Fixed-Bed Column Adsorption Modeling of MnO4- Ions from Acidic Aqueous Solutions on Activated Carbons Prepared with the Biomass

Activated carbons calcined at 400˚C and 600˚C (AC-400 and AC-600), prepared using palm nuts, collected in the town of Franceville in Gabon, were used to study the dynamic adsorption of MnO4- ions in acidic media on fixed bed column and on the kinetic modeling of experimental data of breakthrough curves of MnO4- ions obtained. Results on the adsorption of MnO4- ions in fixed-bed dynamics obtained on AC-400 and AC-600 adsorbents beds indicated that the AC-400 bed appears to be the most efficient in removing MnO4- ions in acidic media. Indeed, the adsorbed amounts, the adsorbed capacities at saturation and the elimination percentage of MnO4- ions obtained with AC-400 (31.24 mg;52.06 mg·g-1 and 41.65% respectively) were higher compared to those obtained with AC-600 (9.87 mg;16.45 mg·g-1 and 17.79% respectively). The breakthrough curves kinetic modeling revealed that the Thomas model and the pseudo-first-order kinetic model were the most suitable models to describe the adsorption of MnO4- ions on adsorbents studied in our experimental conditions. The results of the intraparticle diffusion model showed that intraparticle diffusion was involved in the adsorption mechanism of MnO4- ions on investigated adsorbents and was not the limiting step and the only process controlling MnO4- ions adsorption. In contrast to AC-400, the intraparticle diffusion on AC-600 bed plays an important role in the adsorption mechanism of MnO4- ions.

Positive carbon isotope excursions:global correlation and genesis in the Middle-Upper Ordovician in the northern Tarim Basin,Northwest China

Stable carbon isotope ratio （δ13Ccarb） analysis has been widely applied to the study of the inter-conti- nental or global marine carbonate correlation. Large-scale Cambrian-Ordovician carbonate platforms were developed in the Tarim Basin. But research on fluctuation character- istics and global correlation of δ13Ccarb is still weak. Based on conodont biostratigraphy and whole-rock δ13Ccarb data in the Tahe oil-gas field of the northern Tarim Basin, the global correlation and genesis of positive carbon isotope excursions in the Darriwilian--Early Katian was exam- ined. Three positive excursions were identified in the Tahe oil-gas field including the middle Darriwilian carbon iso- tope excursion （MDICE）, the Guttenberg carbon isotope excursion （GICE）, and a positive excursion within the Pygodus anserinus conodont zone which is named the Early Sandbian carbon isotope excursion （ESICE） in this paper. Furthermore, these positive excursions had no direct relation with sea level fluctuations. MDICE and GICE could be globally correlated. The Middle-Upper Ordovi- cian Saergan Formation source rocks of the Kalpin outcrops were in accordance with the geological time of MDICE and ESICE. GICE had close relationship with the source rock of the Lianglitag Formation in the basin.Massive organic carbon burial was an important factor controlling the genesis of these positive excursions.

Newly Identified Silicate Carbon Stars from IRAS Low-Resolution Spectra

The discovery of silicate carbon star poses a challenge to the theory of stellar evolution in the late stage, hence it is important to look for more silicate carbon stars. To this end we have carried out cross-identifications between the new IRAS Low-Resolution Spectrum （LRS） database and the new carbon star catalog, CGCS3. We have found nine new silicate carbon stars with silicate features around 10μm and/or 18 μm. These newly identified stars are located in the Regions Ilia and VII in the IRAS two-color diagram, which means they indeed have typical far infrared colors of silicate carbon stars. The infrared properties of each of these sources are discussed.

Effect of ZnO on Oxidation Resistance of Low Carbon MgO-C Refractories

Al-containing low carbon MgO - C refractories were prepared using 70% （in mass, the same hereinafter） fused magnesia （ ≤3 mm）, 24% fused magnesia powder （ 〈0. 074 mm） , 3% flake graphite, 3% Al powder and 4% phenolic resin （extra-added） as the basic formulation. Influence of ZnO addhion on oxidation resistance of the materials was investigated by adding 1% ZnO to substitute fused magnesia powder. The relationship between in-situ formed spinel and ZnO in the matrix was discussed by comparing apparent porosity, cold crushing strength, and phase evolution of the materials matrix. The oxidation resistances of the two materials were compared by observing the formed dense MgO layer between the decarburized layer and the original layer. The result shows that adding ZnO in MgO - C refractories accelerates the in-situ formation of ZnAl204 spinel and the formation of dense MgO layer, thus improves the oxidation resistance of the low carbon MgO - C refractories.

PRODUCTION OF ULTRA-FINEα-AL_2O_3 PO WDERSFROM AMMONIUM A LUMINUM CARBONATE HY DROXIDE

Synthesis of a m m oniu m alu min u m carbonate hydroxide ( A A C H) w as investigated usinga m m oniu m alu min u m sulfate and a m moniu m hydro carbonate as the starting m aterials . Itw as found that A A C Hcan be synthesized by adding a m m oniu m alu m inu m sulfate solution torapidly stirred a m moniu m hydro - carbonate solution at a tem perature of 30 ℃. A A C Hcantransfor m to α Al2 O3 co m pletely by calcining at 1100 ℃ for 1 hour , and the obtained po w ders , with a particle size of 100 n m , can be sintered to 98 99 % relative density at 1500 ℃for 2 hours .

Multiple Ionization of Argon Induced by Carbon Ions at 20-500 keV/u Energies

We measure the multiple ionization cross-section ratios Rk1 of Ar impacted by Cw＋ （q= 1-3） ions in the energy range of 20-500 keV/u. The measured ratios Rkl increase with the projectile energy at lower energies, and reach the maximum at energies of 50-150 keV/u, then decrease for higher energies, We also use the classical over barrier ionization model to calculate the ratios Rk1, and the calculation results are in good agreement with the data, which suggest that the multiple ionization process is described by the sequential over-barrier ionization process,

Influences of Al and Si Powders on Microstructure and Hot Mechanical Properties of Al_2O_3-C Slide Plates

The basic formulation of Al2O3- C slide plates was65%（ in mass,the same hereinafter） white fused corundum particles,25% white fused corundum fines,6% active α-Al2O3 micropowder,4% carbon black and flake graphite, and additional 4% phenolic resin.Based on this formulation,3% Al powder,3% Si powder,and 3% Al ＋ 3% Si powder were used to substitute equivalent white corundum fines to improve the hot mechanical properties of Al2O3- C slide plates. The specimens with dimensions of 140 mm × 25 mm × 25 mm were pressed at 150 MPa,dried at 200 ℃ for 24 h,and hot treated at 1 400 ℃ for 3 h in carbon embedded condition. Then hot modulus of rupture and thermal shock resistance of the specimens were tested and the phase compositions and microstructure were analyzed. The results show that specimen with 3% Al powder has the higher hot modulus of rupture but lower residual modulus of rupture after thermal shock than the specimen with3% Si powder; the specimen with 3% Al ＋ 3% Si powders exhibits the highest hot modulus of rupture and the best thermal shock resistance; the change of mechanical property is closely related with the in-situ formed nonoxides： AlN in the form of bars is formed in specimens with Al powder; fibrous SiC whiskers are formed in specimens with Si powder; in the specimens with both Al and Sipowders,besides AlN and SiC whiskers,hexagonal tabular SiAlON is in-situ synthesized,which interlocks with each other.

Coupling metal-organic frameworks and wood-based carbon for water remediation

Fresh and clean water is highly demanded throughout the world.To effectively address the need,nanomaterials enabled nanotechnology has been explored as a means of more efficient,reliable,and environmentally friendly approach towards water treatment practices.One concern in adopting nanomaterials is how to retrieve them from water body to avoid secondary contamination.In this work,the earth abundant and sustainable wood,e.g.,basswood,was selected and carbonized into porous carbon as host skeleton,and metal-organic frameworks(MOFs),e.g.,MOF-199 with extremely high surface area,were grown throughout all channels in the porous basswood carbon.Targeting the traditional organic pollutant,methyl orange(MO),the combination of MOFs and basswood carbon(MOFs@carbon)demonstrates a remarkable adsorption capacity,which is 243%and 454%higher than basswood carbon and MOF-199,respectively.Such an outstanding adsorption performance originates from that the positively charged carbon pulls MO molecules close to carbon surface,leading to a high MO molecule concentration,and then the concentration gradient drives the MO molecules to be stored inside MOFs,functioning like pockets.These findings highlight the potential application of coupled MOFs and biomass carbon in addressing water remediation.

DFT Thermodynamic Research of the Pyrolysis Mechanism of the Carbon Matrix PrecursorTol uene for Carbon Material

Based on the experiments, the standard enthalpy△H■of the possible pyrolysis reactions of the carbon matrix precursor toluene was investigated by means of DFT method UB3LYP/ 3-21G *(based on semi-empirical method UAM1 and ab initio method UHF/3-21G*). The com- putation results with UB3LYP/3-21G* coincide with the experimental values well. Then, the mechanism for all types of the pyrolysis reactions of toluene was studied by UB3LYP/3-21G * The geometries of the reactant and the product radicals were optimized, meanwhile, the standard thermodynamic parameters of the pyrolysis reaction at different temperatures (298, 773, 843, 963 and 1 073 K) were calculated. The thermodynamic computation result shows that when the pyrolysis temperature of toluene is lower than 963 K, the reaction path supported by thermody- namics is that the C-H bond of the methyl on the benzene ring breaks and bitoluene form, while the temperature increases (about 1 073 K), the thermodynamic calculation result turns to support the reaction path producing phenyl radicals and methyl radicals. This mechanism is in accord with the experiments.

A unified analysis of a micro-beam,droplet and CNT ring adhered on a substrate:Calculation of variation with movable boundaries

In this study, we developed a general method to analytically tackle a kind of movable boundary problem from the viewpoint of energy variation. Having grouped the adhesion of a micro-beam, droplet and carbon nanotube （CNT） ring on a substrate into one framework, we used the developed line of reasoning to investigate the adhesion behaviors of these systems. Based upon the derived governing equations and transversality conditions, explicit solutions involving the critical parameters and morphologies for the three systems are successfully obtained, and then the parameter analogies and common characteristics of them are thor- oughly investigated. The presented method has been verified via the concept of energy release rate in fracture mechanics. Our analyses provide a new approach for exploring the mechanism of different systems with similarities as well as for understanding the unity of nature. The analysis results may be beneficial for the design of nano-structured materi- als, and hold potential for enhancing their mechanical, chemical, optical and electronic properties.

Kinetic Modeling the Formation of Low-mature Gases and Analysis of the Possibility to Be Accumulated

At present, shallow gases have received much attention due to low cost in exploration and production. Low-mature gases, as one significant origin to shallow gas, turns to be an important research topic. The present understanding of low-mature gases is confined within some geological cases, and few laboratory studies have been reported. Therefore, the potential and characters of low- mature gases are not clear up to now. Here, two premature samples （one coal and the other shale） were pyrolyzed in a gold confined system. The gaseous components including hydrocarbon gases and non-hydrocarbon gases were analyzed. Based on kinetic modeling, the formation of low-mature gases was modeled. The results showed that during low mature stage, about 178 mL/gTOC gas was generated from the shale and 100 mL/gTOC from the coal. Two third to three fourth of the generated gases are non-hydrocarbon gases such as H2S and CO2. The total yields of C1-5 for the two samples are almost the same, 30-40 mL/gTOC, but individual gaseous hydrocarbon is different. The shale has much lower C1 but higher C2-5, whereas the coal has higher C1 but lower C2-5. Hydrocarbon gases formed during low-mature stage are very wet. The stable carbon isotope ratios of methane range from -40‰ to -50‰ （PDB）, in good consistence with empiric criterion for low-mature gases summed up by the previous researchers. The generation characters suggest that the low-mature gases could be accumulated to form an economic gas reservoir, but most of them occur only as associated gases.

Influences of ZrO_2-SiC Composite Powder and Commercial SiC on Properties of Al_2O_3-C Refractories

In order to improve oxidation resistance and ther- mal shock resistance of Al2O3-C refractories, two groups of specimens were prepared with phenolic resin as binder, adding 0, 2 wt% , 4 wt% and 6 wt% commercial SiC or ZrO2-SiC composite powder synthesized from zircon respectively to Al2O3- C refractories, pressing at 200 MPa, drying fully at 250℃, and then carbon embedded firing at 1400℃ for 2 h. Oxidation resistance and thermal shock resistance were researched, phase composition was analyzed by XRD. The results showed that the oxidation of SiC in additives could protect carbon in specimens effectively and thus decreased the mass loss ratio and oxidation area, and improved the oxidation resistance of the specimen. Thermal shock resistance was improved owing to the micro crack toughening of ZrO2 and grain toughening of SiC. In this experiment, the specimens with 6 wt% ZrO2 -SiC composite powder or 6 wt% SiC powder had the best oxidation resistance and thermal shock resistance.

Novel application of PEG/SDS interaction as a wettability modifier of hydrophobic carbonate surfaces

Wettability alteration of carbonate reservoirs from oil-wet to water-wet is an important method to increase the efficiency of oil recovery. Interaction between surfactants and polymers can enhance the effectiveness of surfactants in EOR applications. In this study, the interaction of polyethylene glycol(PEG) with an ionic surfactant, sodium dodecyl sulphate(SDS),is evaluated on an oil-wet carbonate rock surface by using contact angle measurements. The results reveal that wettability alteration of carbonate rocks is achieved through PEG/SDS interaction on the rock surface above a critical aggregation concentration(CAC). The behaviour of PEG/SDS aqueous solutions is evaluated using surface and interfacial tension measurements. Furthermore, the effect of PEG and SDS concentrations and impact of electrolyte addition on PEG/SDS interaction are investigated. It is shown that electrolyte(NaCl) can effectively decrease the CAC values and accordingly initiate the wettability alteration of rocks. Moreover, in a constant SDS concentration, the addition of NaCl leads to a reduction in the contact angle, which can also be obtained by increasing the aging time, temperature and pre-adsorption of PEG on the rock surface.

Molecular simulation studies of hydrocarbon and carbon dioxide adsorption on coal

Sorption isotherms of hydrocarbon and carbon dioxide （CO2） provide crucial information for designing processes to sequester CO2 and recover natural gas from unmineable coal beds. Methane （CH4）, ethane （C2H6）, and CO2 adsorption isotherms on dry coal and the temperature effect on their maximum sorption capacity have been studied by performing combined Monte Carlo （MC） and molecular dynamics （MD） simulations at temperatures of 308 and 370 K （35 and 97 ~C） and at pressures up to 10 MPa. Simulation results demonstrate that absolute sorption （expressed as a mass basis） divided by bulk gas density has negligible temperature effect on CH4, C2H6, and CO2 sorption on dry coal when pressure is over 6 MPa. CO2 is more closely packed due to stronger interaction with coal and the stronger interaction between CO2 mole- cules compared, respectively, with the interactions between hydrocarbons and coal and between hydrocarbons. The results of this work suggest that the ＂a＂ constant （pro- portional to TcPc） in the Peng-Robinson equation of state is an important factor affecting the sorption behavior of hydrocarbons. CO2 injection pressures of lower than 8 MPa may be desirable for CH4 recovery and CO2 sequestration. This study provides a quantitative under- standing of the effects of temperature on coal sorptioncapacity for CH4, C2H6, and CO2 from a microscopic perspective.

血红素加氧酶-1与帕金森病的研究

血红素加氧酶-1(heme oxygenase-1,HO-1)是一种内源性抗氧化酶,具有抗氧化、抗炎、抗凋亡、促血管生成、细胞保护的作用[1-2]。今将HO-1与帕金森病(parkinson's disease,PD)关系的研究进展进行综述。1.HO-1及其抗氧化性血红素加氧酶(heme oxygenase,HO)是一种广泛分布于组织细胞中的血红素降解的限速酶,能催化血红素氧化分解为胆绿素、一氧化碳(carbon monoxide,CO)和游离二价铁(Fe2+),胆绿素在胆绿素还原酶的作用下迅速还原成胆红素。人体内有3种HO同工酶,即HO-1、HO-2和HO-3。HO-1也称热休克蛋白32(heat shock protein32,HSP32),是一种诱导型应激反应蛋白,主要分布于细胞的微粒体、细胞膜穴样内陷、线粒体和胞核。在正常情况下其表达较低,各种应激因素如血红素、重金属、化学物、感染、损伤、高温等引起细胞应激时,HO-1的表达上调,HO-1是应激早期发挥作用的抗氧化酶蛋白。

Effect of Pyrophyllite Particle Size on Properties of AI_2O_3-SiC-C Bricks for Iron Ladles

The Al2O3 -SiC-C bricks for iron ladles were pre-pared asing bauxite, fused corundum,pyrophyllite, SiC powder and flake graphite as main starting materials, and phenolic resin as binder. The effect of pyroph,yllite particle size on permanent change in dimensions, cold crushing strength, oxidation resistance, and corrosion resistance of Al2O3 - SiC - C bricks was investigated. The results show that with the decrease of the pyrophyllite particle size, the permanent change in dimensions of Al2O3 - SiC - C bricks decreases, cold crushing strength increases, the oxidation resistance at 1400 ℃ increases, and the corrosion resistance at 1500℃ decreases.

Flexibility of Burned Al_2O_3-C Due to Bending Tests at Room Temperature

Simple three-point bending test at ambient tempera- ture characterized the mechanical behavior of burned Al2O3 -C refractories before and after thermal shock in association with the processing parameters （graphite content and coking temperature, etc. ）. The results showed that non-linear plastic-elastic behavior under load lower than cold modulus of rupture （CMOR） was registered in all specimens and real linear elastic behavior could be identified after the first load, The total deformation could be divided into two parts, plastic and elastic areas. The graphite content and joint bonding system of carbon and ceramic phases were responsible for mechanical behavior of Al2O3 - C refractories.

Effects of Resins with Different Molecular Structures on Properties of MgO-C Bricks

Resins PFG-4 , PFG-8 and a reference resin （resin A） were used as binders of MgO - C bricks, effects of the resins with different molecular structures on wettability of magnesia, on physical properties, mechanical properties, oxidation resistance and thermal expansion properties of MgO- C bricks were researched. The results show that the microstructures of solidified resins with different mo- lecular structures are different, which have obvious effect on the cold mechanical properties of MgO - C brick, but little effect on the oxidation resistance, thermal perform- ance and expansion properties.

Effect of Treated Graphite on Properties of Al_2O_3-SiC-C Castables

Al2O3 - SiC - C castables with 2% pitch or 2%, 4% and 6% treated graphite, respectively, were prepared based on the basic formulation of traditional Al2O3 - SiC - C castables. The flowability of castables, and bulk density, volume stability, strength, oxidation resistance and slag resistance of specimens fired at 110 ℃, 1 100 ℃, and 1 500 9Z respectively were comparatively studied. The results showed that： （1） With carbon source changing from pitch to treated graphite and the increase of treated graphite addition, water addition of castables increased, bulk density of specimens fired at different temperatures increased firstly and then decreased, strength after drying decreased obviously, strength after firing and oxidation resistance changed slightly, hot modulus of rupture increased obviously; （2） Slag resistance of specimen with treated graphite was worse than that of specimen with the same amount of pitch, but the former was obviously improved with the increase of treated graphite addition.

The electrochemical behavior of N-n-undecy1-N＇-（sodium-p- amino-benzenesulfonate） thiourea and its interaction with bovine serum albumin

In pH 5.5 phosphate buffer solution, N-n-undecyl-N＇-（sodium-p-amino-benzenesulfonate） thiourea （UPT） produced a pair of redox peaks on the bare glassy carbon electrode. At the multi-walled carbon nanotube （MWNT） modified electrode, the electrochemical behavior of UPT enhanced greatly. In the presence of bovine serum albumin （BSA）, the peak currents of UPT decreased linearly due to the formation of a super-molecular complex. This method was successfully applied to the determination of BSA in a bovine serum sample.