thermal hazard evaluation of carbon nanotubes with sulfuric acid by DSC

Many concerns over unsafe or unknown properties of multi-walled carbon nanotubes (MWNTs) have been raised. The thermal characteristics regarding stability would represent potential hazards during the production or utilization stage and could be determined by calorimetric tests for various thermokinetic parameters. Differential scanning calorimetry (DSC) was employed to evaluate the thermokinetic parameters for MWNTs at various compositions. Thermoanalytical curves showed that the average heat of decomposition (ΔH _d) of the MWNTs samples in a manufacturing process was about 31,723 J g⁻¹, by identifying them as an inherently hazardous material. In this study, significant thermal analysis appeared in the presence of sulfuric acid (H₂SO₄). From the DSC experiments, the purification process of MWNTs could induce an unexpected reaction in the condition of batch addition with reactants of H₂SO₄. The results can be applied for designing emergency relief system and emergency rescue strategies during a perturbed situation or accident.     

Removal of SO2 and the simultaneous removal of SO2 and NO from simulated flue gas streams using dielectric barrier discharge plasmas

A gas-phase oxidation method using dielectric barrier discharges (DBDs) has been developed to remove SO₂ and to simultaneously remove SO₂ and NO from gas streams that are similar to gas streams generated by the combustion of fossil fuels. SO₂ and NO removal efficiencies are evaluated as a function of applied voltage, temperature, and concentrations of SO₂, NO, H₂O_(g), and NH3. With constant H₂O_(g) concentration, both SO₂ and NO removal efficiencies increase with increasing temperature from 100 to 160°C. At 160°C with 15% by volume H₂0_(g), more than 95% of the NO and 32% of the S0₂ are simultaneously removed from the gas stream. Injection of NH₃ into the gas stream caused an increase in S0₂ removal efficiency to essentially 100%. These results indicate that DBD plasmas have the potential to simultaneously remove SO₂ and NO from gas streams generated by large-scale fossil fuel combustors.     

Transition metal chemistry of oxime-containing ligands,IX

The vibrational (conventional and far-infrared) and diffuse-reflectance spectra in conjunction with magnetic susceptibility measurements over a temperature range down to liquid nitrogen temperature are reported and discussed for the complexes; [Mn(HPOX)₂ X ₂]; [Mn(HMPX)₂ X ₂]; [Fe(HPOX)(POX) X ₂] and [Fe(HMPX)(MPX) X ₂](whereHPOX=pyridine-2-aldoxime (C₆H₆N₂O);POX=C₆H₅N₂O;HMPX=6-Methylpyridine-2-aldoxime (C₇H₈N₂O);MPX=C₇H₇N₂O;X=Cl, Br, I, NO₃, NCS, or OA c andX ₂=SO₄). On the basis of these physical studies a six-coordinated structure is suggested for the manganese(II) and iron(III) complexes.Mössbauer spectra, measured at room-temperature and liquid nitrogen temperature also indicated a six-coordinate geometry for iron(III) complexes.

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Übergangsmetallkomplexe mit Oxim-enthaltenden Liganden, IX. Spektroskopische und magnetische Untersuchungen von Mn(II)- und Fe(II)-Komplexen mit Pyridin-2-aldoxim und 6-Methylpyridin-2-aldoxim

Zusammenfassung Es wurden Komplexe von Pyridin-2-aldoxim (HPOX) und 6-Methylpyridin-2-aldoxim (HMPX) vom Typ [Mn(HPOX)₂ X ₂], [Mn(HMPX)₂ X ₂], [Fe(HPOX)(POX)X ₂] und [Fe(HMPX)(MPX)X ₂] (X=Cl, Br, I, NO₃, NCS, OA c;X ₂=SO₄) dargestellt. Die Diskussion erfolgt basierend auf Infrarot-spektroskopie (inklusive fernes IR), Messungen der magnetischen Suszeptibilität (Temp. bis zu fl. N₂) undMössbauer-Spektroskopie.

     

Alum (KAl(SO<Subscript>4</Subscript>)<Subscript>2</Subscript> · 12H<Subscript>2</Subscript>O) Catalyzed One-Pot Synthesis of Coumarins under Solvent-Free Conditions

Summary. Alum (KAl(SO₄)₂ · 12H₂O) is used as an efficient catalyst in the Pechmann condensation of phenol derivatives with β-keto esters leading to the formation of coumarins in excellent yields under solvent-free conditions. This methodology offers significant improvements for the synthesis of coumarins with regard to the yield of products, simplicity in operation, and green aspects by avoiding toxic catalysts and solvents.     

Degradation of ferric EDTA by Burkhol cepacia

EDTA, the target compound of this study from the effluent of secondary biotreatment units, can be biodegraded by special microorganisms. So far, there are three species of microorganisms—Agrobacterium, Gram-negative BNCI, and DSM9103—that can degrade EDTA and are published in the literature. We have successfully isolated a bacterial strain that can degrade EDTA. It was identified as Burkhol cepacia, an aerobic species, elliptically shaped with a length of 5–15 μm. The growth medium contains 1000 mg/L of ferric-EDTA as carbon source, 750 mg/L of (NH₄)₂SO₄+(NH₂)₂CO as nitrogen source, and 1000 mg/L of KH₂PO₄ as phosphorus source, and mineral factors such as Fe and Mg. Incubated at pH, 7.0, 30°C, and 150 rpm on a shaker for 15 d, the average specific growth rate of this microbe is 0.135 d⁻¹, which shows that the respective degradation efficiency of Fe-EDTA and Cu-EDTA is 90 and 75% individually.