[en] In order to study the effects of infrared radiation hot air coupled drying (IRHA) on Acetes chinensis drying characteristics, low field nuclear magnetic resonance spectroscopy (NMR) and hydrogen proton imaging (MRI) were used to analyze the combination form of dry matters and water, as well the drying characteristics under different drying temperature, radiation distances and material loads. The results showed that drying temperature had a major impact on the drying rate of acetes and the drying process entered the slowdown drying stage directly. Mathematical models were selected to fit the drying process, and the Two-term model (R² > 0.9998) was found to have the highest degree of fit to the drying process, which could be used to describe and predict the IRHA drying process. Moisture diffusivity is an important indicator of the internal moisture transfer during the drying process. The Fick's second law of diffusion was employed to calculate the value of moisture effective diffusivity coefficient (D_eff), which ranged from 4.47 × 10^-10 m² · s^-1 to 1.295 × 10^-9 m² · s^-1 with the temperature of 50 ∼ 80℃. The activation energy determined with Arrhenius equation was 34.24 kJ · moL^-1 for the drying of acetes by IRHA drying, which was in the reasonable range. The dry matter of acetes was combined more and more tightly with water during the drying process, and free and non-flowable water gradually disappeared. At the end of drying, only the combined water existed, and the amount of combined water increased, which might result from the conversion of the non-flowable water. This explained microscopically the reason for the decrease in drying rate in the late drying stage from microcosmic level. This research provided theoretical and technical foundation for IRHA drying of acetes. (authors)

[en] This paper discusses the removal of nitric oxide (NO) with low-temperature selective catalytic reduction driven by a dielectric barrier discharge with ammonia (NH₃) as a reductant. We explored the effects of NH₃, O₂, temperature and water under different applied voltage on NO removal at atmospheric pressure. The results showed that when the gas concentration ration of NH₃/NO was 0.23–0.67, the NO removal efficiency and the energy consumption was acceptable. The NO removal efficiency reached 84% under an applied voltage of 7 kV, 400 ppm NO and 90 ppm NH₃ at a temperature of 150 °C. Water vapor had a negative effect because NO formation reactions were strengthened and NH₃ was oxidized directly rather than reduced NO molecules. The outlet gas components were observed via Fourier transform infrared spectroscopy for revealing the decomposition process and mechanism. (paper)

[en] This study aimed to discuss the removal of hydrogen sulfide (H₂S) with non-thermal plasma produced by a multilayer tubular dielectric barrier discharge reactor, which is useful in the field of plasma environmental applications. We explored the influence of various factors upon H₂S removal efficiency (${\mathrm{\eta <!--\; ??\; -->}}_{{\mathrm{H}}_2\mathrm{S}}$) and energy yield (Ey), such as specific energy density (SED), initial concentration, gas flow velocity and the reactor configuration. The study showed that we can achieve ${\mathrm{\eta <!--\; ??\; -->}}_{{\mathrm{H}}_2\mathrm{S}}$ of 91% and the best Ey of 3100 mg kWh⁻¹ when we set the SED, gas flow velocity, initial H₂S concentration and layers of quartz tubes at 33.2 J l⁻¹, 8.0 m s⁻¹, 30 mg m⁻³ and five layers, correspondingly. The average rate constant for the decomposition of hydrogen sulfide was 0.206 g m⁻³ s⁻¹. In addition, we also presented the optimized working conditions, by-product analysis and decomposition mechanism. (paper)

[en] The experiment was carried out in a cylindrical dielectric barrier discharge (DBD) reactor assisted with a catalyst to decompose toluene under different humidity. In order to explore the synergistic effect on removing toluene in the catalysis-DBD reactor, this paper investigated the decomposition efficiency and the energy consumption in the catalysis-DBD and the non-catalyst DBD reactors under different humidity. The results showed that the catalysis-DBD reactor had a better performance than the non-catalysis one at the humidity ratio of 0.4%, and the removal efficiency of toluene could reach 88.6% in the catalysis-DBD reactor, while it was only 59.9% in the non-catalytic reactor. However, there was no significant difference in the removal efficiency of toluene between the two reactors when the humidities were 1.2% and 2.4%. Additionally, the degradation products were also analyzed in order to gain a better understanding of the mechanism of decomposing toluene in a catalysis-DBD reactor. (paper)

[en] This paper discusses the conversion of nitric oxide (NO) with a low-temperature plasma induced by a catalytic packed-bed dielectric barrier discharge (DBD) reactor. Alumina oxide (Al₂O₃), glass (SiO₂) and zirconium oxide (ZrO₂), three different spherical packed materials of the same size, were each present in the DBD reactor. The NO conversion under varying input voltage and specific energy density, and the effects of catalysts (titanium dioxide (TiO₂) and manganese oxide (MnO _x ) coated on Al₂O₃) on NO conversion were investigated. The experimental results showed that NO conversion was greatly enhanced in the presence of packed materials in the reactor, and the catalytic packed bed of MnO _x /Al₂O₃ showed better performance than that of TiO₂/Al₂O₃. The surface and crystal structures of the materials and catalysts were characterized through scanning electron microscopy analysis. The final products were clearly observed by a Fourier transform infrared spectrometer and provided a better understanding of NO conversion. (paper)

[en] The destruction of gaseous styrene was studied using a low-temperature plasma induced by tubular multilayer dielectric barrier discharge (DBD). The results indicate that the applied voltage, gas flow rate, inlet styrene concentration and reactor configuration play important roles in styrene removal efficiency (η_styrene) and energy yield (EY). Values of η_styrene and EY reached 96% and 15567 mg/kWh when the applied voltage, gas flow rate, inlet styrene concentration and layers of quartz tubes were set at 10.8 kV, 5.0 m/s, 229 mg/m³ and 5 layers, respectively. A qualitative analysis of the byproducts and a detailed discussion of the reaction mechanism are also presented. The results could facilitate industrial applications of the new DBD reactor for waste gas treatment. (plasma technology)

[en] Highlights: • P species & fractions in sewage sludges are compared and figured out quantitively. • P species & fractions mainly depend on P removal and sludge treatment process. • Quantitative characterization of Fe/Al–P is requisite for advanced P recovery. • Anaerobic fermentation + low strength acid is recommended for advanced P recovery. Phosphorus recovery from municipal sewage sludge is a promising way to alleviate the shortage of phosphorus resources. However, the recovery efficiency and cost depend greatly on phosphorus species and fractions in different sewage sludges, i.e., waste activated sludge and chemically enhanced primary sludge. In this review, the phosphorous (sub-)species and fractions in waste activated sludge and chemically enhanced primary sludge are systematically overviewed and compared. The factors affecting phosphorus fractions, including wastewater treatment process, as well as sludge treatment methods and conditions are summarized and discussed; it is found that phosphorus removal method and sludge treatment process are the dominant factors. The characterization methods of phosphorus species and fractions in sewage sludge are reviewed; non-destructive extraction of poly-P and microscopic IP characterization need more attention. Anaerobic fermentation is the preferable solution to achieve advanced phosphorus release both from waste activated sludge and chemically enhanced primary sludge, because it can make phosphorus species and fractions more suitable for recovery. A post low strength acid extraction after anaerobic fermentation is recommended to facilitate phosphorous release and improve the total recovery rate.