Nitrogen evolution was studied during the co-combustion of hydrothermally treated municipal solid wastes (HT MSW) and coal in a bubbling fluidized bed (BFB). HT MSW blending ratios as 10%, 20% and 30% (wt.%) were selected and tested at 700, 800, 900 °C. Emissions of NO and N2O from blends were measured and compared with the results of mono-combustion trials. Moreover, concentrations of precursors like NH3 and HCN were also quantified. The results are summarized as follows: NO emissions were predominant in all the cases, which rose with increasing temperature. The blending of HT MSW contributed to the NO reduction. N2O emissions decreased with temperature rising and the blending of HT MSW also presented positive effects. At 30% HT MSW addition, both NO and N2O emissions showed the lowest values (391.85 ppm and 55.33 ppm, respectively at 900 °C). For the precursors, more HCN was detected than NH3 and both played important roles on the gas side nitrogen evolution. 相似文献
Journal of Material Cycles and Waste Management - Bio-drying has been proved to be a promising method for treatment of MSW (municipal solid waste) and sewage sludge due to its high energy... 相似文献
MnO2 microspheres with various surface structures were prepared using the hydrothermal method, and Au/MnO2 catalysts were synthesized using the sol-gel method. We obtained three MnO2 microspheres and Au/MnO2 samples: coherent solid spheres covered with wire-like nanostructures, solid spheres with nanosheets, and hierarchical hollow microspheres with nanoplatelets and nanorods. We investigated the properties and catalytic activities of formaldehyde oxidation at room temperature. Crystalline structures of MnO2 are the main factor affecting the catalytic activities of these samples, and γ-MnO2 shows high catalytic performance. The excellent redox properties are responsible for the catalytic ability of γ-MnO2. The gold-supported interaction can change the redox properties of catalysts and accelerate surface oxygen species transition, which can account for the catalytic activity enhancement of Au/MnO2. We also studied intermediate species. The dioxymethylene (DOM) and formate species formed on the catalyst surface were considered intermediates, and were ultimately transformed into hydrocarbonate and carbonate and then decomposed into CO2. A proposed mechanism of formaldehyde oxidation over Au/MnO2 catalysts was also obtained. 相似文献
Bio-drying can enhance the sortability and heating value of municipal solid waste (MSW), consequently improving energy recovery. Bio-drying followed by size sorting was adopted for MSW with high water content to improve its combustibility and reduce potential environmental pollution during the follow-up incineration. The effects of bio-drying and waste particle size on heating values, acid gas and heavy metal emission potential were investigated. The results show that, the water content of MSW decreased from 73.0% to 48.3% after bio-drying, whereas its lower heating value (LHV) increased by 157%. The heavy metal concentrations increased by around 60% due to the loss of dry materials mainly resulting from biodegradation of food residues. The bio-dried waste fractions with particle size higher than 45 mm were mainly composed of plastics and papers, and were preferable for the production of refuse derived fuel (RDF) in view of higher LHV as well as lower heavy metal concentration and emission. However, due to the higher chlorine content and HCl emission potential, attention should be paid to acid gas and dioxin pollution control. Although LHVs of the waste fractions with size <45 mm increased by around 2× after bio-drying, they were still below the quality standards for RDF and much higher heavy metal pollution potential was observed. Different incineration strategies could be adopted for different particle size fractions of MSW, regarding to their combustibility and pollution property. 相似文献
AbstractAnalysis of inorganic and organic contaminants in foodstuffs aids in understanding the human exposure to these compounds via consumption. In this study, an edible mushroom species (Leccinum scabrum) and top soil samples were analysed for essential and toxic substances including phosphorus and inorganic elements over a period of three fruiting seasons. Analysis of silver (Ag), aluminium (Al), barium (Ba), calcium (Ca), cadmium (Cd), cobalt (Co), copper (Cu), iron (Fe), mercury (Hg), potassium (K), magnesium (Mg), manganese (Mn), sodium (Na), nickel (Ni), phosphorus (P), lead (Pb), rubidium (Rb), strontium (Sr) and zinc (Zn) in mushrooms and topsoil were performed using inductively coupled plasma optical emission spectroscopy (ICP-OES) with ultrasonic cross flow nebulizer. Total mercury was determined by cold-vapour atomic absorption spectroscopy (CV-AAS). The results exhibited wide variation in concentrations of metals between soil and mushroom (cap and stipes) during three fruiting seasons. Positive bioconcentration factors (BFCs) indicate on bioaccumulation of several metals including, Cd, Cu, Hg, K, Mg, Na, P, Rb and Zn in caps and stipes of fruitbodies of this mushroom, while other metals such as Al, Ba, Ca, Co, Fe, Mn, Ni, Pb and Sr were not exhibiting significant positive BFCs. Over a period studied, the caps were characterised by different (p?<?0.05) concentrations of Al, Co, Cu, Hg, Mn, Ni, P, Pb and Sr. Contamination profiles, temporal fluctuations, BCFs should be taken into consideration when assessing the nutritional value of this mushroom. 相似文献
Environmental Science and Pollution Research - The rapid economic development in China places a large demand for energy, and as a result, thermal power plants in China are producing an enormous... 相似文献
Environmental Science and Pollution Research - The accelerated urbanization in China was already coupled with a steadily increasing demand for energy usage. The present study major aim was to... 相似文献
Nanoplastics are widely distributed in freshwater environments, but few studies have addressed their effects on freshwater algae, especially on harmful algae. In this study, the effects of polystyrene (PS) nanoplastics on Microcystis aeruginosa (M. aeruginosa) growth, as well as microcystin (MC) production and release, were investigated over the whole growth period. The results show that PS nanoplastics caused a dose-dependent inhibitory effect on M. aeruginosa growth and a dose-dependent increase in the aggregation rate peaking at 60.16% and 46.34%, respectively, when the PS nanoplastic concentration was 100 mg/L. This caused significant growth of M. aeruginosa with a specific growth rate up to 0.41 d?1 (50 mg/L PS nanoplastics). After a brief period of rapid growth, the tested algal cells steadily grew. In addition, the increase in PS nanoplastics concentration promoted the production and release of MC. When the PS nanoplastic concentration was 100 mg/L, the content of the intracellular (intra-) and extracellular (extra-) MC increased to 199.1 and 166.5 μg/L, respectively, on day 26, which was 31.4% and 31.1% higher, respectively, than the control. Our results provide insights into the action mechanism of nanoplastics on harmful algae and the potential risks to freshwater environments.
Environmental Science and Pollution Research - Inland freshwater lakes have been widely considered as significant sources of CO2 to the atmosphere. However, long-term measurements of CO2 dynamics... 相似文献