Higher Oxidation Efficiency Research Articles

Isothermal protein detection assay based on high efficient T7 RNA polymerase transcription-mediated amplification system and graphene oxide fluorescence switch platform

An isothermal protein detection assay based on high efficient T7 RNA polymerase transcription-mediated amplification system and graphene oxide (GO) fluorescence switch platform is developed. The assay consists of specific aptamer-protein recognition, high efficient T7 RNA polymerase transcription-mediated amplification of DNA aptamer, convenient and rapid GO fluorescence switch platform for the detection of ssRNA transcripts. Thrombin from human plasma is used as an example to demonstrate the feasibility of the assay. Experimental results show that the detection limit of the assay is 10 pM of thrombin. A calibration curve with a linearity range from 10pM to 10nM is established, thus, make quantitative analysis possible. The assay can specific discriminate thrombin from other proteins. It holds great promise in protein detection due to its sensitivity and specificity.

Moisture Monitoring and Control in Gas-Phase Biofilters to Achieve High Ammonia Removal Efficiency and Low Nitrous Oxide Generation

Abstract. Biofiltration is a relatively low-cost method for the treatment of large flow rates of livestock air emissions that usually contain low concentrations of ammonia. Moisture content is a key factor that determines the success of biofilters since low moisture content can reduce ammonia removal efficiency while high moisture content may increase production of nitrous oxide, which is a powerful greenhouse gas. Controlling moisture content at 45% to 55% (wet basis) is recommended to achieve high ammonia removal and low nitrous oxide generation. This study aims to develop an impedance-based moisture sensor, together with a well-designed water pump control strategy, to provide a real-time biofilter moisture content monitoring and control method with the purpose of maintaining reliable biofilter performance. A high-frequency large-format moisture sensor that is able to measure medium moisture content within a 30 cm A— 30 cm A— 15 cm (L A— W A— H) space was developed and tested. The sensor was sensitive to moisture content ranging from 15% to 63%. A water pump control strategy was designed to maintain the moisture contents within 44% to 49% in two identical bench-scale cylindrical (ID = 45 cm, H = 50 cm) biofilters packed with a commonly used medium. In a one-month test, the sensor readings were stable and sensitive to moisture changes. The moisture contents were successfully managed within 44% to 47%, and the overall moisture changes were as low as 1.08% and 0.30% for the two biofilters, respectively, according to a water balance calculation. Moisture contents measured by oven-drying were 5% to 10% higher than the sensor-measured results. We believe the differences displayed between the sensor-measured results and the oven-drying results are acceptable for biofilter applications. The two biofilters showed high ammonia removal efficiencies (82% to 92%) and low nitrous oxide concentrations (0 to 0.32 ppm), demonstrating the feasibility of the moisture monitoring and control method in bench-scale biofilters.

Influence of reaction conditions on the ozonation process

Abstract This paper is focused on the influence of granulated activated carbon (GAC) and zeolite as catalysts as well as influences of temperature and pH on the ozonation process. From obtained results it can be concluded that the addition of granulated activated carbon and zeolite to model wastewater has a positive effect on the efficiency and degradation rate of methylene blue oxidation with ozone. The highest oxidation efficiency was observed in the alkaline pH range for which radical reaction mechanism of ozone is characteristic. From the results obtained during the study of the effect of temperature on the ozonation process it follows that both the efficiency and the rate of oxidation of methylene blue grow with increasing temperature.

Preservation of mitochondrial functional integrity in mitochondria isolated from small cryopreserved mouse brain areas

Studies of mitochondrial bioenergetics in brain pathophysiology are often precluded by the need to isolate mitochondria immediately after tissue dissection from a large number of brain biopsies for comparative studies. Here we present a procedure of cryopreservation of small brain areas from which mitochondrial enriched fractions (crude mitochondria) with high oxidative phosphorylation efficiency can be isolated. Small mouse brain areas were frozen and stored in a solution containing glycerol as cryoprotectant. Crude mitochondria were isolated by differential centrifugation from both cryopreserved and freshly explanted brain samples and were compared with respect to their ability to generate membrane potential and produce ATP. Intactness of outer and inner mitochondrial membranes was verified by polarographic ascorbate and cytochrome c tests and spectrophotometric assay of citrate synthase activity. Preservation of structural integrity and oxidative phosphorylation efficiency was successfully obtained in crude mitochondria isolated from different areas of cryopreserved mouse brain samples. Long-term cryopreservation of small brain areas from which intact and phosphorylating mitochondria can be isolated for the study of mitochondrial bioenergetics will significantly expand the study of mitochondrial defects in neurological pathologies, allowing large comparative studies and favoring interlaboratory and interdisciplinary analyses.

Cobalt(II) sequestration on fungal biogenic manganese oxide enhanced by manganese(II) oxidase activity

We examined the ability of biogenic manganese oxide (BMO) formed in the cultures of a Mn(II) oxidizing fungus, Acremonium strictum strain KR21-2, to sequester Co(II) and found that the newly formed BMO effectively sequestered Co(II) under aerobic conditions with virtually no release of Mn(II). Under anaerobic conditions, smaller amounts of Co(II) were sequestered and a significant amount of Mn(II) was released. Similar trends were observed when the BMOs were poisoned with 50mM NaN3 or heated at 85°C for 1h. X-ray absorption near-edge structure spectroscopy and two-step extraction confirmed that oxidation of Co(II) to Co(III) occurs with BMOs with higher oxidation efficiency under aerobic conditions. These results demonstrate that BMOs can reoxidize Mn(II) through the Mn(II) oxidase associated with the BMO phase and can subsequently provide a new reaction site for Co sequestration. The ability of BMO to sequester Co(II) was also found to be long lasting in 20mM 4-(2-hydroxyethyl)-1-piperazineethanesulphonic acid (HEPES) buffer (pH 7.0) containing no nutrients to maintain fungal growth, because sequential treatment of BMOs with the Co(II) solution every 24h for at least 8days led to Co(II) sequestration. In addition, Co accumulation in the solid phase was eventually 2.48-fold relative to the accumulation of Mn oxide (molar ratio). X-ray diffraction results suggest that the continuing Co(II) oxidation by newly formed BMOs results in the formation of heterogenite (β-CoOOH) aggregates. Assays using the concentrated Mn(II) oxidase crude solution showed that the preformed Mn oxide phase was important for further Mn(II) oxidation in coexisting Co(II). The fact that the coexisting Co(II) was less inhibitory to Mn(II) oxidation if the preformed Mn oxide phase was present suggests a possible electron path from Co(II) to the final electron acceptor O2 through BMO and Mn(II) oxidase in BMO/enzyme aggregation. These results suggest that fungal BMOs supporting Mn(II) oxidase activity can serve as an effective Co(II) sequestering material, without the need for additional nutrients.

Preparation and characterization of Pd/N codoped TiO2 photocatalysts with high visible light photocatalytic activity

Pd/N codoped TiO 2 photocatalysts were prepared by annealing nanotubular titanic acid, uniformly dispersed urea, and palladium chloride in air or nitrogen atmosphere. The resultant photocatalysts were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, UV-Vis diffuse reflectance spectroscopy, photoluminescence spectroscopy, and electron spin resonance spectroscopy. The results showed that the calcination atmosphere played an important role in the morphology, crystal structure, spectral absorption, oxygen vacancy concentration, and visible light photocatalytic performance of the catalysts. The photocatalytic performance of samples calcined in an air atmosphere was better than those calcined in a nitrogen atmosphere. The visible light photocatalytic activity of the samples was investigated by monitoring the photocatalytic oxidation of propylene. It was found that the samples prepared at 400 °C in air possessed the highest photocatalytic activity under visible light irradiation (λ ≥ 420 nm). The mechanism of the visible light response of the Pd/N codoped TiO 2 photocatalysts was discussed in depth, and the origin of the visible light photocatalytic activity was attributed to both the elemental Pt/N dopants and the existence of oxygen vacancies. Pd/N codoped TiO 2 photocatalysts showed high efficiency for the visible light photocatalytic oxidation of propylene. The origin of visible light photocatalytic activity was attributed to both Pt and N dopant elements and the formation of single-electron-trapped oxygen vacancies.

Tuning the photocatalytic selectivity of TiO2 anatase nanoplates by altering the exposed crystal facets content

TiO2 anatase nanoplates were fabricated by a solvothermal method using titanium isopropoxide as a titanium precursor and HF as a capping agent in order to enhance the formation of the {001} crystal facets of the anatase crystal. Two different surface modification procedures were applied in order to remove the adsorbed fluoride anions on the {001} crystal facets of the nanoplates. The first procedure was by calcining the as-prepared TiO2 anatase nanoplates up to 600°C and the second one was by washing them with a NaOH aqueous solution. Importantly, the surface modification procedure leads to the formation of two different morphologies of the TiO2 anatase nanoplates which exhibited tunable photocatalytic selectivity in air pollutants purification. The calcined nanoplates became larger and their {101} crystal facets expanded by shrinking the {001} crystal facets. In contrast the washed nanoplates maintained their shape which was formed by the solvothermal method. All samples that were calcined or washed, exhibited high photonic efficiency for air pollutants oxidation. The calcined TiO2 anatase nanoplates exhibited the best photocatalytic activity in oxidizing the NO gas to NO2 and NO3− whereas the washed TiO2 anatase nanoplates, preserving the initial morphology, exhibited the best photocatalytic activity in decomposing acetaldehyde. The dominant exposed {101} or {001} crystal facets of the TiO2 anatase nanoplates is the key factor in tuning the adsorption selectivity of the air pollutants.

Structure-Guided Systems-Level Engineering of Oxidation-Prone Methionine Residues in Catalytic Domain of an Alkaline α-Amylase from Alkalimonas amylolytica for Significant Improvement of Both Oxidative Stability and Catalytic Efficiency

High oxidative stability and catalytic efficiency are required for the alkaline α-amylases to keep the enzymatic performance under the harsh conditions in detergent industries. In this work, we attempted to significantly improve both the oxidative stability and catalytic efficiency of an alkaline α-amylase from Alkalimonas amylolytica by engineering the five oxidation-prone methionine residues around the catalytic domain via a systematic approach. Specifically, based on the tertiary structure analysis, five methionines (Met 145, Met 214, Met 229, Met 247 and Met 317) were individually substituted with oxidation-resistant threonine, isoleucine and alaline, respectively. Among the created 15 mutants, 7 mutants M145A, M145I, M214A, M229A, M229T, M247T and M317I showed significantly enhanced oxidative stability or catalytic efficiency. In previous work, we found that the replacement of M247 with leucine could significantly improve the oxidative stability. Thus, these 8 positive mutants (M145A, M145I, M214A, M229A, M229T, M247T, M247L and M317I) were used to conduct the second round of combinational mutations. Among the constructed 85 mutants (25 two-point mutants, 36 three-point mutants, 16 four-point mutants and 8 five-point mutants), the mutant M145I-214A-229T-247T-317I showed a 5.4-fold increase in oxidative stability and a 3.0-fold increase in catalytic efficiency. Interestingly, the specific activity, alkaline stability and thermal stability of this mutant were also increased. The increase of salt bridge and hydrogen bonds around the catalytic domain contributed to the significantly improved catalytic efficiency and stability, as revealed by the three-dimensional structure model of wild-type alkaline α-amylase and its mutant M145I-214A-229T-247T-317I. With the significantly improved oxidative stability and catalytic efficiency, the mutant M145I-214A-229T-247T-317I has a great potential as a detergent additive, and this structure-guided systems engineering strategy may be useful for the protein engineering of the other microbial enzymes to fulfill industrial requirements.

Sulfation of Pt/Al2O3 catalyst for soot oxidation: High utilization of NO2 and oxidation of surface oxygenated complexes

The sulfated Pt/Al2O3 catalyst was synthesized by impregnating H2SO4 on the Pt/Al2O3 catalyst. It exhibits higher catalytic activity than Pt/Al2O3 for soot oxidation under loose contact conditions in a feed flow containing NO and O2. Further studies ascribe its good activity to a synergistic effect between sulfate species and platinum. Firstly, the electronegative sulfate species may improve the oxidation-resistance of metallic platinum in the oxidizing atmosphere, which is important for achieving high NO↔NO2↔soot recycling efficiency; Secondly, the sulfate species inhibit the NOx adsorption on the alumina support, leading to a preferential adsorption of NOx on the surface of soot rather than on the catalyst, and thus provide more chances for NO2-soot reaction to generate the surface oxygenated complexes (SOCs); Finally, the sulfate species can promote the further decomposition of these SOCs species, resulting in a high catalytic efficiency for soot oxidation.

A novel Au-Pt@PPy(polypyrrole) coral-like structure: Facile synthesis, high SERS effect, and good electro catalytic activity

The Au–Pt@PPy(polypyrrole) with a novel three-dimensional structure was synthesized by a facile one-pot reaction. Raman spectra, transmission electron microscopy (TEM), scanning electron microscopy (SEM), UV–vis spectroscopy (UV–vis), and cyclic voltammograms (CV) were employed to characterize the complex. TEM and SEM results indicated that the products had novel three-dimensional (3D) multi-branch structures, which were controllable by simply adjusting the ratios of HAuCl4 to H2PtCl6 added. Raman characterization proved that the products had significant surface-enhanced Raman effect with the aid of long-range effect of the enhanced electromagnetic (EM) field and roughness in nanometer-scale. CV results showed that the Au–Pt@PPy with coral-like structure had high catalytic efficiency for methanol oxidation.

A novel high-efficiency visible-light sensitive Ag2CO3 photocatalyst with universal photodegradation performances: Simple synthesis, reaction mechanism and first-principles study

A novel high-efficiency visible-light sensitive Ag2CO3 semiconductor photocatalyst was prepared by a simple ion-exchange method based on a strategy incorporating of p-block C element into a narrow bandgap Ag2O. This photocatalyst exhibits universal high-efficient degradation ability for typically several RhB, MO and MB dyes. Getting insight into degradation patterns of dyes over Ag2CO3 identifies they are self-oxidation behavior of semiconductor rather than the effect of photosensitization. The reaction mechanism investigated by a series of radical trapping experiments, not only ascertains the major photoreaction approaches of dyes on the surface of Ag2CO3, but also reveals the unique universality advantage that arises from selective using one of many activated species to decompose many kinds of dyes such as RhB, MO and MB. The theoretical calculation based on first-principles provides inherently essential evidences for high-efficient oxidation performance of Ag2CO3 photocatalyst.

K7[CoIIICoII(H2O)W11O39]: a molecular mixed-valence Keggin polyoxometalate catalyst of high stability and efficiency for visible light-driven water oxidation

Water-soluble K7[CoIIICoII(H2O)W11O39] (1) was tested as the first cobalt-containing Keggin polyoxometalate catalyst for efficient O2 production via both visible-light driven and thermal water oxidation. Under the optimal photocatalytic conditions [photoirradiation at λ ≥ 420 nm, [Ru(bpy)3]Cl2 as the photosensor, Na2S2O8 as the oxidant in borate buffer (pH = 9.0)],the turnover number (TON) can reach as high as 360, the initial quantum yield and the initial turnover frequency (TOF) for the first 60 seconds was 27% and 0.5 s−1, respectively. Variables of the photocatalytic reaction, including catalyst concentrations, buffer types and concentrations, pHs, dye concentrations, oxidant concentrations, etc., were systemically studied. The oxygen atoms of the evolved oxygen came from water, as confirmed by isotope-labeled experiments. In the thermal water oxidation, the TON and oxygen yield were measured to be 15 and 60%, respectively. The stability of 1 was tested and confirmed with multiple experiments (laser flash photolysis, DLS, CV, FT-IR, EDX, and catalyst recycling) within the photocatalytic water oxidation duration, which ruled out the possibility that neither the free Co2+ ions were present in the reaction solution nor were cobalt oxide/hydroxide nanoparticles in situ formed from the assumed decomposition of 1. All the evidence stated here collectively supports that 1 is the true molecular catalyst. In addition, the recycled sample was reused for water oxidation catalysis and showed similar catalytic behaviors (kinetics and activity) to that of the freshly prepared catalyst. No insoluble forms where found when the borate buffer solution of 1 was aged for 2 months, whereas its analogue, K8[CoIICoII(H2O)W11O39] (4), is rapidly decomposed to a blue-purple cobalt oxide precipitate in borate buffer. The stability difference between 1 and 4 indicates that the +3 oxidation state of the central cobalt in 1 plays a vital role in maintaining the structural integrity. A series of other Keggin-type POMs, such as K6[CoIIW12O40] (2), K5[CoIIIW12O40] (3), K6[SiCoII(H2O)W11O39] (5), and K5[PCoII(H2O)W11O39] (6), were also evaluated for their catalytic activity by comparison with 1. Our study demonstrates that the unique structural features of the mixed-valent central and peripheral cobalt atoms are essential for 1 to maintain both catalytic stability and efficiency.

Heterogeneous Oxidation of Methylene Blue with Surface-Modified Iron-Amended Activated Carbon

The present study aims to develop effective adsorption and oxidation of synthetic dye in wastewater by using the newly synthesized iron-amended activated carbon. Recently synthetic dye-containing wastewater has gained more attention due to its mass discharge, high toxicity and low biodegradation. For enhancing adsorption of dye and oxidative regeneration of dye-exhausted activated carbon, the novel amendment of iron-deposited granular activated carbon (GAC) was developed. It was to amend ferrous ion onto the acid-pretreated GAC when pH of iron solution was higher than the pH at point of zero charge (pH, pzc) of the GAC. Methylene blue (MB) in water was adsorbed onto the acid-treated iron- amended GAC (Fe-GAC) followed by single or multiple applications of H2O2. Batch experiments were carried out to study the adsorption isotherm and kinetics indicating adsorption of MB onto the Fe-GAC followed Langmuir isotherm and the pseudo-second order kinetics. The Fe-GACshowed the maximum adsorption capacity (qm) of 238.1 ± 0.78 mg/g which was higher than the virgin GAC with qm of 175.4 ± 13.6 mg/g at 20?C, pH 6 and the initial concentration of 20 - 200 mg/L. The heterogeneous Fenton oxidation of MB in the Fe-GAC revealedthat increasing the H2O2 loading from 7 to 140 mmol H2O2/mmol MB led to enhancing the oxidation efficiency of MB in the GAC from 62.6% to 100% due to the increased generation of hydroxyl radicals. Further enhancement of oxidation of MB in the Fe-GAC was made by the multiple application of H2O2 while minimizing OH radical scavenging often occurring at high concentration of H2O2. Therefore, the acid-treated iron-amended GAC would provide excellent adsorption capacity for MB and high oxidation efficiency of MB in the GAC with multiple applications of H2O2 and optimum iron loading.

Ce3+-Gd3+ co-doped high efficiency oxide glasses and transfer efficiency from Gd3+ to Ce3+

The rare earth Ce3+ ion doped SiO2-B2O3-BaO-Gd2O3 system is synthesized by high-temperature melting method. The density, transmission, excitation spectra and scintillating properties of the glasses are investigated. The results indicate that all the samples have good physical and scintillating properties. The emission peak wavelength of all samples is 390 nm under X-ray radiation. Gd3+ ions have a negative impact on scintillating properties when its concentration reaches a certain level. Gd3+ ions sensitize the luminescence of Ce3+ ions, and the ideal concentration is 15 mol% for Gd3+ ions. Also the decay characteristics of Ce3+ and Gd3+ ions are investigated. These samples have potential practical applications in high energy physics.

Evaluation of the efficiency and the drive cycle emissions for a hydrogen direct-injection engine

Hydrogen is seen as a sustainable energy carrier for transportation because it can be generated using renewable energy sources and it is a favorable fuel for clean vehicle powertrains. Hydrogen internal-combustion engines have been identified as a cost-effective consumer of hydrogen in the near term to aid in the development of a large-scale hydrogen infrastructure. Current research on hydrogen internal-combustion engines is directed by a series of efficiency and emissions targets defined by the US Department of Energy including a peak brake thermal efficiency of 45% and nitrogen oxide emissions of less than 0.07 g/mile. A high-efficiency hydrogen direct-injection engine was developed at Argonne National Laboratory to take advantage of the combustion characteristics of hydrogen. The engine employs a lean control strategy with turbocharging for power density comparable with that of gasoline engines. The injection strategy was optimized through collaborative three-dimensional computational fluid dynamics and experimental efforts to achieve mixture stratification that is beneficial for both a high efficiency and low nitrogen oxide emissions. The efficiency maps of the hydrogen engine demonstrate a peak brake thermal efficiency of 45.5% together with nitrogen oxide maps showing emissions of less than 0.10 g/kW h in much of the operating regime. In order to evaluate the driving-cycle nitrogen oxide emissions, the engine maps were fed into a vehicle simulation assuming a midsize sedan with a conventional (non-hybrid) powertrain. With a 3.0 l hydrogen engine, nitrogen oxide emissions from a Urban Dynamometer Driving Schedule cycle are 0.017 g/mile which fulfills the project goal and are even sufficiently low to meet the Super-Ultra-Low-Emissions Vehicle II emissions specification. The city or highway fuel economy, normalized to gallons of gasoline, is 32.4/51.5 mile/gal(US) for a combined average of 38.9 mile/gal(US), exceeding the 2016 Corporate Average Fuel Economy standard. Further vehicle simulations were performed to show the effect of engine downsizing. With a smaller 2.0 l engine, nitrogen oxide emissions increase to 0.028 g/mile, which still exceeds the US Department of Energy target together with the benefit of a fuel economy improvement to 45.4 mile/gal(US) (combined).

Visualization of In Situ Oxidation Process Between Plasma and Liquid Phase in Two Dielectric Barrier Discharge Plasma Reactors Using Planar Laser Induced Fluorescence Technique

Cold atmospheric plasma is considered to be a promising approach for decontamination purposes, e.g. dyeing water decoloration. In order to better understand the complex mechanism of the plasma physics coupled with the plasma chemistry involved in the interaction of the polluted water with the discharge plasma, a novel approach was proposed to study the in situ oxidation process between the plasma and liquid phase in two dielectric barrier discharge (DBD) plasma reactors with different bottom shape (concave vs. plane), by using the planar laser induced fluorescence technique to visualize the process dynamics. Rhodamine B was employed as the tracer dye, which was gradually decomposed by the combined effect of the chemically active radicals (OH, O, H2O2, etc.) as well as the intense UV radiation in the DBD plasma process. The results showed that the DBD plasma filaments induced certain fluctuation on the Rhodamine B liquid layer, which accordingly intensified the mass transfer to a large extent thus accelerated the oxidation process. The comparison of the measured concentration fields in the two DBD plasma reactors illustrated that the DBD reactor #1 with concave bottom showed higher oxidation efficiency than the DBD reactor #2 with plane bottom. Additionally, the experiments demonstrated that the oxidation efficiency in the DBD plasma water treatment was much better than that in the reactor with pure oxidation by ozone gas, which can be further improved by injecting the additional oxygen gas bubbles into the liquid phase in the plasma reactor.

Oxygen defects: The key parameter controlling the activity and selectivity of mesoporous copper-doped ceria for the total oxidation of naphthalene

Mesoporous CeO2 modified by the addition of copper has shown high efficiency for the total oxidation of naphthalene. High activity and 100% selectivity to carbon dioxide throughout the whole range of temperatures studied were achieved for copper loadings of 3.6% and lower. The catalytic behaviour has been related to the concentration of surface oxygen defects. A clear correlation between the concentration of surface oxygen defects (determined by XPS and DRIFTS) and the catalytic performance has been identified. Catalytic activity increased as copper was incorporated into the ceria up to 3.6%. In this range of copper content the copper was incorporated into the cubic fluorite lattice of CeO2 and this was confirmed using XRD and electron diffraction studies. For copper ceria catalysts with higher copper contents the concentration of oxygen defects decreased and an additional dispersed monoclinic CuO phase with a low intrinsic activity was formed, thus leading to a decrease of both the activity and the selectivity to CO2.

High Efficient Glucose Oxidation by Ordered Molecular Assembly inside Carbon Nanotube Forests

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Granulation of Nitrifying Bacteria in a Sequencing Batch Reactor for Biological Stabilisation of Source-Separated Urine

Biological stabilisation of human urine highly depends on the abundance and activities of nitrifying bacteria. However, it is quite difficult to enrich nitrifiers as bio-aggregation by self-immobilized biomass. In this study, granulation of nitrifying bacteria involving inoculation strategy was developed. Two sequencing batch reactors, the one inoculated with nitrifying bacteria and the other inoculated with aerobic granules, were operated in laboratory side by side with a feeding of urine solution. Aerobic nitrifying granules (ANG), with compact morphological structure and good nitrifying activity, were achieved in the reactor inoculated with aerobic granules. Enrichment of nitrifying bacteria favors the nutrient uptake, and hence, to obtain a high ammonia oxidation efficiency. Nonetheless, nitrite accumulation gradually dominated in reactor, partly attributes to a high concentration of free nitrous acid and free ammonia in bulk. The matured ANG had a rather stable microbial profile, as that a number of activated bacteria occupied the surface of granule. It was also found that ANG were much more impermeable than aerobic granules and activated sludge, which was demonstrated as smaller porosities, and therewith an excellent settleability. The results herein reveal that granulation of nitrifying bacteria could enrich the biomass to implement stabilisation of urine in biological way.

Comparing spiro-OMeTAD and P3HT hole conductors in efficient solid state dye-sensitized solar cells

Two hole conductor materials, spiro-OMeTAD and P3HT, were compared in solid-state dye-sensitized solar cells. Two organic dyes containing one anchor unit (D35) or two anchor units (M3) were used in the comparison. Absorbed photon to current conversion efficiency close to unity was obtained for the devices with spiro-OMeTAD. Energy conversion efficiencies of 4.7% and 4.9% were measured for the devices with spiro-OMeTAD and the dyes D35 and M3, respectively. For the devices using the P3HT hole conductor the results were rather different comparing the two dye molecules, with energy conversion efficiencies of 3.2% and 0.5% for D35 and M3, respectively. Photo-induced absorption measurements suggest that the regeneration of the dyes, and the polymer infiltration, is not complete using P3HT, while spiro-OMeTAD regenerates the dyes efficiently. However, the TiO(2)/D35/P3HT system shows rather high energy conversion efficiency and electrochemical oxidation of the dyes on TiO(2) indicates that D35 have a more efficient dye to dye hole conduction than M3, which thereby might explain the higher performance. The dye hole conduction may therefore be of significant importance for optimizing the energy conversion in such hybrid TiO(2)/dye/polymer systems.