Numerical and experimental study on the biofiltration of toluene vapor

We have solved both steady state and transient problems on the biofiltration of toluene vapor. The effect of inlet toluene concentration and inlet gas-flow rate on the removal rate of toluene and the elimination capacity of a lab-scale biofilter has been investigated. In this study, the effectiveness factor was a function of pollutant concentration. The dynamic solutions show good agreement with experimental results. At an inlet toluene concentration of 100 ppm, the diffusion of toluene into biofilm was obviously a rate determining step. Above 200 ppm, however, biofilm already showed full activity. The steady-state simulation confirmed that the change of elimination capacity obtained by increasing only inlet toluene concentration was the same as that obtained by increasing only flow rate of contaminated air. The maximum possible performance is about 20 g/m³h with no addition of nutrients.     

Fabrication of platinum nanoparticle counter electrode for highly efficient dye-sensitized solar cells by controlled thermal reduction time

We report the effect of the thermal reduction time during sintering on the electrocatalytic activity and the morphology of platinum nanoparticles (Pt-NPs) fabricated using thermal decomposition method. A uniform and dense distribution of Pt-NPs on fluorine-doped tin oxide glass substrate was achieved by controlling the thermal reduction time higher than 15 min and this morphology of Pt-NPs was responded for high electrocatalytic performance of counter electrode (CE). As expected, the excellent electrocatalytic activity with low charge-transfer resistance of 1.04 Ω cm² and highly conductivity of Pt-NPs CE prepared at the thermal reduction time of 15 min during sintering was obtained, which was desirable for dye-sensitized solar cells. The energy conversion efficiency of 9.43 % was obtained for the thermal reduction time of 15 min with fill factor of 63.05 %, J _sc of 18.82 mA cm^?2 and V _oc of 795 mV.     

Phenol decomposition in water cathode of DC atmospheric pressure discharge in air

We studied phenol decomposition in aqueous solution under the action of DC discharge at atmospheric pressure in air. The decomposition efficiency was 0.017 molecules per 100 eV. When the kinetics of forming destruction products was studied in detail, the peculiarities of air plasma action were revealed for the first time. Plasma action not only results in the formation of oxygen-containing products, which are usually formed under oxygen plasma action (hydroxyhenols, carboxylic acids, aldehydes), but also the formation of nitro phenols. The treatment is accompanied by hydrogen peroxide formation, a pH decrease, and nitric and nitrous acids formation. We also discussed the possible mechanism of the processes and the role of some active species in chemical transformations after determining some parameters of the discharge.     

Thermodynamic investigation of methanol and dimethyl ether synthesis from CO2 Hydrogenation

The thermodynamics involved in the catalytic hydrogenation of CO₂ have been examined extensively. By assuming that methanol and dimethyl ether (DME) are the main products, two reaction systems each consisting of two pararell reactions were analyzed and compared in terms of the equilibrium yield and selectivity of the useful products, methanol and DME. The calculation results demonstrated that the production of DME allows much higher oxygenate yield and selectivity than that of methanol.     

Electrochemical properties of all solid state Li/S battery

All-solid-state lithium/sulfur (Li/S) battery is prepared using siloxane cross-linked network solid electrolyte at room temperature. The solid electrolytes show high ionic conductivity and good electrochemical stability with lithium and sulfur. In the first discharge curve, all-solid-state Li/S battery shows three plateau potential regions of 2.4 V, 2.12 V and 2.00 V, respectively. The battery shows the first discharge capacity of 1044 mAh g^?1-sulfur at room temperature. This first discharge capacity rapidly decreases in 4th cycle and remains at 512 mAh g^?1-sulfur after 10 cycles.     

Electrochemical properties of magnesium doped LiFePO4 cathode material prepared by sol–gel method

Magnesium doped Li_1?2xMg_xFePO₄/C (x = 0.00, 0.01, 0.03, 0.05) cathode materials were synthesized by sol–gel method, and the effect of magnesium doping as well as its content on the electrochemical properties for lithium batteries was also investigated_. Their morphology was studied with field emission scanning electron microscope and Li_1?2xMg_xFePO₄ materials showed the olivine phase without impurities. The thin carbon layer of Li_1?2xMg_xFePO₄/C was confirmed by high resolution transmission electron microscopy. The magnesium doped Li_1?2xMg_xFePO₄/C particles were smaller than those undoped. The Li_1?2xMg_xFePO₄/C materials showed better cycling behavior than undoped LiFePO₄, especially at high C-rate in which Li_0.94Mg_0.03FePO₄/C composition exhibited the best electrochemical properties.     

聚合物前驱体法制备纳米Ba0.5Sr0.5TiO3粉体的研究

分析比较了三种工艺对制备纳米Ba0.5Sr0.5TiO3(BST55)粉体的影响,得到了优化的聚合物前驱体法制备工艺.并利用TG-DSC、IR、XRD、SEM分析了BST55干凝胶的热分解过程、化学组成、物相变化以及形貌.实验结果表明,加入适量的乙烯基三乙氧基硅烷偶联剂(TM-12)能改善BST55粒子的粒度及聚集形态;先采用聚合物前驱体法制备BST55/PMMA复合材料干凝胶,然后在700 ℃煅烧可形成粒径介于80～100 nm之间的BST55粒子.     

Ordered SnO nanoparticles in MWCNT as a functional host material for high-rate lithium-sulfur battery cathode

Lithium-sulfur battery has become one of the most promising candidates for next generation batteries,and it is still restricted due to the low sulfur conductivity,large volume expansion and severe polysulfide shuttling.Herein,we present a novel hybrid electrode with a ternary nanomaterial based on sulfur-impregnated multiwalled carbon nanotubes filled with ordered tin-monoxide nanoparticles (MWCNT-SnO/S).Using a dry plasma reduction method,a mechanically robust material is prepared as a cathode host material for lithium-sulfur batteries.The MWCNT-SnO/S electrode exhibits high conductivity,good ability to capture polysulfides,and small volume change during a repeated charge-discharge process.In situ transmission electron microscopy and ultraviolet-visible absorption results indicate that the MWCNT-SnO host efficiently suppresses volume expansion during lithiation and reduces polysulfide dissolution into the electrolyte.Furthermore,the ordered SnO nanoparticles in the MWCNTs facilitate fast ion/electron transfer during the redox reactions by acting as connective links between the walls of the MWCNTs.The MWCNT-SnO/S cathode with a high sulfur content of 70 wt.％ exhibits an initial discharge capacity of 1,682.4 mAh·g-1 at 167.5 mA·g-1 (0.1 C rate) and retains a capacity of 530.1 mAh·g-1 at 0.5 C after 1,000 cycles with nearly 100％ Coulombic efficiency.Furthermore,the electrode exhibits the high capacity even at a high current rate of 20 C.     

Surface free energy changes of stainless steel after one atmospheric pressure plasma treatment

Stainless steel plates (AISI 304L) were treated by an atmospheric pressure plasma treatment at room temperature in order to modify the surface properties. After plasma treatment, the surface wettability and the surface free energy were both improved. The wettability and the surface free energy of stainless steel plates before and after plasma treatment were measured from the results of contact angle test. Through the results of contact angle and surface free energy, optimum plasma treatment conditions were obtained, such as the treatment time of 60 sec and the treatment power of 120 W. In addition to this, the optimum aging time was 3 to 5 min in air.     

Preparation of a reticulated polyurethane foam grafted with poly(acrylic acid) through atmospheric pressure plasma treatment and its lysozyme immobilization

We successfully introduced peroxide groups onto the surface of PU(Polyurethane) foam(10 PPI) through one atmospheric pressure plasma treatment and sequentially grafted PAAc(poly(acrylic acid)) on the surface of PU through radical copolymerization. The plasma treatment can generate large amount of peroxides on the surface of PU foam and the peroxide groups act as initiators for further grafting of PAAc in the monomer solution. To introduce large amount of peroxides on the surface of PU foam, we studied the effect of plasma rf-power and treatment time on the maximum grafting of PAAc. Through this study, we found that the optimum plasma treatment condition was the rf-power of 100 W and the treatment time of 100 s. On the other hand, we also studied the effect of graft reaction conditions such as temperature, monomer concentration and reaction time on the change of grafting degree (GD). The GD increased with increasing temperature and increased with reaction time before it leveled off at 3 h after reaction started. At low concentration of AAc, the GD was very low but it showed a maximum at the monomer concentration between 60 and 70%. The surface of the modified PU foam was qualitatively and quantitatively analyzed through the use of FT-IR and weight measurement, respectively. We also observed the surface change before and after plasma induced graft co-polymerization through photo and SEM analysis. Finally, we confirmed that the PU foams grafted with PAAc successfully immobilized lysozyme and other proteins from hen egg white.